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[Terry Martin]

I too read that, but I got the impression this caused noise in the "noise floor", as opposed to RF interference.   I discounted that it would apply to my situation.  If I'm wrong, please correct my understanding.   Thanks. 

I also had something in the back of my mind about G2 systems not playing nicely with some sources (Aviom personal mixers and some digital consoles), and found this PDF from Allen and Heath which seems to confirm a cable mod to reduce noise? I haven't ever experienced this but maybe it jogs the memory of someone else here who has seen this. support.allen-heath.com/Knowledgebase/Article/GetAttachment/416/12

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[Ike Zimbel]

We don't have dropouts once the band gets going.  Just RF interference between songs or low level content. 


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You might try contacting Sennheiser and see if they still have the firmware for the G2 system. I had some back-and-forth with a Sennheiser tech a couple of years ago about whether or not their systems can drift out-of-spec over time. The upshot of that was that yes, they can, but all of the adjustments are in FW, so the answer is to update or reload the existing firmware. This was in the closing weeks of a tour, so I did not get a chance to check this out and see if it yielded the desired results.
I just took a very quick look around the Sennheiser site and did not find anything for G2, which is why I suggest contacting them.
The only other thing I can suggest is that if you are consistently playing smaller stages, so you are essentially right on top of the transmitters, you might try the squelch on the "Hi" setting and see if things quiet down. Note that this might make things worse when you are away from the stage, like in the dressing room...reading 20 years worth of graffiti, whilst waiting to go on stage

[Luke Geis]

I have a couple of ideas / thoughts. I for one have been unlucky with antenna's and have gone through three in the past several years. I don't use them often and I am not an abuser, but they just seem to fail on me. I know that the antenna's are to blame because I can see the diversity drop on the bad one and the subsequent dropout follows. Replace it with a known good one and the problem is gone! If you can watch your antenna strength fall on the meter, it may simply be the offending sides antenna. Swap the antenna's and see if the problem follows it.

Next is Squelch. This is one thing that is often overlooked. The lowest setting you can have it at that does not get interference is the best. If the squelch is too high you can have too low of an outbound signal to the receiver and the squelch won't open up for it to get that signal. So play with the squelch settings. If you are not getting spikes of RF or have at least a low noise floor, then having a high squelch setting won't make things any better.

The next thing on my mind is termination. You mention using a combiner and I assume you're using it with a 50ohm cable? Be certain you are using a 50ohm cable that is within the specified length for your unit. This length is usually no longer than 50'. You may really need a directional antenna? Omni is nice, but it will have less range than a directional one. Also antenna spacing and ground plane is important. A 1/4 wave antenna is essentially an omni antenna and requires a ground plane to work. It MUST have a metal surface at least the size of the antenna next to it. A whip on the rack ears is acceptable. You cannot use whip style antenna's on a stand connected by a long BNC without a ground plane ( large piece of metal ) connected to it. A 1/2 wave antenna ( more likely to be your omni paddles ) do not require a ground plane, but still don't offer any advantage other than being able to be remotely located. They need to be at least 16" apart and ideally one placed in each of the 1/3rds of your performance area.  Also LOS ( Line Of Sight ) is important. The antenna's must be above head height and ideally the body packs also should be exposed to the antenna's LOS.

As to diversity, you don't have that it seems with the G2 version of RF, so you rely heavily on brute force. Be sure you have good LOS, a clean noise free RF signal chosen and be sure to employ an intermodulation calculator. If your antenna's are not impaired and work 100%, you have the correct ohm and length of cable, the antenna's are placed optimally and you have good RF assignments, you should not have any problems.

[Henry Cohen]

We don't have dropouts once the band gets going.  Just RF interference between songs or low level content.

This seems the primary symptom. So a few thoughts . . .

