[Asterisk-Users] feature - VM gain adjust?

[Rich Adamson]

I'm toying with adding a feature request to provide some sort of
gain setting for voicemail when accessed from "certain" interfaces.
Maybe something like voicemail=6.0 (db) within a specific channel
section of zapata.conf corresponding to a pstn line.

Situation:
1. Someone calls into asterisk and leaves a voicemail. The sound
is recorded at some volume well below 0 db, and is directly related
to the distance asterisk is from the central office (pstn cable 
loss) plus whatever distance the user placing the call is from
his/her central office.
2. I receive a text message that a voicemail was left.
3. I call into asterisk remotely (assume from a cell phone) and
retreive the voicemail. My location creates another xx db of loss
between myself and asterisk, and voicemail can hardly be heard.

Actual Measured Values:
1. Asterisk is 5.6 db from the central office. Called from one
pstn line, through the central office, to asterisk and sending a
1004 hz tone at 0db. Recorded the tone into voicemail. (Tone should
have been recorded at about 11.2db, two times the cable loss)
2. Called into asterisk again, this time to retreive the voicemail
and measured the 1004 hz tone from voicemail. It was -36db "actual". 
This retreival added another 11.2db of loss due to pstn interfaces 
and plant loss.
3. The calls were through a TDM FXO module with rx and tx gains
set to 0. (Changing rx and tx gain to +3 db and repeating the test
resulted in a measured -30.5db signal, but these settings create
unwanted echo issues. Therefore adjusting channel gain is not an
option.)

The end result is that retreiving any voicemail message left from
a distant location and retreived from a distant location can hardly
be heard. By adding the proposed voicemail=6.0 statement to the
appropriate channel, any calls connected to voicemail via that
channel would effectively increase transmission levels by 6db (or
whatever the setting happened to be). In this example case, the
setting would increase the vm volume by 12db (or about 24db measured
in the above).

Anyone have any thoughts on this?

Rich