Echo when connected Tandberg 880 via DVD recorder

[turbo]

When I connect my Tandberg 880 via a DVD recorder, the echo cancellation doesn't seem to work. The other side can hear themselves from my side or I can hear myself from their side.

Have anyone come across this problem?

[robertk]

When I connect my Tandberg 880 via a DVD recorder, the echo cancellation doesn't seem to work. The other side can hear themselves from my side or I can hear myself from their side.

Have anyone come across this problem?

Yes, it is because Tandberg MIX the audio FROM the VCR input together with normal audio.

After years of nagging they added the option AUTO on the VCR input, however they still haven't understood that it has to be enabled by default. (If you don't have an option AUTO, then you have too old software)

Just go into the AUDIO settings, and change it to AUTO for the VCR input. (remeber that Tandberg saves this settings on all PRESET positions, so reset them all with this setting set to AUTO)

Now you will only get audio from your DVD/VCR when you send the VCR video, IE press the VCR button.

Some day maybe Tandberg understands how a VCR operates and change the default behaviour on the VCR audio input to AUTO mode by default :^)


//Robert

[trapehzoid]

maybe he's just plugged into the wrong input. If you plug into the aux incorrectly, the mix minus is different.

The auto setting simply means the vcr audio input will be heard only when the VCR input is selected. It has nothing to do with if the far-end would hear echo or not. Worst case, they would hear echo when the VCR is chosen, and not when it was.. and how would that solve his problem?

Either the EC is turned off (which you can do per input), or more then likely he's not using the correct inputs.

[trapehzoid]

plus.. hearing yourself from their side has nothing to do at all with your audio setup. If you hear yourself DELAYED, its their side. If you hear yourself immediatly (like a PA system), then you have your inputs plugged in wrong. You are plugged into the AUX instead of the VCR audio inputs.

[robertk]

maybe he's just plugged into the wrong input. If you plug into the aux incorrectly, the mix minus is different.


This might be the case ofcourse...



The auto setting simply means the vcr audio input will be heard only when the VCR input is selected. It has nothing to do with if the far-end would hear echo or not. Worst case, they would hear echo when the VCR is chosen, and not when it was.. and how would that solve his problem?


Aha, one more person who, like Tandberg, don't understand how a VCR works :)

IF you connect a VCR for both recording and playback on a Tandberg. AND select the AV input to record the conference. Then instead of recording your conference you just leave the VCR idling on that channel (av1 or whatever) then the audio from VCR out on your Tandberg will go to the AV input on the VCR and the VCR will pass it trough to the AV out, wich is connected to the VCR input on the Tandberg. You will hear the MIXED Local and Remote audio in your conference.

By selecting AUTO on the VCR input you will stop this behaviour and only hear the audio from the VCR when you actually want to play something from it.




Either the EC is turned off (which you can do per input), or more then likely he's not using the correct inputs.

Maybe, but most likely not.


//Robert

[robertk]

plus.. hearing yourself from their side has nothing to do at all with your audio setup. If you hear yourself DELAYED, its their side. If you hear yourself immediatly (like a PA system), then you have your inputs plugged in wrong. You are plugged into the AUX instead of the VCR audio inputs.

Sure, but he says he hear BOTH his own voice AND the remote, and the same at the remote end, they hear themselves also.

I put my money on the AUTO setting for VCR input :)


//Robert

[trapehzoid]

IF you connect a VCR for both recording and playback on a Tandberg. AND select the AV input to record the conference. Then instead of recording your conference you just leave the VCR idling on that channel (av1 or whatever) then the audio from VCR out on your Tandberg will go to the AV input on the VCR and the VCR will pass it trough to the AV out, wich is connected to the VCR input on the Tandberg. You will hear the MIXED Local and Remote audio in your conference.

Incorrect.

The mix minus setup on the VCR inputs and outputs are setup so that the VCR input is

- played locally (so the local audience hears it)
- sent to far-end (so the remote site hears it)

The transmit audio to the remote site is MICS+AUXIN+VCRIN

Audioout1 is a mix of remote audio+VCRIN+AUXIN
VCROUT is a mix of remote audio+MICS+AUXIN

So yes, you will hear the VCR audio locally (by design). Its not the VCR loop that makes you hear it locally, its the mix minus. Want to prove it? That's why you hear a DVD player plugged into the VCR input locally! No loop in the VCR in/out there.

The VCR 'auto' setting changes NONE of that. The only thing 'auto' does is turn the audio input on or off (completely, so neither side hears its) depending on the video source selected. It does not change the mix minus AT ALL.

Where a VCR will cause echo is when you hook the audio out of the codec to the input of the VCR, and the VCR output to the codec, and the VCR is in a recording or monitor mode where it outputs what its recording. This creates a loop out of the codec, right back into it. This is why the VCR input has a specialized echo canceller on that input, just to eliminate that loop. It is NOT the loop why you hear it locally in normal operation. Its in the documentation, and the simple prove it to yourself test is the DVD player.. its output only.. yet you hear it locally in the room.

the VCR auto setting does NOTHING to the mix minus setup of the codec.. it simply acts as an auto enable/disable of the VCR audio input based on source selection.

Its mix minus that makes you hear the VCR input locally. I got $10 bucks that says the guys echo problem is using the inputs/outputs incorrectly.

[trapehzoid]

Sure, but he says he hear BOTH his own voice AND the remote, and the same at the remote end, they hear themselves also.



MIC is sent to both AUX OUT, VCR OUT, and to the remote site. Remote audio is sent to main out, aux out, and vcr out.

The audio feedback is real-time and so loud when using the Aux inputs that its likely the far-end is hearing echo because of it. He might just have his TV plugged into out 2 instead of out 1.. you'll get this behavior there too.

The easy way to tell that is like I said before.. if you hear your own microphones coming through the loudspeaker real-time.. your problem is using the audio outputs incorrectly.

[trapehzoid]

ps.. that's also why the 'auto' setting doesn't change or affect what the VCR is recording at all during the conference... the mix minus never changes.

[robertk]

Incorrect.
Its mix minus that makes you hear the VCR input locally. I got $10 bucks that says the guys echo problem is using the inputs/outputs incorrectly.

I am defeated, you are ofcourse correct about the VCR output :)


//Robert

[trapehzoid]

I got a new bet.. he's using output1 and 2 from the codec to try to put stereo in the TV.