Re: Frequencies was Re: AW: AW: OT: new Macbook wíthOUT Firewire :(

["Bob Amstadt" <bobld@amstadt.com>]

I haven't done a research study on sample rates, but I have studied the 
subject in the classroom and in the real world.  As you increase the 
sample 
rate, you build a better quality representation of the original signal.  
In 
terms of what you hear, this will translate to a lower noise floor. 
Personally, I don't know how much better, but if you have equipment 
capable 
of handling 192kHz sampling instead of 48kHz, then you might as well use 
it. 
If you are a professional recording studio, you want to use the absolute 
best that you can afford.

On the other hand, you can record at 44.1kHz and 48kHz and find that the 
quality of sound is exactly what you want.  In fact, if you are going to 
distribute the music digitally on CD or compatible with a CD then you will 
be providing the listener with music sampled at 44.1kHz no matter what 
frequency you originally sampled it at.  There is no advantage to 192kHz 
sampling and down converting to 48 over simply sampling at 48kHz in the 
first place.

As for aliasing effects that were discussed, all A/D converters use an 
anti-aliasing filter before the actual conversion.  This prevents beat 
frequencies from appearing in the audio.  In fact, modern A/D converters 
use 
a two-step anti-aliasing filter that provides a very sharp cut off of the 
dangerous frequencies.  So, you aren't going to hear beat frequencies in 
the 
result because the difference in frequency between the original signal and 
the sampling rate are large enough that the resulting aliases are outside 
of 
the audible rangle.

Bob