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Re: long cable runs with electret microphones

Subject: Re: long cable runs with electret microphones
From: madl74
Date: Tue Mar 31, 2015 6:52 am ((PDT))
> I am talking like 15+ meters, in nature (far from urban EMI). I wonder ho=
w
> much can such thing affect quality.
> One thing that comes to mind is external preamp next to mics, which would=

> boost their level. But is it really necessary?

Jonas,

I've got a total of 450 meters of double cable on drums which I use in my
bit of wood. I use MKH mics which have a low actual impedance, and match th=
e
cable impedance into a mixer, but this is an extreme case. This requires
balanced line working and I still picked up some hum which I traced to an
electricity supply ground which had a few volts on it. The problem was
grounded XLR shells on the ground and when I insulated them the hum went.
The whole house must have been at a volt or so of AC compared with the real=

ground ground.

This is an extreme case but the limit for about 15 metre runs depends on th=
e
actual (not the rated) impedance of the mic and recorder input.

As ever, I recommend an A-B test with short cables and then the long cables=
.
If you can't hear the difference, stop worrying. :-)

Many mics are unbalanced, with one signal lead connected to ground as with=

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