freeverb - a more recently developed Schroeder reverberator is “Freeverb” – a public domain C++ program by “Jezar at Dreampoint” used extensively in the free-software world. It uses four Schroeder allpasses in series and eight parallel Schroeder-Moorer filtered-feedback comb filters for each audio channel, and is said to be especially well tuned.

The figure shows the default signal-processing settings for the Freeverb left stereo channel. Processing for the right channel is obtained by adding an integer to each of the twelve delay-line lengths. This integer is called stereospread, and its default value is 23.