Effect of Stimulus Speed Error on Measured Room Acoustic Parameters

Impulse response measurements based on deconvolution techniques normally require a connection between the stimulus generator and the response recording device. This is inconvenient for long distance measurements, in particular of room acoustics. Playing the excitation signal from a CD generally introduces errors due to a speed mismatch between the CD player and the response recorder. It is investigated which speed differences are to be expected, and how common room acoustic parameters are affected. It is found that MLS stimuli are not really usable. On the other hand, sweeps allow large speed errors and can be used in a broad range of situations. Parameters based on short initial energy intervals are prone to errors when measured with stimuli played too fast rather than too slowly.