In another topic a while back we discussed using one brand of receiver with another brand of transmitter, with our usual style of fors and againsts. This week I came across it from another viewpoint. I was in the venue, a visiting company were setting up. The familiar one two, check was going on, but one sounded very bad. Cutting out and the very obvious sounds of intermod style inerference. It was clear the guy was really stuck - so I went to have a look. JTS receivers with two handheld JTS transmitters and two Sennheiser lav packs. No familiar frequencies in the rack. To cut a long story shorts, with just one JTS tx on, it came up on two channels - one the 'real' one and a half scale RF reading from one of the intermod products. Turned out they chose the frequencies at random from pre-programmed ones in the receivers. I shifted their system in the absence of a set of JTS ones) to the ones on my licence, that I know srok fine with Sennheisers (and Trantecs) as mentioned in the other post. Intermod interference went away, and the two lav packs functioned. They did, however, not sound good. Unlike the favourable report I gave on how a Senn tx sounds good on a Trantec receiver, Sennheisers sound muffled and very bassy on JTS receivers. They also react badly to peaks, such as the mic in the wrong place picking up a blast of air. No amount of low end filtering works, I suspect the deviation of the Sennheisers is much wider than the JTS receivers can cope with - it's that kind of 'thump'.

It's crazy people think frequencies are just like mobile phone numbers, as long as you have any number, dial it in and it works! He said they'd had problems with most venues and assumed one mic was faulty!

I don't get it.
Why would anyone not use a reciever/transmitter of the same make, model all of the time?
Surely this would remove all of the afore mentioned problems?

John Denim.

Well I guess the thing is maybe you have a rack of handhelds and receivers and also a couple (as in this example) of lavalier systems. You are only using 2 h/hs and 2 lavs, so why bother with setting up the extra proper receivers - we all know, but it seems obvious.

I've got a rack of Trantecs and a rack of Sennheisers - because I like the sound senns make on the 'wrong' receivers, the sennheiser rack is in the pit, covered in junk! If I need more than 8 channels, I'll dig it out. As I rarely need that many, it isn't worth doing it properly!

I've had similair results with a set of old Sennheiser SK2012's and em2003's. The thing that we hadn't realised was that the sennheiser transmitters were employing a "hidyn" compander, whilst the expander in the receiver was "hidynplus" - sounded rather strange. A quick swap of receiver to the proper one sorted the problem immediately.

Just shows that even with the same manufacturer, all is not always straightforward.

I did an experiment a few weeks back with my JTS receiver. I need to get a signal across a field for a project coming up in november (sounds cold and wet already!). I was attempting to use my In ear monitor transmitter and JTS receiver together to from a radio link.
Before I started I sort of guessed it wouldn't work but the kit was out anyway and it took 30 seconds to try. Needless to say it didn't!
Is the JTS pilot tone the same as the sennheiser one then? I couldn't get the mute to lift on my JTS receivers, despite full scale RF and audio being present from the IEM transmitter (db technologies). So I guess that's the pilot tone causing issues.
I don't think the pilot tone can be turned off on the JTS's and to be honest, for the expander/compander issues listed above, I don't think it would sound particularly good anyway!

Yes they are both 32.767 KHz ( measured) but the Sennheiser transmits at 2.5 KHz deviation and the JTS at 5 KHz devation with new batteries. I think that the level alters in discreet steps with the battery voltage in both cases. This means that a Sennheiser transmitter will not be received by the JTS receiver but it may work in reverse. The difference in companding is a separate issue. You cannot switch off the pilot tone detector on a JTS receiver but can on a Sennheiser.
Brian

Yeah I know, two very different things. I was more thnking that even if you could get the JTS receiver to pick up the db tech transmitter (by getting around the pilot tone issue) it still wouldn't sound all that great due to differences in compander/expander.

As fot the mention of the German Military site, you've gotta love low band VHF!
I'm not sure where the German military frequencies fall, compared with our radio mics, but you may have stood a better chance with D band radio mics.

High power RF is a strange one. The radar at my workplace is about 1 track mile from the theatre I do a lot of work at. Another soundie used to get tons of interference in 4 second intervals (one rotation) if the conditions were right. There again, it does have a couple of Megawatt's EIRP! Think it just swamps the AGC on the receiver which sticks its' hands up and goes "I give up!"