1) Let's define terms.
"Dropout" means a loss of RF signal at the receiver. This can be caused by by any number of factors: insufficient transmitter RF power output; lossy coax; bad antenna; incorrect choice of antenna type; incorrect deployment of antenna; obstructions, etc.
"Interference" means other co-channel RF energy from a different source (another transmitter; intermodulation product; broadband noise from power supplies, digital devices, motors, video walls, etc.) reaching the receiver antenna, along with your transmitter's intended signal, with sufficient energy level to interfere with proper receiver demodulation/decoding.

2) Let's parse the description.
"We don't have dropouts once the band gets going." Does this mean you do have dropouts "between songs or low level content", OR, do you have interference "between songs or low level content"? Pedantics aside, the difference can be telling.

3) So this leads to the obvious question: What could possibly be different between the band actually performing a number, and the interlude between numbers? The things that come to mind are:
- Audio levels at all stages of signal flow, but especially that in the mixing console's bus that feeds the IEM mix(es), and of course the audio signal level feeding the transmitter;
- Movement of the performers, that may place them out of sufficient RF signal range;
- Movement of set pieces;
- Movement of stage hands/techs;
- Changes in lighting and/or video wall cues/content;
- Anything else, no matter how inconsequential it may seem?

4) Is it at all possible, the problem is always there (the dropout or interference, whichever it actually is) during the actual number, but it's masked by the higher acoustical noise levels that comes from actual playing and singing?

I'm going to take a stab in the dark and speculate it's a combination of factors, with the primary one being a less than optimum RF deployment, as others have stated. A proper transmitter combiner, low loss coax (sized accordingly to the length you need), a directional antenna mounted above people's heads with an unobstructed line of sight to the performers, is the best place to start. Then, just as importantly, ensure you're operating in clear spectrum with coordinated frequencies - IEMs AND wireless mics (and wireless intercom if applicable). Once a known and proper RF deployment is in place, the most significant variable is [mostly] eliminated and you can move on to other factors. 

[Luke Geis]

After reading the OP again and seeing only between songs, I am now in the firm belief it is squelch based.

Between songs the level will be low and the signal may not go above the squelch threshold. It may seem like a dropout, but it is simply the receiver negating the transmission.

What is your current squelch setting?

[John Sulek]

After reading the OP again and seeing only between songs, I am now in the firm belief it is squelch based.

Between songs the level will be low and the signal may not go above the squelch threshold. It may seem like a dropout, but it is simply the receiver negating the transmission.

What is your current squelch setting?

Earlier in the thread the OP stated that the squelch is in the "mid" setting which I believe is the factory default (been a while since I used a G2 system).
Also the pilot tone is on, so the packs won't be opening up the audio path unless they see the pilot tone from the tx. So the question would be...do the packs lose the pilot tone when the noise/interference/dropout happens.
At the distances I think we are looking at from tx to rx....squelch is not the determining factor IMHO.
If you have to up the squelch setting at 30 feet or so from the antenna...than you are either in a very noisy rf environment or you are using the squelch to overcome something else that is wrong.

[Luke Geis]

The audio signal still has to be higher than the squelch threshold to open it up.

per the G2 instruction manual:

The receiver is equipped with a squelch that can be adjusted via the “SQELCH”
menu. The squelch eliminates annoying noise when the transmitter is
switched off. It also suppresses sudden noise when there is no longer
sufficient transmitter power received by the receiver.

-------There are three possible squelch settings:
 LO = low
 MID = middle
 HI = high
Selecting the setting “LO” reduces the squelch threshold, selecting the
setting “HI” increases the squelch threshold. Adjust the squelch threshold –
with the transmitter switched off – to the lowest possible setting that
suppresses hissing noise.

64
IMPORTANT! Notes:
- If the squelch threshold is adjusted too high, the transmission range will
be reduced. Therefore, always adjust the squelch threshold to the
lowest possible setting.
- When in the setting mode of the “SQELCH” menu, pressing the
button for more than three seconds will switch the squelch off.
“SQ.OFF” appears on the display. If no RF signal is being received, hissing
noise will occur. This setting is for test purposes only. 


