Building a Room Full of Balanced Harmonics

Hi Sonic

What I like is that you are exploring all the space in your room.

How do you deal with individual recording codes?

Let me think about your suggestion on more threads....

In the meantime, what are "recording codes" that you refer to?

Recordings have a signature all their own and when you tweak to that recording the next recording you put on sounds a little out of tune.

Do you tune to a bunch of recordings at the same time or go from recording to recording and tune in each recording?

Hi Michael

About the recording codes…..Sonic does not have a structured process to implement Tunes beyond some very basic practices which go something like this:

1. Because I cold start l never consider the first sound I hear as indicative of anything. The system must have had about three hours of music play time after a cold start to tell me anything. But that doesn’t mean I can’t get enjoyable background music during this time.

2. The aircon and humidity of the room and system must be given time to settle.

3. Acoustic room Tuning are normally applied before a cold start and obviously anything to do with electrics are done cold.

4. Acoustic room Tuning are followed by a Boo! test and while no definitive judgments are made, some impressions are gained. Obviously if the Boo! fails that is flag but not necessarily the end. If the sound shifts up, it can be fixed but is another flag, if it shifts down that is a good sign that we got something nice and could be made stronger.

5. Then when the system is warmed up, I would put on a CD from my “familiar list”….it is quite a long list, mostly classical, some jazz, never any audiophile discs.

6. First thing listened for is TONE. If Tone is wrong, that is voices and instruments (classical musick, mostly period instruments) are wrong, no point of going further. But I don’t encounter this with Michael’s gear. When I was doing the tweak of the week with audiophile gear, Tone smash ups were common.

7. Second thing is if the perceived volume for a given pre amp setting falls, I get suspicious. OTOH if the volume rises, this is a sign that the tune is likely to work. This may not apply to electrical things like a new tube of course because the gain is almost sure to be affected.

8. Sonic knows that often things are not all one way. We might get wonderful tone, nice width but no depth or some combination of good and not so great. This is where settling comes in and secondary tuning may be needed. There will be a period of a CD being played on repeat several times then listened to once. Then days and days of listening sessions follow to allow for settling and I find that this is the most telling phase.

9. I don’t tune for a specific disk because then the next disk will need a new tuning. Some Tunees may like this and that is perfectly fine but as some of you know my listening sessions cover usually three CDs and for the longer sessions, more and more SPs and LPs are getting into the listening. At one time cassettes may be played (sadly those tapes shed too much oxide in this climate).

Right now Sonic is listening to Mingus, later I am planning some Mozart string quartets, then a recording of steel drums that I found in a cheap throwaway bin….then there may be a couple of Handel’s Concerti Grossi (Harnoncourt/Concentus Musicus Wein on Teldec). Its about enjoying musick and there is just so much wonderful musick to be heard.

Comments Michael and Zonees?

Sonic

I'm a complusive CD tweaker  

It's really a terrible habbit and one if I don't have more than one system gets me in trouble. I very rarely will give up on a recording till I find it's code even if I have to redo the whole system. For sanity sake I will grab one of my references just to make sure I'm not going nuts (short trip). I usually find out if the sound is tilted up that it is the recording has not balanced itself against the system's settings. When I go through this I think why can't there just be a standard but this will never happen. I have not ran in to many recording though that can not be unlocked but you really got to know your system to do this, and have to be willing to sacrifice the next recording as being sounding right.

Do you ever find CD's that you pass on because you can tell the code is too far off?

Sometimes I will put weird ones on the shelf but make note to come back to them to unlock them.

Hi Michael

There are only two recordings in my collection that are beyond the pale...so bad that the value of the music is overcome. One is a CD, one is a LP.

The CD is a Burt Bacharach "Best of" collection and the LP is a first generation PCM recording from digital-to-disc of Mozart's Divertimentos. This LP is such an early generation of digital that it sounds like a beta test thing. Fools a listener with what appears to be excellent resolution for the first 5 seconds then it is awful all the way. Wiry, edgy, metallic with a kind of unnatural inter-note silence (record noise aside). Must have been before dithering was applied. It gives listening fatigue in a minute. Digital at its worst and applied to vinyl too. The Bacharach CD is compressed to something like 3:1 so the whole music sounds lifeless with no dynamic inflection.

