Weird recording artefact

[Jakester]

So, my odd travails with Reaper continue. 

I have just been doing some recording of drum tracks, using mics into my XR18 into Reaper. As I was playing and listening to the recording, there's this weird pulse noise. 

None of the faders 'jump' in Reaper and it doesn't seem to have recorded (I junked the tracks anyway but forgot to check whether it was actually recorded) but in the XR18 mix app it's clearly showing as coming in from the USB audio return - see video (there is audio but it was a phone mic into headphones so very faint!). 

 

I checked all the mic connections at both ends, turned off any appliances etc but it was still happening. 

Never happened before - does anyone have any ideas what it could be (and therefore how to get rid of it!)

Edited January 12, 2021 by Jakester

[WinterMute]

Could be almost anything connected to your system, could be coming top the earth to.

Get your system set up so you can see it happening and then start turning stuff off unit by unit (might want to mute your speakers.) start with instruments/amps then go through till you've just got the MBP and the interface turned on, that should tell you where it's coming from.

It doesn't look regular so it could be a dry joint in a cable.

[Nigel Sleaford]

I’ve had some mics which picked up a regular pulsing noise from a hard drive? I remember cheap Behringer, and a couple of AKG mikes as culprits.

[Jakester]

I did think of that, but it’s an SSD so no moving parts!

It’s not happened since, but after going though and checking everything I did find a dodgy cable, which I’ve replaced.

Hopefully that was the cause!