Tuning a New World of Computer Audio Playback

Posts : 2227 Join date : 2009-09-18

Hello Zonees

As Sonic waits for Mr Green to post the pix for this thread and give his comments, here is something for newer Tunees (Welcome to Tuneland Bierfeldt ) -- a thread from the old website which when Sonic first read it caused me great mental turbulence though over time, this is where the Tune started for Sonic:

From Michael (May 2005)

Hi TuneLand,

Many of us have been listening for a long, long time and we know what we like and don't like. When our sound hits that certain thing, then and only then do we really feel at home with our sound. With me, this sound is a harmonic. If I hear this harmonic in my recording then the world is happy again and when it is not there it is musical misery. For some reason, this harmonic, when it is hit, opens up everything. It is a midrange air harmonic that lies just below the attack of the piece of music’s strike. If this harmonic is right for me then the girth of the music seems to be all important and the flow is so in the pocket that everything seems right with my world.

I use this cue probably more than any other cue in my listening. For example, if I hear a guitar lead that is attacking too bright for me, I will lower the fundamental body of the lead so it almost sounds like a midrange note instead of a high note with no body or girth. Now when I look for this harmonic, I always want to be very careful of the music around it so that it keeps in balance as well.

Here's the thing about this hidden harmonic. It is the very harmonic that smoothes everything out and keeps your system from being brittle. I have a hard time living in the upper attack zone only without support.

Some of the wonderful things that this harmonic does for me is take the music out of the speaker, for example, or spreads the live performance crowd all around me. It also makes everything so real and present. Listening to things like Lesleys and vocals is unbelievable. The air around an instrument breaks evenly as well, without drifting to one side or the other until the very end of the movement.

I'll do just about anything for my hidden harmonic. Very Happy

From Michael (October 2005)

Hi Tuneland,

Many of you have now converted to the way of the Tune and I can tell that some of you have heard the hidden harmonic that I talked about awhile ago now. Most of you start to hear it when you get my speakers. Why? It's because of the secret of the acoustical instrument. By the time you get to the speaker part of your system, you've got to let it all hang out.

You hear people talk about how their drivers sound. Well, the truth of it is you want to hear as little of this sound as possible. What you do want to hear is the reality of music and that means that you need the hidden harmonics to be introduced to the room and then the room needs to introduce them to you ears. A free resonant speaker is the only type of speaker that can reproduce this sound and these harmonics. Free resonant speakers know how to work with a room because these speakers are half room and half speaker.

After you get your system and room ready, you're free resonant speakers will reproduce the deepest and roundest notes you can hear from a speaker. It's almost frightening to go from a high end speaker to a free resonant speaker because you all of a sudden start hearing around the notes and instruments being played and that, my friend, is the secret to the hidden harmonic. Listening to a true spherical wave pattern is a big step away from any other type of listening. Sure, energy is spherical. But, if you don't have the whole picture, you only will at best hear this 2D flattened version.

And thank goodness for letting a free resonant speaker and system settle. Will I ever become a multiple musical, per night listener again? I have serious doubts. Hearing a piece of music develop over several days is just something that I just can get over as a listener. That hidden harmonic gets richer by the day and the music becomes so much more real that it is definitely like listening to a different piece of music each time.

Oh, give me that big fat hidden harmonic. Thin systems, you can head for the dumpster.

And from Hiend1 (October 2005)

Hi Tuneland,

Do you know what Michael is talking about ? Yes of course is "The hidden Harmonic"!!

One year ago Michael always told me to just listen for harmonics of the music and forget about any others sonics things. Then I said to myself "Huh! Michael must be gone nuts! What is he talking about? "

Once I have experienced "The hidden Harmonic" then I realised that what Michael has been teaching us slowly one step at a time really made sense. I have been following his instructions since day one and nowadays I just want to listen to hidden harmonic of a piece of music whenever a CD is being played on my system

If you followed every small step that he told you to do so patiently, you will evenually discover "The hidden Harmonic"

The surround air of the girth & harmonics around the notes and instruments being played was SO AMAZING Shocked The wave pattern just moving To and Fro around the instruments being played was SO FASCINATED THAT YOU WANT TO LISTEN FOR MORE..... MORE....... MORE...... this is why Michael, Jim, me,......... listening chairs are always warm
_________________
Music Is My Life !

Posts : 2227 Join date : 2009-09-18

Greetings Michael and Zonees cheers

Sonic thinks that I have reached the point of understanding and ability to tune my room so that means Sonic can start the simplification process.

The simplification process is to cut the number of components in the system chain, use as far as possible one mains outlet to power the gear and do tune actions to adjust the system to work with the room that is now more damped (though without foam) and the simplified equipment chain.

All this starts with the removal of the Janis W-1 subwoofer, the Paradigm x30 crossover and Rotel amp.

Earlier attempts to remove the Janis W-1 subwoofer and Paradigm x30 crossover and the Rotel amp had always ended in tears because the bass went thin and the room could not support such a tune. What resulted was a narrowing of the type of music that could be enjoyably played, restricted to small scale renaissance, baroque works and Indian music, with most other types of music sounded thin and irritating to varying degrees.

After all this time Sonic may have learnt something…..I think Exclamation

So out went the Janis W-1 subwoofer, the Rotel amp and the Paradigm x30 crossover. The sound went thin….as expected…..but this time Sonic was ready Cool

Such a large change in the system must be met with Tuning – you cannot make such a big change and not have to Tune.

I moved the speakers back a foot towards the front wall to get more bass and Sonic got more bass.

With the removal of the crossover and Rotel amp, Sonic could now power the whole system – Rega turntable, phono stage, DAC, preamp, SEA-10 and main amp off one mains outlet and distributor board.

The ASUS laptop is powered from another wall socket and the Audio Technica direct drive TT and its phono stage is powered off another mains outlet which is switched off unless I want to use the AT and its phono stage.

Next Sonic wired the Japan Victor Company JVC Nivico Sound Effect Amplifier SEA-10 between the Quicksilver preamp and the main amp and boosted the bass to get the target low frequency extension.

This gave me an acceptably balanced sound. The downside was the amount of bass boost on the JVC SEA-10 needed for good extension which was a disturbing +8db at 40hz!

This amount of boost meant any reasonable playback level will be soaking up amplifier power in the bass and clipping Sonic’s small 90W amplifier on peaks. I could detect muddiness from rising intermodulation distortion as I raised the volume.

However, Sonic did not panic knowing I can reduce the amount of boost needed by tuning the JVC SEA-10.

Till now I have only cut cable ties and loosened some circuit boards and it still sits in its wooden box with the rubber feet. So tuning started – Sonic took the JVC SEA-10 out of its wooden case-sleeve with the rubber feet (which had sat on some Low Tone Redwood blocks) and placed the device on a cedar platform from Michael with his contoured spikes. Some Magic Wood and Harmonic Springs and after a day of settling the amount of bass boost could be reduced. From the starting +8dB we now only needed +6 dB for the balance I wanted. The amp could be heard to breathe easier.

Tuning a New World of Computer Audio Playback - Page 11 S650

Tuning a New World of Computer Audio Playback - Page 11 S650

This view shows how the rear zone (or front zone if you prefer) of the system is less tangled and easier to clean. Zonees can also see that the whole system is powered from a single mains distributor strip.

