The only audio level controls the SX20 has is for the microphones, the line level or content audio inputs don't have any options to adjust the audio level that I know of, the admin guide also doesn't list any options either. Have you tried to plug the audio source into something else to see if it could be the source, and not the codec. The codec should simply pass the audio it receives in.
Ya I'm thinking of reinstalling the firmware. I just don't understand why there is no actual way to monitor or adjust a level input. It's there for the mics but why not the line? Baffling. This unit has been nothing but problems since we started using them. The signal via the hdmi is so weak that it has to plug directly in to a projector to even work. It alsi doesn't pick up the signal from any media boxes ive tried going in to it. 3.5mm mic and line jacks instead of 1/4" or xlr and no analog source input make me question this purchasing decision. It'd be passable if everything worked out of the box, but struggling to find cable and adapter combinations that actually work with the unit is a struggle.
The reason you only have basic microphone audio options is because the SX20 is not meant to be an integrators codec, this is also why it only contains a 3.5mm and RCA inputs, XLR inputs are on the larger integrator codecs. Integrator codecs such as the SX80 allow full control of microphone and line audio options, as well as euroblock connectors for both types of audio inputs. No Cisco codec has a 1/4" audio connector.
The unit provides the functionality so the control should be there in my opinion. I dont think I'm wrong in thinking if you are going to be locked out that it should at least work.
In real world scenarios rarely do you hear people say man I wish this had euroblock connectors for audio. When we met with our cisco rep they really pushed this unit and knew our scenarios. At 8 grand a pop I don't think I should be needing work around for video in, video out and audio ins. Hopefully there are updates down the line or we will have to revisit what our next purchases will be and stick these in only the most basic room scenarios.
Thanks for your help.