Schroeder Reverb Written by Iain McCurdy, 2010 -iadc -odac -dm0 sr = 44100 ksmps = 32 nchnls = 2 0dbfs = 1 ;FLTK INTERFACE CODE;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; FLcolor 255, 255, 255, 0, 0, 0 ;SET INTERFACE COLOURS ; LABEL | WIDTH | HEIGHT | X | Y FLpanel "Schroeder Reverb", 500, 520, 0, 0 ;SWITCHES ON | OFF | TYPE | WIDTH | HEIGHT | X | Y | OPCODE | INS | STARTTIM | IDUR gkOnOff,ihOnOff FLbutton "On/Off", 1, 0, 22, 150, 30, 5, 5, 0, 1, 0, -1 FLsetColor2 255, 255, 50, ihOnOff ;SET SECONDARY COLOUR TO YELLOW ;SLIDERS MIN | MAX | EXP | TYPE | DISP | WIDTH | HEIGHT | X | Y gkingain,ihingain FLslider "Live Input Gain", 0, 1, 0, 23, -1, 140, 20, 350, 5 ;BORDERS TYPE | FONT | SIZE | WIDTH | HEIGHT | X | Y ih FLbox "", 6, 9, 15, 115, 110, 5, 50 ih FLbox "", 6, 9, 15, 115, 110, 130, 50 ih FLbox "", 6, 9, 15, 115, 110, 255, 50 ih FLbox "", 6, 9, 15, 115, 110, 380, 50 ih FLbox "Comb 1", 1, 2, 16, 105, 15, 10, 60 ih FLbox "Comb 2", 1, 2, 16, 105, 15, 135, 60 ih FLbox "Comb 3", 1, 2, 16, 105, 15, 260, 60 ih FLbox "Comb 4", 1, 2, 16, 105, 15, 385, 60 ih FLbox "", 6, 9, 15, 115, 110, 195, 170 ih FLbox "Allpass 1", 1, 2, 16, 105, 15, 198, 180 ih FLbox "", 6, 9, 15, 115, 110, 195, 290 ih FLbox "Allpass 2", 1, 2, 16, 105, 15, 198, 300 ih FLbox "", 6, 9, 15, 490, 40, 5, 475 ih FLbox "Presets:", 1, 4, 16, 60, 20, 20, 485 ;SWITCHES ON | OFF | TYPE | WIDTH | HEIGHT | X | Y | OPCODE | INS | STARTTIM | IDUR, LPT1 LPT2 LPT3 LPT4 RVT1 RVT2 RVT3 RVT4 LPT5 LPT6 RVT5 RVT6 MIX gkLHall,ihLHall FLbutton "Large Hall", 1, 0, 21, 90, 20, 100,485, 0, 3, 0, 0.01, 0.0297, 0.0371, 0.0411, 0.0437,3.5, 3.5, 3.5, 3.5, 0.09683, 0.03292, 2, 2.7, 0.8 gkHall,ihHall FLbutton "Med. Hall", 1, 0, 21, 90, 20, 195,485, 0, 3, 0, 0.01, 0.0297, 0.0371, 0.0411, 0.0437,1.5, 1.5, 1.5, 1.5, 0.03297, 0.04233, 0.5, 0.5, 0.85 gkRoom,ihRoom FLbutton "Med. Room", 1, 0, 21, 90, 20, 290,485, 0, 3, 0, 0.01, 0.0297, 0.0371, 0.0411, 0.0437, 0.8, 0.8, 0.8, 0.8, 0.01297, 0.01233, 0.1, 0.1, 0.85 gkHall,ihSRoom FLbutton "Sm. Room", 1, 0, 21, 90, 20, 385,485, 0, 3, 0, 0.01, 0.0297, 0.0371, 0.0411, 0.0437, 0.3, 0.3, 0.3, 0.3, 0.0029683,0.0023292,0.05, 0.05, 0.9 ;TEXT INPUT BOXES MIN | MAX | STEP | TYPE | WIDTH | HEIGHT | X | Y gklpt1, gihlpt1 FLtext "Loop Time 1", 0.0001, 0.5, 0.0001, 1, 105, 20, 10, 80 gklpt2, gihlpt2 FLtext "Loop Time 2", 0.0001, 0.5, 0.0001, 1, 105, 20, 135, 80 gklpt3, gihlpt3 FLtext "Loop Time 