AN IMPROVED MLS MEASUREMENT SYSTEM FOR ACQUIRING ROOM IMPULSE RESPONSES

Maximum-length sequences (MLSs) have proven very useful for the measurement of acoustical transfer functions . However, measurements are affected by background noise, nonlinearities and time variance in the system under test. These errors can cause a distorted impulse response, add spurious impulses to the measurement or reduce the effective signal-to-noise ratio. The origins of errors made in an MLS measurement system are described with focus on room impulse response (RIR) measurements. Practical solutions are given so that room impulse responses can be acquired with high immunity against nonlinear distortion and noise. Based upon this knowledge a PC-based measurements system was designed and implemented.