perm filename USEMUS.LCS[UP,DOC]4 blob
sn#170561 filedate 1975-07-29 generic text, type T, neo UTF8
00200 ********** Using the Music System -- MUS10 **********
00300
00400 ******* WORK IN PROGRESS -- JUNE 75 -- LELAND SMITH *********
00500
00600 This manual is designed for use with the PDP10 at the Stanford AI lab.
00700 It is quite possible that several features discussed will not be
00800 operative on other installations. See appendix for some details.
00900
01000
01100 MUS10 is a complete sound generating package which exists on the
01200 disk. In its basic form it includes no storage area for sound output,
01300 so when the program is to be run, a number, establishing the core
01400 size, must be given following the program name.
01500
01600 For first attempts type:
01700
01800 R MUS10 10
01900 (All lines must be terminated with the 'RETURN' key.)
02000
02100 At this point the program will type the message:
02200
02300 INPUT?
02400
02500 Basically there are two responses possible. If the program is to
02600 receive further instructions from another file which has been
02700 prepared with an editing program, type:
02800
02900 NAME -- where NAME is the name of the file to be read.
03000 (If NAME has an extension, it must be used!)
03100
03200 If instructions are to be entered by means of the teletype keyboard
03300 (TTY mode), type carriage return (<CR>).
03400
03500 At this point a star (*) will appear which means the program is
03600 awaiting input.
03700
03800 Most complete statements to be read by MUS10 must end with a
03900 semicolon. Several complete statements may be entered on a single
04000 line but it is best not to have the lines too long. More than one
04100 line may be used for a single statement. If the less-than sign (<)
04200 appears everything following on that line will be ignored. Use this
04300 for entering comments.
04400
04500 ***** Note that the above rules DO NOT apply to the syntax
04600 of the SCORE program.
04700
04800 Already present in MUS10 is an "instrument" known as SIMP which has
04900 been set to play a test tone of 'A' (440 hz) for 1/2 second.
05000
05100 In order to play this tone, first get into TTY mode as described
05200 above, then type:
05300
05400 PLAY;SIMP;FINISH;
05500
05600 When the computation has finished the note 'A' will be heard if the
05700 various switches on the sound system are all in the right positions.
05800 (See appendix for this information and information regarding the
05900 filter settings.)
06000
06100 Assuming there were no typographical errors, you will know the comp-
06200 utation is done by the appearance of another star (*). The test tone
06300 may now be repeated several times by typing:
06400
06500 $P N where '$' indicates the 'ALT' key and 'N' is the
06600 number of times the note will play.
06700
06800 If no sound has been heard up to this point repeat the above, using
06900 some large number (e.g.20) for 'N' and go test the various switches
07000 until the tones are heard.
07100
07200 Occasionally a message will appear:
07300
07400 HUNG DEVICE AD
07500
07600 If this happens get expert help.
07700
07800 ******************************************************
07900
08000 The instrument SIMP has five parameters.
08100
08200 P1 = begin time of note (in seconds)
08300 P2 = duration of note " "
08400 P3 = pitch
08500 P4 = amplitude
08600 P5 = wave form (or timbre)
08700
08800 P1 and P2 will have the same significance in all instruments but all
08900 higher numbered parameters are assigned roles according to
09000 convenience. (However it will prove useful to consistently apply P3
09100 and P4 as above.)
09200
09300 Internally all pitch entries become numerical, however the twelve
09400 frequencies of the tempered chromatic scale, from middle C (261.62
09500 hz) up to B may be used in MUS10 by typing the letter names of the
09600 notes. The letter S = #; flats are not used in this program.
09700
09800 Since these letters merely represent the frequencies of each note,
09900 the octave range may be changed multiplying or dividing by multiples
10000 of two. Thus C or A in the octave below middle C would be entered
10100 as C/2 or A/2. In the octave above the basic middle octave these
10200 notes would be C*2 or A*2.
10300
10400 C -- 2 octaves down would be C/4
10500 C -- 3 octaves down would be C/8
10600 C -- 2 octaves up would be C*4
10700 C -- 3 octaves up would be C*8 etc.
10800
10900 To test the use of these letters try:
11000
11100 P3←C;PLAY;SIMP;FINISH;
11200
11300 Now instrument SIMP will play middle C instead of A. The left arrow
11400 (←) indicates that the value of C has been placed in P3, replacing
11500 any value that was previously there. (The left arrow and the equals
11600 sign[=] are interchangeable in this program.)
