Digital Wireless Microphones

[peacefulone61]

I read through a bunch of posts and Have more questions than answers, specifically in light of the new FCC auctions.

If you go with Digital wireless do you have to go with multiple manufactures to get over the 8-12 max microphones that each manufacture seems to claim can operate within a space, or is that a limit to the total amount of devices that can operate regardless of manufacture?

Are Microphones in these frequency likely to be sold off in the near future? ( I am tired of purchasing new equipment and having the frequency sold off a few years later.)

How do these microphones hold up around a heavily WiFi environment for networking like a school running multiple wifi networks as well as things like the wireless DMX and assisted Listing Device?

 

[RC4Wireless]

I can only comment on issues regarding spectrum used for Wireless DMX and WiFi (2.4GHz, 900MHz), and what I've learned from some of our customers using 2.4GHz microphones. Other contributors will have more knowledge about microphones operating in what was the analog tv band, auctioned spectrum, etc.

In general, the lower cost mic systems working at 2.4GHz are more susceptible to clicks, pops, noise bursts, and "smearing" than the higher cost ones. Without naming brands, I can say this is true even for the more trusted ones. Everyone tries to hit a range of price points, you get what you pay for.

Unfortunately, it's simply not possible to make an audio system that will be immune to any amount of other RF activity. The very best you can get in that situation is soft silences (sort of the opposite of a click, much less invasive but still not ideal).

Frequency hopping (FHSS) systems are more likely to invoke clicks and other audible artifacts. Direct sequence (DSSS) is less likely to do so. Note that WiFi uses DSSS, as does RC4Magic wireless DMX. Bluetooth uses FHSS, as does SHoW DMX, W-DMX, and LumenRadio CRMX.

I hope others can steer you towards microphones that are not in the 900Mhz or 2.4GHz bands. If you can do that, then I recommend setting up wireless DMX in the 900MHz band, and leaving WiFi and Bluetooth on it's own at 2.4GHz. Just filling your space with an audience equipped with numerous Bluetooth devices (like fitbit, iWatch, and others) raises the noise floor in a way not encountered in tech or rehearsal.

Hearing assist systems vary widely. The 900MHz systems I've seen so far have been narrow-band analog radio (neither FHSS or DSSS). This makes it straight-forward to configure a 900MHz FHSS system to avoid it's channel, eliminating potential for clicks and pops. Infrared hearing assist is used in many places, it's not RF at all.

Hope some of this helps!

Jim
RC4

 

[TJCornish]

I read through a bunch of posts and Have more questions than answers, specifically in light of the new FCC auctions.

If you go with Digital wireless do you have to go with multiple manufactures to get over the 8-12 max microphones that each manufacture seems to claim can operate within a space, or is that a limit to the total amount of devices that can operate regardless of manufacture?

Are Microphones in these frequency likely to be sold off in the near future? ( I am tired of purchasing new equipment and having the frequency sold off a few years later.)

How do these microphones hold up around a heavily WiFi environment for networking like a school running multiple wifi networks as well as things like the wireless DMX and assisted Listing Device?

We need to differentiate between two different concepts - Digital vs analog, and UHF/VHF vs consumer electronics bands.

Digital microphones are available in all of the above bands - UHF 400-699MHz, VHF 174-215MHz, 2.4GHz, and 900MHz. Digital microphones are a good thing.

The Consumer 2.4GHz and 900MHz bands are the ones with the theoretical 8-12 systems per band, and these all fight with other consumer devices in that band. You will not get 12 systems from Line6 and 12 systems from Shure simultaneously working here, it's a frequency limit, not a manufacturer limit.

I own a number of Line6 systems and have had reasonably good luck with a small number of channels - 4 of them fit fairly nicely around existing Wifi, but more than that is iffy.

Digital UHF/VHF on the other hand is great. They sound MUCH better than analog mics as they have no compander and have a lot lower noise floor than analog. The new VHF offerings are very attractive if you're starting from scratch and don't already have a UHF antenna distribution system.

 

[FMEng]

Some of the 900 and 2.4 manufacturers have devised systems that use link cables so that all units coordinate channel usage in real time. I believe Audio Technica System 10 does that. I would be hesitant to try more than a handful of units unless I know the RF environment and can kill off the wifi. Trying to run systems from more than one manufacturer in 900/2.4 would be suicide because they work on the assumption that they own the band, other than wifi.

 

[themuzicman]

Digital UHF/VHF on the other hand is great. They sound MUCH better than analog mics as they have no compander and have a lot lower noise floor than analog. The new VHF offerings are very attractive if you're starting from scratch and don't already have a UHF antenna distribution system.

This is too true. I mixed a show recently that had a mixture of Sennheiser 9000 Series and SK5212/EM3732's. The 9000 series are so clear that it makes the already great 3732's sound strange - I don't like to mix and match traditional UHF with digital now. I believe that's partially the rationale behind the Lectrosonics SSM hybrid emulation/compatibility mode (besides availability of Sennheiser receivers) - your digital RF will stick out on a well tuned system.

 

[TimmyP1955]

Avoid 2.4GHz like the plague. Shure ULX-D seem to work well, and are easy to set up in multiples - no splitters needed. Yes, the 9000 are wonderful. Sell your house and buy a 9000 setup (Just don't set a mic on top of a Clavinet.)

 

[MNicolai]

The strong market location for WiFi-band wireless microphone systems isn't theaters. These product lines are targeted toward corporate and education environments. You may be able to only make 7-8 systems coexist peacefully together in the same room, but if you put one mic in each room in a school or office and turn the transmit power down, you can make a hundred devices coexist within the same building by putting a couple rooms between repeating channels.