Mailist to discuss all issues regarding the Digitech GSP-2101 Guitar FX Processor

Saber,

Just to clarify, sound speed is about 340 meters/second or 1122 
feet/second. If it was a foot/second you would hear music a minute 
after it was played at a concert room or stadium, VERY BORING I 
GUESS!!!!!

That delay you're mentioning is related to the time the analog 
signal goes through the A/D converters, then the microprocessor to 
apply all the effect algorithms and then out the D/A converters. In 
more contemporary units, with much faster data "bus" and 
microprocessors, you would noticed less of a delay.

If you take a look at the GSP-2101 manual, it actually warns you 
about this fact because if you mix the processed signal with a 100% 
dry one you might perceive some signal degradation or artifacts due 
to what is called phase-cancelling. What happens is, since the two  
sound waves have different "phase synchronization" (in other words 
they start at different points in time), the overlap of their out-of-
sync phases produces them to partially cancel out on those points in 
time where there is an amplitude difference between the two. May 
sound a bit technical, but empirically in the end, what you hear is 
a somehow noticeable sound degradation to a higher or lesser degree.

Therefore, what Digitech advices us not to do is mix a pure dry 
signal coming from the analog section or external FX loop with that 
coming from the internal digital section, as phase cancellation may 
occur.

Why would you want to mix both a pure analog dry with the internal 
processed signal? Most of us using an external distortion unit 
(especially if it's tube based) have tried at some point, intending 
on obtaining a more "warmish and rawish" sound, to keep some of the 
un-processed signal coming out unaltered. Well, Digitech was kind 
enough as to forewarn users about what may happen should you try 
this.

Hope this helps.

Gus.


--- In gsp-2101@yahoogroups.com, "saber540ltd" <saber540ltd@y...> 
wrote:
> 
> I did a little test. Out of curiosity, I recorded my GSP2101 to my 
> computer using Cakewalk, with the effects send going to one track 
and 
> the right output (with the wet/dry mix set to 100% dry) going to 
the 
> other track. When I analyzed the wave data, the right output was 
> around 6-7 ms delayed compared to the effects send. Since sound 
> travels at around 1 foot per second, it should sort of sound like 
> playing 6 feet (2 metres) farther from you're speakers. My 2101 is 
> still at 10MHz though. I don't know if going to 20MHz would make a 
> difference here.
>