3", 0.0001, 0.5, 0.0001, 1, 105, 20, 260, 80 gklpt4, gihlpt4 FLtext "Loop Time 4", 0.0001, 0.5, 0.0001, 1, 105, 20, 385, 80 gkrvt1, gihrvt1 FLtext "Reverb Time 1",0.01, 20, 0.0001, 1, 105, 20, 10, 120 gkrvt2, gihrvt2 FLtext "Reverb Time 2",0.01, 20, 0.0001, 1, 105, 20, 135, 120 gkrvt3, gihrvt3 FLtext "Reverb Time 3",0.01, 20, 0.0001, 1, 105, 20, 260, 120 gkrvt4, gihrvt4 FLtext "Reverb Time 4",0.01, 20, 0.0001, 1, 105, 20, 385, 120 gklpt5, gihlpt5 FLtext "Loop Time 5", 0.0001, 0.5, 0.0001, 1, 105, 20, 198, 200 gkrvt5, gihrvt5 FLtext "Reverb Time 5",0.01, 20, 0.0001, 1, 105, 20, 198, 240 gklpt6, gihlpt6 FLtext "Loop Time 6", 0.0001, 0.5, 0.0001, 1, 105, 20, 198, 320 gkrvt6, gihrvt6 FLtext "Reverb Time 6",0.01, 20, 0.0001, 1, 105, 20, 198, 360 ;SLIDERS MIN | MAX | EXP | TYPE | DISP | WIDTH | HEIGHT | X | Y gkmix,gihmix FLslider "Wet/Dry Mix", 0, 1, 0, 23, -1, 490, 25, 5, 420 ;GENERAL_TEXT_SETTINGS SIZE | FONT | ALIGN | RED | GREEN | BLUE FLlabel 13, 1, 3, 255, 255, 255 ;LABELS MADE INVISIBLE (I.E. SAME COLOR AS PANEL) ;BUTTON BANKS TYPE | NUMX | NUMY | WIDTH | HEIGHT | X | Y | OPCODE | INS | STARTTIM | DUR gkinput, ihinput FLbutBank 14, 1, 2, 18, 40, 230, 0, -1 ;GENERAL_TEXT_SETTINGS SIZE | FONT | ALIGN | RED | GREEN | BLUE FLlabel 13, 1, 3, 0, 0, 0 ;LABELS MADE VISIBLE AGAIN ;TEXT BOXES TYPE | FONT | SIZE | WIDTH | HEIGHT | X | Y ih FLbox "Input", 1, 5, 14, 50, 20, 180, 0 ih FLbox "Drum Loop", 1, 5, 14, 75, 20, 250, 0 ih FLbox "Live ", 1, 5, 14, 75, 20, 250, 20 ;SET INITIAL VALUES OF FLTK VALUATORS VALUE | HANDLE FLsetVal_i 0.0297, gihlpt1 FLsetVal_i 0.0371, gihlpt2 FLsetVal_i 0.0411, gihlpt3 FLsetVal_i 0.0437, gihlpt4 FLsetVal_i 3.5, gihrvt1 FLsetVal_i 3.5, gihrvt2 FLsetVal_i 3.5, gihrvt3 FLsetVal_i 3.5, gihrvt4 FLsetVal_i 0.09683, gihlpt5 FLsetVal_i 0.03292, gihlpt6 FLsetVal_i 2, gihrvt5 FLsetVal_i 2.7, gihrvt6 FLsetVal_i 0.8, gihmix FLpanel_end ;INSTRUCTIONS AND INFO PANEL FLpanel " ", 515, 600, 512, 0 FLscroll 515, 600, 0, 0 ;TEXT BOXES TYPE | FONT | SIZE | WIDTH | HEIGHT | X | Y ih FLbox " Schroeder Reverb ", 1, 5, 14, 490, 20, 5, 0 ih FLbox "-------------------------------------------------------------", 1, 5, 14, 490, 20, 5, 20 ih FLbox "The Schroeder reverb represents a reverb design that was ", 1, 5, 14, 490, 20, 5, 40 ih FLbox "invented in the early 1960s and that has been used often ", 1, 5, 14, 490, 20, 5, 60 ih FLbox "since. Today, with increases in