Sonic

Greetings Zonees

Here's something interesting: yesterday, I noticed that the images sizes of instruments were not musically equal in the Left and Right sides of the soundstage with those on the Right a bit smaller and reduced in projection.

A tune up later and I found the cause. The RCA jacks of the interconnect linking the Quicksilver to the Rega were pushed further into their jacks compared to those on the Left channel.

Michael suggests that interconnect plugs are not pushed into the jacks till they seat but should be just making contact because it sounds better this way.

He is right. The more the jack is pushed in, the smaller and constricted the images get. The biggest images and good girth are found just when the signal pin makes contact. To be safe give it a slight twist and a push to seat the signal pin and the earth ring safely. We don't want a connector coming loose in the middle of the music. The bang might damage equipment. The minimum contact sounds the biggest and best.

Sonic

Hi Michael and Zonees

After Sonic found good benefit using mini Tune Strips behind the small shutters on my front wall, the next logical step is for me to try mini Tune Strips on the other Shutters on the ceiling and ceiling/side wall seams to control the acoustics of the room.  I started here:



Sounded good but in the settling phase, a “hole in the middle” effect developed where the middle images started to lose color and girth even though there was not any middle stage recession happening.

The effect of this seemed to show that Sonic has got the mid stage pressure zone about right as it is no more burn is required in the centre.  

Next up, I’ll mount a couple of mini Tune Strips further to the Right and Left and see what the effect might be.  All this shows, at least to Sonic that the map of PZs in my front upper room zone is fairly complex.  Maybe it is the high ceiling and hard wall combo Michael taught us about.

Sonic

Hi Michael and Zonees

While Sonic is experimenting with mini-Tune Strips in the ceiling and upper side shutter positions, here is something on my phono stage which I tuned.

I got a Tube Box-S from Pro-ject.  It is priced in this town at around US$580 and it comes with 12AX7 tubes and user adjustable input impedance for MC cartridges and input capacitance for MM cartridges. As far as outboard phono units go, it sits at the good value end of the price range which starts at approx US$200 with the solid state device from Rotel, then it goes all the way up in cost to things that cost more than a big BMW sedan.



Pix source: manufacturer’s website

So the Tube box-S is wired up, input impedance set to 270 pFs – you can only select 50 pF, 150 pF, 270 pF and 370 pF using dip switches – which is correct for the Shure M97xE (recommended 200 – 300 pFs) and the Stanton 500/5217 (recommended 275 pF).  The 47k Ohm resistance is fixed for MM cartridges.

First impressions are good – better than the built-in phono stage of the Pioneer tube integrated amp I been using as a phono stage with TJ Full Music 12AX7s in the phono section.  The bass was tighter and steadier and the trebles more textured with the Tube Box-S.  Nice giant stage in mono with SPs too.   So after some days of burning in, the tuning started by Sonic.

The tube cages were removed followed by the metal sleeve case.  Sonic found a small PC board inside and the layout looks like the tubes are applied as output stages and not for RIAA time constants….also the 810 gm unit weight came substantially from the metal sleeve case!  The front panel and other stuff are plastic with a metallised feel.  The PC board sans tubes is a lightweight affair.

Now Sonic is pointing this out because consumer expectation thinks “solid and weighty” are marks of quality and for whatever motivation, Pro-ject gives this feel.  Of course they may need the thickness of metal to meet some EMI standard so I give them the benefit of the doubt, but the active bits are unimpressive and ordinary.

Also the instruction sheet was wrong – they indicate the input and output sockets on opposite sides of the chassis from the physical product.  Also reference is made in the literature to a sub-sonic filter which doesn’t exist on the product….

However, lightweight is actually a nice thing for Tunees.  So up the PC board went with its lower case onto MW squares and machine wound
matt Harmonic Feet.




Remember – metal should be separated from metal by MW or other woods from Mr Green.

Got a much better sound.  Then I put the TJ Full Music tubes into the Tube Box S replacing the Pro-ject branded tubes.  For a while things sounded too tubey and warm with treble rolled off, like the old Mullards but settling paid off in a couple of days, the musick was fine.  Very nice balance with a well defined bass, good projection and treble that gave clarity to different cymbals and bells even when played way down in level but with body….not tsssss but “bong!”. The stock tubes were bright and in the end sounded thin but I won’t feel critical with a device that this price point.

