SH Spotlight What sounds just like the analog master tape: CD, Vinyl, SACD or a 1:1 analog Reel tape copy?

We heard exactly this, comparing a Magnavox CDB-650 to a Phase Linear CD player, listening to the explosion tail at the end of Don Dorsey's "Ascent" [Telarc, Erich Kunzel & Cincinnati Pops Orchestra, Time Warp].
There also used to be a test disc, can't remember whose, which imposed a very tiny (LSB?) tone on top of a high-level, very low frequency tone, like 0.1 Hz. The idea was you could listen to the high frequency tone as the low frequency pushed it through the whole range of DC offsets in the converter to see how linear it was.

 

I'm curious Steve and others with the equipment, how does the sampling rate and bit depth affect this?
And if someone could post the same music samples (doesn't have to be reverb) from the SAME original* at different resolutions, that could be VERY cool!!!

I'm not aware of any demo discs like this, aside from one DVD that Alpine made where the SAME EXACT MASTER from 96/24 was downsampled to 48/24 and the 44/16 IIRC. Hmm, except the DVD wouldn't be carrying 44.1 so either it was a DVD which I doubt or maybe it was 48/16?

*as a counter-example, I don't consider CD vs. DSD layers on a hybrid disc to be a valid comparison, since I've read how levels sometimes differ and maybe the masterings are not the same.

 

Yes, so I used to make noise floor FFT measurements with a 22 kHz at 1 LSB (Denon Hi-Fi check CD, though I think it was actually another disc I used). That kept the converters from detecting all zeros and muting, in other words not letting them CHEAT!
That was some very effective marketing to beat up on competitors, if I may pat myself on the back!

 

Nothing wrong with steam boilers...

 

I’m a bit confused why you think that DSD would still be better than a more modern PCM A/D. Given that at the time you said the CD had the right tonality but lacked resolution, wouldn’t hi-res PCM have the right tone and the resolution? Therefore wouldn’t it at least equal DSD?

 

Sorry, this is a little off topic of your latest post, but I just read your original thread and it made think of a question that I've always been curious about.
I'm a huge fan of your Doors S/T DCC releases.

Which do you think sounds more identical to the master tape; the cd or the vinyl?

 

You apparently missed the update posted by Steve...

 

And vinyl records have the RIAA pre emphasis and then de-emphasis on playback..
A mountain of EQ happens twice before it hits your speakers.......

That's why CD's were perfect from the beginning..

 

I have a 32.8P-224 111A7 +++++ copy that is exactly like the first Japanese press. All levels match up.

 

'Perfect' isn't accurate. At all.

 

Seems to me that the main post has been effectively updated such that with better and current DSD recording devices that DSD can in fact match up with the laquered vinyl. Is that a fair statement?

 

Wondering if the thread title ought to be amended to include other lossless formats such as DVDA or Blu Ray hires audio.

 

Interesting paper from the AES:
http://drewdaniels.com/audible.pdf
Audibility of a CD-Standard A/D/A Loop Inserted
into High-Resolution Audio Playback*

One thing I noticed after spending 20 hours mixing a song from 2" analog, fully in the analog domain is that no matter what I mixed to, it never quite sounded the same, no matter what I mixed to. I've used brandy new Studers, older Ampex, Otari, MCI (ehhh), CD mastering 1610's with Appogee, etc...

Could just be psycho-acoustic ear fatigue...

One thing I have noticed is the poor controls in impedance matching between gear during comparisons. That can cause all kindsa issues.
Great book here on transmission line theory:

a pdf of some math:
https://s2629002012.files.wordpress.com/2012/11/huitransmissionlines.pdf

And someone mentioned analog phone lines - Heavyside was a major factor in getting long trans-continental stuff to work:
Oliver Heaviside - Wikipedia

One of things he did was eventually known as the lorentz force and it's effect on transmission lines:
Lorentz force - Wikipedia

"In physics (particularly in electromagnetism) the Lorentz force is the combination of electric and magnetic force on a point charge due to electromagnetic fields. A particle of charge q moving with a velocity v in an electric field E and a magnetic field B experiences a force

F = q E + q v × B {\displaystyle \mathbf {F} =q\mathbf {E} +q\mathbf {v} \times \mathbf {B} } {\mathbf {F}}=q{\mathbf {E}}+q{\mathbf {v}}\times {\mathbf {B}}

(in SI units[1][2]). Variations on this basic formula describe the magnetic force on a current-carrying wire (sometimes called Laplace force), the electromotive force in a wire loop moving through a magnetic field (an aspect of Faraday's law of induction), and the force on a charged particle which might be traveling near the speed of light (relativistic form of the Lorentz force). "

Again lots of math - but a great note here:
:"Between 1880 and 1887, Heaviside developed the operational calculus using p for the differential operator, (which Boole[10] had previously denoted by D), giving a method of solving differential equations by direct solution as algebraic equations. This later caused a great deal of controversy, owing to its lack of rigour. He famously said, "Mathematics is an experimental science, and definitions do not come first, but later on."[11] On another occasion he asked somewhat more defensively, "Shall I refuse my dinner because I do not fully understand the process of digestion?"[12]"


With a lot of the RF stuff I deal with, it can be daunting. But even at AF frequencies, source/load impedance and characteristic impedance of the interconnect can be become a significant factor causing subtle issues in efficient transfer.

