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Why a phase problem when adding reverb?

Member for

21 years
As the question asks, when I do even a rough mix of some sounds I'll add some reverb. As I turn up the return I here a BIG time phase difference!
It makes me want to shut it off. I notice this particularly when monitoring in headphones, less in the mains.

I also here this when I do a mix on a DAW sometimes.

Can anyone give insight on what causes this, and if there is a fix for it?

Thanks! :)


Member for

18 years 6 months

MisterBlue Mon, 11/10/2003 - 19:29
Most likely the reverb has some phase shifted direct signal in it. If you use the reverb in Send/Return mode make sure that you have a 100% "wet" signal, meaning that no direct signal passes through. Otherwise the delay that is unavoidably introduced will result in these kind of effects. For the reverb alone the small delay/phase shift doesn't really make a difference (unless it is of course too long).

Pretty sure that that is the cause of your problem. Are you using a plug-in on a DAW or is it an external hardware unit ? Just wondering, my advice/conclusion is the same in both cases.


Member for

21 years

Member Tue, 11/11/2003 - 07:08
Mister blue, that is a really good suggestion, and makes a lot of sense. Thank you. I am working in both a hardware and a DAW environment depending on where I am. I will have to try your idea!

In hardware I am using a typical send/return setup to the console. The main reverb is a Lexicon MPX1. In Software on the DAW, usually a reverb plug-in (Hopefully one day a UAD-1 or Powercore.)

Member for

21 years

Member Tue, 11/11/2003 - 12:57
I didn't read all of the posts but its most likely theres still some of the originall signal present in the reverb, when going through an aux send and return, in the digital or analog world thers going to be a slight delay, if you send a signal into and aux going into say a reverb thers a delay so if theres some of the original signal left in the effect that is going to phase and comb, obviously this won't be a problem with a reverb or various effect cause they are completly different than the original "dry" signal, and a slight delay won't be noticable, but if you delay a copy of a signal be somthing tiny like 1ms, or 8 samples that is going to phase, so I would check the wet dry blend and make sure its on 100% wet. Really the only reason to have an outboard effect or plugin wet /dry blend on to anything other than 100% wet is when you wan't to add phasing or running it on an insert.