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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Wireless and Communications => Topic started by: Pete Erskine on November 13, 2016, 08:39:44 pm

Title: Video LED walls and RF
Post by: Pete Erskine on November 13, 2016, 08:39:44 pm
I have been hired to work on a music tour which will have a full 5mm LED video wall up stage and decorative LED flooring around the perimeter of the half court size stage.  I was able to pre approve the manufacturers of the LED panels which makes all the difference in the world. Both of these LED screens have very low RF emissions in the UHF band

The US wall is from VER equipment rentals and is the Revolution Display 5mm product and has been tested to comply with FCC emissions, for what that's worth.  The report is in the file folder.

The floor panel is manufactured by Tait and since it is only used by them and not sold does not need any FCC type approval it seems.

In the spectrum scans,
RED is the power off level,
GREEN is the spectrum directly at the front of the center of a 10' x 10' screen within 5" and
BLUE is the same but in the back of the panel.  Clearly more emissions out the back

The first Picture is the VER 5mm and the second, the Tait floor.


The full scan files are at:
VER files (https://www.dropbox.com/s/wsetjhickhgpm8u/Seacauss%20NJ%20USA%20VER%20shop%2011-11-2016%20Pete%20Erskine.zip?dl=1)
TAIT files (https://www.dropbox.com/s/4ssv86tnx54rnlc/Lititz%20PA%20USA%20Tait%2011-11-2016%20Pete%20Erskine.zip?dl=1)
Title: Re: Video LED walls and RF
Post by: Mark Hadman on November 14, 2016, 06:13:01 am
I'm interested to know what scanner you're using here, and also what level of interference you'd see before you thought the LED wall would make your job impossible.
Title: Re: Video LED walls and RF
Post by: Neil White on November 14, 2016, 09:24:21 am
I have been hired to work on a music tour which will have a full 5mm LED video wall up stage and decorative LED flooring around the perimeter of the half court size stage.  I was able to pre approve the manufacturers of the LED panels which makes all the difference in the world. Both of these LED screens have very low RF emissions in the UHF band

Do you have anything special planned for the Antenna systems to help mitigate the remaining RF from the screens?
Title: Re: Video LED walls and RF
Post by: Pete Erskine on November 14, 2016, 09:29:49 am
I'm interested to know what scanner you're using here, and also what level of interference you'd see before you thought the LED wall would make your job impossible.

The scans were done with a TTI PSA Series 5 and combined in photoshop.  these LED are great and dont increase the noise floor more than a dB or so.

In 2007 I was rushed to a tour which had bad RF in the floor - +10-15dB across the board.  Solution for ears was to hang omni antennas 10' above the performers and an extensive search for freqs which had the least issues.  I have been around a lot of LED walls and floors and generally they are not good.

Do you have anything special planned for the Antenna systems to help mitigate the remaining RF from the screens?

These screens will not be an issue as long as the performers are not back of the screen.  Probably will use Shure UA874 on sides of the stage for mics and Sennheiser A5000CP for ears.  I will locate as far DS as possible to avoid the LED.  Possibly there will be an additional set DSC since the stage is 150' deep.   There are 18 ear mixes so I will probably break them into 3 antennas.  on for key performers and a SL and SR set closest to the performers who use those ears.
Title: Re: Video LED walls and RF
Post by: Neil White on November 14, 2016, 03:05:14 pm
These screens will not be an issue as long as the performers are not back of the screen.  Probably will use Shure UA874 on sides of the stage for mics and Sennheiser A5000CP for ears.  I will locate as far DS as possible to avoid the LED.  Possibly there will be an additional set DSC since the stage is 150' deep.   There are 18 ear mixes so I will probably break them into 3 antennas.  on for key performers and a SL and SR set closest to the performers who use those ears.

Do you prefer a wideband antenna to something like a Sennheiser A12 with internal filtering? Do you typically deploy any filtering on your RX antennas?

Would you place IEM transmits locally at SL and SR and run long audio/control cabling or have all transmits centralised with longer antenna runs?
Title: Re: Video LED walls and RF
Post by: Pete Erskine on November 15, 2016, 08:32:17 am
Do you prefer a wideband antenna to something like a Sennheiser A12 with internal filtering? Do you typically deploy any filtering on your RX antennas?

Would you place IEM transmits locally at SL and SR and run long audio/control cabling or have all transmits centralised with longer antenna runs?

on tour the coords change a lot so filtering is not practical.

TX will be all in one place with longer antenna cables.  None over 150'