[asterisk-users] I can hear my own voice through the headset

[Dave Platt]

> Here is my IP-PBX setupmy setup is : sips softphone <-> asterisk <-> xorcom PSTN gateway <-> pstn line to telcoi'm using xlite for windows

> when I make a phone call (sip - outgoing channel),I can hear my own voice so clear. it's very annoying mewhen talking a little loud... any solution? 

Two questions:

(1) Does the problem occur when you make a SIP-to-SIP call, without
    the PSTN being involved?

(2) When you hear your own voice in the headset, is it delayed, or
    is just an immediate louder-than-you-want "side-tone"?

If it *does* occur in SIP-to-SIP calls, this would rule out your
XORCOM and the PSTN as the cause.  If it's only occurring in
SIP-to-PSTN calls, then the XORCOM and PSTN (or the interaction
between them) is a likely suspect.

There are several things which can cause this sort of problem.

(A) Direct acoustic feedback within the headset.  In this case, you'd
    probably hear it even if the headset was unplugged entirely.  The
    only cure is to buy a better headset.

(B) Incorrect audio-mixer settings in your PC.  To the PC audio
    infrastructure, a headset usually "looks like" a microphone
    and a separate speaker.  The audio mixer (hardware and software)
    usually has an ability to mix some of what the microphone "hears"
    into the speaker output.  If this "knob" is turned up too high,
    you'll hear your own voice too loudly.  If too low, you won't
    hear your own voice at all when you speak into the headset, and
    many people find this lack of side-tone to be confusing.

    The cure here is to adjust the audio side-tone level, either
    in your Windows audio-mixer control panel, or in X-Lite (if
    it has such an adjustment).

(C) Electrical "reflection" from an analog impedance discontinuity
    in the analog telephone-line system.  This can result from
    a mismatch between the telephone wiring, and the PSTN interface
    device, and can occur at any point in the analog transmission.

    If the loud side-tone you hear is *not* delayed noticeably,
    then the impedance mismatch might be at your XORCOM/PSTN
    interface.  The XORCOM may have a software adjustment or
    jumper setting, to match its audio impedance to that of your
    local phone line... try fiddling with these settings to see
    if they reduce the excessive side-tone level.

    If the loud side-tone you hear is delayed (it sounds a bit
    like an echo) then it may very well be at the "far end" of
    the phone line, outside of your own physical control... it
    might be at your local phone office, or anywhere between you
    and the far end of the phone connection.  Not much you can do
    about this.

(D) Audio feedback at the far end of the call, in a cheap phone
    handset.  Sometimes, audio from the "back side" of the speaker
    in a handset travels through the body of the handset and is
    picked up by the microphone, and results in an audible delayed
    "echo" of the voice from the far end of the line.  Using a
    better handset, or stuffing the handset full of audio damping
    material (cloth or cotton or fiberglass) is the cure here.