Originally Posted by Styrak
Don't worry about any other sound than the BB. You should be measuring the BB, not the first sound generated.
Hmm... some back-of-the-envelope calcs indicates that, to closely estimate the muzzle fps, the audio rig I'll be putting together will use two sheets of paper, with paper mounting frames 1 m apart, and muzzle set a 30 cm from first paper mount. Pickup mic would be set at the halfway mark of the mounts to pickup the impacts from both sheets. The proposed 30 cm separation distance would be used to help isolate the bb/paper impacts from the initial piston noise, and to avoid potential tearing of the first sheet from the muzzle blast (not expected, just being cautious). A baffled bb trap is proposed for the far end, with possible dense foam applied to the baffles to absorb kinetic energy as the bb is being trapped. The software I intend to use is AudioEdit.
Does this setup sound reasonable?