ProSoundWeb Community

Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Pro AV Forum => Topic started by: Johnny Owens on January 22, 2013, 03:43:21 pm

Title: Wireless Audio Transmitters
Post by: Johnny Owens on January 22, 2013, 03:43:21 pm
 when using, say a four pack of wireless, how close can the frequencies be without crosstalk?  I usually like to keep them separated as, 560.000 and 560.500.  Would frequencies that close have potential of crosstalk?
Title: Re: Wireless Audio Transmitters
Post by: Jordan Wolf on January 22, 2013, 04:42:25 pm
when using, say a four pack of wireless, how close can the frequencies be without crosstalk?  I usually like to keep them separated as, 560.000 and 560.500.  Would frequencies that close have potential of crosstalk?
Johnny,

My rule of thumb is at least 1MHz separation between transmitter frequencies.

However, there are other things to consider: what make & model of wireless device are you using?

I know that Shure and Sennheiser both have software programs that calculate the frequencies that can cause issues when using multiple transmitters, especially in close proximity to one another (called intermodulation, or IM products).  Most manufacturers also supply pre-programmed "groups" that you can use to keep these IM products from being an issue.
Title: Re: Wireless Audio Transmitters
Post by: Mac Kerr on January 22, 2013, 05:06:26 pm
when using, say a four pack of wireless, how close can the frequencies be without crosstalk?  I usually like to keep them separated as, 560.000 and 560.500.  Would frequencies that close have potential of crosstalk?

It depends on the model of wireless, but 400KHz is usually fine. what is more important is that they are the right frequencies. With more than 2 RF mics you have to be aware of intermodulation products. With just a few mics you can probably get by with the frequency groups that the manufacturer has recommended. With lots of mics they generally do not suffice, and IM software like PWS's IAS is needed.

Mac
Title: Re: Wireless Audio Transmitters
Post by: Kellen Tyburski on January 23, 2013, 11:43:13 am
It depends on the model of wireless, but 400KHz is usually fine. what is more important is that they are the right frequencies. With more than 2 RF mics you have to be aware of intermodulation products. With just a few mics you can probably get by with the frequency groups that the manufacturer has recommended. With lots of mics they generally do not suffice, and IM software like PWS's IAS is needed.

Mac

+1, especially if the transmitters are close to each other. If you are looking for something cheap/free Shure's WWB6b or earlier version is a good option.