We get feedback/howling in our church

It is very difficult to use our sound system, which is around ten years old, because if we turn up the level to something which people can hear, we get horrible howling sounds from the speakers. I´ve been told this is called feedback. Can you help?

Feedback in a sound system only occurs when the sound coming from speakers re-enters through a microphone and is then amplifed again and again.

Therefore the most common cause of feedback is that the microphones are somehow pointing at a speaker or a very direct wall reflection from a speaker.

Solution: ensure that no microphones are pointing directly at any speakers, and be very careful of omnidirectional pickup (all directions) as you are asking for problems!

The second most common cause is that the amplification (or gain) of the system is too high. In churches this is common if the speakers are inefficient or pointing in the wrong direction, or the wrong type of speaker. This forces the level to be turned up to compensate and will eventually lead to feedback.

Solution: if you have older speakers, consider installing modern speakers with a well defined coverage pattern (such as the JBL Control range of speakers). Often this can be a straight swap for your existing speakers. Turn down the level at the mixer a little too, and if you have tone or EQ controls then try to reduce the level at problematic frequencies.

The third most common cause is the wrong type of microphone. Very often, churches use vocal/singers microphones for lectern and readers microphones. Vocal mics are designed for efficient pickup at about 2 inches, but users at a lectern are more than 2 feet away. Again, this forces the input gain level of the system to have to be set too high, and feedback will be likely to happen.

Solution: replace any dynamic vocal mics (such as the Shure SM58) with condenser microphones (our best choice is the Audio Technica ATM33a) if they are used for speech only. Ensure that singers are right up to their vocal microphones too, so that the gain can be kept low - just watch how pop singers almost eat their microphones.

We are available to answer any questions you may have - don´t forget that the sound quality in your church is as important to us as it is to you. As one of the leading suppliers of audio equipment exclusively to churches, we have seen pretty much everything, and we love to help!

Hope that your sound problems are improved by these changes.