Firmware Version

Volume Settings

Output headphone volume. Limiting ouput volume to 0.8 due to distortions at high volume.

0.75

EQ Settings

Adjust the individual filter parameters to change the EQ frequency response. The filters are based on 'peaking' Biquad design.



Psycho-acoustic Bass Enhancer

Enhances bass by mixing a mono, low-pass filtered copy of the original stereo signal, back into the stereo signal, which is then optionally high pass filtered (to remove inaudible subsonic frequencies).

0
0

Auto Volume

Compressor/expander to help reduce clipping with sudden loud noises.

0
0
0
  • Max Gain is the maximum gain that can be applied for expanding.
  • Response controls the integration time for the compressor. Larger values average the volume over a longer time, allowing short-term peaks through.
  • 'Soft knee' compressor is used to progressively compress louder values which are near to or above the threshold (the louder they are, the greater the compression).
  • 'Hard limit' compressor decrease all values above the threshold to the same loudness.
  • Threshold is specified as a range between -96dBFS to 0dBFS (dB relative to full scale), where -18dBFS is a typical value.
  • Attack is the rate of decrease in gain when the signal is over threshold. Too high of an attack causes an unnatural sound as the input signal may be distorted. Too low of an attack may cause saturation of the output as the incoming signal is not compressed quickly enough.
  • Decay controls how fast gain is restored once the level drops below threshold. It is typically set to a longer value than attack. It is desirable to use very slow decay rate to avoid any distortion in the signal and prevent the AVC from entering a continuous attack-decay loop.

Pulse USB Power

Most USB battery powerbank will turn off if consumed current is too low. This option periodically wastes current to keep USB power on. Experiment to find the lowest values for your battery pack. Each pulse consumes about ~35mA. If this is not enough, you can connect A0 pin with a short wire to GND to consume more current (~50mA).

Save to flash and restart the board to take effect. This feature is disabled automatically if the USB is plugged to a computer.