Hi,
I'm a amateur sound engineer and do some production work for some local churches.
A few months ago we had a Gospel Show. I had just aquired a new set of 15" 550 watt speakers and installed these with my excisting and proven 10" 250 watt speakers.
We wanted to try something new and hooked up a canon camcorder to a video switch box that ran a composite video signal to a projector.
All worked fine until we started to turn up the volume, then the video signal got so distorted that it finally just went blank.
The problem that we experienced was that when we pushed up the volume the video signal from the video camera and towards the front projector mounted in the roof was distorted, the louder the volume the more distortion.
Once the music got to loud the signal would totally disappear going to the projector, and we would have a no signal message.
We tried to change over to the PC to atleast show the words of the song, the same thing happened.
I have researched some and think it was the strong magnetic fields from the 15" speakers that caused the EMF intererence on the video signal.
Luckly as the camera seem to be shielded the recording went fine, we could just not show it live on the projector.
I have tried to find answers to the problem, it seems that it would be EMF interference, I'm trying to find a solution to the problem.
I have been thinking of opening the speaker boxes and building a "shield bucket" around the magnets, not sure how to go about this, and where to buy the correct material.
Shielding the speakers seem to be the only answer, along with changing the composite video cables to twisted pair, shielded with a ground cable attached. I've not found the correct shielding matterial yet to try this, would appreciate any help and suggestions.
The church is hooked up to the projector using composite video, all though a VGA cable is available, I used a laptop on this with better results but still distortion, the church computer is not setup with a second graphics card.
I live in Johannesburg in South Africa.
Any suggestions greatly appreciated.
Thanks for a great site.
Regards
JP
