A bank of adaptive filters is updated via a parallel or direct/parallel narrowband active noise control (ANC) system uses an error signal. This work presents a delayless filter bank to separate the frequency components of the error signal based on the sinusoidal frequencies of input signals to update the corresponding adaptive filters in a direct/parallel structure. A cost function is also proposed to develop an adaptive algorithm in order to reduce noise and increase convergence speed for this complete direct/parallel narrowband ANC system. Theoretical analysis results demonstrate the increased convergence speed. Moreover, the analysis results and increased noise reduction are verified based on simulation results.