11700
11800 PLAY;SIMP;FINISH; must be typed so the new note will be computed.
11900 After it is first heard it may be repeated as indicated above.
12000
12100 If frequencies other than those of the tempered scale are to be
12200 played, a number may be used instead of a letter.
12300
12400 P3←1000;PLAY;SIMP;FINISH; will play a tone at 1000 hz.
12500
12600
12700 The amplitude scale available is the range of number from 0 to 2047.
12800 (This upper limit is set by the number of bits [12] used for the
12900 sound samples. See appendix.) P4 has been set at 1200 for the test
13000 tone. This may be reset using the same method as described before.
13100
13200 P4←100;P3←GS*2;PLAY;SIMP;FINISH;
13300
13400 This will play a G# above the middle octave at amplitude 100.
13500
13600 The duration of the tone may be changed be resetting P2.
13700
13800 P2←.1; etc. will play a note of 1/10 sec. duration.
13900
14000 If longer notes are desired the core being used must be expanded to
14100 allow for more storage space. At the established sampling rate
14200 (10000, see appendix.) 3.33k of core is needed for each second of
14300 sound. Since 1/2" may be played when MUS10 has 10k, 14k is needed
14400 for 1 1/2", 17k for 2 1/2", 20k for 3 1/2", etc. (Methods for
14500 playing much longer examples are described in SCORE.MAN.)
14600
14700 ********** SETTING CORE SIZE *********
14800
14900 To increase the core size type CALL, then C N where N is the core
15000 size desired. Then type CON (=continue) to return to where you
15100 previously were in the program.
15200
15300 When several parameters are to be changed at once the following
15400 type-in format should be used:
15500
15600 PLAY;SIMP 0 .2 FS/2 850;FINISH;
15700
15800 This will play F# below middle C for 2/10" at an amplitude of 850.
15900 (Please note that P5, the wave form for SIMP, will be dealt with
16000 later.)
16100
16200 ********** COMMAS **********
16300
16400 Commas may be used to separate the parameters and if nothing precedes
16500 a comma the contents of that parameter remains unchanged. Also any
16600 parameter numbers higher than the length of the list will not be
16700 affected.
16800
16900 PLAY;SIMP ,.3,,1200;FINISH; changes only P2 and P4.
17000
17100 ******************************************************
17200
17300 A string of notes may be played with the following input:
17400
17500 PLAY;SIMP 0 .2 C 1500;SIMP .2,,D;SIMP .4,,E;
17600 SIMP .6,,C;FINISH;
17700
17800 In this case P1 must be updated for each note. (Never overlap an
17900 instrument with itself. Distortion will occur.) P2, the note
18000 duration remains unchanged, so the commas suffice for the last three
18100 notes. P4, coming at the end of the list for the first note need
18200 only be stated once if it is not to change.
18300
18400 Rests are created by simply leaving some time between the end of one
18500 note (P1+P2) and the beginning of the next (the new P1).
18600
18700 PLAY;SIMP 0 .2 C;SIMP .5;FINISH; will play C for 2/10",
18800 rest for 3/10" and then play another C for 2/10".
18900
19000
19100 ********** FUNCTIONS **********
19200
19300 The wave form in P5 is entered by means of a name which is used by
19400 the program to locate a list, or array, of numbers (512) which
19500 describe the wave. The names used for this purpose will always be F
19600 followed directly by a number. These arrays will be called
19700 "functions."
19800
19900 Only one function is in MUS10, although more can be added. The
20000 function present is known as F1 and describes a sine wave. To see
20100 this wave on the CRT type:
20200
20300 SEE(F1);
20400
20500 To clear the screen hit the 'ESC' key followed by a 'C'. (This is
20600 called ESCAPE C.) <CR> will bring back the typescript display if it
20700 is gone.
20800
20900 Functions may be created with an external program called FUNC or
21000 within MUS10 itself by means of two routines called SYNTH and SEG.
21100 SYNTH is used to create composites made by adding various harmonics
21200 together. The form of F1 could be changed in the following manner:
21300
21400 SYNTH(F1); 1,1 2,1 3,.5 999;
21500
21600 In the three pairs of numbers the first of each pair represents the
21700 harmonic number and the second the relative amplitude of that
21800 harmonic. Thus the ratios of harmonics 1, 2 and 3 will be 1:1:.5 .
