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-   -   Easy question, Wireless Mics (https://www.dvinfo.net/forum/all-things-audio/327197-easy-question-wireless-mics.html)

Arthur Abramov August 27th, 2009 03:51 AM

Easy question, Wireless Mics
 
Ok, so when shooting a wedding i noticed they use a wireless device (Sennheizer) they plug it to the DJs equipment and the camera , so how Does it really work.? the lavalier mics are not even plugged right?

It's confusing with all the words; 'transmitter' , 'receiver' , 'UHF Transmission'.

-for example, Sennheiser Evolution G2 100 Series. = if i buy this then can i connect 2 lavalier mics into the same device when i'm interviewing two people ?

Help :) please the experts bring it on.

Thanks
Arthur.

Andrew Smith August 27th, 2009 04:03 AM

I think you might be noticing a situation where there is one mic (and transmitter) and two receivers. One goes in to the DJ gear (which doubles as the PA system for the event itself), and the other goes straight in to the camera (for the recording).

This way both the audience and the video camera get the best audio possible of the speaking parts.

Andrew

PS. I could always be wrong. Bit hard to figure out from what you have written.

John Willett August 27th, 2009 04:18 AM

OK......................................

"Transmitter" sends the signal - it converts audio into an RF signal that is then sent by radio waves.

"Receiver" is the unit thar receives these signals and converts them back to audio.

"UHF Transmission" means "Ultra High Frequency", which is hundreds of megaHerts, rather than tens.

I guess that at the wedding they were using a stereo in-ear monitor system to send the sound to the camera - a stereo mains transmitter and a stereo battery receiver that, instead of using headphones, was connected to the camera to get the disco sound directly.

Steve House August 27th, 2009 04:23 AM

It's a radio setup with a transmitter and a receiver, similar in principle to a walkie-talkie. A lav mic or an audio output from the DJ's gear plugs into the transmitter while the audio output of the receiver plugs into the camera's audio inputs. Transmitters are also available that plug onto a hand-held stick mic, as are integrated units where the transmitter is built into the body of the mic itself.

"UHF Transmission" refers to the frequency range the units are operating on. Regular AM radio broadcasts are in the Medium Frequency (MF) band, FM radio, the first 13 TV channels, and air traffic control are in the VHF (Very High Frequency) band, the higher numbers TV channels, cell phones, a lot of police and taxi dispatchers operate in higher frequencies than that, the Ultra High Frequency (UHF) band. Wireless mics also operate in that same general frequency range as UHF TV.

Note that you can plug just 1 mic or line-level signal source into a transmitter at a time. If you need to record more than 1 source at once, such as putting lavs on each of two interview subjects, you need a transmitter/receiver pair for each mic or signal source.

Note that the G2 has been superceded by the G3. If you're consiering purchasing a used G2, be advised that the changes brought on by the recent switch to digital TV in the States caused the FCC to make it illegal to use mics operating in some of the segments of the UHF band that were previously in common use. If a wireless' operating frequency is between 695mHz and 806mHz, it's illegal to sell or operate and if you use one you may have a lot of problems with interference from other kinds of radio transmissions that are starting up in the band. Before purchasing a G2 set from someone, you need to insure it doesn't fall into that 700mHz band (and until the new regulations that was one of the most common bands).

Arthur Abramov August 27th, 2009 02:56 PM

Thanks guys for your input.

Steve - the g2 has "Frequency A / 518 - 554MHz" so no illegal stuff there if its not 700Mhz, so its cool right? although the higher the Frequency the bigger the radius of reception right i guess.?

anyway i'm buying from the store,brand new.

Steve House August 27th, 2009 04:08 PM

Quote:

Originally Posted by Arthur Abramov (Post 1277535)
Thanks guys for your input.

Steve - the g2 has "Frequency A / 518 - 554MHz" so no illegal stuff there if its not 700Mhz, so its cool right? although the higher the Frequency the bigger the radius of reception right i guess.?

anyway i'm buying from the store,brand new.

Yes, no problem with legality in that band.

No, the radius of reception is not related to the frequency, per se. The radius of good reception is the result of the interaction of a large number of factors. As an extreme example, trans-oceanic shortwave broadcasts and long-distance military communications are on HF frequencies far, far LOWER than the frequencies wireless mics and TV broadcasters operate on. Visit Sennheiser's web site support pages and take a look at their frequency selection. What's important is that there are no nearby broadcasters or other services in your area operating on close frequencies, etc.

John Willett August 28th, 2009 06:32 AM

Quote:

Originally Posted by Arthur Abramov (Post 1277535)
anyway i'm buying from the store,brand new.

Then *don't* buy G2 - go for the new G3 instead. The camera receiver is much better than the G2.

Guy Cochran August 28th, 2009 10:21 AM

Quote:

Originally Posted by John Willett (Post 1280377)
Then *don't* buy G2 - go for the new G3 instead. The camera receiver is much better than the G2.

John, are G3 portable receivers already available in stores in your area? They're still unavailable in the US. We're excited for the new models to hit the shelves here!

John Willett August 29th, 2009 02:40 AM

Quote:

Originally Posted by Guy Cochran (Post 1281044)
John, are G3 portable receivers already available in stores in your area? They're still unavailable in the US. We're excited for the new models to hit the shelves here!

Sweetwater in the USA appear to have the G3 in stock. So I assume it is available over there.

Floris van Eck October 5th, 2009 12:10 PM

What are the main differences between the G2 and G3 kits?

I saw a nice deal for a G2 set which I might buy.

But if the G3 is much better in quality, I might pay the $100 extra or something.


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