Cisco TelePresence SX20, Software version: TC6.2.0.20b1616 Echoe Cancellation

[Sarg .]

Hello Community,

I am trying to turn on Echo-cancellation on the Sx20 without much success.  I cannot actually see the option on the GUI to turn it on .  Does anyone know how to go about doing this.

The reason I want to turn on echeo cancellation is becuase when I call someone, the other person can hear his voice echoe becuase the TV sound is being played back to the caller via the Mic.

Cheers

[Magnus Ohm]

Hi Serenity

I recommend that you upgrade to TC6.3. Please read the following extract from the TC6.3 release notes:

Echo delay is automatically set

In earlier TC softwareversions,an experimental configuration (xConfiguration Experimental AudioecReferenceDelay) could be used to adjust the time slot for echo cancellation.

This is valuable when monitors with big delays are used for TelePresence. On integrated devices like EX and MX series, the systems have overall low latency so the echo cancellation is working correctly.

When using high latency monitors (typically consumer TV ́s with image processing) using HDMI audio output, the delay in the output can be so great that it arrives outside the time envelope that the echo canceller is using and thus is not corrected. This causes an echo. An automatic echo reference delay detection mechanism has been implemented for SX20 and C series codecs except C20 in TC6.3, which replaces the earlier experimental configuration.

Due to restricted CPU performance in the C20, the automatic detection feature is disabled and the value has to be manually set. The value is set by xConfiguration Audio EcReferenceDelay Mode.

In the beginning of a call, any abnormal delay (more than 30-40 ms) will trigger this algorithm and move the time slot for the echo cancellation detection,to correct any issues with echo.

Hope this helps.

/Magnus

[Sarg .]

Top man ! let me go off and test and get back to you with feedback.

Cheers

[Sarg .]

Well it didn't really work that well. The echoes stops when only one mic is used. but when I used two mics it gets an echoe. I think I will downgrade us the "xConfiguration Experimental AudioecReferenceDelay". do you think I will have this configuration option in "  TC 6.1 ?

[Jorgen Rehnstrand]

Hi Magnus

I have a Customer with a SX20 and TC 6.3 connected via HDMI to a Sharp Aquas LCD 60" LC-60LE651E.

They experience echo problem, have you heard anything about this problem with Shapr LED monitors?

Regards Jorgen

[Magnus Ohm]

First of all:

Is it the people behind the Sharp and SX20 that is hearing the echo or is it the far end that is hearing echo from the SX20 & Sharp monitor?

If you do a on the sx20:

xstatus //EcReferenceDelay

What are the values shown here?

Another option would be to put the monitor into a low delay mode like Game mode if possible.

/Magnus

[Jorgen Rehnstrand]

It´s the people in the room that hears the echo. We have tested with different systems rooms and the problem is localy. When we downgraded the system to TC 6.1 the problem stopped.

[Magnus Ohm]

So you hear the echo locally then the issue is usually on the far end. Did you do the exact same call? How is the call made? OBTP? CUCM? VCS?

It might be a good idea to open a TAC case here to dig into it. If you have not already opened one?

/Magnus

[vincentmol]

I have been reading up about echo and for some reason Sharp is mentioned a lot. I guess they use slower than normal CPU or their software is not as efficient. This causes a longer then usual delay between input and output.

Sharp has a 'Game mode' and it goes under the name of 'Vyper Drive'. This will reduce image and sound quality but that is with every brand/model. Do NOT use movie or sport mode for sure. They increase the amount of processing that is done and that will increase lag.

Other setting to help with echo is to have the output of the SX20 set as close as possible to the screen resolution. This reduces the amount of processing the TV has to do and thus reduces delay caused by the TV. If you have to pick between downscaling or upscaling, pick downscaling. Downscaling is faster than upscaling and processing delay in the end point shouldn't be a concern.

Firmware 6.3 changes the Audio ecReferenceDelay automatically so this firmware is recommanded.