Formerly, specialized hardware was required for DSPs. Nowadays almost any ordinary computer will do fine.
This plug-in implements the ideas of Digital Room Correction. Unlike the name suggests, this will not only compensate for resonances of your room but also your speakers response.
The concept is to do some measurements to characterize your room and your equipment and calculate an inverse transformation that will be applied to the sound before it is passed to speakers. You will be swept off your feet by the results!
The DRC123 plug-in features this for PM123. Which other audio player goes that far?
Whatever you do, you will need a very linear Microphone. The quality of the microphone immediately limits the quality of the compensation. Furthermore the microphone amplifier must also be very linear. You think all of this is very expensive? It isn't! Read the microphone page for recommendations.
Secondly you need a full duplex sound card. Again, you think it is expensive? It isn't! Almost any sound device is adequate to your needs, as long as it operates reliable in the way that it does not drop samples. This explicitly includes on board devices with a quite bad signal to noise ratio.
Oh, well, last but not least you need a sufficiently fast CPU. But don't fear, anything from 500 MHz up should be fine, although I recommend twice as much. The plug-in is well optimized. (Thanks to the superior FFTW library.)
At the configuration page select a working directory and setup the recording parameters.
To know what to compensate for you need to do at least one measurements of your sound equipment and listening room. But more than one measurement is strongly recommended. Depending on your sound card and you measurement setup it might be required to do a single calibration first.
Now it is time to calculate the inverse transformation function.
Now you are done. You only have to pass the sound through the inverse transformation. This is done on the fly by the plug-in. This step is also called deconvolution.
This plug-in will support all of the steps except for the prerequisites, of course. Now listen to the new crisp sound!