OT - Sample Rate Question (Nyquist???) -Sound Forge - PC

Subject:OT - Sample Rate Question (Nyquist???) Posted by: TielBr Date:8/29/2005 8:53:20 PM Ok,… Off-topic perhaps, but I have a general question for anyone that might know… As far as sample rates go, why the need for anything beyond 44 KHz? I may be totally off track here, but I do have a background in electronics, work for a major cellular company, and am still lost. Most of my knowledge here is in wave propagation, and it is entirely possible that in the digital storage realm, I’m a mental midget. BUT there is a thing called the Nyquist Frequency. With this in mind, when transmitting information, you must have a carrier frequency that is double that of the information that you wish to transmit. In the audio realm, the highest possible recorded frequency is debated to be between 20KHx – 22KHz. That would make the Nyquist Frequency about 44Khz. I imagine that would be the reason that the Red Book standard sample rate for audio CD’s is 44.1 KHz, just over the Theoretical Nyquist Frequency, possibly allowing for some headroom. If that is the case, then why all the craze about 96+Khz Sample rates, and when I listen to an MP3 with a sample rate anywhere below 128K, the cymbals and other higher frequency instruments sound all funky to me. I get the fact that different compression techniques will yield different results, but if it’s over 44 KHz, than why can we hear the difference. I’m really interested to know what’s up with this, so if anyone knows the answer, or can theorize what’s up, please let me know. Thx, B.
Subject:RE: OT - Sample Rate Question (Nyquist???) Reply by: rraud Date:8/30/2005 7:44:04 AM Ask this question over at the Crossfade forum.
Subject:RE: OT - Sample Rate Question (Nyquist???) Reply by: Chienworks Date:8/30/2005 10:19:58 AM There are some replies to your post in the Vegas audio forum.

Ok,… Off-topic perhaps, but I have a general question for anyone that might know…

As far as sample rates go, why the need for anything beyond 44 KHz? I may be totally off track here, but I do have a background in electronics, work for a major cellular company, and am still lost.

Most of my knowledge here is in wave propagation, and it is entirely possible that in the digital storage realm, I’m a mental midget. BUT there is a thing called the Nyquist Frequency. With this in mind, when transmitting information, you must have a carrier frequency that is double that of the information that you wish to transmit. In the audio realm, the highest possible recorded frequency is debated to be between 20KHx – 22KHz. That would make the Nyquist Frequency about 44Khz. I imagine that would be the reason that the Red Book standard sample rate for audio CD’s is 44.1 KHz, just over the Theoretical Nyquist Frequency, possibly allowing for some headroom.

If that is the case, then why all the craze about 96+Khz Sample rates, and when I listen to an MP3 with a sample rate anywhere below 128K, the cymbals and other higher frequency instruments sound all funky to me.

I get the fact that different compression techniques will yield different results, but if it’s over 44 KHz, than why can we hear the difference.

I’m really interested to know what’s up with this, so if anyone knows the answer, or can theorize what’s up, please let me know.

Thx,
B.