computing power, more ", 1, 5, 14, 490, 20, 5, 80 ih FLbox "elaborate designs have replaced the Schroeder design but it ", 1, 5, 14, 490, 20, 5, 100 ih FLbox "is still used and in fact Csound's freeverb is based on it. ", 1, 5, 14, 490, 20, 5, 120 ih FLbox "In the Schroeder algorithm the input sound is passed through ", 1, 5, 14, 490, 20, 5, 140 ih FLbox "four or more comb filters in parallel and the mix of their ", 1, 5, 14, 490, 20, 5, 160 ih FLbox "outputs in passed through two allpass filters in series. The ", 1, 5, 14, 490, 20, 5, 180 ih FLbox "layout of the controls for the filters in the GUI opposite ", 1, 5, 14, 490, 20, 5, 200 ih FLbox "therefore reflects this scheme as the signal passes from top ", 1, 5, 14, 490, 20, 5, 220 ih FLbox "to bottom. ", 1, 5, 14, 490, 20, 5, 240 ih FLbox "The comb filters create the main body of the reverb and the ", 1, 5, 14, 490, 20, 5, 260 ih FLbox "allpass filters serve to 'scatter' ringing artefacts created ", 1, 5, 14, 490, 20, 5, 280 ih FLbox "by the comb filters. ", 1, 5, 14, 490, 20, 5, 300 ih FLbox "The key to minimizing ringing artefacts is chosing ", 1, 5, 14, 490, 20, 5, 320 ih FLbox "appropriate values of the loop times of the filters. If ", 1, 5, 14, 490, 20, 5, 340 ih FLbox "values are too low ringing will become obvious but if they ", 1, 5, 14, 490, 20, 5, 360 ih FLbox "are too large individual echoes will be heard in a 'grainy' ", 1, 5, 14, 490, 20, 5, 380 ih FLbox "sounding reverb tail. Loop times should all be different and ", 1, 5, 14, 490, 20, 5, 400 ih FLbox "should be prime to prevent periodicity between different ", 1, 5, 14, 490, 20, 5, 420 ih FLbox "filters which would again result in ringing artefacts. ", 1, 5, 14, 490, 20, 5, 440 ih FLbox "In this example all controls for each filter are included but", 1, 5, 14, 490, 20, 5, 460 ih FLbox "obviously in a finished instrument multiple parameters would ", 1, 5, 14, 490, 20, 5, 480 ih FLbox "be combined within a more descriptive global control named ", 1, 5, 14, 490, 20, 5, 500 ih FLbox "something live reverb time or room size. ", 1, 5, 14, 490, 20, 5, 520 ih FLbox "To emulate smaller room reverbs in will be necessary to ", 1, 5, 14, 490, 20, 5, 540 ih FLbox "reduce some of the loop times, particularly those of the ", 1, 5, 14, 490, 20, 5, 560 ih FLbox "allpass filters in order for this to be possible. ", 1, 5, 14, 490, 20, 5, 580 ih FLbox "This basic