The Black Hole......

Ed, no luck.
It’s in the schematics of the early (mid 80ies) Japanese CD players as a building block, no internals shown, no other information found.
But it seems they were not passive circuits, as the block shows connection for signal input, signal output, +/_
I can’t find them in any European or American brand CD player .

George

Thanks George,

I remember using I think it was Toko (now Murata) products, that I got from Digikey. I do recall a multipin package, but not if it had active buffering. I may have used them in an A/D used for speech recognition research. That project is where a local college was doing the research and one of the faculty ad built the A/D front end using the state of the art Sony chip version of the Stockham converter. It was built into a custom made solid copper chassis. When all was said and done it really only delivered 12 bits of accuracy.

I built a few for them with a bit better performance use a larger box, more digital noise shielding and things like a DC servo. Turned out one of the graduate students set up a side business selling copies of my design at a lower price to the school and many of the other working groups!

Now to the important topic of cats! My experience of cats is their persistence of memory is at best a few days and possibly hours. However as we discussed before the fight or flight response is more neuro-chemical. So the agitation remains even after the stimulus is removed. Once the chemicals (drugs if synthetic) wear off, the response becomes normal. With repetition the response is learned.

One of my neighbors has a very smart cat. If outside in the winter when they are not home, the cat comes into my place to visit. Eats a bit if offered and then goes up to the second floor window and waits until it sees their car arrive! Then it is a hurry to leave. The first time I started the laundry while it was dining, it stopped looked alerted and concerned about the new noise. Once it realized it was stationary it went back to unconcerned eating. The only noise thàt really ever alerted it was if I dropped something. That really scared it for a bit. So I don't actually throw trash into the waste basket while it is around. But it does lead me to wonder how much of clutzes the neighbors might be to have trained the cat about falling objects.

It also has been known to join me on the sofa when I listen to music. Although the first time it heard my sound system it did the same alert response.

Now the neighbor on the other side cat isn't as smart. He only recognizes me and comes to play if I stand on a particular staircase. Anywhere else it seems there is no recognition.

Thre is a cat from the neighbor behind my house and it rarely wants to play. Sometimes does other times does the scared response.

Then there are the dogs... My experience is their long term memory is much beter than cats. Only two around, one is well trained to play. The other is new and still a bit shy, but seems to only come around when it escapes owner control. There used to be a few others all from the not so good neighbor. No clue how to train or even handle them, so after about a year they give them away. I did manage to train one to not jump up on me with muddy feet when I came over to give it water as the owners would leave it out with not even a water bowl. (Bad owner, bad, bad...)

It is nice to have pets one doesn't have to really care for! Best regards Bill and Derfy. 😉
 
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Derfy,

As some records (CDs) are recorded in different studios for different bits there really is no reference standard for the sound.

Now perhaps we can talk about comparing the sounds from a totally electronic source to that of a Strad!

I did once listen to one in a very dead studio. However my full attention was diverted by the quite attractive woman playing it. (A commercial for the band!). ((The local symphony folks often refered to themselves that way.))
 
On the deeper meaning/musical relevance stuff of this back and forth, I'm as lost as you, Chris. I just tried to answer your question to the best I could in terms of how one could have a linear system and end up something close to what is being described. There's a lot of confusing terminology going back and forth and in word form as opposed to forms that might provide greater clarity.

I'm not smart enough to say whether or not this proposal is true. Because it comes from such a stellar source, my inclination is to assume that I just don't understand. Happens a lot. But my questions about fundamentals are never answered, so I'm unsure of its validity.

The magnitude is clear however: it's either mistaken or "Thanks for the check, your Majesty." Hoping it's the latter.