With the tuned phono and the TJ Full Music tubes, Sonic found the Shure and Stanton extracting so much from the grooves of LPs and SP and there was so much musick even from old recordings played for years on Garrard SP25 changers with ceramic cartridges.  With good record cleaning (by machine and fluid vacuumed) this is a medium that is very fault tolerant and lasting.  Maybe even more than the “perfect sound forever” digital.

Sonic is happy with the Tube Box-S as a Tunee because of all the things that can be done with it.  But really is it excellent? No.  Is it a poorly conceived item? That depends on your expectations as an audiophile but we must be fair to anything that performs to this level at this price. Will the over-engineered phono units costing 10x more sound better? Maybe, but certainly not 10x better.   I have to admit I was a little disappointed by the way the design was presented especially the poor documentation.  But the Tube Box S can be tuned and made to give some nice musick.  Was listening to some old LPs – Sebastian Bach’s Brandenburgs, Dusty Springfield and Led Zeppelin (I am not joking!)

Yeah, keeping them LPs and SPs spinnin’

Sonic

Hi Michael and Zonees

Been listening more and more vinyl and SPs over the last few days and seeing digital good sound while analog is listening to great musick.

CDs have wider dynamic range, no noise, flatter bass….better in many audiophile parameters while records sound more like real people and instruments making musick and showing emotion in the process. Now which is High Fidelity and what is this Fidelity to? I know its rhetoric and the answer will fall in favour of analog with all its flaws. Sonic will not for sure dispute the convenience of digital but some suffering for our art makes the experience more meaningful and appreciated.

Remember too that both this system's front ends are not mega buck state-of-the-art things. My inexpensive but Tuned Sony blu-ray player is not fighting a mighty EMT 930. In terms of audiophile perception both the Sony and Sonic's Audio Technica AT 120 table are at the bottom end of the equipment price curve, so it is an eye popping surprise to visitors when they hear the sound, get mentally rattled by the soundstage and instrument size and then learn the cost. That’s the Tune doing its work alright  

Sonic

Hi Michael and Zonees
 
Sonic tried the mini-Tune Strips here:



Like the mini-Tune Strip mounted on the middle front ceiling Shutter, these weakened the pressure zones around them and with settling, the width of the soundstage shrank till we got semi-mono (like using the blend control in the tube Dynaco PAS 2 [also 3] preamps).
This means the Tuning of my front ceiling PZs have gone about as far as I can take them with the Tuning tools I have on hand and Sonic’s ability.

I think the next phase is to work in the zones around the listening chair.  What this set up lacks are the lateral reverberations which characterize real acoustic spaces. Audiophiles’ rooms and systems are notoriously deficient in these side reverb flows. They only do front-to-back reverb which results in the ear-brain’s failure to define the performance spaces. Of course to get the musick from our systems right we assume that this information was captured in the recording process.

Now sharp-eyed Zonees will have noticed that in my pix of the tuned Tube Box-S, the Audio Technica turntable is back on its elastomer (rubbery) damping feet instead of resting the bottom surface of the lower turntable casing on MW pieces (1/4 inch thick) as Sonic did in my post a couple of days ago.  The reason for this is when resting the TT on the wood with no damping, I could hear mechanical noise from the turntable motor.  The level is low, I can only hear it when my ears are about two inches from the platter spindle but any mechanical or electrical noise in the TT system is going to get into the music signal and corrupt it.

Sonic goes by the rule with turntables or any acoustic-electric transducer that if you can hear the vibrations or you can feel anything with your finger tips applied to the turntable, the vibrations will interfere with the musick and messing about with the purity of sound we hear through some form of acoustic feedback.

Sonic

Hi Zonees

If any Zonees wonder what I did, look at the mini Shutters at the top of the side walls. Behind the nearer one you can see a mini-Tune Strip mounted behind it. While not so clear, there is also another mini-Tune Strip behind the mini Shutter on the opposite wall. These didn't work while the mini-Tune Strips behind the mini Shutters at the top of the front wall worked admirably.

Sonic

Hi Michael and Zonees

Here’s something of interest….the majority opinion among audiophiles is that analog is better than digital. Analog sounds real (however you define it), digital may be precise sounding but hard and cold. DSD/SACD is as good as analog, Red Book CD at best gets close but not there.