The pilot tone option can be turned on or off as well. This is from the G2 manual:

Via the “Pilot” menu, you can activate or deactivate the pilot tone evaluation
of the receiver. The pilot tone is used
- to code the transmitter’s stereo signal,
- to support the squelch function (Squelch).
During stereo operation, the transmitter adds the pilot tone to the
transmitted stereo signal and the receiver detects and evaluates the pilot
tone. When the transmitter is set to mono operation, deactivate the pilot
tone evaluation on the receiver.
You can combine units of first and second generation ew 300 IEM systems
without any problems.

Now the next question is if the pilot tone is on for both the transmitters and the receivers? You can turn it off or on for each one.

Also from teh G2 manual:

- To avoid overmodulating the receiver, observe a minimum distance of 5 m
between transmitting and receiving antennas.


I have also found that if you have an antenna that is failing, it will not show equal RF diversity in the RF display even if at close distances. When my antennas would fail, they would change in RF power a lot and would drop out when the circumstances were presented. The receiver requires both A & B RF transmissions to work correctly. If one side drops out you loose diversity and there will be a dropout. Keep trying things. Here is a link to the G2 IEM manual:

http://www.synergyaudio.co.uk/sites/default/files/techdocs/Sennheiser%20-%20G2%20IEM300.pdf

[Mac Kerr]

The audio signal still has to be higher than the squelch threshold to open it up.

per the G2 instruction manual:

The receiver is equipped with a squelch that can be adjusted via the “SQELCH”
menu. The squelch eliminates annoying noise when the transmitter is
switched off. It also suppresses sudden noise when there is no longer
sufficient transmitter power received by the receiver.

The RF signal of the carrier needs to be above the squelch level, not the audio signal.

Mac

[John Sulek]

I have also found that if you have an antenna that is failing, it will not show equal RF diversity in the RF display even if at close distances. When my antennas would fail, they would change in RF power a lot and would drop out when the circumstances were presented. The receiver requires both A & B RF transmissions to work correctly. If one side drops out you loose diversity and there will be a dropout.

This is confusing to me.
- I didn't think the G2 receivers used the headphone cable as an antenna so how do you get diversity with only the one antenna on the receiving pack
- the A and B rf transmission? I stand by to be corrected by folks smarter than I am, but there is only one rf transmission that is picked up by two ("A "and "B") receiving antennae (or receivers) in a diversity system.

[Terry Martin]

Hi Henry.  I will try to respond to your questions/comments.....

1)  I'm not sure what we are experiencing per your definitions.  We can hear the swooshes/lasers, and when we do, I see the RF meter reduce a bar or two on the receivers.  I call this RF interference, but I could likely be wrong. 

2)  We observe the swooshes/laser sounds in between songs (and this occurs randomly) or prior to performance (no high level audio input).  I'm not sure if that is interference or a dropout.  We do not hear a lapse in audio when we are playing.  I referred to a dropout as a loss of signal.  We do not get loss of signal.

3)  I'm pretty sure that our gain staging is ok.  I have the signal from console to transmitter where is just doesn't engage the peak warning (red screen).  We don't have a dedicated monitor engineer, therefore if I see a red screen, I turn the bus down for that particular mix.  I've only had to do that recently when we acquired the X32 Rack.  Prior to that, my analog board was quite dialed in.  This is not the scientific way of doing this, but it has worked in my situation.  I'm open to suggestions.

