I’m looping/overdubbing with an acoustic guitar using a pickup machine. Each time it loops, there is a hum that also overdubs. Here are some things I have tried:
•Different outlets for octatrack and interface to prevent ground loop
•Turning guitar completely down and recording nothing. The hum is still present and overdubs, increasing in volume each time
•Unplugging USB
•Double checking recording settings. Input A only
•Switching to a brand new guitar cable
Any and all help is appreciated. Thanks for looking!
Maybe a DI box or preamp could help boost the signal to noise ratio so you can at least reduce the hum in relation to your actual signal?
Also, hum is normally a very low frequency like 50Hz which is not needed for acoustic guitar recordings anyway. Have you got something that can filter out everything below the usable frequency range before going into OT?
Try to unplug unused gear.
Change your guitar, or your house!
If you can’t reduce the hum, try to reduce it with EQ. It can be very precise. Eventually combine 2 peak eq.
There’s also a noise gate Control > Inputs.
I’d give it a try.
If you record hum, it’s present at the source (I guess you ruled out the OT itself by recording with nothing plugged in at all?). Tell us about your guitar, what brand/preamp/pickup do you use? And what environment you are recording in? There’s a lot of electromagnetic radiation going on in a studio’s control room, that’s easily picked up by guitar pickups. Sometimes just changing your position eliminates a good part of it. It really can be anything, from computer screens to lighting dimmers, cheap power supplies…
I never even gave a second thought to noise reduction pedals but I picked up one of those mid 80s Boss analog multi-effects to use on synths and I’ve actually been using it on DI guitar into the Octatrack a lot. One of the things in it is a stripped down, one-knob version of the old Boss NS-2 circuit and I’m actually shocked by how well it works.
Are you using a magnetic pickup or a piezo? I’ve had good luck reducing hum in single coil acoustic soundhole pickups by opening up the output jack and soldering an extra wire to the shield/sleeve lug, with the other end soldered to a small alligator clip I can attach to something metal that the strings touch (might be harder on a flat-top guitar with a non-conductive bridge and nut- I do it on the tailpiece of an arch top mandolin, so all the strings are shorted together), so that the strings are grounded and your body blocks most of the RF as long as you’re touching them. Was night and day on the mandolin, it went from unusably noisy to dead silent but the results will probably vary depending on the specific pickup and trye of interference.
It’s also possible you have a ground loop of some kind, especially if you’re using a piezo pickup since that’s not really susceptible to RF and should normally be pretty quiet.
If you go the preamp route and can find a good price, the L.R. Baggs Para-acoustic DI is really nice. Only down side is it’s battery-only, but that’s usually better from a noise standpoint anyway.
It could also be the case that you have a dimmer switch on somewhere in your house causing the interference. Had a maddening time figuring that out once.