Schroeder can be quickly improved upon by ", 1, 5, 14, 490, 20, 5, 600 ih FLbox "incorporating additional comb filters and perhaps one or two ", 1, 5, 14, 490, 20, 5, 620 ih FLbox "additional allpass filters. Adding too many allpass filters ", 1, 5, 14, 490, 20, 5, 640 ih FLbox "will delay the onset of the reverb tail excessively. ", 1, 5, 14, 490, 20, 5, 660 ih FLbox "Four preset buttons change reverb time and loop times for all", 1, 5, 14, 490, 20, 5, 680 ih FLbox "filters and offer suggested starting points for different ", 1, 5, 14, 490, 20, 5, 700 ih FLbox "reverb effects. ", 1, 5, 14, 490, 20, 5, 720 FLscroll_end FLpanel_end FLrun ;RUN THE FLTK WIDGET THREAD ;END OF FLTK INTERFACE CODE;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; instr tables gisine ftgen 0, 0, 4096, 10, 1 ;SINE WAVE gaRvbSend init 0 ;GLOBAL AUDIO VARIABLE INITIALIZED TO ZERO endin instr 1 ;SOUND GENERATING INSTRUMENT if gkOnOff=0 then ;IF ON/OFF SWITCH IS OFF... turnoff ;TURN THIS INSTRUMENT OFF endif ;END OF THIS CONDITIONAL BRANCH ; gaRvbSend diskin2 "808loopMono.wav", 1, 0, 1 ;READ IN STEREO SOUND FILE WITH LOOPING ON if gkinput==0 then ;IF INPUT 'Drum Loop' IS SELECTED... gaRvbSend diskin2 "808loopMono.wav", 1, 0, 1 ;GENERATE 1 AUDIO SIGNALS FROM A MONO SOUND FILE (NOTE THE USE OF A GLOBAL VARIABLE) else ;OTHERWISE gaRvbSend inch 1 ;TAKE INPUT FROM COMPUTER'S AUDIO INPUT gaRvbSend = gaRvbSend * gkingain ;SCALE USING 'Input Gain' SLIDER endif ;END OF CONDITIONAL BRANCHING endin instr 2 ;REVERB - ALWAYS ON ktrigger changed gklpt1, gklpt2, gklpt3, gklpt4, gklpt5, gklpt6 ;IF ANY OF THE INPUT ARGUMENTS CHANGES GENERATE A MOMENTARY '1' VALUE (BAND) if ktrigger=1 then ;IF QUERY IS TRUE... reinit UPDATE ;BEGIN A REINITIALIZATION PASS FROM LABEL 'UPDATE' IN ORDER TO FORCE AN UPDATE OF I-RATE CONTROLLERS endif ;END OF THIS CONDITIONAL BRANCH UPDATE: ;LABEL CALLED 'UPDATE' ilpt1 limit i(gklpt1), 0.0001, 0.5 ;LIMIT LOOP TIME PARAMETER - ESSENTIALLY TO PREVENT VALUES OF ZERO BEING GIVEN TO THE OPCODE WHICH WOULD BE BAD ilpt2 limit i(gklpt2), 0.0001, 0.5 ;LIMIT LOOP TIME PARAMETER - ESSENTIALLY TO PREVENT VALUES OF ZERO BEING GIVEN TO THE OPCODE WHICH WOULD BE BAD ilpt3 limit i(gklpt3), 0.0001, 0.5 ;LIMIT LOOP TIME PARAMETER - ESSENTIALLY TO PREVENT VALUES OF ZERO BEING GIVEN TO THE OPCODE WHICH WOULD BE BAD ilpt4 limit i(gklpt4), 0.0001, 0.5 ;LIMIT LOOP TIME PARAMETER - ESSENTIALLY TO