How to capture voices in a large room on a phone

Discussion in 'The Projects Forum' started by playingForFun, Jul 20, 2008.

  1. playingForFun

    Thread Starter New Member

    Jul 20, 2008
    I did do a search before I posted. However, I apologize in advance if I missed a similar question.

    A little background: we had a large group of friends meeting regularly, but then a few moved away. They want to be able to at least call in and listen in on the meetings. We tried a series of speakerphones, but the people over the phone can't hear very well (maybe I need to replace the phone's mics with more powerful ones?). So, I was interested in exploring alternatives. I wasn't sure where to begin. So, any help / pointers where I can start exploring is appreciated.

    So, I want to build a simpler version of something like Polycom's conference phones (the mic part). However, I am mainly interested in getting a wide coverage (40 X 10 feet) for input / microphone part of the phone (half duplex) and be able to transmit voices into the phone [there is typically only one person talking at a time].

    thanks in advance!!
  2. Audioguru

    New Member

    Dec 20, 2007
    Polycom's wesite doesn't work today so I couldn't see their large room conference system.

    Most large room conference systems use a voice detector at each mic to turn on only one mic at a time. Then background noise and room echoes are not transmitted, and sound from the distant end from the speakers in the room are not causing false switching.
  3. thingmaker3

    Retired Moderator

    May 16, 2005
    This is a long-shot, but...

    When a Polycom system is first plugged in, it adjusts itself for ambient room noise. Then it beeps once.

    If the system in question is indeed a Polycom, how noisy was the environment when you plugged it in? You might get away with unplugging it and plugging back in on a quiet evening.
  4. Audioguru

    New Member

    Dec 20, 2007
    I saw Polycom tele-conference speakerphones many years ago when they premiered. They made a few seconds of pink noise in the room to set up their echo-cancellers so that they can try to be full duplex and cancel the distant end sound from being transmitted back to the distant end as a long distance echo. It had nothing to do with the noise level in the room. Their conference phones have not changed (maybe the software is improved) for about 15 years.

    Polycom's website works now.
    Their large room tele-conference unit the VTX100 has only two extra mics and has a range of 20 feet. It should cover your 40 feet by 10 feet room perfectly. Polycom's website has a demo with an ordinary speakerphone with the person is 18 feet away and cannot be heard. Then the demo switches to two of their conference phones connected together and the person 18 feet away is heard perfectly.