Wide bandwidth = necessary?


Hi folks, there is one paradigm that bothers me a bit: many experts and audiophiles are stating that Red Book technology is outdated because of it's bandwidth limited function. I've read the human ear is capable of perception of frequencies beyond the normal human hearing, up to 40kHz. But this is only with live music! When listening to recorded music there is a restricted bandwidth because many microphones can only pick up frequencies up to 20kHz. So why the need for more and more bandwidth with regard to digital sound reproduction technology? What is not present in the recording can't be heard either, even with very wide bandwidth music reproduction gear.
What is also laughable is that many vinyl adepts say that phono playback gear can reproduce tones as high as 40kHz and that is one of the reasons phono playback sounds more "natural" than digital playback. This is a bit of a contradictio in terminis because most LP's are very band limited (30Hz to 16kHz is quite common). Your comments please.

Chris
dazzdax

Showing 3 responses by eldartford

The oft-quoted sampling rate of twice the highest frequency of interest applies to regeneration of a continuous analog sine wave. That ain't music. In practice, even for non-musical signals at least a four to one ratio is desirable.
Viridian...I have long believed that our sense of hearing includes a "waveform steepness" factor quite independent of frequency response. I came up with this idea a couple of decades ago when I found out that I could hear the introduction/removal of a low pass filter at a frequency well above the frequency at which I became stone-deaf to a sine wave (the usual test signal). This would also explain why a supertweeter operating above 20KHz makes an audible difference.
Almarg...My experience with the digital representation of analog waveforms (precision servos in missile guidance systems) leads me to the conclusion that, in the real world, four times the highest frequency of interest is the minimum requirement for good performance. Audio signals are no doubt even more demanding than servo error signals.

Shadorne...The Low Pass filter in question was pure analog 6 or 12 dB. There were no artifacts in the passbvand of my degraded hearing range.