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The life and times of james Hart: his family, his music, life in Luton and his occasional escapes onto the internet.

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Sunday, 27 July 2008

Adding microphones to church sound reinforcement - economically!

In an attempt to reduce the use of our vicar's lapel radio microphone at church, since it gets through 9 volt batteries at a terrifying rate, I made some plans to put static microphones on the lectern (moving the existing gooseneck microphone to the pulpit) and the altar, since that's where a fair amount of the action happens.

Fortunately, there were enough inputs to the main amplifier to accommodate new microphones; even better, both the lectern and pulpit already had cabling to them. So, the challenge was to find some reasonably economical microphones and an easy way to run a new lead from the altar.

I'm well aware that purists and many professionals are extremely dismissive of Behringer equipment, since it tends to be very inexpensive but I already have a few bits, and have no complaints with the quality or performance (save for a little ire at the LED backlight on their cheapo valve mic pre-amp!). You're not going to get top-studio sound out of that equipment, but often that's more down to the character of the 'boutique' equipment, rather than any small increase in noise and distortion (since modern design has helped to reduce them simply and significantly) from the cheaper kit.

I popped to Charing Cross Road and Denmark Street in central London a couple of weeks back and a small shop called Rockstop Music helpfully sold me a pair of Behringer C2 small diaphram condenser microphones (designed to be used as a matched stereo pair) for £45 - amazing, given their sensitivity. With five pounds worth of accessories from Maplin (a little gooseneck and a desk stand; the microphones already come with a clip and small popshield), the lectern microphone was a job quickly, and easily done.

For the cabling, I was a little creative - since the PA takes a balanced signal, I thought it might be interesting (and again, very economical, since there was an offcut remaining from work) to see if I could use some CAT-5 network cable to take the low-level audio the 40 metres to the amplifier input. Since the elements of the cable are already twisted, this presented something of an opportunity, if it worked!

My intention was to use one colour, which is normally twisted as a pair, for the signal; orange for 'hot', orange/white for 'cold', then use both brown and brown/white for 'ground' and the remainder for the 'shield'. It seemed to work - at 22pF/m, capacitance at nominal 600 ohms isn't an issue for frequency response, and it was very quiet, too, with no hum induced from the long run. Add to that the neutral colour of the cable and, for little more than £50, (or ten Duracell batteries!) both microphones have made a very beneficial difference, and, with their cardioid pattern, give really good audio coverage - mainly where the books are, so most likely to be used!

Behringer C2 on the lecternBehringer C2 on the lectern

Posted by james at July 27, 2008 10:17 PM

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