Rare is the audio writer who says digital trounces analog. One such is Mike Pappas who writes/wrote for Postive Feedback. I found this reply by him to a reader in Volume 6, Number 3:

“Hello, Tre’

……in my book my book, for what ever it is worth, digital sounds more like music to me than analog. The whole point of the conditioning of your hearing is the predilection to be comfortable with what you are familiar with.

If you spend time listening to music in large concerts halls, LP will probably mimic these experiences more accurately than digital. Of course I am not saying that analog is more accurate - it just so happens that its problems (lack of full power bandwidth for example) are pretty close to what happens in a large venue. I have heard large scale orchestral works in large venues, and they certainly have a very mellow high end. I have also heard a good friend of mine who plays violin for the Metropolitan Opera practicing in a small room. I can tell you you couldn’t get his sound on an LP if your life depended on it. There was way too much high frequency information.

Of course my experience with studio recording environments also gives me a much different perspective on what “music” is than the typical audiophile has. Back in the dark LP days, you always had to place the kick drum in the centre of the mix to keep the cutting stylus from digging through the lacquer and into the aluminum substrate. Obviously digital doesn’t have these problems to contend with.

My issue revolves around manufacturers and reviewers who are looking for some sort of digital nirvana that “sounds” like LPs. From where I sit, this is a big step backwards.

Your premise about what is music is and how LPs fill that for you are based upon your perspective and conditioning. My premise about digital being more accurate is based upon my experience, conditions and perspective also. In my book, music happen for me in the digital realm……Mike Pappas, PF Senior Technical Editor”

Sonic

Sonic,

I have been reading your posts with interest. Like you, lp listening using mm or mi cartridges has been enjoyable recently. I won’t get into a debate over which is better digital or analog. I enjoy both except for digital players employing oversampling dacs as I have commented in the past. The Mag DVD player using Michael’s mini clamp continues to impress with its very analog like sound. Playing with all of wood pieces that Michael supplied with the min clamp has given me a good perspective regarding the degrees of bass that can be extracted from the music. I continue to use the smaller platform bass to place beneath either an amp or integrated for improved sound. When my amp mini platform arrives, I will start a new journey assessing which amp or integrated works best with the other system components. We will also decide how to move forward with a turntable platform.

I am happy the Project Tube Box-S is tuning well for you. My phono preamp is an older unit constructed by a now deceased craftsman, George Wright. The tube preamp consists of 4 tubes (212AX7s and 2 12Au7s) in a light copper chassis. An umbilical cord attaches to a power supply with a 6x4 rectifier and a 6EM7 sweep tube. This phono pre is one of the few with dual volume controls. I have been listening to many old lps recently like early Chicago, Blue Oyster Cult, Blood Sweat &Tears, Miles Davis Bitches Brew, Allman Brothers, Crosby, Stills, Nash & Young, and others. There are lots of old records awaiting a listen that I haven’t had time to clean a play.

Good to hear from you Garp!

You are right -- let's not get into the endless debates about digital vs analog or all the comparisons like tape vs LP, does analog have infinite resolution and all that. It vexes the soul when we should be enjoying the musick and maybe drama that our hobby gives us.

Sonic once heard an LP set of Sir Lawrence Olivier performing Othello, might have been a 16 rpm disc set. I wish I could have that in my collection and King Lear too.

I think so much of the debates around equipment is to a kind of one-upmanship and to avoid discussion on aesthetics. Aesthethics is abstruse. Sonic means it is easier for audiophiles to talk about 200W vs 500W, two-channel vs four than CSNY vs Allman Bros and Mahler vs Massenet. Whatever your musical preference I am in no position to disagree. The music we listen to may touch only us in the whole universe and there is no argument about that at all.

BTW, what was your observation about oversampling DACs? Could you give me the link or recount it briefly.

Sonic

Sonic,

I have only encountered a few oversampling dacs that did not cause me listening fatigue. It does not require a very long period, often less than 5 minutes, for me to feel what I call digital glare. In my experience, most up sampling adds a bit of air and can sometimes reduce harshness, but it's all downhill after that. Most asynchronous (sample-rate conversion) up sampling dacs turn me off to music listening. I had almost given up on digital until the Magnavox DVD player entered my system. Many are using non oversampling dacs from Audio Note, MDHT and other manufacturers to avoid the glare. Still others are using older players from the 80s and 90s with the older op amps.