Tuning a New World of Computer Audio Playback - Page 11 S651

Tuning a New World of Computer Audio Playback - Page 11 S651

More tuning of the JVC SEA-10 is ahead and Sonic knows I can get the bass boost required to below +6 dB, maybe even get to Neutral which will then allow the JVC SEA-10 to return to its role as a tool to adjust for recordings rather than for the overall system character.

Let’s see if all this results in a new direction that marks progress for me or this is yet another one of Sonic’s circular frustrations. There is sufficient evidence this time to point to the former Very Happy

Sonic

Posts : 115 Join date : 2015-03-03

Hi Sonic

We wanted to visit your thread and say "Happy Holidays" cheers

Hi Sonic

If your recordings range as much as mine do you will probably see the +6 to +8 widen.

As I am always talking about the differences in recorded codes per recordings it amazes me the industry still in 2016 (almost 17) doesn't come back to equalizers. If I didn't use my tuning toys as an equalizer I would have one (equalizer) in every system.

Going a step further, when I have several systems and am feeling lazy and there is a big difference between two recordings I find myself jumping systems after I listen 30 seconds or so. Talk about amazing, it still blows my mind when I take a recording that seemingly is horrible, and play it on one of the other systems and sit there in shock or at least a fresh starting point.

I'm happy to see the mentions of hidden harmonics again.

Posts : 2227 Join date : 2009-09-18

Hi rotelguy rendeer

Thank you for the greetings of the Season! Same to you, fellow–Tunee rotelguy, and have a good 2017 Exclamation

Hi Michael Very Happy

Sonic does not understand “If your recordings range as much as mine do you will probably see the +6 to +8 widen."

Could you elaborate what seeing the +6 to +8 widen means?

Yes, we haven’t heard much of “hidden harmonics” recently.

Now I know one possible reason (beyond over-eagerness) why Sonic has said on several occasions I have “heard the tune” only to go round in some circles later.

It is possible Sonic actually got the system to develop the “hidden harmonics” by following Mr Green's guidance and the example of fellow-Tunees but lost the harmonics later for some reason like making changes too fast and not understanding my room’s habit of settling back to a hard, ringy default sound – something which Michael helped Sonic identify and resolve at least partially.

Sonic

Posts : 2227 Join date : 2009-09-18

Hi Zonees

My understanding of Michael’s concept of “settling” was influenced in part by this writing of Mr Green’s written in May 2005.

Hope this helps other Zonees.

Hi Tuneland,

You know how Jim (the late Jim Bookhard) is always talking about the 24 hour settle after a tweak? Well this is such a fun thing to play with. I just put on my piece of music after the 24 hour waiting and it is a blast when you get the tweak right.

Learning to listen to the pre-settled tweak is a real art form. It's so tempting to make the judgment on the sound to soon, but as you learn your system's temperament, you will learn the "slide" as it pertains to the settling process. DON'T get rushed when you are tweaking. This is where the slide is so important. We can learn to anticipate our systems reaction as we learn how it naturally wants to break in. This takes time to learn but is so much fun when you get the hang of it. If you look at my writing room system, you will see that I have positioned my blocks on a certain side of my rack.

I do this because I know my system, after being leveled, isn't really leveled. It is just waiting to settle again because energy lives to move, but I use this now to my favor instead of fighting it. I use it as a part of my tweaking. I now have an energy friend that I have learned to predict its moods and movements.

Cooter asked a question about how did his system change sound so much overnight? Well, this is the miracle of life and energy; it never stops. The world, life, and energy are one big tuning process that keeps moving even if we are thinking we are standing still. The magic of tuning and adapting is the only answer to this beautiful constant truth. Anything shy of tuning is permanently out of tune. This is why I try to get people to move past the locked in perceptions of mass. It doesn't and never will work. Learning to make the settling of your system become your friend will make you a much happier person.

Look at your system as magical, continual moving moments of music. Don't try to make it stand still because it won't. Instead, learn to anticipate the magic and feel blessed when the moment is right and when you're done, look forward to the next adventure.

Music is a moment, as life is. Participate in it and even anticipate it and you will see that settling can be a great friend.
_________________
Michael Green

Then in March 2006 Michael wrote:

I just put the wood between the points on my equipment platforms and the tile floor NO Exclamation

Now I have to let it settle.

Will somebody turn up the clock for me? Sorry Michael, Nature has it's own plans. One thing for sure is definitely complaining neighbors. Without changing the volume my writing table is now vibrating to the music.

"Sonic does not understand “If your recordings range as much as mine do you will probably see the +6 to +8 widen."

Could you elaborate what seeing the +6 to +8 widen means?"

Hi Sonic

Recordings in my collection range (in playback) from no bass at all to an overabundance of bass. Now here's where the comment comes into play.

Let's say I'm listening to a recording that is done at a mastering house that is bass shy and another recording that is mastered from a bass plus setup. These two recordings both have the bass response but because the two mastering studios adjust them from different EQ biases the apparent bass dynamics may range drastically different from each other until these recordings are EQed at their different respective levels.

It's not necessarily a problem with the recordings bass EQ bias settings as much as it is our playback system's flexibility concerning dynamic ranges.

In this hobby we talk a lot about dynamic ranges, but what is interesting is we sometimes expect different recordings to somehow have the same set of EQed bias standards, which of course has never really happened past tape and phono attempts at correction. Well, I should also mention that half of the industry back in the EQ days made bass boast available. In reality the dynamic range of bass responses are far bigger in the production end than it is in the playback realm. Real dynamic range has to be stepped down a couple of times before it's played back in someone's home or car. This has always been the case or we would be wearing our speaker drivers on our faces after the units exploded.

When we get into the mid-low to low-end waves, our rooms have to supply the bass volume because the cone or panel will not give a true execution of the pressure if the room does not cooperate in response. The dynamic range that exist in a room is much more than we extract most of the time, or the flip side of this is, the unbalance that takes place through the exited environment. This is why I say "it's there we just need to find it".

This is when we need to separate ourselves from the supposed hobby of high end audio and get to a more pure form of listening that sometimes walks in the opposite direction from the theories the audiophile world banks on. Put on a thin sounding recording. Is it thin because the recording is actually thin, or, is it thin because we have not match the recorded code to it's proper combination in playback? Many high end audiophiles would say it is the recording, which is actually false. There's no reason for an engineer, be it studio or mastering, to make a recording without bass if the recording has bass. The audiophile community has way over blown this subject so they can conveniently excuse themselves from finding the answer. But those of us who spend our time uncovering the entire recording understand it's a matter of mating code to code.

You might recall, years ago Bill333 sent me 5 versions of the same CD to review (loved the days of working with Bill on these projects). I did review and gave him my findings. What I didn't report on though was returning to those copies and one by one tuning my system to better mate with each of those copies as separate and individual recorded units. What many would have found interesting is the fact that in the end I was able to make these different recordings perform virtually the same.

Sorry, I kinda went off in my own little world there (as usual). Smile

Posts : 2227 Join date : 2009-09-18

Fascinating stuff, Michael Exclamation

Sonic has noticed an effect with my continued use of the Japan Victor Company JVC Sound Effect Amplifier SEA-10.

When I make a change to correct for the sound of an LP or FLAC file – truth to tell, I don’t correct for EPs and less so SPs because the programmes are so short and over in a few minutes its not worth the effort – it appears there is a “time lag” between making a setting on the JVC SEA-10 and before the full effect of the setting appears.

