Purchasing wireless mic system - please check my list!

[yunebug]

Hi everyone,

I'm a drama teacher at a high school and we are getting serious about purchasing a wireless body mic system.
I've been doing a lot of reading and this is what I came up with:

12 x ULXS4 Receivers
12 x ULX1 Bodypack transmitters
12 x MM-PSM EarSet Microphones (microphone madness)
2 x PA805 directional antennas
3 x UA844 distros

We have a 32-channel mixing board, so 12 channels of body mics shouldn't be a problem. We've had rental units in the theater before and we've always needed an antenna for the signal to reach the booth.

Am I missing anything? Need more information? I'd appreciate the help very much. Thank you!

 

[TheaterEd]

Looks about right to me. Might be obvious, but make sure you get a rack to mount all of this in as well.

 

[BobHealey]

I'd think about going down to SLX or up to ULX-D. The ULX-S and ULX-P lines both use 9V batteries, while SLX is AA and ULX-D comes with rechargables and can use AA. My big gripe with SLX is the 3 position gain switch.

If you're having range issues with rental units, I'd think about either mounting the antennas outside the booth, or putting the recievers/antennas at the stage. In addition, for the proposed setup, you're either going to need a pair of passive splitters and a second pair of antennas or a 4th UA844 distro.

Before buying anything, I'd download Wireless Workbench from Shure, and have it try to find 12 open frequencies where you are. You're also going to want to check against the whitespace database and see where your protected bands are, and try to maximize the number of channels you put in those ranges.

Good luck.

 

[Stookeybrd]

To accommodate 12 channels of ULX you'll need 4 UA844 because they do not have a pass through to cascade addition distros to a single pair of antennas. The UA845 has the cascade port, and will keep your number of needed distros to 3.

Anaheim is a pretty dense RF market because of LA and San Diego in the vicinity. The two protected television channels for wireless mics to use interference free from TVBDs are 30(566-572MHz) and 45(656-662MHz). That means you should purchase as many units in the J1 range as you can get your hands on because you just miss out on the M1 band.

 

[yunebug]

Thank you for the replies!

Yes, I have an existing rack and room for 12 receivers. :0)

That is a great point about the 9v batteries. We prefer AAs here and the SLX would be the better choice.

As for the antenna mounting, that's exactly what I was thinking -- mounting a couple of antennas just outside the booth, pointed at the stage. PA805 will still be compatible with the SLX transmitters, won't it?

I will also get cracking on the Wireless Workbench software.

I went to Telecordia's whitespace database for my school's area but don't understand the data. I only see VHF/UHF channels for TV...? hahah

As for UA844 units, this is what I'm trying to achieve:

12 receivers, 3 distros (handles 4 each), and 4 antennas?

 

[yunebug]

To accommodate 12 channels of ULX you'll need 4 UA844 because they do not have a pass through to cascade addition distros to a single pair of antennas. The UA845 has the cascade port, and will keep your number of needed distros to 3.

Anaheim is a pretty dense RF market because of LA and San Diego in the vicinity. The two protected television channels for wireless mics to use interference free from TVBDs are 30(566-572MHz) and 45(656-662MHz). That means you should purchase as many units in the J1 range as you can get your hands on because you just miss out on the M1 band.

By going with the SLX, I'm limited to H5, J3, and L4. Each band is capable of handling 12 channels. This tool from Shure gave me some data:
http://tools.shure.com/freq_app/default.asp?zipcode=92801&system=SLX&miles=50&dispfreq=1

Looks like a few from each of the H5, J3, and L4 bands will be necessary for me to achieve my 12-channel concept.

 

[AudJ]

I don't have this equipment, but probably an extra distro - rf out from each side will be used to split the antenna to the next distro, leaving only 3 mics per unit, unless I am missing something. You will need proper cables for that, as well as any coax cables between units that are not included. That could add up to a lot, depending what is included in the box.

Is there another way to split the antennas?

I recommend you draw out your entire plan in a rough drawing, so you can count cables, and make sure there isn't anything else missing, depending on requirements of the antenna configuration.

 

[BobHealey]

A couple venues with SLX and UA844s do the following for 12 channels: Ant #1 and #2 (the shark fin paddles, not sure the model # off top of head) run the cabling to a passive T splitter, then into the first two pairs of UA844s, each feeding 4 SLX. UA844 #3 with the final four channels has its own dedicated pair of antennas for it, and if more channels were needed, that set will be put on a passive split to feed another UA844.

 

[AudJ]

Just checked the manual, which show one ua844 with antennas, and the output of that one feeding three more ua844 from 3 of the outputs on the first unit. The splitter with an extra set of antennas would work, but it seems to me it would be desireable to have one set. Compare the price of the extra ua844 to the splitter with 2 more antennas, 2 long 50ohm coax cables, and extra short cables from the splitter, I'm guessing it might be cheaper to get the extra distro.

 

[museav]

A basic issue but keep in mind that directional antennas are most effective when the peak sensitivity is aimed at the desired transmitters and any undesired RF sources are off-axis or ideally at the rear null. If you end up with a directional antenna aimed at any potentially interfering RF sources then any gain from the antenna applies to those signals as well as the desired signals, something to consider if you may not be able to move the antennas if such situations occur. For permanent installation where the transmitters are generally all on stage I personally tend to typically use omni antennas remoted near the stage with low loss cable if that is possible.

 

[yunebug]

Very helpful advices. Thank you all so very much. I really want to make sure we do this the right way and I absolutely appreciate all the help.