Some in the digital audio forums go into great detail debating the pros and cons of the OS digital versus NOS digital debate. Those professing the superiority of up sampling are the engineer types that really do not listen critically to music versus those in the NOS camp are serious music listeners. I often use music to relax after a long day at work or after a 60 mile or more bicycle ride. When the music causes me listening fatigue, it is no longer enjoyable. Today, I am happy to say my digital and analog sources are very enjoyable.

Hi Garp

I think Sonic understands what you mean when you talk about a certain glassiness in the high frequencies with the oversampling DACs. I have tried to tune this out using Michael’s devices and to my ears at least it seems to work, though as Sonic writes this I am listening to Handel’s Concerto Grossi by Harnoncourt/Concentus Musicus Wein (Das Alte Werk)…and I can hear it in there subdued yet present.

Have tried to follow the arguments on both sides of the NOS and OS divide. Theoretically the OS has something in their favour but have heard the NOS Audio Notes and 47Labs, the sweetness of musick is with NOS. But like you I am listening to my CDs and records (more records nowadays) and enjoying it immensely.

And it is about enjoying music in this wonderfully varied hobby of ours where, on one hand fans store music in 1 and Os on the cloud, and those who insist that true playback of 1930 shellac discs can only be achieved when played only on equipment of the same era tracking at 100 gms (!) and saying “not!” to playing these recordings on modern cartridges that track at 5 gms far more securely with negligible wear compared to the reproducers of the acoustic gramophones that, as a concession to wear, use wood and thorn needles.

The musical objective doesn’t stop Sonic the tunee. I have been working on the zone around the listening chair and am settling in to something that gives more distinction to the uncorrelated side to side reverberation that marks musical events in live spaces. More on this in the next few days.

Sonic

Hi Guys

I see your having fun.

I think I would judge TT vs Maggie as such. If I'm listening to slightly smaller staging I might take the vinyl, but if I'm going more expansive it's really hard to beat the Maggie. It's even a little hard for me to hear other players in my mind after using maggie for so long. It's so easy to shape and that's something I can't live without.

Hi Zonees

This observation from Michael is a little troubling because in my increasing listening to analog, Sonic has observed that soundstage width of LPs is smaller than digital too.

I attributed this to the cheap playback gear I am using -- budget Audio Technica AT LP120, Shure M97xE and Tube Box-S which is the only analog item in the chain tuned to any degree. The wires from the turntable to the Phono stage are what came with the AT. Sonic consoled myself that on the day I get my dream Garrard 301, Fidelity Research FR66 arm, Koetsu cartridge and Tango transformer the soundstage will be extending down the street….now it appears not. Why is the stage in analog smaller, Michael?

Nonetheless, the image girth and dimensionality from LPs is more realistic I feel.

Sonic

Hi Zonees

Here is what Sonic did around the listening chair zone:



Not a clear picture but here are the details – there are four Space Cones stuck on the bookcase wall vertically at the 1/3 points and horizontally at the half width of each bookcase.  This goes back to an earlier tune which I found I missed. The Space Cones give a sense of harmonic richness but it is a subtle effect but with each tune, the others from Michael get strengthened in effect.  Nice.

But the “big move” was to pull DecoTune stacks forward from their old positions at the corners of the bookcase wall to about 10 inches forward and about 1 foot further apart from each corner.

The bringing forward of the DecoTune stacks emphasized or collected ambience round my head creating more of the lateral uncorrelated reverb effect.  At first I had the stacks almost in line with my ears but I got a strong sense of ambience all round me but I found it something Sonic didn’t like, sounding after a while like rear surround speakers turned up too much.  Real musick never sounds like this.

So I edged the stacks closer to the bookcase wall finally settling on the present 10 inches or so.  There is now no audible reverb that swirls and smears but the sound holds together well.  The lateral setting was so that the axes of the tweeter ribbons don’t point directly at the absorptive backs of the DecoTunes.  They now point into the zone bounded by the DecoTune stacks.

Certainly the zone is leaky given the space between the DecoTune stacks and the bookcase wall but Sonic will soon get Ikea record storage shelves (I think Expedits) and then the wall surface will be extended and effectiveness of this tuned zone will be improved a lot more Sonic is sure.

