Audio frequencies on wireless mic/receivers

I was just about to purcahse a Sennheiser G3 wireless kit, when I noticed there's three different models available - each with a different frequency spectrum. Why is this this important, and should I be looking at any one in particular? A, B & G in the Sennheiser ew 112-p G3 series, btw.

A (516-558 MHz)
B (626-668 MHz)
G (566-608 MHz)

Thanks :)
 
First, there are way more than 3 models available. There are versions that are well into the 700 and (I'm fairly sure) 800 frequencies.

I'm not sure about your location, but here in Australia there's something called the digital divide (it may be called the same thing or something different where you are) where they are allocating a lot more of the spectrum to digital devices like phones and tablets and so on. The frequency reallocation is making a lot of digital devices obsolete, and others harder (or impossible) to use.

You really need to check which areas you're likely to use your wireless devices in and what areas frequencies are most available. If that makes sense?

Over here it's been illegal for a while to sell *NEW* equipment that won't be compliant with future restrictions. Though, that doesn't guarantee that you'll be able to use them. They sell chunks of the frequencies to TV stations (and radio I think) and you're not allowed to transmit on those frequencies. I'd also assume, even if you could transmit on those frequencies, the quality of your recordings would be junk anyway.
 
I was just about to purcahse a Sennheiser G3 wireless kit, when I noticed there's three different models available - each with a different frequency spectrum. Why is this this important, and should I be looking at any one in particular?

Sweetie is essentially correct. There are two reasons why they come with different set freqs:

1. Pretty much all countries/regions as far as I'm aware have laws which govern the division of the wireless radio spectrum. Bands restricted for use to say commercial air traffic, the military, taxi companies, commercial radio stations, etc. Of course, how each country/region divides the spectrum isn't exactly the same, so a wireless kit set to one particular frequency may be legal in one particular region/country while being illegal in another.

2. The band of legal freqs (for private radio broadcast) for a particular region can get pretty crowded depending on the locale. A major metroplois for example is likely to have many taxi and couriers companies operating in the same band of freqs which wireless mics are allowed to use. In this case, it's useful to be able to choose a radio freq (in the allowable band) further away from particularly crowded areas of the allowable band, to avoid break through.

The more expensive wireless kits have selectable freqs rather than being factory fixed to one freq and I believe some have such a wide range of selectable freqs they can be used pretty much anywhere in the world. If you always film in one particular location or within one region then a fixed freq system, obviously fixed to an appropriate freq, would be the cheapest practical option. In certain major cities or if you film in different countries/regions, then a switchable freq system might be the better choice.

The best advise regarding production sound always tends to come back to hiring an experienced local pro PSM. They will know not only the legal freqs for a particular region but from practical experience will know which freq is the most reliable.

One of the funniest experiences I had (many years ago) was editing the dialogue for a scene shot in London. Due to too much noise in the boom, I auditioned the wireless lav track which went something like:

Female character: "Peter please don't, you know what it does to me when you touch my neck like ..."
A second of interference and then: "Oscar four four, what are you riding, a donkey? What's your pick-up ETA?"

This actually gave me some great ideas, then I saw my career flash in front of my eyes and decided to use a different take!! :)

G
 
One of the funniest experiences I had (many years ago) was editing the dialogue for a scene shot in London. Due to too much noise in the boom, I auditioned the wireless lav track which went something like:

Female character: "Peter please don't, you know what it does to me when you touch my neck like ..."
A second of interference and then: "Oscar four four, what are you riding, a donkey? What's your pick-up ETA?"

This actually gave me some great ideas, then I saw my career flash in front of my eyes and decided to use a different take!! :)

Awwwww, c'mon... You do a quick edit for the outtakes/bloopers reel.

I had a project several years ago where the director & producer were downright gloomy and out of sorts for days during ADR sessions (they had neglected my production sound advice....). We finished for the day, I did all of the edits, back-ups, etc., and then created a copy of the session where I Mickey-Moused all of the male characters and Darth Vadered all of the female characters. It was good for a laugh the next day, lightened the mood, and they insisted on a very quick "substitution" mix for a few scenes that got lots of laughs at the after-screening party.
 

A.D.

Inactive
One of my first electric guitars used pick up some kind of eastern european or russian radio station. Not as funny as APE's donkey foreplay, but it made for some pretty cool random industrial effects at rehearsals and gigs. :D
 
Cool, thanks guys. I ended up talking with the dude at B&H. Should be all good. I'm pretty sure it's the same model as the one I usually rent locally, too.

With a spread of selectable frequencies on each unit, within that broad spectrum, I sure hope I don't end up with any audio bleedover stories of my own. :)
 
Awwwww, c'mon... You do a quick edit for the outtakes/bloopers reel.

Nice story! In my case though, I was a sub-contractor on one of those extremely short notice, "up against it" type gigs, so there wasn't the time, nor would it have been appropriate, for me to do the sort of thing you did. As I said though, it did give me some ideas.

With a spread of selectable frequencies on each unit, within that broad spectrum, I sure hope I don't end up with any audio bleedover stories of my own. :)

You shouldn't have much of a problem. I do sometimes get some radio interference on lav tracks but it's not common and even then it's usually just a fraction of a second of interference rather than actual comprehensible radio chatter. Also, all the frequency bands you listed are in the UHF band, which is generally less prone to break-through than units which operate in the VHF band, so you should be good. If you're filming in an unfamiliar locale it's always worth testing some different freqs and/or getting some local advise, as "Sod's Law" dictates that if you do get any interference, it will always be on the best take!

G
 
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