Now this is NOT a treatise for uber expensive cables - in fact, in the lab we've found that properly made cables are usually not the most expensive for use in a specific topology. This is even at low freq domain designs.

I will say that I work with a guy - Gary Stanfill - of Vega Wireless. When i asked him about the claim that some people can hear subtle differences , he mentioned a story of one engineer at Gauss (I believe) that could hear silly low distortion.

And this is really interesting - one of the major semi manufacturers - Linear Tech (now part of Analog Devices) had a guy - Alan Rich. Amazing analog engineer. When I asked him about aural perception he mentioned a story of Walter Jung. Walter is one of the main analog guys at AD. Well know for many of his books on audio. Now he did tell George Massenburg that doing a state variable filter was "impractical"

From:
https://www.massenburg.com/wp-content/uploads/2011/12/GM_ParaEQ.pdf

" One person comes to mind: there was a well-known engineer working next door at Aircraft Armaments who looked at the goals and stated that he felt that the circuit solution was impossible or impractical. His hame was Walt Jung and he went on to write the "IC OpAmp Cookbook" a few years later. "

Note the section right after that:
"Incidentally, during that time I was taking Electrical Engineering at Johns Hopkins University, a school that was as medieval, apathetic and oppressive as schooling in the 60's could get. I got into a row with a 'professor', who looked at a schematic for a gyrator that we had built and declared it "of theoretical interest only", and "impractical" to implement. Seeing this as a sign, I dropped out of college. "


So I digress... Alan, and a bunch of other engineers are at some convention - AES I believe. A lot of heavyweights in the analog engineering world.

So at the time typical IC's were packaged in what they are now, black epoxy resin - note it's black due to the fact that most semis are photosensitive. But back then - and even today for some hi rel stuff - you can get ceramic packaged IC's.

So the story as told to me by Alan was that Walter went 10 for 10 in being able to tell the difference between an epoxy packaged opamp vs. a ceramic one - even tho both were cut from the same fab wafer. He mentioned no one could believe it. But he did it.

When I mentioned this to Gary Stanfill, he said, yea he was always surprised at the level that some humans can discern audio. One story he told was about their dealings with Shafer Vega wireless guitar rigs and Van Halen. they came off the road had these beat up belt packs. So Gary has the tech repair them and put newer stuff in the the analog sections.

After the road manager picked them up a while later they got a nasty call of "What the hell'd you do to our wireless rigs?"

Gary had the tech get them and put back in all the older analog stuff.

So just like you really never know what someone else is thinking (tho with me it's usually "Shut up stoopid hippie!!) you never really can say what's perceptible to other listeners.

 

The other question is whether a valid test was conducted at all - ie a properly controlled DBX to ensure level matching and eliminating human expectation biases.

At a well known Australian studio I was associated with in the 80s/90s, they did proper controlled tests whenever they upgraded their equipment or processes. I was at one of their testing sessions when they installed a significant upgrade to their CD production master processes. There were about a dozen of us participating including their techos, mastering engineers, sessional musicians and even the lunch lady. None of us could hear a difference between the production CD and its analog tape source. The thing is it was not a 'wow' moment but rather a "phew" of relief from the staff because the equipment and processes were working correctly.

These were the days when most CDs that were AAD had a disclaimer on the back label stating that the higher resolution of CD can reveal the limitations of the analog tape (eg tape hiss), which many of the unfuttzed transfers certainly did. Vinyl always sounded different to the source, whether it was analog or digital, for reasons that are totally understood.

 

You may not be aware that "debate of objectivist/subjectivist principles, and/or double-blind testing" is "unacceptable" here on SHF (check out the Forum Policies link at the bottom of this and every forum page). I think it's a good policy as those topics are controversial and often lead to discussions that get threads shut down.

So, my only response to your post is: not everyone agrees that DBX is the only valid test, or even a valid test.

Fwiw, I was given an ok to answer your post, but I'm not going to make any additional posts re: DBX.

Fred

 

Well I'm glad that one of the top Australian studios (and most others) do not subscribe to that that view when testing equipment and processes.

Subjectivity is of course important for mixing and mastering, but that has nothing to do with whether a format or process is accurate to source.

 

I have to say this has been a fascinating read.

Thanks to everyone's participation. Some great knowledge transfer here.

 

I’m still having a problem understanding how a medium with 40db channel separation (test acetate) sounded almost identical to a master tape.

 

People also don't understand how we hear dithering 100+ dB. down in digital audio. The answer is simply that our hearing is not linear no matter how badly our brain and "understanding" wants it to be.

 

Bumping Steve's update.

To avoid confusion it really should be added to his original post as an addendum--if possible.

 

I really think DSD has a very analog feel. Hi res PCM can be quite enjoyable, but does not quite touch what DSD can do. I think the comparison to vinyl makes sense, but then again you'll have to do without pops, clicks, and warpage and those are really important to me .... not.

 

I still don't understand -- unless the master tape had just 40db channel separation as well?