Re: [asterisk-users] 1.8.3 - IAX - echo - jitterbuffer
On Mon, Mar 7, 2011 at 6:53 PM, Dave Platt dpl...@radagast.org wrote: I'm using iaxagent on a Droid X to connect by IAX to 1.8.3 at the office. 1.8.3 has sip phones. The audio is fine on the Droid X side. On the office side, they hear an echo of _their_ speech, not mine. The office uses sip-providers generally without any echo problem. Where do I start to figure this out? How do I narrow it down? Can I figure out if it is an iaxagent problem? Could using jitterbuffer cause this? One thing you must consider, is that this echo they're hearing may be entirely an acoustic one, within (or around) the Droid itself. It's very possible for the microphone in a handset to pick up sound being emitted by the handset's speaker. This acoustic feedback can occur within the handset itself (sound from the speaker leaks through the chassis of the handset and reaches the microphone from behind), via mechanical coupling through the handset body, or by the mic picking up the sound from the outside (after it has come out of the speaker into the air). The best way to determine whether this is the case, is probably to shut down the speaker and isolate the mic... plug in an earphone which has a separate mic on its cord, and see if the callers still report the echo. If they do, it's due to electronic or digital goofs somewhere, but if they do not, it's due to acoustic feedback at the handset. There are (in principle) three ways to reduce or eliminate the echo: - Damp it out physically - block the acoustic feedback pathways. In a small USB phone handset I have, I found it necessary to stuff the open spaces inside the handset with cotton and foam, to block the back-wave from the speaker before it reached the microphone. - Use software which has some sort of VOX (voice-operated switch) detection or squelching... so that when the sound level at the microphone is less than you'd get by speaking into the mic, the handset cuts off the mic audio pathway entirely, and sends only silence (or sends nothing at all, although Asterisk doesn't always deal gracefully with this). - Use a better handset. I get no acoustic echo from the Droid X when I make a standard cell call, even at full volume. Nor is the blogosphere full of complaints about echos on Droid X. It's also physically one of the largest, if not the largest, cell phone. This may mean that the call function in android has really good echo cancelling. -- _ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] 1.8.3 - IAX - echo - jitterbuffer
sean darcy wrote: BTW, if you haven't, try iaxagent on your phone. Sean, I'm probably one of the very few that have an Android and refuse to get a Google account. Does the developer have a site where iaxagent can be downloaded? I wouldn't mind giving it a try. Doug -- Ben Franklin quote: Those who would give up Essential Liberty to purchase a little Temporary Safety, deserve neither Liberty nor Safety. -- _ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] 1.8.3 - IAX - echo - jitterbuffer
On 8 Mar 2011, at 02:12, sean darcy wrote: On 03/07/2011 05:26 PM, Kevin P. Fleming wrote: On 03/07/2011 04:15 PM, sean darcy wrote: I'm using iaxagent on a Droid X to connect by IAX to 1.8.3 at the office. 1.8.3 has sip phones. The audio is fine on the Droid X side. On the office side, they hear an echo of _their_ speech, not mine. The office uses sip-providers generally without any echo problem. Where do I start to figure this out? How do I narrow it down? Can I figure out if it is an iaxagent problem? Could using jitterbuffer cause this? This is probably acoustic echo from your phone. The jitterbuffer has nothing to do with this. Yup. Turning down the volume on the call reduces the echo. Of course, now I can barely hear the office! I can keep the volume up on standard calls from the Droid X, which suggests that Android has some echo cancelling on phone calls. I'll try to see if the developer of iaxagent can do anything. BTW, if you haven't, try iaxagent on your phone. It's a very clever use of the iax protocol and leverages iax's strengths. iax makes a lot of sense on mobiles, dealing with the NAT issues from inconsistent access points easily. Thanks for the help. sean Anyone know how iaxagent is accessing the speaker/mic ? In theory the phone should have echo cancellation built-in, but it may only be enabled in certain cases. T. Tim Panton - Web/VoIP consultant and implementor www.westhawk.co.uk -- _ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
[asterisk-users] 1.8.3 - IAX - echo - jitterbuffer
