Originally Posted by jnjn
The brickwall gets rid of all the nasty high frequency stuff that is a consequence of the sampling/reconstruction. Without it, there would probably be as much aliasing noise as music.
An infinite sampling rate is just another word for analog...
Perhaps lavrytech can elaborate for us on the tradeoffs between sampling rate, reconstruction word depth, aliasing, and brickwalls.
I contacted Dan and asked him to take a look at the on-going discussion. He is busy with new designs; but took a minute to address the question of how many samples are required for good results:
"At 44.1KHz, 1 second contains 44100 samples, so .1sec contains 4410 samples. There are 441 samples in 10 milliseconds.
At 96KHz, there are 960 samples in 10 milliseconds…
Clearly to reach perfection we need infinite time. But to stay practical one needs to define an acceptable performance goal. The answer depends on what one may want a filter to do. One may wish for good enough characteristics to satisfy say 24 bits accuracy (144db which is around 0.00000596%). One may need say 120dB (around 20 bits thus 0.0001%), or what not.
There are as many answers as there are possible filter designs. But in all cases, a good DSP designer can accomplish even a very demanding task with a few hundred samples, or even less.