The video has some problems. First, a scope won't reveal if the sine wave is "exactly" and/or a "perfect" sine wave. For instance, if the fundamental frequency is altered slightly, the scope will never reveal it. Even an amp with 5% or more harmonic distortion will be quite difficult to see on a scope. Now consider an entire orchestra, singing. Evidently, we must believe what he says.
If other frequencies are introduced, the scope will never reveal it. What do I mean by that? The distortion analyzer shows nothing but the fundamental frequency and harmonics. If the fundamental frequency is slightly altered, it will not be seen.
When dealing with bit depth, "stair steps" (16 bit, 65,536 values, 24 bit, we have 16,777,216 values), very rarely is the analog signal going to be exactly on a "value"/"step" during the sample period. The signal will be in between, so which value is chosen, an upper or lower value? Whichever value is chosen, the slope/rise time is altered between samples by definition, thus the fundamental frequency is also slightly altered between samples, said instrument won't reveal to us.
We won't have to worry about the slope exceeding 20khz unless the harmonic is quite high in frequency. Eight bit alters the slope/rise time even more, plus 8 bit lacks dynamics, inner detail even more than 16 bit. The inference that 8 bit, even 16 bit is enough for high quality music is the opposite of what Philips engineers believed, but RCA marketed 16 bit players anyway, and the rest is history.
Notice the Gibb's effect. It is within 20khz which is to be expected, Notice its amplitude value is high compared to the rectangular wave. Any Intermodulation distortion in the system, whether it be from speakers, electrical components, will cause mixing with this ringing, and cause non musical tones in the audio band.
It takes two samples to recreate a sine wave. At 10khz, there are only 4 samples per cycle, 5khz only 8 samples. However, music is not a simple sine wave nor a rectangular wave with equal repetitive waveforms. Music is complex with all sorts of phase relationships between instruments and their waveforms. Think it can reproduce the music perfectly when parts tolerances enter the picture and values are altered?
Ever notice the "digititus" I have heard it called, especially at higher frequencies. A grain, roughness, grittiness etc, cymbals don't sound right, sounds like glass breaking. Attempting to claim analog is 13 bit is not entirely accurate, as the needle follows the grooves in a continuous motion, not just periodically sampling. 44.1k means a cutoff of ~20khz, yet study after study demonstrates that each "ear" can perceive to at least 5us (5 microseconds) rise time differences, in layman's terms comes across as attack times.
16 bit may be good enough for one's average system, but some want better, with both higher sampling rate and higher bit, wider bandwidth. So why be against higher quality, memory is easily available and cheap.
Now I like digital and use it often, convenient, but I use 20 bit or higher if possible.
Continue on with your discussion.
keep on truckin
joe