The "clear digi-swishies" are anti-aliasing artifacts and related distortion due to poor filtering and other A/D converter design issues. What you are hearing is obviously NOT what is missing (unless you can hear above 20kHz) - you are hearing "in-band" artifacts caused by the fact the converter can't properly deal with those higher frequencies. It's true that triangles and similar instruments will show poor AD converter design - but that is not proof that Nyquist does not work.
Just FYI: I've done "key jingle tests" recordings in high-end ADR facilities - largely regarded as THE torture test for high frequencies - with a Stage-Tec True-Match converter at 32/48 - and no one in the room could hear any artifacts whatsoever... and that was 15 years ago...
Rob Poretti - Sales Engineer - Archiving
Cube-Tec North America LLC
Vox.905.827.0741 Fax.905.901.9996 Cel.905.510.6785
From: Association for Recorded Sound Discussion List [mailto:[log in to unmask]] On Behalf Of Tom Fine
Sent: August 29, 2014 10:44 AM
To: [log in to unmask]
Subject: Re: [ARSCLIST] recording "cleanup" plugins and 192/24
Because HD download sellers such as HDTracks and Acoustic Sounds are selling 192/24 versions, and because audio equipment manufacturers are touting and marketing the "superiority" of super-high-rez digital audio, ABX testing is irrelevant from a business standpoint. My question centers around what post-transfer production tools are available at 192/24. I already have clients requesting 192/24, including having me spec it in documentation for grant applications. No one has specifically requested DSD yet.
Aside from Don Cox's comments about potential usefulness distinguishing ticks and pops from musical content, I'm wondering if a higher sampling rate allows for truer capture of tape hiss? I would think that the bias trap rolls off HF somewhere before 96kHz, but maybe not? I'm not saying any human can hear any of this ultra-HF information but I am saying that it interacts with frequencies in the human hearing range, just as sub-sonic information does (which is why one has to be very careful how one works with rumble on disk transfers, blanket high-passing can really screw up other frequencies because it removes phase-cancellations and boosts or cuts harmonics of the sub-sonic frequencies).
I have seen demonstrations where a later-era tape machine, for instance an Ampex ATR-100, can record and reproduce frequencies far above the human hearing range. Richard Hess has discussed ultra-HF overtones captured in his organ recordings using less-than-later-era tape recorders.
If you want to hear why Nyquist doesn't work with real musical instruments, listen to triangle or sleighbell tones anywhere above -12dBfs on any CD recorded or transferred at 44.1kHz. One almost all such CDs I've heard, there are clearly digi-swishies (sound somewhat like flangeing and phase-shifting) in the very top primary tones and harmonics. And I certainly cannot hear the alleged upper end of CD reproduction, my hearing tops out around 16kHz these days, in a quiet room.
Back to 192/24 (or even higher resolutions), I think it's here to stay and I'm wondering when the mainstream production tools will catch up, or if what I was told by two top mastering studios reflected the fact that they have out-dated versions of the tools?
-- Tom Fine
On Fri, 29 Aug 2014 10:09:12 -0400, Rob Poretti - Cube-Tec <[log in to unmask]> wrote:
I would argue that this is true up until 24/96. I've done a LOT of
> restoration and 24/96 will let you visually distinguish stuff (if you
> are zooming in enough) that you can’t actually HEAR. Conversely, I've
> never heard problems at that sample rate, that I could not see...
> Admittedly low frequency thumps often do not show on simple waveform
> displays but are easily show on time/spectral displays.
> Regarding some earlier comments on the sound quality virtues of 24/96
> versus 24/192: if someone has a link to a paper or presentation, that
> performs a proper ABX test between the two ... and showing conclusive
> results, please post it here...
> Rob Poretti - Sales Engineer - Archiving Cube-Tec North America LLC
> Vox.905.827.0741 Fax.905.901.9996 Cel.905.510.6785
> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]] On Behalf Of Don Cox
> Sent: August 29, 2014 10:36 AM
> To: [log in to unmask]
> Subject: Re: [ARSCLIST] recording "cleanup" plugins and 192/24
> On 29/08/2014, Eric Jacobs wrote:
> > I m not sure that there is that much more information present at >
> 192/24, and the algorithms from Cube-Tec perform equally well at
> > 192/24 as they do at 96/24. It can be argued that there is more >
> spatial information (two-channel or multi-channel) available at
> 192/24 > since the human brain can perceive very small L/R
> differences, but > many listening systems and rooms are not up to the
> task of reproducing > those spatial differences faithfully (i.e. due
> to room reflections).
> > For the most part, I m just as happy with a 192/24 as a 96/24 >
> recording. The leap from 44/16 to 96/24 is huge, but the leap from
> > 96/24 to 192/24 is more incremental. The chief limitation for many
> > recordings is not the media or the format, but the recording itself.
> > The main advantage of higher sample rates is that they make it
> > easier to
> distinguish clicks from music.
> So they could be very useful when digisizing from disc, but only if
> you have a cartridge with at least some response up at those ultrasonic frequencies.
> Don Cox
> [log in to unmask]