DSP Effects

DSP, or Digital Signal Processing, allows you to apply effect filters to your in-game audio. As of now, DSP effects are only available in Panda if you use the FMOD audio library. By default, Panda ships using the OpenAL audio library but FMOD can be enabled simply by editing Config.prc. Please keep in mind that using FMOD in a commercial application will require purchasing a license.

You will need to change this line in your Config.prc: (some versions of Panda3D might already be set to FMOD)

audio-library-name p3openal_audio

To this:

audio-library-name p3fmod_audio

The FilterProperties Object

Any DSP you add to your sound will require the use of FilterProperties, which is a list of filters and their coefficients. Start with this import:

from panda3d.core import FilterProperties

This will allow you to create lists of filters, like this one:

fp = FilterProperties()

This just adds a blank filter list. From here we can add whatever filter we’d like. To stay consistent with the example below, we’ll add a reverb effect.

fp.addReverb(0.6, 0.5, 0.1, 0.1, 0.1)

All this really does is add this particular reverb to our filter list - sound is not yet affected. To apply these filters to our audio output, use:


where audioMgr is an AudioManager object, most likely base.sfxManagerList or base.musicManager.

Depending on the sound you use, reverb may be very or only slightly noticeable; try using a quick sound at first, like a clap.

You can add more than just reverb to your sound. The full list of available filters is here:


Below is a sample program for adding a reverb effect:

# This is just to ensure that we are using FMOD. In your application,
# please edit the Config.prc file that you distribute
from panda3d.core import loadPrcFileData
loadPrcFileData("", "audio-library-name p3fmod_audio")

from direct.showbase.ShowBase import ShowBase
from panda3d.core import FilterProperties

base = ShowBase()

mySound = loader.loadSfx("models/audio/sfx/GUI_rollover.wav")

fp = FilterProperties()
fp.addReverb(0.6, 0.5, 0.1, 0.1, 0.1)