This paper presented a method of designing low-power feedback active noise control filter
optimized for headphones/earphones. Using constrained optimization, we obtained a high order FIR noise
control filter to ensure reasonable noise attenuation performance at high sampling frequency environment.
Then using infinite impulse response (IIR) approximation method called Balanced Model Truncation (BMT),
we obtained a low order IIR noise control filter suitable for low-power digital signal processing system like
headphones/earphones. For further performance improvement, we utilized frequency warping method so that
we could obtain more accurately approximated IIR filter and we ensured system stability by reconstructing
the low order IIR filter in form of cascaded second order IIR filters. ANC simulation with white noise and
stability test verified that the proposed algorithm had superior attenuation performance and better
robustness compared to the conventional algorithm.