Delayless subband active noise control

Wideband active noise control systems can often involve adaptive filter lengths with hundreds of taps. The high computational burden associated with such long filters can be reduced substantially by using subband processing, which has been widely employed in acoustic echo cancellation. A new technique for subband active noise control is introduced that eliminates the delay while retaining the computational and convergence speed advantages of subband processing. A numerical example using 32 subbands with measured room impulse responses demonstrates the workability of the delayless subband technique. Comparison with a conventional fullband active noise control algorithm shows that for an adaptive filter length of 512 taps, the computational load is reduced by a factor of about 3.<>