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by teilo
3277 days ago
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> This is theoric considerations, not practical. With all due respect, there is nothing remotely practical about the theoretical ability of any medium to record frequencies above 22Khz. Do you play your CD4 quadrophonic records to your pets? On what? Ribbon tweeters? Furthermore, the ability to perceive dynamic range attenuates with frequency. So once again, you are back at the limits of human hearing, even if I accept what you say about the theoretical DR of vinyl. And what if what you say is true? Can you show me any recording with a dynamic range exceeding, say, 70dB? It is also relevant that the dynamic range of vinyl is a function of the circumference of a track, and decreases as the record plays. It also decreases every time you play a record. And what you say about DACs has not been true for many years. These days, even run-of-the-mill DACs employ oversampling. |
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Oversampling does not solve the issue i have commented, which is that 44KHz is too low. Read about filtering at the ADC and DAC stages. Read about the pros/cons of using FIR-digital, IIR-digital, brickwall-analog filters at them. Oversampling with a FIR filter was already used on the second CD player on the market, the Marantz CD63 aka Philips CD-100 of 1980. All through the eighties all kinds of DAC+filter combinations have been used and now in 2017, despite any combination you use, higher-resolution (say, 96Khz sampling rate) audio sounds better. 44KHz isn't enough.
You see, what happens is as you approach the 22KHz limit, all sorts of nasty stuff will happen with the audio. No matter what filter you use, the upper octave (say 10-20KHz) will have any of the following ills:
- ringing - rippled frequency response - wild phase shifts. - pre-echo or post-echo
So, again, let me repeat: 44KHz isn't high enough. Using a higher sampling rate like 96KHz or more, allows to move such problems away from the audible range.
> With all due respect, there is nothing remotely practical about the theoretical ability of any medium to record frequencies above 22Khz. Do you play your CD4 quadrophonic records to your pets? On what? Ribbon tweeters?
Yes there is. What this means is that a system that can resolve up to 50KHz will have clearer reproduction of the 10-20KHz range, which is so important to add definition to the sound. "Clearer" as in "less artifacts and distortions."
> It is also relevant that the dynamic range of vinyl is a function of the circumference of a track, and decreases as the record plays. It also decreases every time you play a record.
What decreases on the inner grooves is the ability to record higher levels for the high frequency ranges (>14Khz). And even this is a limitation that is self-imposed by record cutting engineers to make the record easily playable on the cheapest kind of stylus, the 0.7mil spherical stylus.
Advanced stylus shapes (line-contact, shibata, hyperelliptical, Fritz Gyger FG70, JICO SAS) wouldn't have any problem with this.