gkim Posted September 23, 2016 Report Share Posted September 23, 2016 Hi guys, I'm on a feature and have run across a strange problem. I'm using lectro smqv tx and dual srb receivers into a 633. -All receivers are set to +5 -All 633 channels receiving lavs are set to line -All receivers are using ta3 to ta3 connectors -All receivers are using the same cos-11 lavs -All tx have audio levels set to 23 (for testing purposes) The problem is that 2 tx, set at audio levels of 23 with normal dialog sound normal, and show up on the 633 meters around 0. Fine. The other 2 tx, also set to audio levels of 23, with normal dialog are super hot. They're clipping. I had to turn them down to 8. I've tried the following troubleshooting: -ensuring all cables are wired for line level -switching mics (they are all the same) -rebooting 633 It seems like a tx issue. They are all the same smqv, same lav mics but 2 are fine at 23, and the other 2 are hot as hell. Can't figure out what I'm missing. Any help would be mucho appreciated. Quote Link to comment Share on other sites More sharing options...
Olle Sjostrom Posted September 23, 2016 Report Share Posted September 23, 2016 Are the transmitters the same block? Could you try switching the rxs? Does the clipping occur in the TX itself or on the receiver or the mixer? If you were to attenuate those Txs, you're doing level 23 now so go down to 16, does that make the audio better? Quote Link to comment Share on other sites More sharing options...
gkim Posted September 23, 2016 Author Report Share Posted September 23, 2016 Thx for the reply! Clipping happens at tx. Actor was yelling across street in scene, turned down tx to 8, and i could still hear it. It was ok on the 633 meters (bouncing around 0). Concerns: 1. Dropping rx level below +5 isn't line anymore and degrades signal 2. Improper gain staging. Has this happened to you before? Quote Link to comment Share on other sites More sharing options...
Peter Mega Posted September 23, 2016 Report Share Posted September 23, 2016 Possibly mic wiring. Check your COS11 wiring. It could be the 2 hot ones are wired for non servo bias inputs. Does the problem move with those particular mic heads? ie if you use the 2 hot ones in the other transmitters, do they run hot on those as well? If you're not using the mic heads in older transmitters that are non servo, the best wiring is SERVO ONLY wiring scheme. See Lectro website for diagrams. Quote Link to comment Share on other sites More sharing options...
Mungo Posted September 23, 2016 Report Share Posted September 23, 2016 TRIM on channels 4 to 6? Easy to overlook. Quote Link to comment Share on other sites More sharing options...
BWilson Posted September 23, 2016 Report Share Posted September 23, 2016 As Peter said above.Also, are the hot mic's possibly going into inputs 4-6 on the 633? You may have the input gain wound up, which can be done in the ISO menu for each input. Quote Link to comment Share on other sites More sharing options...
gkim Posted September 23, 2016 Author Report Share Posted September 23, 2016 Crap- right. Forgot how to adjust trim on those. Quote Link to comment Share on other sites More sharing options...
Adam White Posted September 23, 2016 Report Share Posted September 23, 2016 Use the test tones on the SRs - make sure they're all matched. I set them to 0dbfs (or -1)with the limiters off. That's max modulation from the transmitter so there's no way you can clip at the mixer - shows you exactly how much headroom is at the transmitter. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Gordonmoore1 Posted September 23, 2016 Report Share Posted September 23, 2016 Check your audio meters on the receivers - are they indicating a big difference? From 23 to 8 is a 15dB difference - that would definitely show on the receiver meters. What are the LED indicators on the transmitters showing? - The hot ones (if the problem is in the transmitters) should show vastly different LED action - if the transmitter LEDS are behaving the same and the receiver modulation meters are acting similar, the problem lies down stream. Quote Link to comment Share on other sites More sharing options...
chrismedr Posted September 23, 2016 Report Share Posted September 23, 2016 9 hours ago, BWilson said: Also, are the hot mic's possibly going into inputs 4-6 on the 633? You may have the input gain wound up, which can be done in the ISO menu for each input. 8 hours ago, gkim said: Crap- right. Forgot how to adjust trim on those. Seems from the response of gkim that it was indeed the (internal) gain on the line level input of the 633 (easy to overlook because the dial only adjusts the post fade). chris Quote Link to comment Share on other sites More sharing options...
gkim Posted September 24, 2016 Author Report Share Posted September 24, 2016 Eeee gads...it was the trim on channels 4-6. Occam's razor. Well, thanks to you guys, i can teoubleshoot cos-11 wiring and check by sending tone to rx. This community is awesome Quote Link to comment Share on other sites More sharing options...
Adam White Posted September 24, 2016 Report Share Posted September 24, 2016 and check by sending tone to rx. This community is awesome Just to clarify - you can only send tone from rx to mixer, not tx to rx. It's helpful in getting those trims to match between 1-3 and 4-6. Glad you worked it out. Cheers Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
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