Let’s say a recording is “honky”, so Sonic drops the 1 khz by -2dB and it sounds right from the outset but 2/3 through the one hour recording, this -2dB is often heard to be too much and that -1dB is all that is required. I have yet to find that a greater amount of boost or cut in the direction taken has been required. Meaning if Sonic started with +2dB boost, I have never so far ever needed +4dB boost later. It has always been actually less.

In the end, the amount of boost or cut required for programme material is actually only +/- 1dB, at most +/- 3dB boost or cut. A relatively small correction when you come to think of it. For the room system correcting, I have required +8dB at 40hz with +6dB is the average needed to achieve balance. Sonic suspects of the amp at 90W is adequate in driving and bringing out the bass of Magneplanar MG1.5QRs which are known to be power hungry. Though now I have set up a simpler system and heard the advantages, Sonic is not going back to the subwoofered system. Now Sonic has to deal with the bass reproduction in this system/room.

Michael – care to comment?

Sonic

Posts : 2227 Join date : 2009-09-18

Correction:

In yesterday's post Sonic typed: Sonic suspects of the amp at 90W is adequate in driving and bringing out the bass of Magneplanar MG1.5QRs which are known to be power hungry. Though now I have set up a simpler system and heard the advantages, Sonic is not going back to the subwoofered system. Now Sonic has to deal with the bass reproduction in this system/room.

I made a typo. It should have read: Sonic suspects of the amp at 90W is INadequate in driving and bringing out the bass of Magneplanar MG1.5QRs which are known to be power hungry.

Sonic

Posts : 2227 Join date : 2009-09-18

Greetings Zonees

Sonic is persisting with the simpler system. Here are pictures of the overall system – the Magneplanar MG1.5QRs having been moved back about 2 feet towards the front wall in order to bring up the low end.

Tuning a New World of Computer Audio Playback - Page 11 M1769

Tuning a New World of Computer Audio Playback - Page 11 M1769

These pictures also show a short-lived experiment done by Sonic where I turned the Magneplanars around so the mylar faces the listener as in the standard Magneplanar MG1.5QRs. Astute Zonees will see in these pictures that the terminal plate is not visible meaning they are facing mylar forward.

The original Magneplanars had the magnet plate pointing towards the listener and designer Jim Winey said that the mylar side has some audible anomalies and the designed approach was the magnet side towards the listener. Curiously in the 1990s Magnepan turned their speakers around without noticeably changing anything else.

With the Magneplanar MG1.5QRs placed so the mylar side is facing the listening chair, Sonic found the sound very quickly became unnaturally midrangey and piercing. So the state of affairs in these pictures exist no longer. The magnet sides of the Magneplanar MG1.5QRs face Sonic once again. Now the sound is no longer “spikey” and everything sounds coherent again. A failed experiment this week, one that gave me some exercise, and an instructional one too.

On my remark yesterday about amp power, Sonic has a growing feeling that the bass in this system is inadequately extended when the Magneplanars are driven full range. The low end is also loose and the whole sound is lacking in the startle-factor of good dynamics. Now my Rega amp puts out a respectable 90W, tested to do better than its rated 85W. However, Sonic is told that Magneplanars need multiples of this power to really get going. Like requiring at least 200W into 8 ohms, and lots of current and bass control to get them making musick. I wonder if this is true?

Sonic is noticing a lack of dynamics, bass extension and control in my system without the Janis W-1 subwoofer system. Though one thing is this that Sonic hears, that the 15 inch Janis W1 subwoofer has a thickness that gave the impression of a lot of bass emitted from the system.

Another Idea
Anyway, here are the Magneplanar MG1.5QRs turned around and a view of the upper front corners. Sonic is wondering if the standard-sized Corner Tunes in these pictures are too small in relation to the room and if I used x2 sized Corner Tunes (either special order from Michael or a few Corner Tunes stitched together to form big ones – that is 6 Corner Tunes will make one Double Sized Corner Tune) will completely sort the room out.

Tuning a New World of Computer Audio Playback - Page 11 M1770

Tuning a New World of Computer Audio Playback - Page 11 M1770

Sonic

Posts : 2227 Join date : 2009-09-18

Greetings Zonees

Here’s an interview with someone that Mr Green probably knows – John Curl. Sonic found this on the Parasound website – go see http://www.parasound.com/pdfs/JCinterview.pdf for any bits I may have missed.

In 1989 John Curl was introduced to Parasound's founder, Richard Schram and since then, Curl has designed all of Parasound's high-power amplifiers and consulted on the design of the low-level circuits of many of its other components.

Curl earned the respect of everyone at Parasound by being somewhat conservative and uncompromising in his approach to circuit topology and component selection. He insists on using only the finest parts and balanced circuits. He avoids the use of capacitors and inductors in the circuit path.

On the other hand, he has learned to avoid the excesses of design that can turn a great design into an overly-expensive design exercise. Curl and Parasound are dedicated to delivering products that offer very high value at reasonable prices.

"He wouldn't last a week in a mass market receiver factory," says Schram. "The accountants would probably reject every part he picked because it cost too much. At the same time, he knows how to make a very, very good product at what we consider to be a reasonable price."

Here is an interview with John Curl recorded in August 1999.

Q: John, you’ve been designing amps and preamps for over 30 years. Is it still a challenge? Are you having fun?

JC: Yes, it’s still great. It never ends. We keep solving problems and then turning over new ones. It’s very much like modern physics - it continually evolves. We have never yet been able to make a completely perfect amplifier at any price. And then there is the challenge of making very, very good amplifiers in a way that is cost effective.

Q: All your amplifier designs for Parasound use balanced, fully complementary circuits. Why do you do this?

JC: Well, it’s inherently more linear. That type of design, all else being equal, always has less distortion. It’s pointless to design something that is prone to distortion and then try to remove the distortion. You might as well start right and then work from there.

I sometimes compare it to automobile engines, like a big Detroit V8 engine that's been made for the past 30 - 40 years. It's powerful, but basic design is relatively compromised when compared with something like a Porsche or a Ferrari.

There is a reason for that -- it’s not just a mark up, it’s a matter of refinement. Porsche and Ferrari start with really sophisticated designs and then they refine them further.

Q: All the power amplifiers you have designed for Parasound run pure Class A bias at low-to-moderate signal levels. How important is Class A bias?

JC: All else being equal the more Class A you have the better. We don’t need a full Class A amplifier, because people don’t listen to full power levels all the time.

They really need only 10 Watts or so because that is where most of our listening is done. However, getting that 10 Watts of Class A is really quite a feat considering of the all other constraints of having 200 Watts Class AB in reserve.

The Class A portion is always smoother and better, while the Class AB is always a bit rougher because it is against the law of physics. It breaks the music into positive and negative cycles and then splices them back together. Only one side is working while the other side isn’t... it’s the nature of the beast.

You can sometimes see the transition on a scope; it may not be very much but it will be there. It will also generate more high order harmonics. By definition, Class AB is not as linear as Class A, but it is certainly much more efficient. So it’s better and easier to run as much Class A as possible.

Q: Is there anything else you can say about the Class A situation? One of the things you were talking about before was noise. You know, high order harmonics and things like that.

JC: Well, see this is the deal. When you’re working with both sides of an output stage you actually have a true push/pull situation, you cancel out the even order harmonics. This is because you have one device turning on and the other device turning off and they are summing together. And actually the second harmonic just sums out - it cancels out.

However, if only one side is on, the second harmonic cannot be canceled because there’s nothing to cancel it with. But people will say, 'wait a minute I didn’t measure any significant increase in the second harmonic. What happened?'

