Posted for YoSamuel@aol.com:

 I may have a unique problem with my Chelton EFIS. The voice that tells you
 "check engine", "terrain terrain" etc. is so quiet in flight that I can
bearly
 hear it. On the ground before engine start, the voice volume is normal. I am
 
 running the latest software in which the volume control is not functional. I
 do hear the tone that alerts for cautions in flight better, but it too could
 
 be at a higher volume. I'm told that the tone and the voice emminate from the
 same chip and of course use the same wires. My audio panel is the Garmin
 340.  The pins from the Chelton to the Garmin check out to the correct
unmuted
 position. The wires show very small impedance, about .4 ohms. We have tried
 alternate Chelton boxes, Garmin 340's and headsets. All to no avail.
 
 Any ideas?
 
 Thanks. Dave Link.

[ 5.x software on an IDU1 (exp) screen is locked at max vol... the IDU3
(cert) boxes have more and louder voice alerts. What I do is crank the
headset amp to the max, and lower the vol on the radio and intercom
and I can hear the IDU1 fine, but boy, when the monroy traffic alerter
kick in, I get quite a jump :-)  -Rob ]