Sonic

sonic

"Why is the stage in analog smaller, Michael?"

mg

One of the great things about this hobby is that there is so much music stored. Years from now we're going to be able to have different types of sources and systems that hopefully will give us more insight to the recordings we have. Reel to reel and vinyl were two wonderful hosts of the signal. One of the things that made them so fun was the mechanics of them. They allowed and needed us to tweak them. When set just so the music blossoms, but we also have to realize that physical conditions of anything dictate much of what we hear.

No matter how much I liked vinyl I was haunted by it's truth. At best I had 15 minutes of magic. I was an audiophile DJ and had to replay or move on, there was no repeat button. As charming as LP's are they are round pieces of plastic with a straight needle riding them. There's no physical way to really get that round/straight/shrinking/grooved combo to do the absolute and in time another source will bump it.

When you look at the history of vinyl you can see that the record companies needed to choose a size and speed that could be called a standard. If not you would have had so many different types of tables and motors that the industry would have not come together as the great communicator that we have come to know it as. We shaped the whole long play idea around this size and made a hobby based on 15 to 20 some minute rides.

Digital should by all measures blow away vinyl and if you guys were the guys helping the manufactures of the CD with what you can do listening wise who knows how far they could go.

One thing I have noticed with vinyl is a space limiting factor. I've had two players in my life time that have gone past the staging limits. One was in Atlanta and one in Ohio, but both of these still did not compare to the size of CD. I think if vinyl would have experimented with more configurations they would have figured out how to make things bigger but this will now never be done. Vinyl has reached it's current limits but it's still a wonderful pressure zone filling source and still has tricks up it's sleeve that digital has a hard time producing, or at least until the maggie came along, which I still look at and say "how".

To answer the question, I think it's because of the weight the arm has to put on the record that keeps the stage slightly smaller, but finding that prefect point of pressure is something that may never be found. Grado made a cartridge once that gave the biggest stage but I think the production was changed from the original after a couple of years and the magic that happened was gone. Cartridges that are made for focus also are the ones that give the smallest stages, so it's easy to get stuck on going after detail at the expense of space.

I use to listen at peoples places in the industry and was always shocked that the reviewer or expert didn't notice that the stage just got smaller when they went after focus   . I use to want to say something but didn't want to make waves during their glory burst.

I do think there is a better digital source yet to be made but that's only going to happen when the powers at be become better listeners and wanting to break past the small audiophile boxed sound. For now though for the folks who want the vinyl sound I would say the best of that world would be the maggie and tubes. For those who are willing to go to the pain of tweaking there is another way, but it is touching.

added note to the last post

While writing this last post I put on S & G's live "concert in central park" (one of the best crowd recordings ever) and have to put in this note. After settling at the same volume for one play through the crowd went from detailed to real. This is something that will never happen with vinyl as you get your one play through. That one play through may indeed beat up on a one play through on a CD (maybe) but that second play through and there after....well....I'll take the CD.

I am always (when a system is set up well) in shock at that second and beyond play through. There are really no words for this part of the hobby and to me this is really listening. If some can put up with flipping a record I can easily live with settling. That's just me and my lifestyle though as I'm setup more for writing or doing something while the settling is happening then coming in to enjoy it. I also very seldom listen to a recording through only once. Seems like my life has taken on this first time "play through" is for small tweaks or a volume setting and the next time (or times) is my real listen. I usually let it play till it pulls me into the room.

Sonic.beaver wrote:

Hi Zonees

Here is what Sonic did around the listening chair zone:



Not a clear picture but here are the details – there are four Space Cones stuck on the bookcase wall vertically at the 1/3 points and horizontally at the half width of each bookcase.  This goes back to an earlier tune which I found I missed. The Space Cones give a sense of harmonic richness but it is a subtle effect but with each tune, the others from Michael get strengthened in effect.  Nice.

But the “big move” was to pull DecoTune stacks forward from their old positions at the corners of the bookcase wall to about 10 inches forward and about 1 foot further apart from each corner.

The bringing forward of the DecoTune stacks emphasized or collected ambience round my head creating more of the lateral uncorrelated reverb effect.  At first I had the stacks almost in line with my ears but I got a strong sense of ambience all round me but I found it something Sonic didn’t like, sounding after a while like rear surround speakers turned up too much.  Real musick never sounds like this.

So I edged the stacks closer to the bookcase wall finally settling on the present 10 inches or so.  There is now no audible reverb that swirls and smears but the sound holds together well.  The lateral setting was so that the axes of the tweeter ribbons don’t point directly at the absorptive backs of the DecoTunes.  They now point into the zone bounded by the DecoTune stacks.