21900
22000 The size of the second number of each pair is important only in its
22100 relation to the other amplitude numbers. The number 999 is used to
22200 signal the termination of a string of entries.
22300
22400 Several pairs may entered and harmonic numbers up to 256 may be used
22500 but in practice great care must be taken to avoid the "foldover"
22600 effect which occurs when frequencies higher than one half the
22700 sampling rate are present. (See appendix.)
22800
22900 It should be pointed out that the fundamental (harmonic #1) need not
23000 be present in a wave.
23100
23200 SYNTH(F1); 10,1 12,1 15,1 999; will give the three notes of a
23300 minor chord. After this has been entered the following will cause a
23400 C minor chord to play:
23500
23600 PLAY;SIMP 0 .5 GS/8;FINISH;
23700
23800 While the lowest Ab (or G#) on the piano keyboard has been indicated,
23900 since the wave form includes only the 10th, 12th and 16th harmonics,
24000 the notes middle C, Eb and G will be heard.
24100
24200 Several experiments with different wave forms should be made. Be
24300 sure to SEE the waves so a visual-aural connection might be made.
24400
24500 A function may be changed in the middle of PLAY routine but it must
24600 be noted that the new wave definition must follow! the note which it
24700 is to affect.
24800
24900 In PLAY;SIMP 0 .3 D 1000;SIMP .3;SYNTH(F1); 1,.7 3,.2
25000 5,.1 999;SIMP .6,,E;FINISH; the newly defined wave
25100 will be heard in the second and third notes.
25200
25300
25400 If you wish to have several functions with different names available
25500 and you do not create them with the FUNC program, their names must be
25600 "declared" to MUS10. Suppose you wish to have F2, F3 and F4. You
25700 must type directly to MUS10 (or into an EDIT file which will be read
25800 by MUS10) the following:
25900
26000 ARRAY F2,F3,F4(512);
26100
26200 The "(512)" indicates that each function array will require 512 words
26300 of storage. Thus at this point the free storage left for sound
26400 samples has been reduced by 1 1/2K so you must increase the size of
26500 your core if you want to have the same amount of playing time as
26600 before.
26700
26800 The following example will play a sequence of notes wherein are heard
26900 the 10th, 14th and 18th harmonics of a low C, then the 10th, 13th and
27000 16th, and finally the 10th, 12th and 14th harmonics.
27100 As each SYNTH function is typed in the wave will be
27200 displayed. If you wish a clear screen after the last one has
27300 appeared, hit the 'ESC' key followed by a 'C'. (This is called ESCAPE
27400 C.)
27500
27600 ARRAY F2,F3(512);
27700 SYNTH(F1);10,1 14,1 18,1 999;
27800 SYNTH(F2);10,1 13,1 16,1 999;
27900 SYNTH(F3);10,1 12,1 14,1 999;
28000 PLAY;SIMP 0 .3 C/4 2000 F1;
28100 SIMP .3,,,,F2;SIMP .6,,,,F3;FINISH;
28200
28300
28350
28400 From this point on it would probably be better to prepare any
28500 input for MUS10 which requires more than a couple of lines of typing
28600 with the SOS editor. Typographical errors are inevitable and when an
28700 error is made near the beginning of a string of input typed directly
28800 to MUS10 you most likely will have to retype everything.
00100
00200 A type of flow-chart diagram for SIMP would appear as follows:
00300
00400 P4 MAG*P3
00500 | |
00600 ↓ ↓
00700 ***************
00800 * * OSCIL
00900 * * U1 (UNIT GENERATOR ONE)
01000 * P5 *
01100 * *
01200 * *
01300 *********
01400 |
01500 ↓
01600 *****
01700 * OUT *
01800 * A *
01900 *****
02000
02100 The top left input, P4, serves simply as a multiplier for the numbers
02200 found in the wave form array, P5. The particular number from the
02300 array to be multiplied is determined by the number in the upper right
02400 input. The upper right input, in this case P3, when processed by
02500 "MAG" (the "magic" number) becomes the increment, the rate at which
02600 the wave form array is stepped through. The "magic" number is found
02700 by dividing the array length, 512, by the sampling rate, 10000.
02800
02900 512/SRATE=.0512 (Higher sampling rates will be discussed later.)