- Movement of the performers - prior to acquiring the X32 Rack, we almost always used the 1/4 wave (stock) Sennheiser antenna for all 4 IEM transmitters.  We always had adequate coverage - never a swoosh or laser sound in the IEMs.
- Movement of set pieces - nothing changed.
- Movement of stage hands/techs - stage hands and techs are band members (LOL).
- Changes in lighting and/or video wall cues/content - we did add some new LEDs to the lighting rig at the same time as the X32 Rack, but I have unplugged those to isolate, and the LEDs do not appear to be causing this condition.
- Anything else, no matter how inconsequential it may seem - a rotating influx of new guitars by guitar player and bass player, but that has been typical.  Prior to X32 Rack, we did not have this condition (regardless of what guitar the knuckleheads brought in).  They both run direct (no amp) on stage.

4)  It is possible that it has always been there.  I questioned the X32 Rack for weeks - maybe it is just so clean (vs the Mix Wiz) that we can now hear the interference??  The rack that houses the gear is different now.  With the Mix Wiz, I had a larger slant rack with mixer, guitar wireless, wireless mic, 4 separate IEM units, a power supply, and a splitter - all in 1 rack.  The IEM system was dead quite - but we were also running mono.  With the X32 Rack, we went stereo - part of the reason for the new mixer.

In the other thread, I did get some feedback about frequency coordination, and I took that persons advice.  Changed all of the wireless gear to the recommended frequencies.  It may have helped slightly as the noise was still there, but it wasn't as loud and obnoxious in the IEMs.  But it was still there. 

Obviously some gear was changed, the location of some gear has changed, and the format of receiving audio signal has changed.  But I'm starting to believe the real changepoint is going to stereo format.  I have now created a scene in the X32 Rack for mono mode, and changed all of the receivers back to focus/mono mode.  We go out again on March 11 (where I have confirmed IEM interference in the past), so I'm betting  that our interference will be gone.

I appreciate you pros taking the time to help a lounge lizard like me.  I haven't been a regular at PSW for years, but I used to be here daily in the old forum.  We've actually got a great show and are quite popular.  Everything was good (other than the heavy rack) with the old setup - I probably should have just left it alone.

Terry
https://www.facebook.com/BombshellRox

This seems the primary symptom. So a few thoughts . . .

1) Let's define terms.
"Dropout" means a loss of RF signal at the receiver. This can be caused by by any number of factors: insufficient transmitter RF power output; lossy coax; bad antenna; incorrect choice of antenna type; incorrect deployment of antenna; obstructions, etc.
"Interference" means other co-channel RF energy from a different source (another transmitter; intermodulation product; broadband noise from power supplies, digital devices, motors, video walls, etc.) reaching the receiver antenna, along with your transmitter's intended signal, with sufficient energy level to interfere with proper receiver demodulation/decoding.

2) Let's parse the description.
"We don't have dropouts once the band gets going." Does this mean you do have dropouts "between songs or low level content", OR, do you have interference "between songs or low level content"? Pedantics aside, the difference can be telling.

3) So this leads to the obvious question: What could possibly be different between the band actually performing a number, and the interlude between numbers? The things that come to mind are:
- Audio levels at all stages of signal flow, but especially that in the mixing console's bus that feeds the IEM mix(es), and of course the audio signal level feeding the transmitter;
- Movement of the performers, that may place them out of sufficient RF signal range;
- Movement of set pieces;
- Movement of stage hands/techs;
- Changes in lighting and/or video wall cues/content;
- Anything else, no matter how inconsequential it may seem?

4) Is it at all possible, the problem is always there (the dropout or interference, whichever it actually is) during the actual number, but it's masked by the higher acoustical noise levels that comes from actual playing and singing?

I'm going to take a stab in the dark and speculate it's a combination of factors, with the primary one being a less than optimum RF deployment, as others have stated. A proper transmitter combiner, low loss coax (sized accordingly to the length you need), a directional antenna mounted above people's heads with an unobstructed line of sight to the performers, is the best place to start. Then, just as importantly, ensure you're operating in clear spectrum with coordinated frequencies - IEMs AND wireless mics (and wireless intercom if applicable). Once a known and proper RF deployment is in place, the most significant variable is [mostly] eliminated and you can move on to other factors.

[ProSoundWeb Community]