Hi guys

How can I mount a speaker and mic on a plane without getting feedback? The plane(speaker and mic) needs to be mounted on the ceiling.

The speaker need to be heard reasonably well, and the mic needs to be able to pick up voice.

 

Is the speaker re-broadcasting what the microphone is picking up?

 

Is the speaker re-broadcasting what the microphone is picking up?

It's going to be a two way communication. The speaker is connected to the the mic on the other end with similar configuration. The speaker is suppose to broadcast whatever from the other end.

The goal is enable people in different room can speak to each other. But I believe I am having feedback problem.

 

Try changing the phase of the speaker. If this does not work then the fixes get more expensive.

Graphic equalizer - Notch out the frequency of the predominant feedback frequency.

Feedback killer - A delay generator for audio use. This device inserts very small amounts of delay to change the phase of the feedback.

Check music stores for both of these devices.

 

You can also use an echo cancellation mic. A signal from the speaker is fed back out of phase into the microphone preamp circuit thereby cancelling the sound picked up from the speaker.

 

That's why they make "press-to-talk, release-to-listen" switches...

 

Try changing the phase of the speaker. If this does not work then the fixes get more expensive.

Graphic equalizer - Notch out the frequency of the predominant feedback frequency.

Feedback killer - A delay generator for audio use. This device inserts very small amounts of delay to change the phase of the feedback.

Check music stores for both of these devices.

What do you mean by changing the phase of the speaker? Like switching the connection of the two wires to the speaker?

 

That's why they make "press-to-talk, release-to-listen" switches...

This might be a good solution in other case, but not in this one.

 

You can also use an echo cancellation mic. A signal from the speaker is fed back out of phase into the microphone preamp circuit thereby cancelling the sound picked up from the speaker.

Never know this, I think I need to google this, thanks!

 

What do you mean by changing the phase of the speaker? Like switching the connection of the two wires to the speaker?

Yes, just swap the speaker wires. Sometimes it works.

 

The pickup pattern of the mic makes a difference, too...an omnidirectional capsule is going to "hear" the speaker lot more than one with a more unidirectional pickup pattern.

 

The speaker is suppose to broadcast whatever from the other end.

Because of sound reflections in each room that will inevitably lead to feedback unless a) each room is made anechoic or b) both mics are muted, made highly directional or screened, to prevent pickup from general room noise. A signal feeding the speaker in a given room could perhaps be used to mute the mic in that room?

 

Because of sound reflections in each room that will inevitably lead to feedback unless a) each room is made anechoic or b) both mics are muted, made highly directional or screened, to prevent pickup from general room noise. A signal feeding the speaker in a given room could perhaps be used to mute the mic in that room?

That might be a good solution for my application, I will talk to other people and see what they think.

 

Hi guys

I found this:
http://electronics.stackexchange.com/questions/27421/hybrid-phone-echo-cancellation-circuit
It looks like something I need, but I don't understand this:
http://i.stack.imgur.com/MBevM.png
where he use a transformer to combine 4 wires (in my case) into two wires. That will make my application better if I can do that.

Any thought?