zapco HDSP-V Series, Руководство пользователя

Страница: 46 / 50

46
WHY THE LOOPS WORK AND HOW
The signal paths for the loop functions can be made in the analog world using RCA Patch cords.
Unfortunately, that doesn’t work right and consequently it doesn’t sound right. The problem is time,
and when there is a problem with time there is a problem with phase. When you create a loop with
patch cords, you are feeding a signal back into the processor a full processing cycle behind where it
started and mixing it out of time with another signal. To solve this problem the program must delay all
the other signals so the looped signal will be correct in time and phase.
Secondly: The lower the frequency, the more processing power it takes to reproduce them accurately.
So, to save processing power, the common practice is to simply down-sample the lower frequencies
on the assumption that you will never know. Zapco has taken a different approach, we absolutely
loaded up power on bands 1~15 with double precision filters because if you want it to sound right
you can’t just do the easy stuff. So, when you set up a 60-band EQ, you want bands 1~15 of both the
target channel and the Loop channel to be in the low frequencies and bands 16~30 to be in the
higher frequencies.
Also: You will notice that Bands 1~15 can go anywhere in the frequency spectrum while Bands 16~30
must stay above 630 Hz. This is to avoid sound imperfections that can result from using the higher
band filters in the low frequencies.
Everything we have done with the HDSP processors has been done to make this the best sounding
DSP... period.