Last night I had a strange issue with our UHF-R mics, and this was the second time the issue has happened.
Yesterday, we did an all-day conference so our 10 UR4D’s were powered on at about 6am, and then they ran all day. Everything worked great as usual through the conference which ended at 4:30pm. We took a half hour break and then started soundchecking for another event. When we started soundchecking all of our RF mics were distorting. Every mic: both handheld and beltpack units.We had a similar incident a couple weeks ago on a Sunday. The mics were fine in the morning, but then in the afternoon they were distorting.
The transmitters all appeared to have plenty of headroom in Wireless Workbench in both instances.
Last night, we worked around the issue with one of the microphones by patching the headphone jack on a receiver into a DI and into our splitter to our consoles. So it seems like the distortion has only been happening on the XLR outputs.
I find it hard to believe that we would have 10 UR4D receivers all go bad at one time. So I’m trying to troubleshoot this and my question is, do you guys have any ideas on what could possibly be inducing distortion on the XLR outputs of our receivers? Crazy one-in-a-million ideas are welcome here.
After multiple emails and phone calls, the source of the problem was found, and it was not the Shure products. The customer supplied this information:
Last weekend I was finally able to isolate the problem to our new broadcast console, a Digico SD-10 that we installed a few months ago. Basically, when the stage racks for the console are powered down, the distortion happens. Since we don’t use the broadcast desk for every event, and the broadcast guys have been inconsistent in when they power things down, we’ve had a hard time connecting this to the issue.
We’re still not sure why the issue is happening, though. At this point, the best theory is there is some kind of impedance change on the Digico’s stage racks when they power down, and this change is causing the transformers in our 3-way split to oversaturate when connecting a line level device. But last night I was finally confident enough to use our UHF-R stuff again, and it performed great just as it has for all the years we’ve owned it.
Thank you, guys, for all your time and patience in helping us chase this issue. The support we receive from you guys is a big reason why I continue to invest in Shure equipment.
NOTE: Shure recommended that UHF-R audio be monintored at the headphone jack on the receiver. The audio was satisfactory heard via headphones. Therefore, the root problem had to be downstream of the UHF-R equipment.