To me, BobHealy's post makes most sense to me (because I'm green when it comes to pro audio):

A couple venues with SLX and UA844s do the following for 12 channels: Ant #1 and #2 (the shark fin paddles, not sure the model # off top of head) run the cabling to a passive T splitter, then into the first two pairs of UA844s, each feeding 4 SLX. UA844 #3 with the final four channels has its own dedicated pair of antennas for it, and if more channels were needed, that set will be put on a passive split to feed another UA844.

So antenna 1 and 2 split into four lines which go into two UA844s and antenna 3 and 4 go directly into the third UA844. If I need to expand, use splitters on antenna 3 & 4 to go into a fourth UA844 to manage up to 16 receivers. That makes most sense to me and I think I'm going to head in that direction.

As for the omni directional antenna, I would LOVE to have one mounted near the stage with low loss cable running to the booth - other than running it on the floor alongside the seats with gaff tape, the space simply just doesn't allow it to look "neat". Besides, we've had successful productions with the shark fin Shure antennas so I think we're going to go with those.

So,

4 x PA805 antennas
2 x UA221 splitters
3 x US844 distros
12 x SLX receivers
12 x SLX1 transmitters
12 x MicrophoneMadness headsets
and necessary antenna cables, audio cables
and lots of condoms.

Sound about right?

 

[BobHealey]

Make sure you've got good frequencies, and talk to your dealer/Shure. RF can be very frustrating, especially in a dense area. One theater I volunteer at can't use any 2.4 GHz devices due to the spectrum being completely saturated with 802.11 devices (having 5000 people all with at least one, often 3 devices will do that). Another theater I volunteer at is < 500 feet from a bar with live music and < 1/4 mi from a major road house. Not uncommon to find something stomping on a wireless unit during a show.

I'm not a professional at all, just someone who works with big computers for his day job and volunteers at various places in upstate NY.

 

[dboomer]

RF can be very frustrating, especially in a dense area. One theater I volunteer at can't use any 2.4 GHz devices due to the spectrum being completely saturated with 802.11 devices (having 5000 people all with at least one, often 3 devices will do that).

I think you need to look further at that. The problem is not that there are devices there but rather what wireless you try to use there as well as the relationship Of WAPs to receiver antennas. If 5000 devices was the problem then they'd all take each other off the air.

OTOH what will you do next year when white space cell phone service hits the market and a lot of the available TV UHF band gets hit?

 

[yunebug]

Perhaps now would be a good time to refer to a professional nearby... lol xD

Thank you all again for your help. I will look further into the available frequencies. We've done shows here before with rental units without much problems, so I KNOW a certain section of frequencies exist! I shall find them!!!

 

[dboomer]

I will look further into the available frequencies. We've done shows here before with rental units without much problems, so I KNOW a certain section of frequencies exist! I shall find them!!!

Available today and avaiable next year will likely be a different story. Someone was kind enough to lookup and list your "protected" frequencies Channel 30 (566-572MHz) and Channel 45 (656-662 MHz). Those channels in your area are exclusively for the use of wireless mics and cannot be used by white space devices (which will start showing up more and more). And of the two the best industry guess would be to pick those below 600 MHz is it will likely be auctioned off and/or re-assigned in the next year or three.

 

[BobHealey]

I think you need to look further at that. The problem is not that there are devices there but rather what wireless you try to use there as well as the relationship Of WAPs to receiver antennas. If 5000 devices was the problem then they'd all take each other off the air.

OTOH what will you do next year when white space cell phone service hits the market and a lot of the available TV UHF band gets hit?

The university in question is trying to remove all WAPs not installed by network services, but from the student theater, I can see at least 4 official WAP plus 2 unofficial ones of varying strengths depending on where I am in the building. Their plan to deal with TVB devices is a.) get the ancient AT VHF gear from the mid 90's fully working again (at least the ones still on clear channels after the DTV switch), and start saving for ULX-Ds to run in high density mode in a protected channel, and live with not being able to have more than 8 - 12 working wireless out of the 27 channels installed. (16 VHF, 11 UHF)

 

[dboomer]

The university in question is trying to remove all WAPs not installed by network services, but from the student theater, I can see at least 4 official WAP plus 2 unofficial ones of varying strengths depending on where I am in the building. Their plan to deal with TVB devices is a.) get the ancient AT VHF gear from the mid 90's fully working again (at least the ones still on clear channels after the DTV switch), and start saving for ULX-Ds to run in high density mode in a protected channel, and live with not being able to have more than 8 - 12 working wireless out of the 27 channels installed. (16 VHF, 11 UHF)

The number (and power) of WAPs is a factor ... but how many channels are in use (and how many are really necessary). If all the WAPs are on the same channel it's easy to use wireless mics around that. But even that is not the limiting factor necessarly. New wireless technologies can use "frequency diversity" (which basically means the signal is not sent on a single channel at a time) which enables them to be used even on top of multiple wi-fi channels. In the USA if you use wi-fi 1-6-11 at the same time you have basically filled the entire band but I have sucessfully used 8-12 2.4G digital wireless with no problems numbers of times at multiple venues.

What happens is the "data" (not the audio) is sent in sub-packets. That typically allows you to lose almost 75% of the data before you lose audio by using error correction/concealment. To actually drop out you must lose more consecutive packets than is statistically probable (although it can happen, it rarely does). Technically strong interference to these systems whether from wi-fi or anything else only affects maximum range (again usually not a problem).

 

[TimmyP1955]

ULX-D. No antenna splitters needed, as they are built in (which helps to or completely pays for the cost difference in the units). The auto transmitter gain-setting is a very nice feature. The 4 channel units save a lot of rack space. If you get any handhelds, I like the SM84 capsule the best by far.

I'm very happy with our MM mics as compared to our E6s, other than the MM's ear loops being very wimpy (they told me that if you call, you can request a stiffer version).