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Anthony T
Contributor

Mic problems with SX80

I'm hoping someone here can offer some assistance with a problem.

 

I've a client that we've done a new install with 4 Shure MX202W/C microphone connected directly to the SX80.

 

At first there was an actual problem with the codec that required RMA, but now with the replacement the mics just don't seem to work. They were installed by an AV company, and seem to be properly connected to the euroblock connectors, +/- and ground.  But the codec shows them as Inactive in the web interface. We get momentary individual Active status as they are plugged in or removed from the back. The terminal connections all seem solid. We've tried them in all 8 of the available connectors. We tried reversing +/- on one of the mics in case the wire colors were weird.

 

The SX80 is running CE9.4.1 code.  All the mic inputs are set to defaults:

Level: 58
Mode: On

Type: microphone

Dereverberation: Off

Echocontrol: On

Noise Reduction: On

Equalizer Mode: off

MuteOnInactiveVideo: off

VideoInputSource: 1

 

Does anyone have any ideas what could be wrong?  Cisco TAC doesn't seem to have any more ideas.

1 ACCEPTED SOLUTION

Accepted Solutions

Without the in-line pre-amp, there is no power to the microphone capsule, so you won't get any audio from them.  The condenser microphone capsules (and the active circuitry they contain) need to be powered to work.  The SX80 can be set to provide the phantom power, but there needs to be something (the pre-amp) present to correctly take this power and convert it to be suitable for that particular microphone.  While not specific to your exact microphone, there is some information here that explains it in a reasonable way: Preamp for condenser mic - do I have to use it?

Wayne
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View solution in original post

4 REPLIES 4
Wayne DeNardi
VIP Advisor

Might be a dumb question, but have you checked that the inline preamp is connected between the microphone and the SX80 to properly power the mic capsule?

Wayne
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Apparently not a dumb question.  Apparently the inline preamps were not used.

Would this prevent the codec from seeing any signal at all, and therefore seeing the line as Inactive?

You wouldn't just see a lower level of signal?

Without the in-line pre-amp, there is no power to the microphone capsule, so you won't get any audio from them.  The condenser microphone capsules (and the active circuitry they contain) need to be powered to work.  The SX80 can be set to provide the phantom power, but there needs to be something (the pre-amp) present to correctly take this power and convert it to be suitable for that particular microphone.  While not specific to your exact microphone, there is some information here that explains it in a reasonable way: Preamp for condenser mic - do I have to use it?

Wayne
--
Please remember to rate responses and to mark your question as answered if appropriate.

View solution in original post

Thanks Wayne.  That article explains it nicely.

I now have support from both Cisco and Shure stating the same thing, and now I have to get this rectified.

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