Understanding radio mics
Sun, 15 June 2008, 09:28 pmDavid Ashton13 posts in thread
Understanding radio mics
Sun, 15 June 2008, 09:28 pmAs this is the tech talk column I thought it may be a good idea to cover some of the common problem areas and start with this common problem.
Now you will see mics with 16, 32, 300, 700 or 1440 channels, this does not mean that you can use anything like that number of mics together.
Radio transmitters are like musical instruments [in that they produce harmonics which are multiples of the base frequency], and these harmonics interact with each other to restrict the number of usable channels.
As an example, the Redback 16 channel mics have 6 channels which can work together, the main mics I hire are the 700 channel series but only 16-17 channels will work together.To get more channels I am now getting in the Sennheiser 1440 channel units and while they are coy about exactly how many channels I will get, it should be 24+.
Now other areas to consider are interference from other radio sources like in ear monitors, which tend to use the same bands and radio talkback systems which I am now also importing as prices are lowering.
If you are using half a dozen radio mics there is not likely to be a problem but once you start adding talkback and in ear monitors you will need some specialized assistance.
And as I said in an earlier piece, the radio part is only the beginning, the complexity of multi mic mixing a live show added to the potential harmonic interference means that rehearsing with the full system is crucial and failure to do this and find potential problems can lead to disaster.
In short, radio mics are not a panacea so please bear this in mind.
G'donya you! finally we
Mon, 16 June 2008, 02:26 pmG'donya you!
finally we have some real 'tech talk' for a change! Instead of the usual 'warm props' &/or 'Luvvies speakfest that this section has fallen into.
I'm a sparkie by trade & when it comes to radio, I liken it to refrigeration & motor cars, have always been a black hole to me. Not from the basic principals, but all the the excuse given by pseudo audio engineers of why 'IT' don't work as it was designed to do!
I shouldn't knock 'frigies' or 'mechanics', as some of my better friends are even audio techs 'n luvvies.
as you mentioned 'talk back' systems as well, I'm in the process of applying for the new "ignite grant via DCA & ITA. Thus deciding whether to go for radio headset talk backs or to actually install a wired 'TB' system. I have had a few problems in the past with doing shows, using these mickey mouse toy radio head sets, with them drooping out on the cue or interference so bad they hurt the old ear drums.
Especially at our old venue, which has just been refurbished [which we have christened the 'cockpit Theatre'] Phoenix Theatre in Cockburn.
The venue is underneath a power network of High tension cables & luckily is not also a major Bus depot, which the Council got moved for the new 'CPAC" complex. But the power cable pylons was outside their budget & will still be there.
This even happens with Jands gear, that we have hired on occasions, so it is not the fault of the toy Tandy sets & the like.
I know I have mentioned this situation before with you recently, but I'm ancient & visually impaired when it comes to seeing sound & radio waves.
Sorry to go off on a tangent, but the 'ignite' Grant is too good an opportunity to pass up & I don't want to go thru the drama of going back to using the good old 'traffic light' cuing systems.
So I'm thinking of a basic 4 radio belt packs with Master station &headsets to suit?
{as you mentioned you stock a TB range.]
Also I agree whole heartedly with putting in place a regime of 'idiot checking' radio Mic's & the audio techie instigating a working list of Mic placement/logistics. 'Net Form' {[WWWW sheet]What When Where (& Who)} Prior to performance.[Keeping in mind the 5 P's, which should be 7 P's?]
I realise that battery technology has change over the years, but I always used to have dramas with the rechargeable ones. Luckily that was sorted by being able to get a complimentary carton every now & then of fresh batteries, as part of a promotion for a particular brand. {I won't mention the brand name - But it is surprising what you can get for a few comp tickets!}
TOI TOI TOI CHOOKAS
[May you always play to a full house] Hear the lights & see the sound.