Static eletricity and laviler mics

[Simon Lewis]

It could be static, in which case, try spraying the vicar (or his robes) with antistatic spray, try treating any man made fibre carpet he's walking on, or [joke] tell him not to wear the matching silk camiknickers and bra [/joke] ;-)

 

The fact that the receivers are outside the loop boundary means virtually nothing - the loop signal is probably as strong there as it is inside.

 

However, I've usually found the cracks and pops are due to such items as badly supressed or faulty heating thermostats operating, lighting, problems with battery voltage levels, thermal drift in the receiver, RF dropouts etc.

 

I woudln't rule static out, but tehre are plenty of other variables to check as well !

 

Simon

[marc]

On a similar note, but slightly off topic, (sorry)

 

I was running some filming of a surgical procedure a week ago, live to a small conference room for 15 people to watch, with a 2 way audio link so the surgeon could talk his way through the procedure and the delegates could ask questions.

 

When ever the surgeon used his hot knife thing the radio mic would fall over. now I have done lots of filming in operating theatres and always used radio mics, of varying makes and quality's and never had any problems before.

 

But this mic would sound like it had a 30db pad punched in. now the only thing I can think of is that the surgeon had the hot knife wound right up. These things work by placing a pad usually on the patient’s thigh and connecting it to earth, then passing voltage through the body to create a circuit - as far as I can tell!

 

The radio mic capsule was clipped to the mask and the wire taped down the surgeons back to the transmitter. I am just a bit miffed why it only happened on this one job when we do about 10 a year minimum!

 

But as long as it’s not just me having problems with power and radio mics I will rest easy! after all radio mics are the devils game!

 

Mk

[mac.calder]

But this mic would sound like it had a 30db pad punched in. now the only thing I can think of is that the surgeon had the hot knife wound right up. These things work by placing a pad usually on the patient’s thigh and connecting it to earth, then passing voltage through the body to create a circuit - as far as I can tell!

 

It may not be the radio mike - the pop could be due to the the sound equiptment being on the same circuit as the hot knife due to something like earth dump - the hot knife dumping crud down the earth - or if they are separate circuits, using a circuit which is not 'clean' (I know the hospital my mum works at has 'clean' supplies into the surgury which is completly issolated from the rest of the hospital...) for the hotknife, or your sound being in their clean circuit. It could be as simple as the electromagnetic field generated screwing things up because he had the juice right up.

[Bobbsy]

Some of the tools used for rapid cauterisation in surgery operate using frequencies well up into the RF range and can generate quite a spike of energy which often interfere with audio and TV equipment.

 

Some years back I was working on a programme which involved filming in an operating theatre. I recall the "hot knife" process used then was called diathermy and it caused no end of interference problems.

 

I had a quick Google and a layman's explanation of diathermy can be found at: http://www.surgical-tutor.org.uk/default-h...hermy.htm~right

 

Bob