[LAD] Best way to insert DSP module in audio chain in Linux

Hi,

I want to make is a DSP module that improves the sound quality
of the sound coming from the laptop builtin speakers by applying DSP
(FIR/IIR filters).
I want to route all audio played back (from for
instance an offline WAV or MP3 file, from a movie, or streamed from the internet) to
pass through the
DSP plugin whenever headphones are NOT connected. When headphones are connected no processing should be applied.
I
want to place the DSP module as close to the hardware as possible to
make sure all audio is really routed through the DSP plugin so I always
can enjoy
the DSP improvements made to the sound.

Where should I place this module/DSP code?
- As a plugin to PulseAudio?

- As a plugin to ALSA?
- As its own virtual sound card?

- In the audio driver for my built-in sound card?
- As a kernel module?
 

I have tried loading the LADSPA-module using the module-ladspa-sink in PulseAudio but I am not sure this is the best solution.
I need to remove some limitations in module-ladspa-sink to get it working properly ( multichannel audio, only DSP processing for internal speakers).

My requirements:

1) Must be able to detect if headphones are connected

2) Must be able to process stereo and multichannel (5.1/7.1) formats. I
need the multichannel formats to perform binaural downmixing to
stereo.
So it is important that I can receive multichannel audio and mix it down to stereo and output it to a stereo soundcard.

/Kim
                                               

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Received on Mon Aug 30 16:15:06 2010