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New Member

Message volume going up and down

I know this is a topic that has been addressed in the forum. I have article a from Cisco's website titled Audio Quality. I am having a problem with message volume going up and down. I have Unity 3.1.4. This is what the server has been loaded with so it has not been upgraded. A message will start at the correct volume but then will get very low then will return to normal and go back down. The system is using the default codec. I am confused about which option to change to try to correct this problem.

Cisco Employee

Re: Message volume going up and down

Not sure which audio doc you're looking at... just in case, this is the one you want to refer to out of the troubleshooting guide for 3.1(4):

The setting that will help you here is the AGC (automatic Gain control) - the doc above runs you through everything you need to do. You should use the updated AGC settings in the registry it reccomends and make sure your greetings and voice names are leveled to the same dB level the AGC is set to (-26 db) so everything matches - this is done with the SetVolume utility that is also covered in that doc.

New Member

Re: Message volume going up and down

Ok, I have checked my Unity setting and I see that they match everything this document says. If that is the case you suggested looking at AGC. I have looked at the registry changes that I will need to make. The document suggest creating a DWORD value AGCtargetDB for each port. Now is the document suggesting that I choose -26dB. What affect will a higher or lower value have?

Cisco Employee

Re: Message volume going up and down

The document I have doesn't say anything about setting the AGC value "for each port"... you can't do that - the AGC value is system wide for all CM ports (Dialogic cards have their own settings here).

If you choose to use a different dB setting then as new messages, greetings and voice names are recorded they will be louder or quieter depending. I strongly suggest sticking with -26 since that's what the prompts are recorded at and you'll want to have everything at the same level.

Remember, the AGC settings only affect records, not playbacks so if you're twiddling with the AGC settings and then listening to prerecorded greetings and messages they will still sound exactly the same. That's expected.

I'd be very suprised if you had your AGC configured and active properly that new recordings would still be fluxuating wildly in their volume. It does a reasonably good job of working things towards the target dB during records.

New Member

Re: Message volume going up and down

First if you print the document link that you entered in a earlier response on page 11 of 16 there is a section called Automatic Gain Control. It suggest that you can indeed make the changes to the registry. However I want to do what Cisco suggests. First at least to me the document is not clear. The document likes to speak about Hiss and silence. I do not experience either of these. So exactly what setting should I change?

Cisco Employee

Re: Message volume going up and down

All you need to do is steps 1 through 20 in the "Set Volume Level Utility" which starts in the document here:

There's no need to go through the rest of the advanced stuff. The Set Volume Utility will automatically set your registry settings for the target dB level and the sample rate etc... reccomended in the doc. Once you've run that and you have the values in there it suggests and you restart Unity it should get setup the way you need it.

There's no need to fiddle with the per ports stuff at all - this is not a good idea and I'm not even sure why it's in that doc. Setting the one value in the MIU\1.0\Initalization section is all you need - this will set it for all CM ports in Unity.

The Hiss and Pop discussion it has in there is simply explaining the problems with the default AGC settings in 3.1(3) and how they were fixed in 3.1(4) and later. The new values laid out in the section above (-26 target dB, 8000 sample size, 5 Max dbAdjustment, -45 min dB threshold) prevent those problems... that's all that section is talking about.

If going through steps 1 through 20 at the top of the doc there doesn't do what you need it to, all I can suggest is to open a TAC case and go from there.


Re: Message volume going up and down

It could be CSCdy27331:


The volume level on an IP phone appears to fluctuate during a phone call while using handset or



This happens on calls between 2 IP phones. This has been observed running

the P00303020208 load.


Switch to speaker mode and then back to handset or headset mode


Upgrade to phone load P00303010409 or later

Upgrade to phone load P00303020210 or later

Upgrade to phone load P00303030100 or later


New Member

Re: Message volume going up and down

I am having the same problem.

Did using the Set Volume utility work? There are many posts about this issue, but no one says what fixed it, or whether anything fixed it.

The volume on 99.5% of my calls and messages are fine. It is just the small minority that have a problem with volume fade out. I am hesitant to start changing my volume levels when most calls are fine.

If anyone knows how someone actually fixed this I would love to know.

Thanks in advance,

Aaron Gabrielson

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