All good fortune,
Chris
 
... Still doing research to find out what sounds best to me....
It could be that what sounds best mostly depend on the target speakers and the typical spl listening level of target user. As an example, for his Firstwatt amps Nelson Pass made 1% H2 @1W for his <10W amp, 0.25% H2 @ 1W for 10-18W amp and 0.05% H2 for 20 - 25W amp but <0.005% for his > 25W Pass Labs amps, most of his current design use what he calls negative phase dominant H2. However, further correlation is still yet to be disclosed. You may as well find FFT measurements really helpful to your research.
 
...most of his current design use what he calls negative phase dominant H2…

Not as well formed but i noted that the Dartzeel NHB-468 put it in the same place:

1019Dart468fig09.jpg


Firstwatt SIT-3:

119FWSIT3fig07.jpg


Charts from Stereophile.com

dave
 
Think of a graph of the sine as the amplitude goes up, its not a sine anymore, its distorted, this distortion is in the sidebands, is this a nonlinear system? Yes. So any instrument with envelope will have sidebands. The question is do they matter.
Thanks, so the envelope of a instrument is equivalent to the envelope of an electrical system, it makes perfect sense but a wasn't sure and couldn't find any evidence on line.
 
Ok. But how does this relate to the linear summing of two signals before passing through a (linear) LPF? How is any discussion of musical instruments related?

I still think that we're conflating several meanings of the word "modulation" and that it's tripping us up. Linear systems don't modulate, in the classic (mixtures and harmonics) sense of the word.

And discussions of envelopes in a linear system is a very wrong turn, IMO. Way too easy to jump onto the wrong frog.

All good fortune,
Chris

+1, especially "How is any discussion of musical instruments related?"...

//
 
Derfy,

One idea for recording classical music is to reproduce what the conductor heard. Often that is the person who listens to the recording and has influence on the entire process.

So few have heard it from that position so maybe not the best choice for the public. How about; center, 1/3 of hall length from the stage?

//
 
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Here is a first pass on the delay line network. The cap values for the panels are guesses. I'll have a panel here to measure in a few days i hope and can then update the sim. I'm certain there are other errors but its a start.

I promised to come back with some calculation on the cap value.

C=Ɛ0*A/d

Gives for 4 panels of ca 14x56cm each, a total surface of 0.31m2.
Distance d=2.5mm
Now total Capacity as seen from just 1 side becomes :
C = 8.85e-12*0.31/2.5e-3 = 1.1 nF

That means that two from each side in series presents itself as 0.55nF to the audio signal.
Isn't it amazing that 550pF can produce so much music 😀 😀

It will be quite a job to divide this capacity in 8 separate partitions, so if you can measure them individually, it would be a much more accurate way.

Hans
 
I hope we could discuss this a little further.

A most remarkeable difference with a Fourier transform is that a Fourier transform requires a window that is at least wide enough to capture the lowest frequency of interest. And because the window is wide, temporal information on higher frequencies gets lost. Or rather, temporal resolution is lost.
That's where the wavelets are coming around the corner.
They try to get both optimal temporal resolution as well as optimal frequency resolution in the different parts of time and spectrum.

To be honest, I've never seen a single wavelet on this Audio Forum, so either we can do without or they are too complex to use.
But who knows, there will always have to be a first.
I'm willing to give it a try when someone proposes a representative signal.

Hans
 
DSoTM

Our LBRs were equipped with DRAW (Direct Read After Write) using a play laser on track a few mm behind the write laser to do immediate pit characteristic and data comparisons. An advantage was if there was indeed an E22 or E32 error, we could abort mastering immediately and not waste time. The glass was also EFM decoded and real-time compared against the stored master data using Eclipse ImageVerify.
It bears us to remember how much QC there is in CD manufacture vs how little there was and is in vinyl 🙂


I can't remember the exact year, it was mid-1990s and it was supposed to be an anniversary remastering edition. I never looked for it in shops, having both the commercial CD, Harvest and MFSL LP, and an (ahem) test copy of the one we made.

Cheers!
Howie
Brief scan of the 900 odd versions released suggests there was a 1994 remaster done by Doug Sax. I would assume that might be it?