If you notice, there is a general correlation between the amount of relative trim boost between channels, and the sensitivity of the speakers for those channels. That can explain some of the difference. The amps could also have different sensitivities, i.e. the amount of voltage into the amp to put a certain power out. If all this is true, then there is not much else to do. You might confirm the calibrations using the internal noise generator in the 950. If there is a huge difference, there might be something wrong somewhere. I know there is an issue with the Avia disc that is meant to be used at 85db rather than 75db, but the Video Essentials I believe is meant for 75db. Might double check in the booklet, or the on-screen instructions. If you don't get audible hiss at reasonable distances from the speaker and the calibrations are correct, I'd say it is just sensitivity differences betweeen the speakers / amps.