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Author Topic: Wireless lav audio problems  (Read 2126 times)

Tim McCulloch

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Re: Wireless lav audio problems
« Reply #20 on: February 05, 2021, 05:08:34 pm »

Like Keith asked with the transmitters off do you see any RF receive level on the receivers?
What frequency group are you using, It does appear that Sony uses any WIFI bands for that series of wireless.

A really wild idea..do they use lots of LED lighting in the library, some LED lights pump out a lot of RF noise.

Going with Russell's idea bring up the transmitter audio level till you just at the point of hitting the peak light.

For what it's worth from the wording on the wireless system info I think it's an analog system that uses digital companding.


I type slow you answered some of those questions while I was typing!!

I'm liking this...


Tim - I was AUTO SET-ting in group 1 from my receiver and for this test it was giving me 478.125. BAND on receiver set to TV14-17 but I have tried it on the other settings, 18-21 and 22-25. Have AUTO-SET many times and keep getting same result.

This sounds very much like broadband noise from LED systems.
« Last Edit: February 05, 2021, 05:11:05 pm by Tim McCulloch »
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Mike Caldwell

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Re: Wireless lav audio problems
« Reply #21 on: February 05, 2021, 07:30:17 pm »

I'm liking this...

This sounds very much like broadband noise from LED systems.

And an easy test is go into the library, turn out all the lights and record a test message.

Russell Ault

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Re: Wireless lav audio problems
« Reply #22 on: February 05, 2021, 07:33:07 pm »

{...}
Tested at problem location (school library) and discovered it is 100% related to specifically where I was. Listen to the file below - begins outside the library in a boomy hallway and sounds OK ... once I step into the library within seconds all the audio is sucked away and I am back to the same problem.

Test Outside to Inside Library
{...}

Sorry, one more question, when you were doing this test, where was the RX?

-Russ
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Matt Hill

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Re: Wireless lav audio problems
« Reply #23 on: February 07, 2021, 04:59:49 pm »

Sorry, one more question, when you were doing this test, where was the RX?

-Russ

All fluorescent lights in the library, no LEDs ... also most testing was done with RX and TX close to each other, I know they should be several feet apart at least, but on the actual shoot they were and no difference.
Brought the mics home this weekend to test and just simply beautiful audio, no need to touch anything, even with low level whispering I can hear the room tone beautifully, it doesn't come in and out, unlike this problem I'm having on campuses where it seems like the room tone and everything is just sucked away.
I definitely don't have the knowledge or experience of suggestions I'm getting, but I keep coming back to signal interference since this is so clearly related to the locations I am in. Not sure if there's a fix or workaround bc I've been through every setting on these things and compander change or endless re-syncing of autoset doesn't fix this. Right now my only solutions are boom or change location which is a problem since it appears to happen in some locations on every campus I visit :(
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Mike Caldwell

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Re: Wireless lav audio problems
« Reply #24 on: February 07, 2021, 05:49:35 pm »

Could you go with a hardwired lapel mic?

I don't want to beat the LED idea to death but there are LED fluorescent light tubes that look
like a fluorescent tube only brighter and are drop in replacements.

Russell Ault

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Re: Wireless lav audio problems
« Reply #25 on: February 07, 2021, 06:10:53 pm »

{...} Brought the mics home this weekend to test and just simply beautiful audio, no need to touch anything, even with low level whispering I can hear the room tone beautifully, it doesn't come in and out, unlike this problem I'm having on campuses where it seems like the room tone and everything is just sucked away.
I definitely don't have the knowledge or experience of suggestions I'm getting, but I keep coming back to signal interference since this is so clearly related to the locations I am in. {...}

Okay, that's my gain-staging troubleshooting checklist. Time to look for local interference! :D

I'm assuming you don't have an RF scanner, but would you mind sharing the rough locations of your home and shooting location, or even just a list of all the TV stations in the area? Are the two locations very distant from one another?

Digging into the manual, I'm a bit confused because 478.125 isn't listed in Group 01, only in Groups 00 and 15 (and, of course, only for Band TV1417 at that). Especially given that the frequency never changes (which seems unlikely between two different locations; heck, on a lot of wireless gear channel scanning typically produces different results on immediately-subsequent attempts), are you sure you're using the AUTO SET method correctly? Does CLR SCAN produce different results?