What happened is the second harmonic turned into higher order harmonics, because the amp is only working on half the wave form. So the same nonlinearity, on half the wave form, makes third harmonic. So all of a sudden you don’t see any second harmonics, but you will see a difference in the third. Of course if there is any fourth harmonic, which there usually is, it is fairly innocuous. You could have a lot a fourth harmonic and probably not even notice.

But when it turns into fifth, you will notice it because it’s more dissident. Fifth harmonic is out of tune. Third is tolerable, but fifth is pushing it -- it becomes dissonant.

That’s why people can tolerate these single ended amplifiers. They’re all running pure Class A -- they have to by definition. They won’t work any other way. They have lots of second harmonic; well nobody can easily hear second harmonic. It sounds sweet because it’s still part of the music.

But if it was fifth harmonic, trust me, nobody would want anything that had pure fifth harmonic. Any time you go into Class AB you are creating at least some high order harmonics. It’s converting the even orders that are naturally there and that would be naturally canceled out. But they can’t be canceled anymore, so they have to be converted up. So they have to appear, but they don’t appear as even orders anymore. They appear as odd order, so they add to odd orders that are there already because they can’t be gotten rid of. All of a sudden you see this jump in the high order spectrum.

Normal distortion meters won’t measure this because they just measure the total harmonic distortion; not the individual harmonics. Unless you know what to look for with a spectrum analyzer you won't even know this is happening. Most people just see it as a little glitch on the meter. They don’t know that the whole nature of the distortion has changed.

Q: What about output devices?

JC: Well, Parasound has a very good combination that’s practical. They use bipolar output devices driven by a complementary FET driver stage. You get the best of both worlds.

If you use a transistor driver stage, then the predriver stage -- the one that actually produces all the gain -- will get modulated by the loudspeaker load. In other words, the loudspeaker load reflects itself back as a changing impedance.

Lets say a loudspeaker momentarily changed from 8 ohms to 1 ohm. I have a speaker that does that: a pair of Wilson Audio Tiny Tots. They sound pretty good sometimes, but they are troublesome. They drop to less than half an Ohm at 2,000 cycles. In some amplifiers it can actually reflect that change of impedance back into the driver stage and change the dynamic gain of the amplifier.

The FET driver tends to buffer the load change better than a transistor. And that’s why I prefer FETs in that respect. If FETs were perfect they probably would be better as output transistors than bipolar transistors, but it is almost impossible to build an all-FET amplifier.

I can do it; however American FETs have all the qualities that you could ever want except that they’re unreliable. They break if you look twice at them. You short the output for example, by accident and they invariably break.

Q: Is reliability a major design goal for you?

JC: Absolutely. When I worked with Saul Marantz at Lineage 10 or more years ago, we built a all-FET power amplifier. I had read all the spec sheets and really thought that I had everything covered, but invariably, when we shorted the thing out, it would blow up. It gave me an appreciation for protection circuitry.

Today, I believe in protection circuitry that is noninvasive. It will sense when you’ve shorted something out, and know that something’s wrong and protect the amplifier.

Q: Well, one of the things about Parasound amps, they are very rugged and that’s - is it an important part of your belief in amps?

JC: Well, it's not me that does that. Over the years Parasound has developed some very effective protection circuitry.

It has an output relay that could be problematic in extreme circumstances. It’s kind of like a rev limiter on a car. It doesn't do anything until you exceed the redline, and then it cuts power to keep the engine from blowing. It could reduce your performance sometimes if you like to push your engine beyond the redline.

It depends on what you want. Do you want to be a hot rodder or do you want your engine to hold together? I have an old Porsche and it just can’t breathe. It has a hard time just getting up to 6,000 rpm, which is it’s red line.

You’re saying what am I doing here? I'd better shift because I’m not going anywhere. I also have an Acura and, man, that thing kicks in from 5,000 to 7000 rpm and I’m always going through the rev limiter at 7,000.

If I didn’t have a rev limiter, it’d be gone. Parasound's amps use a very sophisticated protection circuit that they’ve or developed over the years, and basically it's the equivalent of a rev limiter. It senses a number of things and when you’re in trouble and it’s too hot it fires this circuit to open the relay and protect the amplifier and the speakers. It’s a lot better than fuses, because fuses are non - linear. They can’t help it. They are designed to have to heat up before they blow up.

This heating process changes it’s resistance. The resistance invariably rises as the temperature goes up --that’s pretty much the laws of physics-- and of course it’s going to modulate. If you have a lot of current flow, even though you’re below the limit of the fuse, the darn fuse is going to modulate.

Of course, this is almost impossible to measure statically. Once you put a resistive load on and a certain amount of power the fuse is going to up to it’s temperature and stay there and the resistance is not going to change very quickly, so you never know that the fuse is distorting. It only distorts getting up there and then going back down. It doesn’t necessarily distort by the time you’re ready to make the measurements. That’s one of our problems with static measurements. You just don’t know everything that you need to know.

Q: What is your philosophy on power supplies? Should they be tightly regulated?

JC: Actually, I don’t use tightly regulated supplies by comparison to Krell or Levinson standards. They use tightly regulated power supplies and rightly so. If you want a very exotic, heavy and expensive amplifier you should super regulate the power supply. But I feel there is too little to be gained from this.

It’s just too exotic and too expensive, and also too costly as far as heat production is concerned. I’d rather save the heat sink space for the output devices, and we have plenty of those. But we don’t have an infinite amount of space. We’re pushing 100 pounds on our biggest amp, but we’re not going go to 200 or 300 pounds like many of others do at ten times the price.

We make a well regulated design in the sense that it has a lot of transformer and capacitor capability and will maintain itself well under dynamic conditions. Compared to a Levinson or Krell it will actually sag a little if you sustain the drive indefinitely. However, that is nothing compared to the power supply limitations of many of the budget amplifiers and receivers.

Q: How does Parasound's approach differ from Carver's?

JC: Carver’s philosophy was a little bit different in the sense that he didn’t use very much capacitance but he has used a very high voltage capacitor. His idea was to allow a lot of voltage swing -- more than most amplifiers.

Carver was making 350 Watts channel amplifiers way back in the early 70’s. However, when it comes to current drive he had almost no current drive.

And that’s because current drive is a function of the output devices and the amount of power supply capacitance. For a given size capacitor, the higher the voltage rating, the less capacitance there is available.

So if you have a 150 volt capacitor, it may only have 10,000 microfarads capacitance. I would much rather use a 100 volt capacitor at 25,000 microfarads capacitance. The difference is that I can push out current 2 and half times longer and I’ll only sag a little bit. The Carver's design might sag a lot, but since it might start at 130 or 140 volts, it will drop down to 100 volts.

So, while the Carver design would have more dynamic voltage swing, the Parasound would have more dynamic current output.

Q: Why is this important?

JC: Loudspeakers have certain operating conditions where they demand more current than you would ever imagine -- 50 or 60 amperes can be demanded dynamically by a loudspeaker for a very short period of time.

It doesn’t have to be sustained; maybe only for 5 milliseconds or so. If the amplifier can't sustain this current, the capacitors are sagging and it is eternally clipping, or the protection circuits are firing. Something is happening that isn’t necessarily right and I think this makes a difference. Since so many loudspeakers have these high peak current demands, we design our amplifiers to meet this requirement.

Q: What can you tell us about the transformers? Are they very important?

JC: Absolutely, but when we talk about transformers we have to separate power amps and preamps. While they are not perfect, Toroidal transformers are the logical choice for power amplifiers because they are very efficient, they tend to have a fairly low hum field, and they’re readily available in large power ratings.

