Amp Hum

[SouthSIDE Glen]

FWIW, i've done this with some marginal success in the past. it's ugly, but you *can* make it work.....

Oh, absolutely. I didn't mean to minimalize the procedure or to say it wasn't a valid option to add to the deal. I just wanted to specify for those listening in that it wasn't as simple as just recording a solo hum and inverting it; that there were a few more steps involved than that, that's all.

Another potential complication to the procedure, and one that possibly may have caused the only "marginal" success at times is that the procedure assumes there are no variances whatsoever in the frequency of the hum; i.e. that it's a solid 50 or 60Hz hum with no modulations in the carrier frequency whatsoever. In real world situtions this is often not the case. The guitar track may have a 59.9Hz hum in it with a regular 0.5 Hz/sec modulation in it, and when the solo hum was recorded later the hum may be at 60.1 Hz with a random .3Hz fluctuation to it. Those numbers may not seem like much, but their plenty to keep the two hums from cleanly canceling each other out over any reasonable period of time.

While I have the conch shell here, though, I'd like to advance another technique that I have used often with good success:

Gate the guitar tracks just above the noise level of the hum and then go back and add a small reverb tail at the end of the fade just before the point where the gate kicks in.

HTH,

G.

 

[amra]

Woah! That will only work if the inverted hum and the hum on the recorded tracks are lined up to be 180 degrees out of phase. Put another way, the hum on the recorded tracks has to have identical zero crossing points as the hum on the inverted track. If not, not only will the hum not be cancelled, but even more noise will be introduced.

Plus there's the added complication that if you have multiple recorded tracks of guitar with the hum, chances are far more likely than not that the hum will not be in phase between those tracks. This would mean, using the method described, that you'd have to create one hum track for each seperate guitar track and line each one up accordingly to be exactly 180 degrees out of phase with each other.

Finally, using such a method you'd have to make sure that the amplitude (volume) of the hum on each track pair was identical, otherwise the hum will not totally cancel out.

Much easier and cleaner to just beg, borrow, or steal another amp or use amp modeling.

G.

I knew it couldn't be that easy.....lol. There's always a catch.