I'm using iaxagent on a Droid X to connect by IAX to 1.8.3 at the office. 1.8.3 has sip phones. The audio is fine on the Droid X side. On the office side, they hear an echo of _their_ speech, not mine. The office uses sip-providers generally without any echo problem. Where do I start to figure this out? How do I narrow it down? Can I figure out if it is an iaxagent problem? Could using jitterbuffer cause this? Thanks for any help. sean -- _ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] 1.8.3 - IAX - echo - jitterbuffer
On 03/07/2011 04:15 PM, sean darcy wrote: I'm using iaxagent on a Droid X to connect by IAX to 1.8.3 at the office. 1.8.3 has sip phones. The audio is fine on the Droid X side. On the office side, they hear an echo of _their_ speech, not mine. The office uses sip-providers generally without any echo problem. Where do I start to figure this out? How do I narrow it down? Can I figure out if it is an iaxagent problem? Could using jitterbuffer cause this? This is probably acoustic echo from your phone. The jitterbuffer has nothing to do with this. -- Kevin P. Fleming Digium, Inc. | Director of Software Technologies Jabber: kflem...@digium.com | SIP: kpflem...@digium.com | Skype: kpfleming 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA Check us out at www.digium.com www.asterisk.org -- _ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] 1.8.3 - IAX - echo - jitterbuffer
I'm using iaxagent on a Droid X to connect by IAX to 1.8.3 at the office. 1.8.3 has sip phones. The audio is fine on the Droid X side. On the office side, they hear an echo of _their_ speech, not mine. The office uses sip-providers generally without any echo problem. Where do I start to figure this out? How do I narrow it down? Can I figure out if it is an iaxagent problem? Could using jitterbuffer cause this? One thing you must consider, is that this echo they're hearing may be entirely an acoustic one, within (or around) the Droid itself. It's very possible for the microphone in a handset to pick up sound being emitted by the handset's speaker. This acoustic feedback can occur within the handset itself (sound from the speaker leaks through the chassis of the handset and reaches the microphone from behind), via mechanical coupling through the handset body, or by the mic picking up the sound from the outside (after it has come out of the speaker into the air). The best way to determine whether this is the case, is probably to shut down the speaker and isolate the mic... plug in an earphone which has a separate mic on its cord, and see if the callers still report the echo. If they do, it's due to electronic or digital goofs somewhere, but if they do not, it's due to acoustic feedback at the handset. There are (in principle) three ways to reduce or eliminate the echo: - Damp it out physically - block the acoustic feedback pathways. In a small USB phone handset I have, I found it necessary to stuff the open spaces inside the handset with cotton and foam, to block the back-wave from the speaker before it reached the microphone. - Use software which has some sort of VOX (voice-operated switch) detection or squelching... so that when the sound level at the microphone is less than you'd get by speaking into the mic, the handset cuts off the mic audio pathway entirely, and sends only silence (or sends nothing at all, although Asterisk doesn't always deal gracefully with this). - Use a better handset. -- _ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] 1.8.3 - IAX - echo - jitterbuffer
On 03/07/2011 05:26 PM, Kevin P. Fleming wrote: On 03/07/2011 04:15 PM, sean darcy wrote: I'm using iaxagent on a Droid X to connect by IAX to 1.8.3 at the office. 1.8.3 has sip phones. The audio is fine on the Droid X side. On the office side, they hear an echo of _their_ speech, not mine. The office uses sip-providers generally without any echo problem. Where do I start to figure this out? How do I narrow it down? Can I figure out if it is an iaxagent problem? Could using jitterbuffer cause this? This is probably acoustic echo from your phone. The jitterbuffer has nothing to do with this. Yup. Turning down the volume on the call reduces the echo. Of course, now I can barely hear the office! I can keep the volume up on standard calls from the Droid X, which suggests that Android has some echo cancelling on phone calls. I'll try to see if the developer of iaxagent can do anything. BTW, if you haven't, try iaxagent on your phone. It's a very clever use of the iax protocol and leverages iax's strengths. iax makes a lot of sense on mobiles, dealing with the NAT issues from inconsistent access points easily. Thanks for the help. sean -- _ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