For preamplifiers and other line-level components, the old type EI transformers or what’s called a D-core or split C- core transformer is actually better than a toroid.

First of all, they tend to be more compact, and second, and perhaps more importantly, they have very low capacitance between the windings. This can be a problem when Toroids are used in low signal level applications; the windings are on top of each other so they talk to each other. It used to not be so bad but today the AC power is so dirty. Harmonics that are created by high frequency fluorescent lights, fax machines, computers, you name it.

All this new stuff, that’s only been around for maybe the last 10 years, tends to get into the power supply through the transformer and then in to the grounding system and ultimately into our sound system. So then people have to of course use expensive power conditioners to repair the problem but if you fix it in the first place then its not so important.

Q: So how would you fix it in the first place?

JC: By using a transformer that isolates the winding, which is important on low level circuits. The old style EI or the new C- or D-core is the ultimate in that respect -- as long as it is a dual-bobbin winding with physically separate bobbins for the primary and for the secondary. It makes a big difference in sound quality. In power amplifiers, however, that isn’t as important because the levels are just so much higher.

If we had a choice, and if money was not involved, or weight, or anything else, we’d probably use an EI type or special type of transformer.

Q: You are very careful about the resistors you use. How can one low tolerance 47 Ohm resistor sound different from another one?

JC: There are a number of reasons, and we don’t know them all. People tend to think that a resistor is simply a measurement by an ohmmeter -that’s all resistance is. You measure it with an ohmmeter at 1 volt and you say 'okay, this is a 50,000 Ohm resistor.' Aren’t all 50,000 Ohm resistors measured this way all the same? Well, no; not at all.

Any more than you can describe a car by saying it weighs 2500 pounds. All cars that weigh 2500 pounds don’t perform he same, for example. That’s just one measurement. The other resistor measurement is tolerance; how accurate is the resistance.

Traditionally, people use 5% or 10% carbon resistors for most purposes. I don't think these are adequate for carefully balanced audio circuits. At room temperature a 10% resistor might be accurate within 1%, but its value will drift as it heats up. This can really throw a circuit out of balance, which can’t be very good. The newer, high quality 1% resistors hold their values as they heat up. Resistors have other characteristics that effect the sound. One is the type of lead material used.

The lead material of many inexpensive resistors is made of material that can be magnetized -- usually soft steel as far as I can tell. This is actually useful for automated parts insertion machines because they can use electromagnets to handle the resistor by its leads. Steel is also intrinsically rugged and it will stand a tremendous amount of vibration.

The military, for example, doesn’t allow pure copper leads to be used except under very special conditions because, in a missile or something, it might break. They use a special alloy which, I think, has nickel in it.

However, it is also magnetic and it doesn’t sound as good as pure copper. What we try to use is pure copper. Many of the precision resistors -- the really high quality ones, like those made for precision scales and instrumentation -- are made by Holco (which means all copper), Vishay and a number of others. These are all basically non-magnetic because the manufacturers know this can interfere. A stray electro magnetic field can actually be picked up by the circuit, so we try very hard to avoid it. These things are very difficult to measure. When you measure something statically on a test bench, you test at one level and one frequency. That doesn’t place much of a stress on a resistor, so the resistor acclimatizes itself to that condition and just does what it does.

The problem is that music is continually changing so it’s actually affecting the resistor much more than a static test will ever show. This is one of the problems with resistor testing because you have to use fairly sophisticated testing to actually see these problems. You can predict them by looking at the temperature coefficient of the resistor. If it’s 50 parts a million, or 5 parts a million, or 100 parts a million, each one of these is going to be different. That means it is going to change its resistance for every degree of temperature change.

The size of the resistor matters too. If you use a very miniature resistor and put lots of dynamic power change across it, it is going to go from room temperature to maybe 50 degrees Centigrade and back. This rapid change can’t be good. Normally, most resistors in a power amplifier or preamplifier don’t do very much. They have current flowing through them continuously and they stay at a fairly regular temperature once they warm up.

The feedback resistors, however, are very critical because they see the entire output signal and they swing back and forth depending on what the output signal is. They can be audibly affected by temperature changes. Also there is noise. When you measure the resistance of a resistor, you can predict its lowest noise by its value. When you have current flowing through the resistor the noise will increase depending on the quality of the resistor. The cheaper carbon resistors can be extremely noisy, to the point where you put 5 or 10 volts across them and it’s off the map. The higher quality resistors will change in almost no way, it’s almost impossible to measure it.

Q: Okay, what about capacitors?

JC: I learned how to measure a capacitor for the first time about 25 years ago working with Tektronix. They were making a piece of equipment which measured capacitors and they were really worried about the values.

They were doing it with one of their pieces of test equipment -- It’s called a curve tracer. They modified it so it would measure the value of capacitors. They found that ceramic capacitors, for example, had another characteristic they had never been able to see on the screen before and it actually affected the measurement of the value of the cap. It showed a tremendous nonlinearity. Interestingly enough, in this particular test and this method of measurement, only ceramic capacitors showed up to be really bad.

We found that ceramic capacitors really were bad guys. Later we found that we could emulate the same problem indirectly using normal test equipment, but we had to operate the capacitor in some sort of real way. It couldn’t just be sitting there with zero volts across it; it had to be working with some kind of a signal like rolling it off high frequencies, low frequencies or something.

I published a paper in 1978 and Audio magazine article in 1979 that showed this problem with ceramics, and we also found that Tantalum capacitors did almost the same thing. With this particular test (with normal test equipment) you could see the non - linearity of the Tantalum capacitors as well as the ceramics.

This still allowed us, in theory, to use aluminum electrolytics -- we couldn’t find any real problem with them as long as they were used properly -- or any kind of metal film capacitor. A third type of distortion, which has been known for many years, but had been forgotten about, is called dielectric absorption.

This particular problem used to be very important back in the 50s when people used to solve many engineering problems with analog computers. These analog computers would emulate mathematical equations with capacitors, resistors, or amplifiers. Music will also evoke dielectric absorption.

Music tends to not be completely symmetrical at all times, and even though it averages out in the long run it isn’t necessarily a test tone. If you put a symmetrical test tone through a mylar capacitor for example you won’t find any real problem. However if you use an asymmetrical signal you’ll find that it does have dielectric absorption. This is where the dielectric absorbs part of the signal and then spits it back later. Well this can’t be good. Invariably you never get the musical peak, it cannot be completely passed by the capacitor because the capacitor has to take some of the energy from the musical peak.

It stores it like a battery. Fortunately, this material property isn’t shared by Polystyrene, Teflon, or Polypropylene, which is why we tend to use these caps instead of mylar. Tantalum, aluminum, and mylar are pretty bad in this area.

As a result of all this, we have to exclude many types of capacitors because they all have some problems to a greater or lesser degree. Ultimately we wind up with polystyrene, polypropylene, and Teflon. And that’s why we tend to prefer these capacitors when we can. Except for the use of aluminum electrolytic for power supplies , the more capacitors we can eliminate the better it its.

Q: You've always been a proponent of trying to keep the signal path free of inductors and capacitors. Why is this so important?

JC: It’s like this - it is easy enough today to design out capacitors between stages. It is rather redundant and wasteful to add capacitors between stages.