Also, for what it's worth, unless you're very sure about which TV channels you want to be operating on, I'd suggest using Group 09 (regardless of which Band you're on), since this will always give you the largest number of multichannel-compatible frequencies to choose/scan from. (Of course, that only matters if the RX is, in fact, choosing frequencies from the Band/Group you've set; the manual does say it's supposed to, but that doesn't seem to be happening here...)

-Russ
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Matt Hill

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Re: Wireless lav audio problems
« Reply #26 on: February 08, 2021, 04:42:44 pm »

Okay, that's my gain-staging troubleshooting checklist. Time to look for local interference! :D

I'm assuming you don't have an RF scanner, but would you mind sharing the rough locations of your home and shooting location, or even just a list of all the TV stations in the area? Are the two locations very distant from one another?

Digging into the manual, I'm a bit confused because 478.125 isn't listed in Group 01, only in Groups 00 and 15 (and, of course, only for Band TV1417 at that). Especially given that the frequency never changes (which seems unlikely between two different locations; heck, on a lot of wireless gear channel scanning typically produces different results on immediately-subsequent attempts), are you sure you're using the AUTO SET method correctly? Does CLR SCAN produce different results?

Also, for what it's worth, unless you're very sure about which TV channels you want to be operating on, I'd suggest using Group 09 (regardless of which Band you're on), since this will always give you the largest number of multichannel-compatible frequencies to choose/scan from. (Of course, that only matters if the RX is, in fact, choosing frequencies from the Band/Group you've set; the manual does say it's supposed to, but that doesn't seem to be happening here...)

-Russ

Checked on the LED lights - they definitely look like fluorescent, but shut them off anyway and made no difference at all to the problem - thanks for there suggestion though.

Tried using group 9 and re-scanning several times - it does give me different values every time, but never changes the problem. The location of the problem is approx. 1/4 mile from my studio where everything works perfectly. I'm in North Fort Worth, TX, zip code 76244.

There are 2 very large wireless access points in the corners of the library though which were installed in the last 6 months - could these be part of the problem? They were installed across all campuses in our district.

Cisco 9130 AP
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Keith Broughton

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Re: Wireless lav audio problems
« Reply #27 on: February 08, 2021, 07:21:30 pm »



There are 2 very large wireless access points in the corners of the library though which were installed in the last 6 months - could these be part of the problem? They were installed across all campuses in our district.


As far as I understand, these units do not operate in the WiFi band so the access point should not be a problem.
Did you check the RF meters on the receivers with the transmitters off?
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Jason Glass

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Re: Wireless lav audio problems
« Reply #28 on: February 08, 2021, 11:43:57 pm »

Did you check the RF meters on the receivers with the transmitters off?

Hi Matt,

Keith's question has been asked more than once here, because it's an important one to answer.

Also check the troublesome locations for ultrasonic emitters, which are often used for motion sensing automated energy-saver light switches and security systems.  Although I haven't heard of them specifically causing problems with Sony equipment, they can theoretically wreak havoc on TX companders, and are known to cause issues with some older Wisycom hardware+firmware pilot tone squelch circuits.
« Last Edit: February 08, 2021, 11:48:55 pm by Jason Glass »
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Russell Ault

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Re: Wireless lav audio problems
« Reply #29 on: February 09, 2021, 12:08:30 am »

{...} Did you check the RF meters on the receivers with the transmitters off?
{...}Keith's question has been asked more than once here, because it's an important one to answer.{...}

+1!

{...} Also check the troublesome locations for ultrasonic emitters, which are often used for motion sensing automated energy-saver light switches and security systems.  Although I haven't heard of them specifically causing problems with Sony equipment, they can theoretically wreak havoc on TX companders, and are known to cause issues with some older Wisycom hardware+firmware pilot tone squelch circuits.

Oooh, that's a nasty one. (Going to add that to my list!) Is this issue closely related enough to "key test" performance to be able to test for it?

-Russ
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Re: Wireless lav audio problems
« Reply #29 on: February 09, 2021, 12:08:30 am »


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