jabbr

I once wrote a peephole optimizer for the VAX LISP compiler ... in FORTRAN 😂😂😂

Oh god no, you are just inventing definitions here. Who knows what you are saying when your words do not share the common meaning. Xenix has a fascinating history. At one point it had the highest Unix user base. Microsoft licensed Unix from AT&T *before* the IBM PC. IBM didn’t want it, rather DOS and the rest is history. Xenix lives on as SCO Unix. Thats not what we in the technical world consider “vaporware”. Vaporware is a product that has been promised by marketing people but doesn’t exist as a working product. It only exists as the vapor coming out of marketing folks mouths. Xenix existed & worked. It’s a flavor of Unix. Linux took over.

He he this is silly. The reason that "DSD" or more properly "SDM" is in DAC chips is that it is the underlying technology behind modern ADC and DACs. I own one true R2R DAC (PCM) but unfortunately the PCM1704 chip and the Analog Devices equivalents represented the epitome of laser trimmed R2R DAC technology and are largely no longer made. From a technological perspective (cost/performance) SDM has taken over the industry. To think otherwise is just wrong. If the "chip manufacturers" couldn't answer this simple question for you then you were talking to a marketing person with no real clue as to how ADCs nor DACs work. Now DSD is single bit SDM and many chips are multibit SDM, so you could ask an engineer at ESS if its easy for them to convert from single-bit SDM into their internal multibit format ... does the DSC1 FIR stage count as a conversion to 32 bit SDM? Perhaps ESS multibit SDM is similar thermometer code?. In any case it is really easy to understand how DSD DAC works: We are hardly dependent on DAC chips and there are many outstanding custom and discrete implementations available now. Nor are we dependent on source DSD as there is outstanding software to convert PCM to DSD. You might think that SACD is dead (and CD is dying) but the underlying technology is present in 99% of the DACs in existence. SDM is solidly entrenched from a technical perspective.

If no one cares then why bother posting here. This site is less than a rounding error for the market! If no one cares then just listen to MP3 or AAC or Spotify and be done with it. If no one cares then just open your mouth and swallow MQA.

It's all a self fulfilling prophecy if the assumption is that nothing above 20 kHz. No one will record higher and there wouldn't be hi-res recordings with real hi-res content. In that case there would be no difference. The public will accept what is shovelled at it.

There is the idea of the proverbial “grandmother” neuron which fires when you see your grandmother. The existence of face recognition neurons in the IT cortex is very well known. The essay “The Man Who Mistook His Wife for a Hat” was written about a person who had a stroke in this area.

Ok the point is that ultrasonics modulate sound. When you remove ultrasonics, this modulation is also removed. The overall perception is altered. You are probably going to argue that we could apply an equalization filter to the audio to reproduce the perceived sound, except that this modulation differs from person to person and is not guaranteed to be constant over time. You could try to encode the modulation ... then you’d be doing something like MP3... alternatively you could simply record and distribute the full range audio including ultrasonics.

Ha ha!!!

No. First of all I think that the wavelet model that @Miska mentioned more closely responds to the cochlea that the FFT model. I'm not convinced one way or another but erring on the side of caution prefer music in as high a resolution as was recorded/available. Also design equipment to handle above 20kHz ... that isn't difficult ... high-res audio isn't gigaHz. Really I'm just saying that CD Redbook is an assumption.

There are different reports and techniques but here: http://www.hearingreview.com/2009/11/audiologist-invents-ultrasonic-tinnitus-treatment-device/ ... I don't claim to know the details but after 60 seconds of ultrasonics, the effect lasts for e.g. hours. Somehow the ultrasound is doing something to the auditory system.

It has been reported in the literature that ultrasonics can affect tinnitus. This is by definition a non-linear effect ie the ultrasonics are not directly heard, rather modulate the hearing system. The reason this is so important is that it provides a clear cut mechanism for the audibility of ultrasonics — not that you can hear, for example, a 30 kHz tone, rather that the full range sound of a cymbal might sound different than the 20 kHz stopband filtered recording of this cymbal. There are many people who are certain that Redbook CD contains all that we can possibly hear because of something they read about concerning the cochlea. The fact that ultrasonics modulate hearing means this belief is not grounded in certainty.

All these things you state are “known” is what he would say aren’t laws of physics, rather rules of neuroscience.

Hmmm ... perhaps I’m reading into what he is trying to say (this is prose) but consider this: CD uses band limited signals in which a filter has been applied. The filter throws away/alters the information. There are assumptions made that the filtered away information *cannot* be important but this assumption is that. In a stereo 44kHz digitized signal, small phase differences are quantized away also altered by the band limiting filter. The assumption is that they aren’t important. He is suggesting that the brain is particularly sensitive to the timing of axon potentials. There is no law of physics which says whether that’s the case or not. I’m not claiming that this is important but it could be. Again, bandwidth limiting CD is an assumption. MP3 is another assumption.

No idea, but bone conduction is reportedly ultrasonic. Point is that I’m not so sure about the dogma.

A) he isn’t a neurologist B) issues raised go away with higher sampling rates it’s not clear to me that 44.1 kHz recording sampling rates are adequate and ultimately I think he is saying that human audio perception (including skin) isn’t necessarily 20kHz band limited