infrared wireless mics

[dnafe]

Hi All

Didn't know where to post this so...

I have a conference room that will need up to four floor mics for audience participation.

They are exploring all options and the question of using wireless mics came up. Unfortunately there are concerns re: security using UHF/VHF mics.

I mentioned that there are infrared systems...Nady, being a household name makes a system but I have no idea of the quality of hardware or the audio for that matter.

If anyone can shed some light on this topic it would be greatly appreciated

Thanks

Don

[Brad Lunde]

Originally posted by dnafe
Hi All

Didn't know where to post this so...

I have a conference room that will need up to four floor mics for audience participation.

They are exploring all options and the question of using wireless mics came up. Unfortunately there are concerns re: security using UHF/VHF mics.

I mentioned that there are infrared systems...Nady, being a household name makes a system but I have no idea of the quality of hardware or the audio for that matter.

If anyone can shed some light on this topic it would be greatly appreciated

Thanks
Don

Infrared technolgy applies to "line of sight only" situations, like a movie theaters for hearing impaired. Its light: break the "beam" and lose the audio. RF can at least "fill" a room and you can move around.

Wireless mics come in three basic areas: UHF is best, used to be 10-15K per mic now much more reasonable. Its sandwiched in the TV band between local UHF channels. It works like a champ in most situations when you get the right freq. Then there's VHF, also in he TV band. Either of these should not present any conflicts with security wireless, which is generally on other frequencies.

Then there's the low cost wireless, in the 49 meg band. This was the first original cheapo chinese wireless and it absolutely sucks-its the same band as garage door openers and prone to all kinds of interference. But you can buy them for $25.

The bigger wireless mic companies [such as Audio Technica, Sennheiser, Lectrosonics, Shure] have specific freq's they can give you, based on your local TV station freq allocations. They will sandwich a freq between a pair of local stations. Its a bit of a crap shoot these days, as there is SO much wireless in use and the wireless mic companies have no way of knowing what else is in use there. That's why wireless can be frustrating for users. Works great for years, suddenly one day, not work. Its often because of something "new" in the vicinity in wireless or something illegal, like a modified CB (for higher RF power), or something broken or poorly built like a "dirty transmitter" (one that sprays RF output well above and below the actual frequency it is supposed to transmit). I've heard people get real mad over wireless interference, which can't be eliminated really. Like the Pentacostal church pastor who had a illegal CB break in over his in-house wireless (as some CB guy drove by) with words "wow, what a nice ass! I'd like to see that girl naked and sweaty" across his PA to the full congregation! Better wireless is more selective and can be very precise. Cheaper wireless is less selective.

There are a handful of what they call "traveling frequencies" in VHF and UHF, which are supposed to give you country wide clear channel operation, but not always; someone else might have the same traveling freq wireless in the same vicinity. Its a guarantee that the more important the reception the greater the chances of interference! With a good antenna (the most important issue in wireless), you can pick up from a long way away. RF bounces off objects and buildings and can be reinforced or cancelled, just like standing waves in audio. Just like your car radio can pick up from 4 states away one night, barely across town the next.

Brad

[cymatics]

IRP makes a 2.4 GHz spread spectrum digital wireless conference system that uses a proprietary 1024 bit encryption.

I've seen a demo of it.

It's really fuçkin cool.


- jon