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Single coil hum...

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Single coil hum...

Postby jimbobbley » Mon Dec 16, 2019 4:00 pm

Hi all

I recently moved into a new, far more professional studio space and am very much enjoying the extra space and facilities but am becoming more and more frustrated by the guitarist's old friend, namely single coil hum.

I am sure (or at least I think I'm sure) that when I first moved in there wasn't as obvious a problem when recording, but I haven't changed anything particularly obvious that might have caused the problem to worsen. There are rooms above and below me, and it's possible something might have changed with their equipment and / or their wiring, but it'd have to be a fairly large magnet or other source of electromagnetic interference to be causing this hum.

Things I've tried:

- turning all the lights off (often in venues I've found single coils are particularly prone to poorly separated lighting circuits) - no result

- rotating within the room to minimise the problem - slightly better results, but still annoying, and I can't move at all while I'm playing

- using humbuckers - this is non-ideal as sometimes you just need a Strat or a Tele, but even the humbuckers are picking up noise, and weirdly the safe spot to rotate to is about 90 degrees anti-clockwise from the safe spot for single coils!

- making sure it's not a ground loop - it's not, I know what that sounds like and this is definitely some kind of single coil hum / induction

- using a Kemper / different amp / plugging straight in, no effects etc - no difference

- unplugging various bits of kit that may have magnets etc in (Space Echoes, a Revox A700) - no difference

I am due to do some 'proper' recording in this space next spring and while I can just about put up with it for demo-ing at the moment, it'd be great if anyone had any amazing tips to help sort it out (or improve it) before then. I've searched the forum but can't really find anything particularly helpful beyond the obvious...

Thanks in advance
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Re: Single coil hum...

Postby ef37a » Mon Dec 16, 2019 5:25 pm

Hi Jim, The first thing I would suggest is, WTGR "have you become overfussy?"
You seem to imply that this problem has sneaked up on you not suddenly dropped out of the sky? As you rightly point out, electric guitars ARE noisy beasts. I have seen many posts where guitarists have come into a quiet home studio from being 'on the road; and being brassed off with the poor S/N ratio of their guitar kit!

I am sure others will give their experiences but IIRC, with a Mex Strat, properly shielded* I got a noise level at about -70dB fs for a gentle strumm hitting around -18.-20dB fs. That was with the guitar at the null point in the room, i.e. NOT where you can see the PC screen!

I am not at all surprised a hum bucker had a different null point from the single coil. The topology of the coils would do that.

Next job, post a clip of the hum. A few bars at neg 20 then stop and find the minimum hum point. The distribution of the hum frequencies might give us a clue.

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Re: Single coil hum...

Postby Wonks » Mon Dec 16, 2019 5:45 pm

Foil screen the guitar. It won't stop everything but it will reduce it significantly.

If the floor below you have dimmers, then with ceiling lights and wiring, then that's only a few feet away from the guitar. I don't know what sort of floor/ceiling construction you have, but anything fairly light will let a lot of that field through.

I'd have the earth impedance checked. If you don't know what it is currently, then its good to know as a reference, even if it is nice and low. But if it does turn out to be high, getting it sorted might help reduce the noise level.
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