Losing Signal In Left Mic While Recording

[Petoria]

Ahoy.

Here's my problem:

The last couple of shows I've recorded, have had

problems with my binaural mics. It only records from the

right side. The signal for the left just shuts down.

Weird thing tough is that I tested the mics on an opening band

just to adjust the recording level and the first 2 tracks recorded

on the MD, the mics worked in stereo and I got a real good sound. But

when I fired it up again an hour later for the main act, the left mic shuts

off again. I've tested the mics around the house, against my loud

speakers other loud noises and it works fine. Only when I

record in clubs this happens.

I Have been using the radio shack volume attenuator. Some

recordings I had stereo sound, some I did not. Could the

attenuator have something to do with it? Could it be bad

wiring? perhaps something got knocked loose within the

left mic and it's acting all wonky? What are the common

problems when this happens?

Help is much appreciated.

[dex Otaku]

The most common causes are broken cabling/contacts or dirty contacts.

You can check whether the volume control is the problem by testing it with a pair of headphones [i.e. use the headphone volume control -as- a headphone volume control].

Cabling on your mics can be checked by lightly moving the mics and cables around while monitoring or recording. If there's an intermittent break somewhere, the signal should cut in and out.

In any case, you can try cleaning your plugs [using 99% isopropyl alcohol, available at any pharmacy] and jacks. Wipe the plug at the end of the mic cable so that it's not 'wet' but filmed with alcohol and insert it into the mic jack [with the unit OFF] gently 3-4 times and rotate it once or twice. For light oil [from your skin touching the connectors] buildup, this should be sufficient cleaning.

If your cabling is broken, I can only recommend replacing the mics. Yes, they can be fixed, but unless you know exactly what you're doing I would still recommend replacement over repair.

[Petoria]

Tried the volume control with headphones and it worked fine.

I did lightly moved the mics around and the left mic did go in and out. Just my luck that they would go out when I'm recording a show and not when say recording a conversation. Very finicky that way.

Should I still try cleaning the plug and jack? would that make a difference?

[A440]

Which end of the mics were you moving when it went silent? The weak point in a lot of mics is the connection between the cable and the mic itself. If that's what's coming loose when you wiggle the left mic, you're pretty much stuck: either get them carefully repaired or replace them.

It seems like it's not your problem, but the RS attenuator is not the most durable item. Usually it starts fritzing out with static rather than silence, though.

You might be able to save your recording by re-recording it in realtime with a stereo-mono-stereo connection--stereo plug (into the headphone jack) to mono-out plug, then mono-plug to stereo out, either with cables (preferred, so there's less strain on your headphone jack) or adapters. Obviously you have to have something to record it on: your computer, another recorder, etc. You'll lose a little quality, but at least you'll have the recording in mono.

[Petoria]

I wiggled everywhere. This started from the day I bought them mics but it was less severe. I got some full stereo recordings out of it. Guess it got worse as it went along. Replacing them would be the way to go.

The attenuators been good to me. No static... so far.

If I just copy/paste the right channel into the left in cooledit, how much audio quality am I losing there?

[dex Otaku]

Well, since you're basically making a stereo-compatible mono recording by doing so - none, really. You're just accepting that your recording is in mono, really.

[Petoria]

That's good to know.

One last thing:

Could me using the RS attenuator contributed in the

loss of signal in said left mic?

Something about (and I'm quoting someone here):

"The capsules are supposed to get 1.5 volts to 10 volts DC

from either a preamp or the MD recorder. By putting a volume

control in the middle of that it shorts out the power supply

that the mics get."

True?

[dex Otaku]

Yes, actually. True.

I can't say what the actual voltage drop is, but it is negligible enough for things to work properly. The only probable artifact of this [as per the discussion between A440 and I on this] is that you might lose a few dB of distortion-free SPL. [if anyone here remembers their impedance math, you could figure out what the drop is provided we know the actual resistance/impendance of the RSVC].

This would not be related to your problem, though. It still sounds more like a cable problem, though if it's caused by the RSVC it might be simply a dirty potentiometer or something, as A440 already said.

[Petoria]

The someone I quoted is the person who sold me the faulty binaural mics. Said that the RS probably caused the malfunction hence it might nor be covered by his warranty. Since I haven't used the RS long and I had the losing signal problem before I did in fact start using the RS, me thinks it's the cable aswell.

You've been very helpful both of you and I thank you for that.

[A440]

How can I put this most tactfully?

OK: The person who sold you the mics is a lying scumbag.

There is no way in hell that the attenuator would short out the mic (or the power from the MD) or cause any harm whatsoever. The estimable Dex is talking about a negligible effect on the response of the mic, not any sort of damage. If the RS was any danger to the mics or the MD, the pair of mics I have been recording with every few days for the last year would have shown some effect by now, as would the four MD recorders I have used RS attenuators with (MZ-R700, MZ-R900, MZ-N707 and MZ-NHF800).

It's a loose cable, pure and simple. Nothing magic, or even electronic, about it--it's a mechanical flaw. The guy needed a little more solder or a better wire.

I do hope this bozo isn't one of the better-known vendors.