The sensitivity is directly affected by the damping. These little SFI's can be extremely insensitive when highly damped. I more or less gave up trying to use them without amplification.
On a somewhat related note : I had an SFI - K140 transplant ( not sure of the exact model but silver like the 142 ) , which suffered similar troubles initially. The pivot assembly for attaching the headband acts like a huge reflector disc and essentially turns them into tweeters. I drilled much of the plastic away leaving just enough for structural integrity. I then damped the driver very lightly - this is a compromise as the bass then tends to be a little more "loose" ( it is still good bass and not flabby by any means but you can hear the difference when comparing other orthos ) . The damping I used was a thin , dense donut behind the driver - center of driver completely undamped while outer portion reasonably damped. The space is very tight and I used a dense cashmere material , a synthetic chamois would give similar results. The earpads of the sextet and larger airspace will affect the response , probably for the better compared to the smaller AKG but it also means more air for a smaller driver to move. Your experience will guide this theory.
great work thus far ..dB
