Here is a complete list of modules that aRts-0.3.4.1 supported,
with a status how far the port to the KDE2.0 aRts/MCOP version is.

Porting modules is usually a ten-minute task, unless the underlying
features are not yet provided by the new flow system or the general
idea of how things need to be done changed.

Synth_ADD                     done (kdelibs)
Synth_AMAN_CAPTURE            obsolete, see Synth_AMAN_RECORD, converter missing
Synth_AMAN_INJECT             obsolete, see Synth_AMAN_PLAY, ByteStreamToAudio
Synth_ATAN_SATURATE           done (kdemultimedia)
Synth_AUTOPANNER              done (kdemultimedia)
Synth_BRICKWALL_LIMITER       done (kdemultimedia)
Synth_BUS_DOWNLINK            done (kdelibs)
Synth_BUS_UPLINK              done (kdelibs)
Synth_CDELAY                  done (kdemultimedia)
Synth_DATA                    done (kdemultimedia)
Synth_DEBUG                   done (kdemultimedia)
Synth_DELAY                   done (kdemultimedia)
Synth_ENVELOPE_ADSR           done (kdemultimedia)
Synth_FILEPLAY                outfile name issue; called Synth_CAPTURE_WAV now
Synth_FM_SOURCE               done (kdemultimedia)
Synth_FREQUENCY               done (kdelibs)
Synth_FULL_DUPLEX_PLAY        obsolete, now done by Synth_PLAY (kdelibs)
Synth_FULL_DUPLEX_REC         obsolete, now done by Synth_REC (kdelibs)
Synth_FX_CFLANGER             done (kdemultimedia)
Synth_MIDI_DEBUG              done (kdemultimedia)
Synth_MIDI_MAP_ROUTER         todo, must fit in new midi architecture
Synth_MIDI_ROUTER             todo, must fit in new midi architecture
Synth_MIDI_SOURCE             obsolete
Synth_MOOG_VCF                done (kdemultimedia)
Synth_MUL                     done (kdelibs)
Synth_NIL                     done (kdemultimedia)
Synth_PARAM_GET               obsolete
Synth_PARAM_SET               obsolete
Synth_PARAM_SGET              obsolete
Synth_PARAM_SSET              obsolete
Synth_PITCH_SHIFT             done (kdemultimedia)
Synth_PLAY                    done (kdelibs), currently no mono play ability
Synth_PLAY_AKAI               todo
Synth_PLAY_AKAIS              todo
Synth_PLAY_PITCHED_WAV        maybe obsolete (kdelibs version supports speed)
Synth_PLAY_WAV                done (kdelibs)
Synth_PSCALE                  done (kdemultimedia)
Synth_RC                      done (kdemultimedia)
Synth_SEQUENCE                done (kdemultimedia)
Synth_SHELVE_CUTOFF           done (kdemultimedia)
Synth_STDIN                   obsolete
Synth_STDOUT                  obsolete
Synth_STD_EQUALIZER           done (kdemultimedia)
Synth_STRUCT_KILL             obsolete
Synth_TREMOLO                 done (kdemultimedia)
Synth_WAVE_PULSE              done (kdemultimedia, not in aRts 0.3.4.1)
Synth_WAVE_SIN                done (kdelibs)
Synth_WAVE_SOFTSAW            done (kdemultimedia)
Synth_WAVE_SQUARE             done (kdemultimedia)
Synth_WAVE_TRI                done (kdemultimedia)
Synth_XFADE                   done (kdemultimedia)