[LAU] Pro Audio? OT rant.

Thomas Vecchione seablaede at gmail.com
Mon Dec 24 07:17:48 UTC 2012

On Sun, Dec 23, 2012 at 9:29 PM, Chris Bannister <cbannister at slingshot.co.nz
> wrote:

> On Sun, Dec 23, 2012 at 12:39:17PM -0500, Thomas Vecchione wrote:
> > And for the record, the basic reasoning for what I said is simple, and
> has
> > existed for quite some time, that 44.1kHz is capable of containing more
> > than the entire human hearing range of an undamaged ear (Reproducing all
> > frequencies up to just above 22k).
> Yeah, but what about harmonics? For truly PRO work, analog should be
> used. CD's came out as the poor mans quality stereo, it was a compromise
> for high quality vinyl. Just as McDonalds is a poor compromise for a
> quality restaurant. But with the proliferation of advertising, huge
> product selection, the rising cost of the real quality goods; digital
> and McDonalds soon became the norm.

No for many reasons.

1. Harmonics, while they do extend above our range of hearing, and then
above the limits of a 44.1k recording, in that order, the amount of energy
in that high of a frequency generally is so low that even if we could hear
that high it would be questionable whether we would hear it.

Your McDonalds analogy would be a better analogy if applied to lossy
compression, and MP3 in particular, rather than Digital vs Analog.  A more
suitable analogy for digital vs analog is going to the fine restaurant,
having an amazing meal, and then being able to reproduce the exact same
meal every time(Digital), whereas a chef might make small changes to the

> I believe it was Shannon's law which basically stated that the sampling
> frequency should be twice as high as the highest frequency (or
> bandwidth, if the lowest is zero). This was used in telecomunications
> where a 4kHz (actually 3.4kHz but usually rounded off to 4kHz) bandwidth
> was
> considered to be ample to convey human speech at a quality which was
> considered acceptable. Therefore, an 8kHz sample rate was used.
> I believe the same reasoning was used when they started fabricating CDs.
The Shannon-Nyquist theorem was absolutely the primary inspiration behind
the choice of sample rates of CD.  The theorem states that you can
reproduce exactly any frequency that you sample at over twice the
frequency.  So when 44.1 was chosen, it allows for any frequency up to just
above 22kHz to be reproduced exactly.  The limits of the average undamaged
human hearing is 20kHz, and the average limit for typical adult hearing is
probably closer to the 18k range if the ears were well taken care of.  For
most people that listened to loud music, etc. that limit is probably much

> So, consider a musician playing a Stradivarius violin. You'd want to be
> able to reproduce all the tonal richness, and harmonics during the
> recording phase. Some people say the ear can't hear above a certain
> frequency anyway, so it doesn't matter whereas there are others who can
> pick the difference between a Stradivarius violin and an "ordinary"
> violin.
The harmonics in question for a violin are all within the range of human
hearing.  Harmonics occur at a regular mathematical interval above the
fundamental frequency, and the fundamental frequency is generally very low
in the range of our human hearing, for instance, since we are using a
violin as an example, concert tuning a is only 440Hz, meaning your second
harmonic occurs at 880, etc.  very low in the overall range of human

The only exception to this I know of is when you have an interaction of two
different frequencies that create a third 'phantom' frequency that can be
lower than the fundamental of either of the other two (I know there is a
better term for this, but the term I use to describe this in RF/wireless
mics is harmonic intermodulation).

> I also understand that vinyl is now increasingly (very slowly though)
> becoming the preferred medium for listening to music.
Not according to any resource I can think of.  Apple certainly isn't
selling portable vinyl players.  100% of the systems I design and install
for commercial, house of worship, etc. applications have not used vinyl.  I
can't think of the last time I pulled out a vinyl record player.  Not going
to say that some people don't prefer it, and I encourage them to if that is
what floats their boat, but the VAST majority of people are using digital
for many reasons that were listed by Monty Montgomery.

> Remember: If you sample at an infinite frequency you have analog, and
> isn't the idea of quality digital to have a high sample rate.
Actually no you don't really.

The universe is actually closer to digital to analog, as you either have
matter or not.  To have high pressure compressions and low pressure
rarefactions that make up sound waves, you are still moving individual
molecules and the components that make them up.  In the end you end up with
spaces that contain matter and spaces that don't.  So if you were talk
above an infinite sampling rate, you would still end up with a digital
representation really.  And of course at that level you are really only
doing 1 bit sampling, closer to DSD than PCM, and honestly it would be
fairly useless.

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