First of all, they do not help the size of the unit. They’re not very reliable. If anything is going to go bad, the capacitors will probably go bad first ... unless you have catastrophic failure. In short, they don’t really do you any good so. The best capacitor is no capacitor...we don’t need them anymore. In the old days, when we didn’t have complementary circuits, we needed capacitors. When you look at vacuum tubes there is no such thing as a complementary vacuum tube device. So you almost invariably needed transformers and capacitors.

Then again, one of the advantages of the vacuum tubes is that they are very high impedance devices, so the capacitors could be small in value even though they might have to be high voltage. Now, when you use capacitors in solid state transistor equipment, you generally need fairly large value capacitors, but their voltages don’t have to be so high. These situations would seem perfect for aluminum or Tantalum electrolytics. However, these are the ones that are not very reliable and they have all these secondary distortion characteristics....dielectric absorption, nonlinear distortion, and that sort of thing.

So, if you can eliminate these capacitors, why put them in in the first place? Now, some people can say 'what about leakage or safety or something like that?' Well, of course, you have to be careful, and that is what modern protective circuitry is good at. It shuts down the amplifiers if they are behaving abnormally, yet it doesn't impact the signal when the amp is behaving normally. We also use servos, which are basically very precise well matched IC devices.

In the factory, they laser trim them down to one or two millivolts and then we simply use these to compare the output to ground and then adjust very slowly to zero out any offset that might be inherent in the amplifier or preamplifier. It’s easy to do these things now. Thirty years ago it wasn’t easy because we didn’t have FET input ICs, much less very well matched FET input ICs. For example, the JC -2 didn’t have servos because they weren't practical in 1973 when it was designed. Maybe the military could’ve done it, but the real world had to wait until about 1978 or so.

Also, we couldn’t use mylar capacitors, which are fairly efficient coupling capacitors. While mylars are fairly efficient from a size and cost point of view, we realized they have problems with dielectric absorption. I didn’t believe it at first.

I was working with Noel Lee and a company called Symmetry. We designed this crossover and I specified these one microfarad Mylar caps. Noel kept saying he could 'hear the caps' and I thought he was crazy. Its performance was better than aluminum or tantalum electrolytics, and I couldn’t measure anything wrong with my Sound Technology distortion analyzer. So what was I to complain about?

Finally I stopped measuring and started listening, and I realized that the capacitor did have a fundamental flaw. This is where the ear has it all over test equipment. The test equipment is almost always brought on line to actually measure problems the ear hears. So we’re always working in reverse. If we do hear something and we can’t measure it then we try to find ways to measure what we hear. In the end we invariably find a measurement that matches what the ear hears and it becomes very obvious to everybody.

Years ago, there was a time when people used to think you could have a two- or four-foot path difference between loudspeaker components; like the Klipschorn, for example. Everyone said this time difference was inaudible, and it didn’t really matter because Bell Labs' research, Ohm’s law of acoustics, Helmholtz and all these other people believed that the ear was completely insensitive to phase.

So it didn’t matter how you built the speaker as long as it sort of averaged out sort of okay in the room. You could take five microphones and measure them all together, if that measured out okay within a few DB’s then heck with it. Well, that really isn’t true and of course when stereo came along all of a sudden you had these big Klipschorns and they wouldn’t image for anything. At least that was my personal experience. I owned them and I was a believer too. Then I started measuring them and I said 'oh my goodness, this is a problem.'

The late Richard Heyser tried to tell people that a two foot path difference might be audible. People were going crazy and saying this was impossible and it was a big controversy. Now, of course, no fool would design a speaker with a two- or four-foot path difference.

John Dunlavy was very outspoken on the Internet this week, criticizing a loudspeaker that wasn’t completely phase aligned to within one inch. See how we change. I don’t disagree with John Dunlavy, although I do think he is overstating his case in this particular one. But, there was a time when we didn’t.

The same thing happens with capacitors. There was a time when we didn’t know better and we just used any old capacitor as long as it had the right values.

Q: Many companies use cooling fans for their most powerful amplifiers. How do you feel about them?

JC Well, in principle I’m not against cooling fans. We try to put as much heat sink on as possible and if I can find, in fact if I was asked to find I could probably do this, a fairly quiet cooling fan and if it was mounted properly internally or on the bottom it would be very helpful. In fact sometimes I use a cooling fan on my own Parasound, just by on the side of the heat sink.

I have one heat sink that’s slightly miss-calibrated and it tends to go into over temp, so I put a cooling fan on it. It works great but most cooling fans are rather noisy. You always have to have a certain amount on noise but you can go below 20 SPL -- that ought to be quiet enough for almost anyone. Not everybody in the known world, but at least those in the home theatre and that sort of thing. My personal feeling is there is nothing really inherently wrong with fans it’s just that they are often audible, especially cheap ones, because they’re just a cheap add on.

But if you think about, you could use good dampening materials to isolate the fans. One thing I used to do with my Dyna kits, was to put a whisper fan on top blowing down on the tubes. Now this is not the most efficient way, but it’s safer on the fan because the heat’s not passing through it. I would use a rubberized damping material that would fit around the fan so it didn’t vibrate. That was a pretty efficient way of doing things and it extended the life of the vacuum tubes.

Q: That's about all the time we have. Is there anything else that you would like to share?

JC: That’s about it. We keep working on trying to make amplifiers faster, use less feedback and that sort of thing.

I’m working on a new pre amp of my own manufacture. Actually this sort of thing is more like a Formula One car, where the designers push the limits of absolute performance, but they are not fit to drive on the street.

But car companies learn a lot of things from race cars that eventually shows up on production cars.

My newest preamp is extremely exotic. I don’t use any negative feedback at all. This is really an experiment. It has local feedback, but it has only a resistor that sets the gain. It'd like to see if that makes that much difference. This project isn't practical, it's way too expensive, but it helps me to learn how far I can go toward creating the ideal preamplifier.

Posts : 2227 Join date : 2009-09-18

Greetings Zonees

Sonic found that when Magnepan turned their planar loudspeakers around so the mylar side faced the listener and the magnet plate the front wall, they might have indeed made a change.

The change was not to the panel, the mylar, wires, crossover or the magnet. All that remained the same but Sonic did observe that what they did around that time was to change the look of the speakers and in the process added a double grille fabric to the side of the mylar (now facing the listener).

From their first model, Magneplanars were encased in a “sock”. That didn’t change. Now over the “front” (the mylar side) went a second grille cloth coupled to cosmetic wood wings or strips. These wings and strips of wood did not increase baffle area of the speaker. They updated the look of the speakers and the wings made up part of the structure that held the second grille the speaker, while the rear (magnet side) had one layer grille fabric – from the “sock”.

This second layer of grille cloth must have some effect because when Sonic removed this outer grille cloth from my Magneplanar MG1.5QRs, the change was huge Shocked

Would this second grille cloth have been “designed in” by Winey and Co to deal with mylar panel side midrange and phase anomalies Question

With the outer grille removed, these anomalies now audible might have been what led to Sonic’s turning the speaker about and listening from the magnet plate side like all the Magneplanars of old.

On top of this, the second grille had another effect. It made it impossible to see if the conductor wires had separated from the mylar.

Michael has shown that grille cloths have audible effects on the sound and when Sonic told him there were now two grille cloths on one side of the Magneplanar MG1.5QRs, Mr Green was surprised and he did not think this was a good idea. Now Sonic may have figured why this double-grille was adopted.

Sonic

Posts : 2227 Join date : 2009-09-18

Hi Michael and Zonees!