Certainly the zone is leaky given the space between the DecoTune stacks and the bookcase wall but Sonic will soon get Ikea record storage shelves (I think Expedits) and then the wall surface will be extended and effectiveness of this tuned zone will be improved a lot more Sonic is sure.

Sonic

It's interesting to see you doing this. I'm just getting to the point in my listening here where I'm starting to work on my rear pressure. I too am using the Decos and SAM wall. Yesterday when I got the wall set up I was so shocked that I was froze in my listening for a few hours. The pressure around our heads is one of those very exciting tunes for sure and I'm like a kid when this huge affect takes over the system. For mine, that pressure buildup (that surround sound) goes away after the recording plays one time through. The first pass the sound feels like it's almost unbalanced behind me, but when I come back for a listen after it settles a little it's like someone filled up the room with balance and I lose myself inside of the space, not really feeling front or back or even side to side but more a whole feeling of pressure with a easy to listen to and follow stage.

Hi Garp and Zonees

Some things Sonic found on oversampling -

Edited from: http://www.tnt-audio.com/sorgenti/audionote11kit_e.html

When a sampled signal, any sampled signal, is replayed over a DAC, the resulting analogue-domain signal spectrally contains the original information, say the band from 20Hz up to 20kHz, as well as an infinite series of copies (images) of that information, shifted up in the spectrum around half the sampling frequency fs and its integer multiples. With CD, and its 44.1kHz sampling rate, this means that there is music up to 20kHz, then a gap, then garbage from 24.1kHz to 64.1kHz, a gap, garbage from 68.2kHz to 108.2kHz, and so on.

Assuming that we can't hear above 20kHz, it is just fine to listen to such a raw output of a DAC. Our ear constitutes a perfect and sharp low-pass filter, or reconstruction filter, and all we would perceive would be a fine replay of the original sampled signal.

But our amplifiers don't like the spectral images above 20kHz. These can cause nasty intermodulation distortion which folds down into the audible band. And even if they didn't, it still would be an absolute waste of power trying to amplify the images.

Neither do our speaker's tweeters like the images. Tweeters are made to withstand power levels in the order of 5 to 10 Watts. This is fine, even with high-power amps, as the spectral contents of actual music are mostly lumped into the lower frequencies only. But if you confront a tweeter with a digital image, you hit it with all of the bass power of the original signal, magically up-transformed to a higher frequency. And it is not only the first image that hits, but also the second, the third, and so on. R.I.P. Tweeter.

So we really really have to filter the raw output of an audio digital-to-analogue convertor, not so much for sound quality's sake, as for the safety of our gear.

The first Japanese CD-players back in 1980 used sharp high-order analogue filter sections right after the DAC chips. Now it is a very tough job to make a high-order filter with analogue components, keeping an eye on overall cost, and hoping for a decent sonic transparency.
Philips, at the time not able or not willing to make a true 16 bit DAC chip, did things differently. Using oversampling, digital filtering, and noise-shaping they traded DAC resolution against time and hence avoided the need for a 16 bit part and for a steep analogue filter. The Philips machines - and the ones they spawned, notably the first Meridians and Missions - sounded better and the rest is history: quickly everyone adopted upsampling and digital filtering, inserting 1, or 3, or 7 interpolated values in between each pair of original samples.

But how does this all work? Say that you use 4-times oversampling. This raises the original sampling frequency from 44.1kHz (CD) to 176.4kHz. If you combine this with a sharp digital filter cutting above 20kHz, you can clean the whole band from 20kHz to 176.4kHz-20kHz or 156kHz from all nasties. All that is required after DA conversion would be a gentle analogue filter reducing the remaining components above 156kHz.

And everybody was happy for a while. The engineers because they had a seemingly simple solution to a real problem, and the salespeople because now they had a distinguishing specification in what so far had been a market of rather homogeneous products: the race of oversampling figures could begin. Philips with 4x and a true 16 bit DAC, Japan Inc. with 2x, UK-based Cambridge with 16x, Japan Inc. with 8x, then Belgian outfit Audio Discovery with a shocking 32x (8 TDA-1541 convertors in a massive 4-box CD-player looking not unlike Walker's Proscenium turntable), Wadia and Krell following later, and so on.

