Mic Echo Problem

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AaronD

Active Member
The most common source of an echo, is the Monitor being sent to the same device that a Desktop Audio or Audio Output Capture source picks up. Send that source to the Monitor, and now you have a complete loop.

There's a time delay included in that loop, because it goes through the operating system's audio handler. If that delay is long enough, you get a discrete echo. If it's shorter, you get a sort of "reverb" or a "weird metallic sound". All 3 are the same thing, with different amounts of delay.

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If you don't use the Desktop source, set it to Disabled. Same for Mic/Aux. If you have audio sources in your scenes that you don't use, delete them entirely. Don't keep anything around that you don't use; it can only hurt you.

For the argument of, "I didn't change anything!":
The default settings that you have with a fresh installation are for TESTING, NOT PRODUCTION! Once you've seen and heard it work, you need to go through everything and clean it up. Disable everything that you're not going to use, select a specific device for each of what you *will* use, and NEVER leave anything on "Default". That's a ticking time bomb.

Yes, it's a bit technical, but media production is *always* technical. That technicality can be hidden at the expense of being limited to just one thing, but OBS is **SO** versatile that it must necessarily show it to you. And no set of default settings is right for more than just a handful of people. So you have to comb through it yourself and set it to work for you.
 
A

AaronD

Active Member
Another possibility is that the speakers, mic, and the air in between are included in the loop. That's a perfectly valid signal path as well, and is also the reason why sound systems "squeak".

If you can possibly avoid it, you should NEVER have a mic that hears a speaker, which itself has that mic in it. Live sound can't avoid that, and so the rule there is to NEVER have a net gain through the entire loop from the mic back around to the same mic again.
  • If you have a net gain in volume around that loop, it squeaks. If you let it continue, that squeak quickly goes all the way up to the full system power and stays there. The reason it stops is because someone pulled the volume back or hit the mute button.
  • If you're close to equal but not quite there, it rings and eventually dies out, but you can definitely hear that! (and sound guys know to listen for it)
  • If you're sufficiently below equal - a definite net loss from the mic to the speaker and back to the same mic - then it behaves itself, but it's not exactly "studio clean". It doesn't *have* to be "studio clean" for stage work that has all kinds of other noise to cut through anyway, but you might care a bit more than that.
At any rate, draw out your rig, and include ALL the places that EVERY signal goes, and how it gets there. Look for loops, and don't forget that every mic in a given space can hear every speaker in that same space. So that's another set of lines that must necessarily connect those things. If *that* completes a loop, then that could be your problem.
 
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