jsdafx – Digital Audio Effects in JavaScript

Audio Filters

This script demonstrates audio effects resulting from Audio Filters. It is designed for a first insight into the perceptual effect of filtering an audio signal. Besides the different filter functions and their acoustical effect the script offers a first insight into the logarithmic behavior of loudness and frequency resolution of our human acoustical perception.

The following filter types can be set in the lower part of the user interface; their parameters can be controlled by dragging the red dot(s) in the frequency response graph.

• Low-/High-pass filter (LP/HP) with control parameter
  • cut-off frequency
  • all frequencies above (LP) or below (HP) the cut-off frequency are attenuated according to the shown frequency response
• Low/High-frequency shelving filter (LFS/HFS) with control parameters
  • cut-off frequency fc
  • boost/cut
  • all frequencies below (LFS) or above (HFS) the cut-off frequency are boosted/cut according to the selected boost/cut
• Peak filter with control parameters
  • center frequency fc
  • boost/cut
  • Q-factor Q=fc/fb, which controls the bandwidth fb of the boost/cut around the adjusted center frequency fc. Lower Q-factor means wider bandwidth.
  • the peak filter boosts/cuts the center frequency with a bandwidth adjusted by the Q-factor.

The center window shows the frequency response (filter gain versus frequency) of the selected filter functions. You can choose between a linear and a logarithmic frequency axis.

You can choose between two predefined audio signals or your own local audio file to be processed.

Predefined music signal "Funk" is licensed under CC-BY-3.0 by unfinite.

Predefined music signal "Orchestra" is licensed under CC-BY-3.0 by Captain Pretzel.