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

Gus,

I'm aware that summing a delayed signal with the original one will 
cause some harmonics to cancel out and some to be reinforced, like a 
phaser would do with zero modulation. I was only confirming in 
practice what paulscary1 was experiencing. I just thought it would be 
interesting to point out that even with the Mix set to 100% Dry, the 
signal goes through digital processing. But thanks for the additional 
info; I've had the 2101 for around 10 years and didn't remember 
reading that stuff in the manual.

The delay has never really bothered me but I remember reading of 
someone who prefered using external mixing of wet/dry because of the 
delay (I think it was on tubefreak.com). And after reading 
paulscary1's post, I was curious about the actual facts. 


--- In gsp-2101@yahoogroups.com, "gusfmm" <gusfmm@y...> wrote:
> 
> 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.