Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

AGC settings

I am having difficulty adjusting the AGC settings to get the recording of messages coming in from the PSTN to an acceptable level. We have had to drop the input gain on the FXO ports that the calls are coming in on due to echo issues and thus the volume of messgaes recorded is very low. I have tried to adjust the AGC taget db level but I am not making al ot of headway. What is the best way to go about cranking up the volume of the messages Unity records?

1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Re: AGC settings

if you adjust the target dB that will affect _all_ recording regardless of source (voice names, greetings, messages from internal and external) and will cause you to record messages that are slightly louder than the prompts - this is definitely _not_ what you want to do and is a very common mistake. The goal is to work _all_ recordings to -26 so everything matches. As I understand your problem, the PSTN messages are coming in so quiet the AGC is not able to adjust them up enough to meet the levels of everything else (I assume all other recording sources are fine).

You're best bet is to try and give the AGC a somewhat longer leash by letting it adjust a bit more than 5 dB... try 8 for instance and see how it sounds.

7 REPLIES
Cisco Employee

Re: AGC settings

AGC is not really for "boosting" the signal of a recorded message. It's really for normalizing the overall audio on a given message to a consistent level.

Have you checked out some of the audio quality troubleshooting steps?

http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_troubleshooting_guide_chapter09186a0080087146.html#xtocid1

New Member

Re: AGC settings

Yes, I am very familiar with those steps, but I really don't see anything there that I haven't already tried that will help me address the low volume of messgaes recorded from the PSTN. I really can't adjust the input gain higher so I need to try to boos the recording on Unity. Acording to the Docs, the Wavegain settings should be at 0 when AGC is enabled, which they are. Any other thoughts?

Cisco Employee

Re: AGC settings

Which version of Unity are you on?

What are the AGC settings you have set now? There are several relevant settings that you can actually see if you pop open the Set Volume tool (they display at the bottom).

In general adjusting the inbound dB of a message up or down by more than 5 dB is a seriously bad idea so the default settings (depending on which version of Unity you're running) will only allow an adjustment of 5 db max since larger adjustments can cause distortion and make the recorded message sound horrible.

The AGC is intended as a find adjustment to make sure all incoming messages come in or around -26 dB where the prompts are recorded at and where your greetings and voice names should be at as well - if you have messages coming in so quiet there's not a lot we can do without causing problems in other areas as well - if you arbitrarily crank up the record level across the boards then your PSTN messages will sound better but everything else will be "hot" - there's no way to selectively crank up the volumne on incoming messages based on their source, at least not from our end of the pond.

You can _try_ adjusting the "Max dB adjustement" value up a few notches but you risk distorting messages if you go too far with it. This is the "AGCGainThreshold" value found in HKLM\Software\ActiveVoice\MIU\1.0\Initalization.

However, I really don't think flogging Unity to make massive adjustements in wildly varying audio levels coming into it is going to be your long term solution here.

New Member

Re: AGC settings

I'm at 3.1.5 and the AGC settings are all at the default recommended in the Advanced settings tool. I think a slight boost upward might be good enough. I'll try to boost the Max dB adjustment slightly. Can I also adjust the AGCTargetDB value? Which way would make it louder, ie, is -24 louder or quieter than -26?

Cisco Employee

Re: AGC settings

if you adjust the target dB that will affect _all_ recording regardless of source (voice names, greetings, messages from internal and external) and will cause you to record messages that are slightly louder than the prompts - this is definitely _not_ what you want to do and is a very common mistake. The goal is to work _all_ recordings to -26 so everything matches. As I understand your problem, the PSTN messages are coming in so quiet the AGC is not able to adjust them up enough to meet the levels of everything else (I assume all other recording sources are fine).

You're best bet is to try and give the AGC a somewhat longer leash by letting it adjust a bit more than 5 dB... try 8 for instance and see how it sounds.

New Member

Re: AGC settings

I understand now, and it looks like once again you have saved me a lot of pain. I boosted to 8db and the incoming PSTN recordings sound infinately better. Thanks.

Cisco Employee

Re: AGC settings

good deal.

The QA testers started to notice distortion when releveling at or above 10 dB at a crack... it might not be a bad idea for us to to extend the leash to 8 dB by default - those extra 3 dB can make a lot of difference.

254
Views
0
Helpful
7
Replies
CreatePlease login to create content