Huh? Audio Peaking on Shure wireless..


Hi Folks-

Ive been using a Shure T1 trasnmitter and Vp3-CA receiver for about 4 years now. I've had no problems at all, now suddenly the audio peaks and I can't control it!

I've had my Sony TRV900 set on 16Bit, manual with the mic level at about 50%.. now even when I turn it down to 10 or 25% it still peaks and I lose a split second of audio (when it peaked).

Should I be turning down the squelch or the gain? I've never messed with either. I'm not really doing anything new.. maybe a bit more background noise but that is about it.

Puzzled BIG time,
I am not familiar with the recording unit that you are using but perhaps someone else out there will be able to help.

As for the radio mic system - It will not do any harm to adjust the gain and squelch. If you are concerned, use a chinograph pencil or some chalk to mark their current settings so you can always put them back.

Adjust the gain setting until the peak LED comes on intermittently.

The squelch on these things are usually pre set but essentially, reducing the squelch will increase the sensitivity of the mic and increasing it will reduce the sensitivity (basic explanation).

The user manual should provide you with a better explanation and even some troubleshooting tips. Most of the Shure receives have indicator LED's that will help determine the best set up.

If you do not have a manual you should be able to get one from and I think they also have a knowledge base there as well.

Hope this helps.
If the gain controls have no effect on the peaking, it could be because the capsule is dead or dying on the mic. Something could be bent or cracked on the diaphram of the mic, causing it to crackle. OR, it could be a cable short from the mic to the transmitter.

Oh, and don't forget to make sure you check the headphone output of the reciever unit. If it also peaks there, i think its the mic.
Squelch is not for adjusting mic sensitivity. That's what the gain is for. Adjust the gain down until there is 0 peaking. Zero. Not even a flash every once and a while... I mean none. That is bad and could cause more damage.

The squelch is a radio frequency term. It sets the level of ambient radio noise (not audio noise) that will be muted automatically. When you set it low, the reciever will try to demodulate random radio signals it picks up that are not coming from your mic. If you set it too high, the reciever will occasionally mute the mic when it's radio signal gets too low. Set properly, you will only hear what the mic is sending, no extra radio signals, no audio dropouts.

When we talk about adjusting the gain, just to be sure, we are talking about the gain adjustment on the mic pack, not on the reciever. The reciever usually has it's own volume output control which should always be fully up, and of course the squelch control.
The following is taken from the Shure manual for the VP series:

"Rotating the SQUELCH control toward MIN (counterclockwise) makes the receiver more sensitive and increases the system’s range. However, it also allows the signal to become noisier before it is muted. Rotating the SQUELCH control toward MAX (clockwise) reduces the system’s range, but prevents interfering signals and noise from overriding the squelch when the transmitter signal is not present."

anticowboyism was on the right track when stating that Squelch "sets the level of ambient radio noise (not audio noise) that will be muted automatically."

Gain actually increases the volume of the receiver and you want it to be set so that the 'clip' light comes on occasionally. Whilst you do not want this to come on continuously, you do want to see it flicker, so that you know you have a strong signal. Attempting to ampligy a weak signal will only result in added noise.
A good way to look at it but in reality, unless it is on for more than a second or so then you will not be in trouble. Most equipment that I have worked on tend to have the clip light set a little on the sensetives side. I have hooked up quite a few mixers etc to oscilliscopes and found nice clean sin waves even when the clip light is on. HOWEVER - regardless of this, you should always assume that the clip light is an indication of DC voltage in the signal and ensure that it doesn't come on for continious periods.

Also, don't forget to use your ears. Clip lights blow and some units don't have them so always use both your ears and your eyes.

Hope this helps

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