Tie mic feedback - help!

We have problems with our lapel tie clip microphone giving feedback, what can we do about it? Also, would you recommend an EQ to eliminate these problems?

As a first port of call, we would probably NOT suggest adding a Graphic Equaliser to reduce feedback, although of course they can help!

There are a lot of things you can do without resortingEQ to reduce feedback.

• Ensure the speakers are in front of all microphones at all times
• Keep the "on stage" sound level down as low as possible - musicians to play quietly, keep foldback monitors low volume
• Position the lapel microphone high up on the collar (and slightly to the side) so that it is very close to the sound source. This means that the microphone level in the mixer can be kept lower

You need to be very careful if heading down the EQ to reduce feedback route as it is possible to end up with a weak sound if you are not careful - really do think deeply about the actual causes of the feedback first.

However, if you really are having difficulties then a simple EQ can help to give you a little more headroom before feedback occurs. You need as fine frequency band control as possible - 31 is good - so that you don't alter frequencies which are not a problem. See....

Samson 31 Band Graphic Equaliser

Alternatively, a purpose built feedback destroyer can remove feedback without damaging the overall sound of your mix. See...

Samson Advanced Feedback Managment Unit

Finally, using a directional (cardioid) lapel microphone can also help to prevent feedback problems. The EW122G2 Sennheiser lapel microphone is a cardioid microphone, i.e. it has directional pickup. Don't forget that you have to position the microphone facing the right direction!

Sennheiser EW122G2 UHF radio microphone

Hope that this helps!

Tim

Competition Winner!

Thank again to all who participated in our online web shop questionnaire. We are now shipping a large amount of audio equipment including microphones, mixers, speakers, cables and stands to churches across the UK (and even beyond!)

http://www.churchpa.co.uk/store

Thanks to all our loyal customers, and hello to all our new ones.

From Tim Curry, the winner of our microphone ...

"Thanks for sending the mic - I have attached a pic. Sorry its a bit cheesy! I think this is the first time I ve won something like this so I am dead pleased (as is our AV team who think the mic is lovely)"

Thanks to you too Tim, for entering our competition.

Bye for now,

Tim Ridgway.

We have a WINNER

Hi All,

We have drawn a winner for our recent "Store Opening Competition Prize Draw" and the winner is -

Tim Curry from Wendover

Tim is the proud winner of a Shure PG57 Instrument Microphone.

Our thanks to everyone who entered the competition, and thank you all for the words of encouragement as we strive to serve the church community better.

Bye for now,

Tim.

100V Line vs. 8 ohm speakers

Can you explain the difference (in non -technical terms) between 100V and 8 ohm speakers, and which we should choose. We require four speakers in our church.

Many older 100V speakers did not sound very good, and so lots of churches are changing them to modern speakers. However, new speakers, including the Control25 (8ohm) and Control25T (100V) speakers sound the same today. Therefore it is just the manner in which the signal is sent to the speaker which is different between the two systems. If you go for 8ohm speakers, you obviously connect them to the low impedance output from your amplifier and if 100V then connect to that output (note not all amplifiers have a 100V output).

The difference between the two systems comes in the wiring to the speakers. If you use low impedance speakers over long distances (greater than maybe ten metres) you need increasingly thicker copper in the speaker cable otherwise you get a lot of cable loss and distortion. So, for long distances 100V line is much better as you can pretty much use any old speaker cable.

Additionally, you mentioned that you wanted four speakers. With 100V line, you can literally connect all the + terminals together and all the - terminals together in any way the wiring happens to be. With 8 ohm speakers, you need to ensure that the impedance is above 4 ohms, which with four speakers involves wiring pairs in parallel and then connecting the pairs as a serial chain.

Most older churches are wired for 100V line systems as the speakers are both a long way from the amplifier and also the cable is not of thick copper. Therefore if you are updating your system it is highly likely that 100V speakers are suitable.

To say it again, with modern speakers, both 100V and low impedance speakers sound very similar.

Hope this helps,

Tim