Sennheiser Spectera Wireless squelching others (?)

[jTrolt]

Just played an opener last night. VERY large production for headliner after us, running a Sennheiser Spectera system. They had an insane pile of stage gear and props, so they consumed the stage all day, with their gear shut down/idling/covered with black tarps, etc.
While I've been in this situation before, I do not recall having the same problem.

Issue: Our in-ears, of varying brands, experienced interference that was bad enough that we had to pull our IEM's and ask for a (gasp!) live wedge to finish the show.
The interference was completely insufferable, and the Spectera antenna was closest to me. I played a bit with stage position to the point that I concluded that system was certainly contributing to the problem. No, changing frequencies did not help any of us. 15 minute festival setup situation, so almost no time to test, other than flip them on to verify they're functioning. Seemed like they'd be okay with an occasional crackle, but once you started playing, it was pretty much hearing damage levels of pulsing, crackling distorted interference. No question, the closer I got to that antenna, it was completely absurd.

Qualifier: It was downtown Sturgis, peak rally time = the air is completely saturated with RF. However, the previous night, just a block down the road, was a "normal" amount of IEM noise. No Spectera systems in sight on that one.

So- any tech gurus that can testify?
Was it an over-saturated atmosphere, or can that Spectera system wreak havoc on other systems?

Would like to know for certain before I ask someone in the future to shut it down, relocate antenna (fat chance, right?) or ask engineer for live wedges before we play.
Don't want to suffer that noise again.

 

[Mike Caldwell]

The Spectra system is fairly new and $$$$$$ the base station unit is about $10,000 without mics or body packs! It uses one RF carrier channel to carry multiple digital data streams complete with two way communication between the base station and microphones. Actually it uses two channels. one for each direction.
What frequency were you operating on, chances are the Spectra frequency was on top of yours and you were hearing the digital carriers.

 

[jTrolt]

Yeah, I though of the "can't beat 'em then join 'em" approach, until I saw the $30k price tag for a complete system.

I have an older "DB" brand I'm using that initiates at 801.000 and is generally where I leave it.
(I should update, but hey, I have basses to buy, right?)
I tried a few options, being cramped for time on a quick break. Thought I'd cleared it when I dialed up to 805.900 and achieved clarity. Then we started. No good.

Looks like specs show the Spectera running in 1350–1400MHz and 1435–1525MHz. range, so interesting that we clashed.

Again, I'm questioning my own judgement here- maybe it was not 100% related to that system, but an absolute mosh of RF in the area. Still, I can't get past the fact that I could walk right up to that antenna and completely demolish my signal, so there seems to be something to it.

We headline that same venue Friday night in the slot that band had, so it will be our stage this time, and interesting to see how it goes in the absence of that system.
I will update accordingly.

Meanwhile, at least this can serve as a heads up to others to be aware of similar scenarios and have a plan "B" on deck. Sucks being in front of one of the top crowds of the summer with the worst stage sound you could ask for. Festival gigs - not for the faint of heart!
Thankfully, we pulled through and had great response with a super-fun crowd.
One more reason I never run completely amp-less, even with IEM's.
Anything can happen.

 

[s0c9]

I'm no expert, but I would hazard a guess that the interference on 801.000 MHz is from a local TV base station transmission (NOT from the Senn Spectra system) as the 800 MHz band is no longer part of the FCC's "license free" ranges and you (may) be violating Federal Law in using it.

 

[jTrolt]

I'm no expert, but I would hazard a guess that the interference on 801.000 MHz is from a local TV base station transmission (NOT from the Senn Spectra system) as the 800 MHz band is no longer part of the FCC's "license free" ranges and you (may) be violating Federal Law in using it.

I suspect you are correct! Hard to complain when I'm in violation, LOL!

I'll have to pick up an updated system sooner than later. Sadly, others on stage do have updated gear, tried resetting with other frequencies = not fixed.

 

[s0c9]

I suspect you are correct! Hard to complain when I'm in violation, LOL!

I'll have to pick up an updated system sooner than later. Sadly, others on stage do have updated gear, tried resetting with other frequencies = not fixed.

If your other band mates have Shure/Senn systems, the newer ones have scanners (my G3 did and so does my G4) that search for the best open band/channel to use. You may pick a channel and it may work at numerous venues, until you encounter that one location where you get the interference artifacts - noise, his, dropouts, etc. Your only choice is to make a note of the current channel (so you can go back to it), rescan, choose an open band/channel, sync w/ the base and off you go!
Other's units like legato and xvive do NOT have the scan capability, so you get to pick one of the available channels on the unit and hope it solves the problem.

 

[jTrolt]

^Yes^
They did scan/ locked in and still gave up. I'll definitely be grabbing a higher end unit, given our progress into bigger/better shows, and fortunately, respectable paychecks.
I appreciate all the info- all helps make a bit more sense of it all.

 

[Mike Caldwell]

Spectera channels are in the range of something like 450mhz to 600mhz from mic to base station and 1300mhz to 1500mhz from base station
to mic. I think their operating channel bandwidth is only 8mhz and they can put 60 wireless mics into it.
I'm guessing you were just getting crushed and saturated with the Spectera.

Yea your 800mhz is system no longer usable, but it sounded like it worked the day before, maybe something fired up and was broadcasting close to your
frequency in addition to the Spectera system.

Time to go wireless system shopping!

 

[SoundFella]

Sorry to be blunt, but this was entirely your fault. You're using an outdated system, on an illegal frequency, with no coordination. There should have been a festival RF coordinator to tell you what frequency to use. Short of that, you should at least do a proper scan among you and your band mates. Each of you having separate units and operating them independently is a recipe for disaster.

Spectera operates on a single 6mHz band, and would have been within the 470-608 or 657-663 region that's legal in the US. Sure, it's possible that stepping too close to a transmitting antenna, even if not at the same frequency, could overload the receive antenna on your pack.

It's not unreasonable to ask others to turn their transmitters off for your show, but there are a lot of other steps to take to ensure clean IEMS before you reach that point.