How can you tell your LDC is damaged/dying?

[nbiehl]

I've got some AT LDCs that have seen some miles. I've been recording with them this week, and once in a while their output goes to nothing but noise. If I tap the body or play upright bass, I get distorted thumps. Play the doghouse loud enough, and you'll get a brief second of clarity at the highest amplitude, and then back to distortion. Acoustic guitar is just distortion.

I thought this was my 30 year old second hand sound board, but I just realized we've had some issues with distortion at gigs lately too, with a couple of different boards.

How can I tell if my mics are damaged?

 

[ez_willis]

I've got some AT LDCs that have seen some miles. I've been recording with them this week, and once in a while their output goes to nothing but noise. If I tap the body or play upright bass, I get distorted thumps. Play the doghouse loud enough, and you'll get a brief second of clarity at the highest amplitude, and then back to distortion. Acoustic guitar is just distortion.

I thought this was my 30 year old second hand sound board, but I just realized we've had some issues with distortion at gigs lately too, with a couple of different boards.

How can I tell if my mics are damaged?

Once in a while their output goes to nothing but noise. If you tap the body or play upright bass, you'll get distorted thumps. Play the doghouse loud enough, and you'll get a brief second of clarity at the highest amplitude, and then back to distortion. Acoustic guitar is just distortion.

 

[dgatwood]

Might be as simple as a loose wire or a cold solder joint somewhere. Crack it open and have a look. Oh, wait, it's an AT mic. Good luck cracking it open. If it's a loose wire, that's an easy fix, but those things are usually all surface mount, so if it is almost anything else, you're probably out of luck. :| Are you sure your phantom power is sufficient?

 

[darrin_h2000]

Id suspect that it might be a problem with your preamp or interface...I just dont see all of your mics doing this at the same time as being a mic problem...its something that the mics all have in common.

 

[crazydoc]

If you look up and see this while you're using it:

 

[nbiehl]

Oh I see buzzards all the time when I'm in the studio, but they're just waiting for my eventual demise from fatigue and stupidity.

How do I check the phantom power for issues? I have a multi-meter, but I'm not very familiar with it.

The board is a Soundcraft 200 series that I got from a TV station. I have it plugged into a Furman rack-mounted power conditioner.

 

[Shadow_7]

Two options IMO.

1) Use it on a different interface with a different cable. If the problem goes away, it's that other interface.

2) Use a known good or at least newer mic of the same type on the same interface and cables. If that works, it's the mic.

...

3) Use a different cable, it would be the more likely failure point IMO. Unless you do a lot of traveling with the mic, and/or outdoor gigs.

and probably some other usual suspects.

 

[nbiehl]

I'm in a pretty heavily gigging bluegrass band. That mic sees at least one outdoor gig pretty much every weekend, sometimes as many as 3.

 

[darrin_h2000]

I wouldnt use condensers outside...normally the AT mics are pretty good quality.

 

[nbiehl]

Happened again last night. I switched channels on the mixer and the mic worked perfectly right away.

This kind of points a finger at my old Soundcraft, doesn't it.

 

[dgatwood]

Happened again last night. I switched channels on the mixer and the mic worked perfectly right away.

This kind of points a finger at my old Soundcraft, doesn't it.

Definitely. I didn't notice before that multiple mics were doing this. Having multiple mics make weird rushing noises or having no headroom is pretty much a dead giveaway that the phantom power current is insufficient for the mics, and may be cutting out entirely.

Try an outboard phantom power supply and I suspect your problem will go away. Or if it is just one channel or one bank misbehaving, just always use dynamic mics on that bank or that channel.