Radio mic compatibility

[Johnno]

Do radio mic transmitters work with receivers from different manufacturers? If not will mics from different makers work simultaneously on the same channel without interference?

[paulears]

this one

and a few comments here

 

There is another one with some more info - but I can't find it.

 

Lot's of people disagree on this one. All I can say is what I've found.

 

The frequencies nowadays are quite simple to change on most, but not all brands, so that's not a problem. However, most manufacturers have slightly different bandwidths, and most have companding systems that are different too. These work by compressing the audio for transmission, and then expanding it again in the receiver. This helps signal to noise ratio.

 

I said somewhere in one of those other topics that I have a rack of Trantec receivers (4000s) and they work rather well with Sennheiser G1 and G2 transmitters. The companding systems interact in a way that seems to produce the sae kind of sound as if you'd inserted a compresser set to a very gentle ratio. This, to my ears sounds pretty good - and using the real Sennheiser receivers and pfling between Trantec and Senn, the difference is the Trantecs are more 'warm' while the proper receivers are a bit brighter.

 

The other way around - Trantec transmitters on Sennheiser receivers is not so good - this time the companding differences work against you. Feedback is a bit problematic and they just don't sound quite right without careful eq to tame them.

 

As John Wilkinson pointed out - I guess we shouldn't really recommend mix and match, but I'm quite happy to say that my own experience of Trantec RX and Sennheiser TX is safe to recommend. I've tried it, and they work well. For other combinations, you'd need to try them.

 

 

The last bit is straightforward. One mic can go to more than one receiver if you need to have multiple outputs - so you could have a receiver on the stage, and another front of house (if you want, but not normally much point!)

 

You cannot under any circumstances have two transmitters on the same channel. Each one needs it's own frequency.

[Simon Lewis]

In addition to companding, some units use pre/de-emphasis, where the high frequencies are boosted on transmission and attenuated at the receiver in order to achieve noise reduction. I'd guess that if used in the two systems Paul mentions, that it is handled differently!