cstauffer Posted August 9, 2014 Report Share Posted August 9, 2014 I am hoping Larry from Lectro will see this. I have both UH400 and HM400 plug on Transmitters. I like the added gain the HM gives me for my Neumann 81 when I need it. Low talkers...anyway, I just started using it regularly for my boom op over the older black UH400. We have found that it is very susceptible to interference in and around pretty much any camera when the boom has to come over top of it or near it. When we go back to the older UH400 the problem goes away. Have others experienced this? Is there a fix that was incorporated into new production runs of this as I beleive I have an older HM400 from when they first came out. Took me awhile to put it on the boom, I know. My boom op likes the simplicity of the knob over the pushing of the buttons on the HM. He also has to put his reading glasses on to see those numbers, so... CRAIG Quote Link to comment Share on other sites More sharing options...
studiomprd Posted August 9, 2014 Report Share Posted August 9, 2014 Craig: " I am hoping Larry from Lectro will see this." he may, and he has his own email, and Lectro will be open on Monday... Quote Link to comment Share on other sites More sharing options...
Jason A Posted August 10, 2014 Report Share Posted August 10, 2014 In my limited experience with the HM i had some odd interference issues. It was during the NFC West championship game, so pretty heavy rf minefield. I tested out my approved frequencies in different areas inside the stadium with no problem, but as soon as i hit the field i got this weird high end wine type interference. It wasn't like usual rf hits, and it sounded the same on all frequencies so I think it was something responding on the body of the tx itself. I mentioned this to the guy i rented it from and he said he had noticed it himself on few rare occasions. Quote Link to comment Share on other sites More sharing options...
soundpod Posted August 10, 2014 Report Share Posted August 10, 2014 8060noise.mov Does the sound, sound anything like this? I was getting this occasionally with my HM, but not on my UH. I could never replicate it at home, only on set. I found that once I disconnected the ground from the XLR shell in the header lead (Rycote header leads from conn box are wired with shield to shell) I have no longer heard the noise. I guessed that as the HM uses the case as the antenna having the XLR shell connected to ground messed with the antenna of the HM allowing interference from something on set. I'd be interested to hear anyone else with this noise has ground to XLR chassis and if disconnecting fixes the problem. Hope this is of some help. Quote Link to comment Share on other sites More sharing options...
studiomprd Posted August 10, 2014 Report Share Posted August 10, 2014 Nick: " disconnected the ground from the XLR shell " this is an old issue that never gets settled, but I personally do not connect the XLR shells. --and, yes, I do disconnect them when I find them connected! Quote Link to comment Share on other sites More sharing options...
Marc Wielage Posted August 10, 2014 Report Share Posted August 10, 2014 Craig, which block? My understanding is that there have been discussions here about shielding and interference on the Neumann 81's before. I've had zero problems with interference on HM's in Block 19 with Sennheiser MKH40's, MKH50's, and MKH60's. Quote Link to comment Share on other sites More sharing options...
Jason A Posted August 10, 2014 Report Share Posted August 10, 2014 YES! But it was louder in my situation. Again, I was on the field of an NFL game, so likely quite a bit more rf going on. Does the sound, sound anything like this? I was getting this occasionally with my HM, but not on my UH. I could never replicate it at home, only on set. I found that once I disconnected the ground from the XLR shell in the header lead (Rycote header leads from conn box are wired with shield to shell) I have no longer heard the noise. I guessed that as the HM uses the case as the antenna having the XLR shell connected to ground messed with the antenna of the HM allowing interference from something on set. I'd be interested to hear anyone else with this noise has ground to XLR chassis and if disconnecting fixes the problem. Hope this is of some help. Quote Link to comment Share on other sites More sharing options...
cstauffer Posted August 10, 2014 Author Report Share Posted August 10, 2014 Hey Marc, Block 25 is what I am using. Also, I had issues with my 81 before with the UH and the fix, ironically enough, was to attach the XLR shell to ground. I was having problems next to certain lights on set having to do with dimmers attached inline from wall plugs. Attaching the XLR shell made it go away. So maybe, with the HM, severing it will fix all the previous problems with UH, and this new one. Guess I have some experimenting to do... Jason and soundpod...not the sound I was getting. Mine would only kick in around the camera. Probably all the follow focus, and/or the Teradek Bolt, etc... I am seeing the Teradek stuff showing up more and more. Thanks everyone... CRAIG Quote Link to comment Share on other sites More sharing options...
Marc Wielage Posted August 11, 2014 Report Share Posted August 11, 2014 There is a bit of voodoo with grounding and RF interference, and it's not always predictable. The Neumann is a great mic, but this is may be one of those cases where sometimes it might be preferable to get the mic that's most reliable rather than one that has X% better sound quality. On the other hand: I never encountered any interference with the newer Schoeps CMC641's, except for one occasion where we were getting about 2' away from florescent lights. My boom op came at it at a different angle and the problem went away. Crap happens. Quote Link to comment Share on other sites More sharing options...
LarryF Posted August 11, 2014 Report Share Posted August 11, 2014 We are starting to take a look at this but need to get the specific mics and transmitting equipment together for 2.5 and 5 GHz tests. We will have some questions later in the week. Best Regards, Larry Fisher Lectrosonics Quote Link to comment Share on other sites More sharing options...
Wandering Ear Posted August 11, 2014 Report Share Posted August 11, 2014 I have had this issue with my hm, it is prone to interference at times. Heard it with a couple different mics. On occasion I pick up noise in the hm from the zax wireless, and also from cell phones. Quote Link to comment Share on other sites More sharing options...
johngooch Posted August 12, 2014 Report Share Posted August 12, 2014 I have witnessed this problem. In my case It happens with my HM tx gets close to the preston remote focus/zoom/iris systems. The UH tx, no problem. My understanding is that the display screen on the HM is an opening for RF. But it really seems like prestons are putting out alot of RF. When i sent the particular specs of the preston system to Dean at lectro, the response was that it was not realistic for the HM to compete with that powerful of a transmission. The HM is just part of the problem. If the focus puller with his preston got in between my cart and my TXs( body mics and boom), i was for sure going to have a rough time with RF. One of us had to move. I'd still like find a fix- not sure if one is avail. Quote Link to comment Share on other sites More sharing options...
RPSharman Posted August 12, 2014 Report Share Posted August 12, 2014 More often than not, the DP sits at the monitor with remote iris too. So we have remote focus and remote iris happening. Quote Link to comment Share on other sites More sharing options...
bralleput Posted August 13, 2014 Report Share Posted August 13, 2014 Larry,a few years ago at the IBC I gave Gordon a DVD with soundfiles with a test I did with an HM vs Scorpio remote focus (2.4 Ghz) that was causing a lot of "BZZZZ" when the boom got close to the camera.Maybe Gordon has the DVD somewhere overthere in NM?Interesting to hear.We also tested an UM 400 with a PSC 48v box:no problems with Scorpio.(Neumann KMR 81i was the mike)I'm having some hard hits nowadays on my smv/411 (block 24) that come out of the blue,with actors standing just 3 meters from the receiver with RF venue antenna (connected to PSC antenna distr.box) pointed at them..Could be Transvideo 5.8 video transmitter,2.4 C-motion remotefocus......Who knows David Carmiggelt Quote Link to comment Share on other sites More sharing options...
.png.279748a58a2b862b7aa5f3b84126e232.png)
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.