There are those who say that all watts are the same regardless of the type of amp. Does the Tune have an explanation for this view about digital amps which is quite prevalent Question

It is this – which Sonic keeps get told – take a 50W conventional transistor amplifier and compare it with a 500W digital amplifier, the conventional transistor amplifier will sound more energetic, punchy and louder.

An Instance
There is a wealthy audiophile that Sonic and the Saturday Group knows. He is one of great hospitality and friendship so Sonic wishes good readers to note this. Anyway…..he has some big tower speakers made of incredibly dense and massive material, with multiple drivers. He used to have a 300W into 8 ohm amplifier known for its current output and the great outlay of $$$ to buy. He likes to listen at levels that will make trouser legs flap at a 6 foot distance.

Anyway, he and his listening group agreed that 300W amp was inadequate so a digital amp of 1000W into 8 ohms was introduced and the old amp traded in. At great cost from looking at standard price lists in the magazines for this amp.

He almost immediately complained of a lack of drive and punch. He was told by the shop that he had to let it "burn-in". The complaints got more earnest in our Saturday encounters and in just more than a month, word went round that a 1000W digital amp was on the secondhand market. He then bought another amp which must cost him another bundle.

At different price levels, Sonic keeps hearing this story repeated. People I heard have swapped a 50W conventional amp for a 250W digital amp, people have swapped a 100W conventional amp for 700W digital device. And ended up claiming that the more powerful digital amp sounded no more powerful, sometimes weaker than their previous amp.

Of course there are those who swapped a 100W transistor amp for a 60W EL34 tube amp and found the tube amp sounded more powerful – OK this one, there is a possible engineering explanation – better power transfer due to correct impedance matching through the transformer taps with the loudspeakers’ impedance characteristics.

Michael -- any thoughts on this?

Sonic

Posts : 2227 Join date : 2009-09-18

Greetings Zonees

A new tuning move by Sonic

From the pictures in my post of December 9 on this thread, Zonees will have noticed I have moved the Magneplanar MG1.5QRs back a couple of feet.

Tuning a New World of Computer Audio Playback - Page 11 M1769

This has improved the low-end balance but not quite enough. More movement towards the front wall is required Sonic suspects yet I have walked this path before and it resulted in failure. In fact the last time this was attempted and failed was almost exactly a year ago.

In self-review Sonic realized from my notes that each time I tried these alternate speaker placement moves I followed some form of audiophile formula – go for Thirds, go for Fifths, do Cardas placement and so on. In fact my starting speaker placement near the ½ length of my room was derived from something Michael wrote about on the old Tuneland site.

Yet all speaker placements are merely starting points – in my reading, Sonic indeed notices that the speaker placements in the reference systems of writers in the Abso!ute Sound who advocate the Pearson Rule of Thirds resolutely do not conform to Rule.

So these rules are just starting points since we must remember the principle that no two speakers, rooms and systems are the same. Take Sonic’s pair of Magneplanar MG1.5QRs and place them in any other room, it is a truth that the ideal placement will be different from any ideal position in another place. Following the example of others simply cannot work in this case.

This shows how formulaic and follow the herd Sonic can be.... Embarassed

So this time, Sonic decided to do something that might be obvious – throw away the formulae and just move the Magneplanar MG1.5QRs about a few inches at a time every day or two and TRUST WHAT MY EARS TELL ME. If the end result is musical but completely out of step with audiophile theory, Sonic will not be troubled. I will just enjoy the musick and poetry being played, sung and read in my room.

So to start the process, Sonic played music and after a couple of hours of ensemble musick from Couperin, Beethoven Middle Quartets and after that The lettermen (!), Sonic attained a Tuning “trance state” and acted.

The move I made surprised Sonic. It was to bring the speakers closer by five inches per side. The soundstage came into focus and the centre images projected towards me. The bass end did not diminish or falter.

Stop here. Tomorrow or the day after Sonic plans to keep this separation and move the panels back 4 inches rearward and test again.

Till then I’ll bring out a some nice LPs and put them on the turntable, clean the stylus and…… Very Happy

Sonic

Posts : 2227 Join date : 2009-09-18

Greetings Zonees

So three steps were taken of 4 inches each moving the Magneplanar MG1.5QRs now closer together by about 10 inches. This was over a period of 3 days.

Yes, the low-end is filling up. Not yet as deep and full as when the Janis W-1 subwoofer was in use but sufficiently promising. The impatience in Sonic wants to make big of steps but this time I am working not to repeat the mistakes of earlier attempts.

Sonic will keep this up till I hit a spot that gives the right mid and bass balance. Once I hit that spot, then a process of “circulation” will take place – that is small moves around the spot to lock the point. Of course, the Long Term settling takes place which may necessitate small adjustments. Then we are done.

Sonic will not expect the LT settling to invalidate the placement. If it did the audio world will be a very strange and impossible place – I mean how many musick lovers might have the time, enthusiasm to this, not to mention to have personal circumstances that allow this sort of audio practice

I mean look at this good Japanese audiofan and part of his system. Very pleasant audio clutter. What are his audio priorities?

Tuning a New World of Computer Audio Playback - Page 11 S652

Tuning a New World of Computer Audio Playback - Page 11 S652

Source: http://soundartiwakura.jp/bbs/bbs/board.php?bo_table=redeemerphiles&wr_id=39

Look at his turntable – that is a very rare Cotter B-1 assembly. That is a direct drive TT with a Fidelity Research arm mounted on slabs of elastomer and steel and what else in this hugely massive turntable assembly designed by Mitchell Cotter. A rarity that few own and few have heard. Cotter B-1 assembly was only the base and the mounting plates for the turntable and the pad for the arm.

The turntables suitable were either the owner's Technics or Denon direct drives and the arms were Fidelity Research FR-66s (12 inch) and the cartridge moving coils from Fidelity Research musch-liked the FR1 Mk3F ("F" was an abbreviation for "Flat" -- a sign that the rising top end in earlier FR moving coils had been fixed). Whether the FR1 Mk3F solved the problems, Sonic finds too many moving coils have this rising or somewhat "tinselly" top end which sounds like an upward frequency shift.

Wonder what those odd speakers sounded like.....

For Sonic's system, lightweight equipment, natural woods and simple layouts work best – cardinal learnings from Mr Green.

In observing the Season, Sonic is listening to my mono LP set of J S Bach's Christmas Oratorio Very Happy

Sonic

Posts : 2227 Join date : 2009-09-18

Greetings Michael and Zonees

Another three steps over a couple of days (another 12 inches closer towards the front wall) and the bass is filling up better. It sounds to Sonic that we are getting to the close to the right spot. The separation between the speaker panels has not changed from I adjusted it inward on 16th of December.

With this speaker placement Sonic is detecting that increase of bass is showing more certainly that my amp is unable to drive the Magneplanar MG1.5QRs.

As the speakers get more wall reinforcement, the bass that is coming from the system is underdamped in a couple of frequency spots and the extension is not as good as the MG1.5QRs are capable of. They are only OK in response down to 60hz after which the the response drops off too quickly.

Must exercise patience, plan the next steps and above listen study

Sonic

Posts : 2227 Join date : 2009-09-18

Greetings Michael and Zonees

Sonic has likely found what subjectively sounds like the right distance for the Magneplanar MG1.5QRs from the front wall and from the side walls in this room. The bass is still uneven although the extension is better – now about consistent with the technical tests of this size of Magneplanars. The midrange sounds a little odd with a ccertain “sharpness”. Perhaps due to the hard surfaces of the room

Where the panels are now make them 2 feet closer to the front wall than in the pictures in my post of Dec 16 and 4 ½ feet from where they were originally when Sonic was using a subwoofer.