But wait a moment: all that oversampling and obscenely-high-order filtering is signal processing. And whenever you process a signal, you change it. Not necessarily for the better ...

Back to basics, thought some people a couple of years ago, and now we have a growing list of non-oversampling digital sources, combining the raw output of the DAC chips with a simple analogue filter only. Examples of such machines are the 47 Labs DA convertor, our own TNT Convertus, and the latest generation of Audio Notes. With Audio Note the return to non-oversampling ties in with their earlier efforts on transformer-based DAC current-to-voltage conversion: a transformer forms an interesting low-pass filter to be used with a non-filtered DAC.

Technologically, the Audio Note DAC Kit 1.1 is about as simple as it gets. That is, the signal path is simple. The power supplies for the digital parts are endowed with some sophistication: three discrete regulators, built with opamps and pass transistors, and referenced from red LEDs, drive the Crystal CS8412 receiver and the Analog Devices AD1865 18-bit ladder DAC. There is one coax SPDIF input on BNC, and one AES/EBU input on an XLR connector, selected by a switch on the unit's rear panel. Outputs are unbalanced.

The current output of the DAC chip is passively converted into the desired voltage by just a resistor. This resistor's value ultimately determines the DAC 1.1's output voltage, and Audio Note provide information on how to modify the standard 2.5V by changing the conversion resistors. After this follows a CLC filter, its inductor ferrite-cored, and finally a common-cathode triode stage, delivering the necessary gain.

Since this is a no-oversampling DAC, that low-pass CLC filter must cut steeply, starting at a low frequency, lest the end-user fries his/her tweeters. I verified the response of the filter found here with Pspice, and the result is, relative to a 1kHz signal:

Frequency Relative level (dB)
1kHz 0
10kHz +0.25
20kHz -2
30kHz -10
40kHz -17
50kHz -22
100kHz -39
200kHz -57
500kHz -80
1MHz -99

And then from http://www.sakurasystems.com/articles/Kusunoki.html

[Sonic thinks this page contains the most cogent argument against oversampling I have read and sets out the underlying thinking behind the 47Labs NOS DAC.]

Originally, oversampling was developed to allow the use of an analog filter with gentler characteristics as a post-filter, and not to increase the amount of information. Many people still misunderstand this.

The principle of the most popular FIR type digital filter is to shift the original data and overlay them together, not to create an additional one.When it overlays the data by multiplying the coefficient to the original data, there appears new information below 16bit and to recover this finer information, we need a higher bit rate processing.

For example, in case of a high-performance digital filter SM5842, this processing is done in 32bit and the filter round them up to 20bit to the output, creating more errors in the re-quantizing process. Recently, this problem was dealt with and a filter was created which can produce 8 x sampling all at once. But even with that, as long as you can't output the internal word length as it is, there's no way you can prevent the errors to occur.

It may sound contrary, but if you take this error into account, 16bit without oversampling is more accurate than 8x-oversampling/20bit.

YET ON THE OTHER HAND....[a contrary view for OS]

Edited from: http://www.audiokarma.org/forums/showthread.php?t=275623

The advantage to oversampling DACs is the fact that you extend the frequency range that the low pass filtering happens. This is easier and cheaper to do.

Non OS = the filter has to be between 20k and 22.1k (2.1k bandwidth is very narrow)
8x OS = will increase that bandwidth by 8 (16.8k)

Hi Michael and Zonees

"Hello, I'm Johnny Cash" is probably the best (IMO) album ever released by the great Mr Cash. Spare and sparse in places without the later overdone orchestra backing that characterized some of later CBS recordings, this 1969/1970 album is something to hear. Sonic has heard it on vinyl and now got the recording in my collection as a digital reissue.

Anyone familiar with this album?

Listen to "If I were a Carpenter" -- the right channel. There is a piano in there and an acoustic guitar. The detail and the interplay between two the instruments is very clear on my system and while the piano has been scaled down to be the same acoustic size as the guitar the effect is explorable as a listener though Sonic doesn't like piano in this sort of music.

Sonic can also hear different balances being applied to some tracks like they were mixed by another engineer or with another monitoring set up.

Heard this again tonight -- a great recording by a great artist.

In the meantime, my system is almost organic and revealing more of the musick with tunes and settling. More soon.

Sonic