Initial Speakerphone Distortion

[CaseFile]

I have an intermitent problem I have been unable to nail down.
On 8941 sets, if someone makes a speakerphone call to another 8941 that answers using speakerphone...
For the first approx. 8 seconds of the call, there is a loud distortion, almost like feed back.
Then the noise goes away and the call is fine.
The noise can be stopped right away if one of the users turn the mute button on and off.
Then the call is fine.
It occurs to different phones, different users, at different times.

Anybody have any suggestions as to where to look ?

 

[gnrslash4life]

Just 8941 phones? Try a different firmware.

Certifications:
A+
Network+
CCENT
CCNA Voice
TVOICE
CAPPS

 

[CaseFile]

I have used multiple firmwares, and it failed on ucm 8.5 as well as 10.5

 

[trvlr1]

Never used this kind of phone before, but it sounds like they are auto adjusting their settings to get the best sound between compatible phones, is there a setting on the phone that might lock this down and stop the "auto adjust"?
Just a thought.