Sonic will overshoot this setting by getting the panels a little closer to the front wall and hear what happens.

Sonic

Posts : 2227 Join date : 2009-09-18

Greetings Michael and Zonees

Sonic tested the speakers overshooting yesterday’s placement by another 2 inches closer to the front wall and the bass started rolling off again.

The bass roll off was surprisingly sharp Shocked

accompanied with a loss of inner detail in musick being played. So I backed up to where we were as in Sonic’s post yesterday and now we lock in the placement for the Magneplanar MG1.5QRs sans subwoofer.

Some hardness in the midrange is now noticeable and this Sonic surmises is due to the rear of the panels pointing towards and positioned close to a hard wall. I would have to work at tuning this hardness out but first let settling take place and see in what direction things move. I also added a pair of FS-DTs at the side walls ahead of the MG1.5QRs midway between where the speakers are the listening chair to tune the side walls (not to deal with any first reflections). One possibility is to instead use these FS-DTs directly behind the Magneplanars to deal with the rear wave reflecting off the wall directly behind them.

Let’s see. This combination is actually sounding pretty good now Very Happy

Contrast this with a near wall set up layout of a year ago that failed badly. In that case, the Magenplanar MG1.5 QRs were then much closer to the front wall than now. I had placed them so close to the front wall they were past the point of most extended bass and into a spot where the bass was weak. Readers will see that in this failed experiment (posted on January 3, 2016 in “Tuning my Musical Journey”).

Back then, the formula Sonic was following was some odd ratio like 1/7 room length and 1/5 width which put the panels a little under 40 inches from the front wall. I cannot recall where that idea came from! Ridiculously close now that Sonic thinks about it Embarassed

By not patiently moving the Magneplanar MG1.5QRs in an organized manner and trusting my ears to assess the results but following audiophile formulae and jumping about, Sonic missed the “target point” and landed in the ditch.

Now (this present placement) has the panels about 57 inches from the front wall and 34 inches from the sides (at the panel centerline) making the “ratios” close to ¼ length (supposedly a no-no) and 1/5 width.

Look at the pix for Sonic’s post of December 16 and imagine the speakers about 2 feet further back from where they are in the pix and closer to each other by about 6 inches a side and that is what the placement now looks like.

As Sonic listens to some LPs, the soundstage is very good. It is excellent for a nearer-wall placement with the soundstage extending beyond the outer panel edges, forward and rearwards from the speaker plane Very Happy

Another thing is a near 100% certainty now: there is a lack of control in the bass, emphasis at some bass frequencies and poor extension that tells Sonic that my Rega amp is inadequate and this is even after the amp has been tuned – cover off, screws cracked, cable ties cut, rewired with T1, placed on AAB1x1 cones and Low Tone Redwood. The amp might be really short of power, damping factor or both even after these tunes.

Saying this I am not criticising the Rega – a Rega Maia is a very competent amp that tests better than its advertised specs. The Magneplanars, even with their flat resistive load of 4 ohms with a normal peak at the crossover point, however is over the top for this little amp. It appears there is a united observation among Maggie users that lots of Watts and Current are required to get deep and tight bass – something that appears now in Sonic’s experience to be true.

Sonic goes amp hunting next.

Sonic

Posts : 2227 Join date : 2009-09-18

To Michael and Zonees

A Joyous Christmas!

Sonic

Posts : 2227 Join date : 2009-09-18

Greetings Michael and Zonees

With extended listening to musick over Christmas, Sonic is getting more sure that the front-to-back placement of the Magneplanar MG1.5QRs at 57 inches from the front wall and laterally at the 1/5th width points of the room is correct.

One thing Sonic has found with this relocation of the Magneplanar MG1.5QRs is the amount of bass EQ required on the Japan Victor Company (Nivico) Sound Effect Amplifier SEA-10 in the bass is now less. It is now +4db at 40Hz instead of +6db, or even occasionally with some recordings +8dB at this frequency previously.

The good thing is the whole sound is now very coherent, that is pleasant and relaxing to listen to musick and speech through. There is no sense of the bass being out of step with the mids and treble which was the case with the use of a subwoofer system. Not obvious but over time leading to a sense of unease.

The midrange has a glare. Not on every recording, but of sufficient number to tell me it is a system thing. When it is there the glare is irritating. This might be also due to the Rega Maia amp’s lack of power as well.

Updating Zonees on Amplifier Plans

On Sonic’s shortlist for my next amp are:

NAD M22 Hybrid Digital 250W (8 ohms and 4 ohms)

NAD C275BEE 150W (8 ohms and 4 ohms)

Rotel RB1590 350W (8 ohms)

Rotel RB1581 Monoblocks 500W (8 ohms), >750W (4 ohms)

Parasound JC1 Monoblocks 400W (8 ohms), 800W (4 ohms)

Parasound A21 250W (8 ohms), 400W (4 ohms)

Audio Alchemy DPA 1M (digital monoblocks) 325W (8 ohms), 400W (4 ohms)

Sonic is looking for a powerful amp that is priced in what I consider the “best value” range. I mean when you have two well designed amps that both output say 300W, one costing $5,000 and the other $50,000 we need to look hard at what the 10x difference in price represents. The audio world prices have gone crazy…..Sonic means $15,000 for a 5W tube amp or something, turntable costing >$100,000 and so on.

For this reason, some of the well known big transistor amps are not on Sonic’s list. Neither are tube amps because at this target power level, we are looking at gigantic devices that output lots of heat and will drive my aircon power bills up, not to mention the good and reliable ones are not going to be in my target price range.

Second-hand amps (euphemistically called “pre-owned”) are not being considered because of the unknowns – did they fail before, who repaired them, was the repair done right, did the owner try things like special caps that might go BZZZT! on Sonic one day soon?

Sonic

Posts : 318 Join date : 2009-09-21

Hi Sonic,

I've been hearing good things about this digital amplifier on this diyaudio thread. It's 400W per channel, so should be able to do the heavy lifting. It's only about $60 and is available from Parts Express here. So you might want to add this to your audition list. Very Happy

Posts : 2227 Join date : 2009-09-18

Hi Bill333

Thanks for suggesting -- is there a link?

What's the brand?

At $60 I could even buy it and give it a spin. It is only $60 for a 400Wpc amplifier Shocked

Sonic

Posts : 318 Join date : 2009-09-21

Hi Sonic,

There are two links embedded in my post above. I like a lot of things about the new color scheme, but having text and links virtually the same color is not one of them. Click on 'diyaudio thread' and Parts Express 'here'. The brand is Sure Electronics and the model is AA-AB32313. They make a slew of different models, but the chips and topology used in this one are said to be particularly good. I'm a big fan of my Topping TP21 - I haven't heard this one, but it sounds promising. The chips are newer designs than what was used in the TP21, and the topology is different, but I think they may have the same natural, almost tubelike sound.

You'll also need a power supply - the Connexelectronic SMPS 300R is one that was recommended in the thread.

Posts : 2227 Join date : 2009-09-18

Hi Bill333

Appreciate the recommendation -- Sonic had a look at the Sure Electronics device. It is just a circuit board, I'll have to system integrate the thing with the power supply and build the amp from these parts.

I am afraid this is something outside of Sonic's capability. Think I'll be safer sticking to finished products instead of homebrew devices.

Sonic

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