Wireless Interferance

[mp3jrick]

I have a new Audio Technica Freedom 600 series wireless mic. It sometimes begins to make this distorted scratching noise. Even with the mixer pots closed down it comes through at what ever the main volume is set at. It doesn't stop util I unplug the xlr at the mixer. This is embarrasing and very hard on the speakers. I have tried different channels and locations to eliminate RFI and it has improved somewhat.
But, it still makes me paranoid that it will happen at the worst possible time at a gig sometime.
Any ideas on why this is happening?
Rick

[ June 01, 2003, 08:12 AM: Message edited by: mp3jrick ]

[Bill Cronheim]

Hi Rick,

A couple of questions might help in diagnosing the problem.

Where are you placing the receiver?
Are you using new Batterys at each gig?
What type of cable are you using from the receiver to the mixer?

[mp3jrick]

Bill,
First let me say that I am totaly digital. I hav e a hard drive and a external soundcard inside my gig box. I originally had it inside my gig box to make it neat and simplify set up. When the trouble started I tried different channels and moved the reciever to the outside of the box. This helped greatly, however every once in a while I get this odd noise as described which due to the rare frequency of it made me think that it was something else beside location.
I am using a 6' professional 1/4 mono to xlr mic cable. If there is something better please let me know. I'm not sure if the reciever will handle a balanced/shielded cable of not.
Thanks
Rick

Rick...

What frequency/frequencies do those mics operate on?
What type/length/brand of cables do you use? Where in relation to the receiver is the PC placed?
What type of PC is it?
Are 'certain' locations/areas of town being more of a problem than others?
Have you isolated the problem to be pure RF rather than audio?

[mp3jrick]

Matt,
It is a uhf unit. It should be somewhat immune to interferance. This is what I expect from a vhf unit.
My cable is a shielded 6'x1/4 to xlr pro quality cord.
The reciever is now stuck to the front of my gig box to facilitate wiring and the power supply.
I am using a KDS valiant 6000 laptop. 2g proc/xp/268ram.
No pattern or locations to referance to.
It is very ittermittant, which sucks bad.
Sounds like a dirty pot closing down when it happens.
I can have the system idle and this will happen.
Thanks
Rick

[ June 02, 2003, 09:20 PM: Message edited by: mp3jrick ]

[Bill Cronheim]

Rick,

Check to see if the XLR # 1 pin is bussed with the # 2 pin and the sleeve of the 1/4" connector.

Second, you didn't answer the question regarding using a brand new battery for every gig...do you?

If all else fails you can switch your Freeway system for the other frequency group (the Freeways are available in too groups.)

[mp3jrick]

Bill,
The xlr is wired as described, neg with shield to sleeve.
I have tried several batteries.
How do I switch the group frequency?
Rick

[KJDJ]

I love these problems! Noise from digital equipment is random and broadbanded changing Freq. groups prob. won't fix it.

Rick,
Does your recv. have an adjustable squelch? maybe crank it up to kill the noise when the trans. is turned off or goes out of range.
To tell how it's getting in trough the antennas,mic cord,or power. Just disconnect the antennas or colapse themm and see if it stops or less a problem. If it helps you have to move the recv. some where else.
If that didn't help see below.

See if your mixer has balanced mic inputs. if it does wire the 1/4" mono plug end with a TRS (stereo) plug to get the benefit of a true balanced mic connection.

OR, Your recv. should be able to output line level if so use an 1/4" to RCA and RCA Y adaptors to jack it into a stereo line input on your mixer.

OR,OR Get 2 snap-on ferrite filter chokes from Radio Shack. Snap one on the mic cable close to the mixer. Snap the other on the recv. powerline close to the recv. The latter works best if the recv. has a wallwart type power cube.

I have had the prob before with a Senhiser wireless. I had to remote mount the antennas to the top of my slant rack as far away from the computer and CD players as I could.

"Can we Fix it" "Yes We Can" ( Bob the Builder)

[mp3jrick]

Kevin,
I think you are on the right track, thanks for replying.
It did improve when I moved the reciever out of the box. It did improve when I dropped the antennas.
I did notice a squelch adj but haven't screwed with that yet. It is so dam ittermittant that nailing down the fix is difficult. It happens with the mic off also. When It does occurr I just unplug the xlr at the mixer (as fast as I can). I am not sure if the reciever output is stereo or not. Certainly could be wired that way if so, the wire is shielded and closed.
One step at a time I guess, I will let you know what I find.
Rick

[Bill Cronheim]

Hi Rick,

The Audio Technica Freeway UHF series is available in two frequency ranges, each with ten selectable channels. I believe I shipped you the A group (you'll notice either an A or a B on the rear of the receiver.)

Changing groups requires a completely new system. If you think this would help or want to try it, give me a call and I'll arrange a replacement.