Wireless - Power & antenna distribution for 20+ RF mic receivers

[Wolfgang]

I run sound for my school's theatre shows. We have a large theatre (1000+ people) and tend to do fairly large shows. As a result, we regularly run 20+ wireless lavs per show. Right now, they are all just stacked (neatly) next to the board, but I am pushing to get them rack mounted this year. I wanted to not have to find place for 20 a/c adapters inside the rack, which lead me to mic distribution systems. The only problem is that they almost always work 1 distributer to 4 mics. That's alot of wasted rack space for the distributers (I think), and the distributers aren't cheap themselves. We have never really had reception problems, so the antenna distribution isn't my #1 priority. Does anyone know of any mic distribution system that will take more than 4 mics or another system that will, per se, have one a/c input and 10 dc outputs?

As a side note, do the mic's antennas in the back lose alot of reception by being rack mounted?

Thanks,
Wolfgang

[OnWithTheShow]

Wolfgang,

Depending on what size rack you get you can get a power rail for the AC adapters. You might be better off getting a couple paddle antennae and running them to a antennae distro then daisy chaining the receivers it will keep you from having 20 plus opportunities to poke your eye out next time you have to get in the back of the rack.

What model wireless are you using?

[soundlight]

While it will definitely void any warranty on the wireless receivers, we had one of the guys who's really, really good with a soldering iron and good with circuits hook up what amounted to a fanout of the proper mini DC plugs to plug in to the wireless, and got a power supply of the proper voltage and more than enough amperage for all of the wireless receivers, and soldered in the connectors so that all of the wireless units in each of our 3 racks are powered from a single power supply, so one power supply per rack. You just have to get the exact voltage power supply, and it's always good to have a little bit of headroom on amperage.

[jkowtko]

I just bought the parts to do exactly that -- we have 20 wireless receivers on a rack and they all happen to take 12v 2.1mm DC plugs.

iofast.com has plugs with 3 feet of cord attached

advancedgadget.com has plugs with no cord

cables4pc has 12v 5A power supplies.

Supposedly 22 gauge wire will handle 5A at 12v, and 18 gauge wire will handle 10A.

Theoretically all 20 of my receivers (160mA and 200mA) total only 3760mA, so a single 5000mA power supply should work with decent margin of overhead. However I may split between two power supplies and keep a separate Y connector around so I can deal with a broken power supply, if that ever happens.

I also asked the AKG tech on what voltage specs the wireless receivers require, since the power supply was rated at 12v +- 20%. He said anywhere from 5 to 17 volts would work on these receivers, so it looks like there should be plenty of margin of safety for voltage at least.

If anyone else knows of issues of doing this or has seen receivers "burn out" please share. The only risk the tech told me was of voltage starvation and receivers losing signal should the power supply be under-powered.

[Wolfgang]

Originally Posted by OnWithTheShow

Wolfgang,

Depending on what size rack you get you can get a power rail for the AC adapters. You might be better off getting a couple paddle antennae and running them to a antennae distro then daisy chaining the receivers it will keep you from having 20 plus opportunities to poke your eye out next time you have to get in the back of the rack.

What model wireless are you using?

I didn't quite understand what you mean regarding the antenna distros. We use the old sennheiser ones. Almost identical to the current G2's, but the older version.

Wolfgang

[DaveySimps]

I am unaware of any manafacturer that makes such a product. If you do rack mount you mics as you indicated, there is a great potential to have reduced reception, but it is very difficult to predict since so many other factors are at play. I highly recommend the distrobution units. When wired correctly, they help to create a very reliable wireless system. With the way you describe you setup, you are just running on good luck as far as RF intermodulation and interfearence is concerned.

~Dave

[museav]

Since I don't think it has been mentioned, but mounting the receivers inside a rack and possibly even in a different location can affect the reception.

There are pros and cons to a common power supply. It can definitely clean up a rack but if you run everything off one supply then I would suggest keeping a second one handy as any failure will take down all mics. And since most receivers are provided with a power supply, a common supply is usually an added cost rather than any savings.

I don't know of any standard antenna and power distribution unit for 20+ receivers, however many distribution units will let you cascade multiple units off one set of antennas.

[OnWithTheShow]

As a side note, do the mic's antennas in the back lose alot of reception by being rack mounted?

I took this to mean that you have a small antenna hooked up to each receiver. This leading me to recommend shared paddle antenna.

[cdub260]

Originally Posted by Wolfgang

I run sound for my school's theatre shows. We have a large theatre (1000+ people) and tend to do fairly large shows. As a result, we regularly run 20+ wireless lavs per show. Right now, they are all just stacked (neatly) next to the board, but I am pushing to get them rack mounted this year. I wanted to not have to find place for 20 a/c adapters inside the rack, which lead me to mic distribution systems. The only problem is that they almost always work 1 distributer to 4 mics. That's alot of wasted rack space for the distributers (I think), and the distributers aren't cheap themselves. We have never really had reception problems, so the antenna distribution isn't my #1 priority. Does anyone know of any mic distribution system that will take more than 4 mics or another system that will, per se, have one a/c input and 10 dc outputs?

As a side note, do the mic's antennas in the back lose alot of reception by being rack mounted?

Thanks,
Wolfgang

For your power distribution I would recommend a rack mount plug strip or three. You can find them from McMaster-Carr. Go to their site and do a search for rack mount plug strips, then when the results page comes up click on Rack Mount. When the next page comes up, click on View Catalogue Page. You'll be presented with a variety of different types. Just look for the one that most closely resembles your needs.

Hope this helps.

[Wolfgang]

Thanks for all the help. From what I'm hearing, I think I will look into getting distro units for all the mics and then possibly running cascading some of the antennas. THis way, everything is not dependant on one power supply. However, if we can't get all the money to run antenna distros, maybe I will try the homemade power adapters that were suggested above, running perhaps 6 or 8 mics of each adapter so that if one dies, all the mics do go down, as well as keeping a good bag of spare single power adapters about in case part of a power adapter fails.

Originally Posted by cdub260

For your power distribution I would recommend a rack mount plug strip or three. You can find them from McMaster-Carr. Go to their site and do a search for rack mount plug strips, then when the results page comes up click on Rack Mount. When the next page comes up, click on View Catalogue Page. You'll be presented with a variety of different types. Just look for the one that most closely resembles your needs.

Hope this helps.

That also sounds like it would work quite well, and be quite a bit easier and less time consuming than making the power adapters.

Thanks,
Wolfgang