863-865mhz TX-RX Mix and Match ?

[Steve Magee]

Does anyone know if you can mix and match Brands in this allocation ? . For example can you use a Sony belt pack TX with a Sennheiser or Audio Technica on camera RX providing they are both on the same frequencies or are there differences in modulation/bandwidth on different devices ?. I wasn't sure if they all had to confirm to the same set of specs.

Thanks

Steve

[Brian P. Reynolds]

Sometimes it works some time it doesn't, depends on lots of things like coded squelch, pre-emphasis etc.
so perhaps / maybe but don't rely on it.

[Richard Crowley]

You probably have well less than a 50% chance that everything will work as designed. There are several critical factors beyond the operational frequency/channel that are necessary for a transmitter/receiver pair to work properly. If it works at all, it may not be up to the quality of either of the original systems, and more likely than not, it won't work in a usable manner. It really doesn't matter what frequency/band you are asking about.

[Warren Kawamoto]

Audio Technica and Sony? Definitely won't work together. Each has a different way of companding, even if they're on the same frequency.

[Rick Reineke]

If both the transmitter and receiver are set to the exact same frequency it should 'work'. Usually any tone squelch and companders (NR) will have to be disengaged, which will add noise, may be OK for coms but not recording.
For instance, when a few more IFB monitors are needed, many folks will use some lower cost ListenTech Rx.s fed by the Comtec Tx. There will be pumping, breathing and/or noise, but it's usually ok for a friend of the friend of the director or other courtesy listen.

[Paul R Johnson]

I don't know of any systems where the companders can be switched off. I actually do mix and match quite often. I have a rack of Trantec receivers (S4000) and they work rather well with Sennheiser hand helds - the companding works for me, and the end effect is very similar to having a little gentle compression added at the mixer. The reverse is NOT any use at all. Using the Trantec transmitters with the Sennheiser rack receivers makes the audio response very peaky - and in my live work, it makes the system prone to feedback.

Realistically there are also subtle deviation artefacts, but the companding issue is the most critical I have found. To decide, you would have to try them out.

[Rick Reineke]

Yes, it's not possible on the Sennheiser Evolution series to disable the commander circuit, the tone squelch can be defeated though. On the Comtec Tx and the Listentech Rx, the commander can be disabled..though on the LT, the (hardware) switch is well hidden in/under the battery compartment and very tiny and not accessible w/o a jewelers screwdriver of similar. I'm not sure about the Sennheiser IEM receiver, but lots of folks use them for IFB w/ a G2/3 Tx and compander is different

[Paul R Johnson]

Got plenty of Sennheiser IEMs and never noticed any real issues using them as receivers - in fact, if you don't need stereo, they too work pretty well. Which shouldn't work, should it - as Trantec transmitters don't work that well on Sennheiser recievers - but the IEMs could well have different companding because I regularly use a Trantec IEM TX to send audio in mind to a mix of Trantec and Sennheiser receivers. Not sure why this version works - perhaps just because the compander slope difference is hidden in the in-ears - expanding dynamic range a bit?

[Dave Fisk]

You can actually do this with Lectro wireless. I know you can pair the Digital Hybrid stuff with Sennheiser, some Shure, Audio Limited, and maybe some others. There's no official printed list on this. However, I don't know if they have anything up in that frequency range, though. That's up there pretty high. Their L series doesn't even go about 700.

[Paul R Johnson]

The old UK Tv channel 69 - strictly speaking illegal to use now because the Government sold it to the 4G people - but the entire process was a mess and in many parts of the UK, channel 69 is pretty empty. Legally, channel 70 can be covered by most of the available equipment, but you can only get 5 G3 or 4 of pretty well everything else in it. It was always a licensed band, but every manufacturer who sold equipment for that band here 'forgot' to tell the buyers they needed a license, so the Government figured it only held a small number of users, and had no way of knowing about the real user base. Every wedding organiser, small DJ and small bands were using it happily, and many still are - totally unaware of the problems.