PREVENT VALUES OF ZERO BEING GIVEN TO THE OPCODE WHICH WOULD BE BAD ilpt5 limit i(gklpt5), 0.0001, 0.5 ;LIMIT LOOP TIME PARAMETER - ESSENTIALLY TO PREVENT VALUES OF ZERO BEING GIVEN TO THE OPCODE WHICH WOULD BE BAD ilpt6 limit i(gklpt6), 0.0001, 0.5 ;LIMIT LOOP TIME PARAMETER - ESSENTIALLY TO PREVENT VALUES OF ZERO BEING GIVEN TO THE OPCODE WHICH WOULD BE BAD krvt1 limit gkrvt1, 0.01, 20 ;LIMIT REVERB TIME PARAMETER - ESSENTIALLY TO PREVENT VALUES OF ZERO BEING GIVEN TO THE OPCODE WHICH WOULD BE BAD krvt2 limit gkrvt2, 0.01, 20 ;LIMIT REVERB TIME PARAMETER - ESSENTIALLY TO PREVENT VALUES OF ZERO BEING GIVEN TO THE OPCODE WHICH WOULD BE BAD krvt3 limit gkrvt3, 0.01, 20 ;LIMIT REVERB TIME PARAMETER - ESSENTIALLY TO PREVENT VALUES OF ZERO BEING GIVEN TO THE OPCODE WHICH WOULD BE BAD krvt4 limit gkrvt4, 0.01, 20 ;LIMIT REVERB TIME PARAMETER - ESSENTIALLY TO PREVENT VALUES OF ZERO BEING GIVEN TO THE OPCODE WHICH WOULD BE BAD krvt5 limit gkrvt5, 0.01, 20 ;LIMIT REVERB TIME PARAMETER - ESSENTIALLY TO PREVENT VALUES OF ZERO BEING GIVEN TO THE OPCODE WHICH WOULD BE BAD krvt6 limit gkrvt6, 0.01, 20 ;LIMIT REVERB TIME PARAMETER - ESSENTIALLY TO PREVENT VALUES OF ZERO BEING GIVEN TO THE OPCODE WHICH WOULD BE BAD a1 comb gaRvbSend, krvt1, ilpt1 ;COMB FILTER 1 a2 comb gaRvbSend, krvt2, ilpt2 ;COMB FILTER 2 a3 comb gaRvbSend, krvt3, ilpt3 ;COMB FILTER 3 a4 comb gaRvbSend, krvt4, ilpt4 ;COMB FILTER 4 aSum sum a1,a2,a3,a4 ;MIX THE OUTPUT FROM THE FOUR COMB FILTERS a5 alpass aSum, krvt5, ilpt5 ;SEND THE MIXED OUTPUT INTO THE FIRST ALLPASS FILTER aRvb alpass a5, krvt6, ilpt6 ;SEND THE OUTPUT OF THE FIRST ALLPASS FILTER INTO THE SECOND ALLPASS FILTER rireturn ;RETURN FROM REINITIALIZATION PASS (IF APPLICABLE) amix ntrpol aRvb, gaRvbSend, gkmix ;CREATE A MIX BETWEEN THE WET AND DRY SIGNALS. CONTROLLABLE BY THE USER FROM AN ON SCREEN SLIDER outs amix*0.7, amix*0.7 ;SEND WET/DRY MIX AUDIO TO OUTPUTS clear gaRvbSend ;CLEAR GLOBAL AUDIO VARIABLES endin instr 3 ;ACTIVATE PRESETS ;UPDATE FLTK VALUATORS WITH VALUES RECEIVED VIA P-FIELDS FLsetVal_i p4, gihlpt1 FLsetVal_i p5, gihlpt2 FLsetVal_i p6, gihlpt3 FLsetVal_i p7, gihlpt4 FLsetVal_i p8, gihrvt1 FLsetVal_i p9, gihrvt2 FLsetVal_i p10, gihrvt3 FLsetVal_i p11, gihrvt4 FLsetVal_i p12, gihlpt5 FLsetVal_i p13, gihlpt6 FLsetVal_i p14, gihrvt5 FLsetVal_i p15, gihrvt6 FLsetVal_i p16, gihmix endin i "tables" 0 3600 i 2 0.01 3600 ;REVERB INSTRUMENT e