03000
03100 The maximum size of the numbers in the wave array is + or -1. Thus
03200 if P4 is set to 1000 the output of the OSCIL will be numbers in the
03300 range +1000 to -1000 which will describe the wave form put into P5
03400 cycling at the rate given in P3.
03500
03600
03700 The code for entering this instrument follows:
03800
03900 COMPILE;
04000 INSTRUMENT SIMP;
04100 OSCIL(P4,MAG*P3,P5);
04200 OUTA←OUTA+U1;
04300 END;
04400 FINISH;
04500
04600 Several instruments may appear between COMPILE; and FINISH;.
04700
04800
04900 This instrument has only one unit generator (the OSCIL) hence the
05000 output of U1 is added to the contents of OUTA. If there are several
05100 instruments the outputs of all the instruments will be combined in
05200 OUTA for each sample.
05300
05400 It will be noticed when playing instrument SIMP that the sound begins
05500 and ends quite abruptly. This is because no attack-decay envelope
05600 has been applied to the tone. The sound begins at the full amplitude
05700 of P4 and remains at that level for its total duration.
00100
00200 To apply an envelope, another unit generator must be added.
00300
00400
00500 P4 MAG/P2
00600 | |
00700 ↓ ↓
00800 ***************
00900 * * OSCIL
01000 * * U1 (UNIT GENERATOR ONE)
01100 * P5 *
01200 * *
01300 * *
01400 *********
01500 |
01600 | MAG*P3
01700 | |
01800 ↓ ↓
01900 ***************
02000 * * OSCIL
02100 * * U2 (UNIT GENERATOR TWO)
02200 * P6 *
02300 * *
02400 * * COMPILE;
02500 ********* INSTRUMENT TOOT;
02600 | OSCIL(P4,MAG/P2,P5);
02700 ↓ OSCIL(U1,MAG*P3,P6);
02800 ***** OUTA←OUTA+U2;
02900 * OUT * END;
03000 * A * FINISH;
03100 *****
03200
03300 Now that the instrument has been expanded you will note that it is
03400 the output of unit generator two (U2) which goes to OUTA.
03500
03600 P5 will now contain the envelope array. This array is best defined
03700 by the SEG routine. SEG defines the positions of line segments used
03800 to approximate a curve. With SEG several pairs of numbers may be
03900 entered. The first number of each pair is an amplitude, normally in
04000 the range of 0 to 1, and the second is the step number in the array.
04100 The step numbers 1 through 100 are used in SEG. (However internally,
04200 512 array locations are used.) Straight line segments are drawn
04300 between each of the points defined. The following would put a
04400 triangular envelope shape into F2:
04500
04600 ARRAY F2(512);
04700 SEG(F2); 0,1 1,50 0,100;
04800
04900 Note that the routine is terminated when step 100 is reached.
05000 DO NOT USE 999 with SEG.
05100
05200 After having typed in the code for instrument TOOT and the definition
05300 for an envelope in F2, the following will produce a note using that
05400 envelope:
05500
05600 SYNTH(F1);1,1 2,.4 3,.1 999;< Sets the tone color.
05700 PLAY;TOOT 0 .5 A 2000 F2 F1;FINISH;
05800
05900 If two envelopes are to be contrasted add another function and define
06000 it.
06100 ARRAY F3(512);
06200 SEG(F3); 0,1 1,7 .2,25 .1,60 0,100;< Staccato
06300 PLAY;TOOT 0 .2 1000 2000 F3 F1; < P5 has envelope
06400 TOOT .2 .5,,,F2;FINISH;<Plays stac. then sust.(F1 then F2)
06500
00100 In the next example a unit generator will be added above the right
00200 side of the bottom, tone producing unit generator. In this way a
00300 function may be used to describe fluctuations of pitch within the
00400 duration of a note -- much as the previous example gave the
00500 possibility for changing the amplitude during a single note.
00600
00700
00800 MAG*P7-MAG*P3 MAG/P8
00900 P4 MAG/P2 | |
01000 | | ↓ ↓
01100 ↓ ↓ ***************
01200 *************** * * OSCIL
01300 * * OSCIL * * U2
01400 * * U1 * P9 *
01500 * P5 * * *
01600 * * * *
01700 * * *********
01800 ********* MAG*P3 |
01900 | | _____________|
02000 |________ _↓___↓_
02100 | \ /
02200 | \ + /
02300 | \_/
02400 | |
02500 ↓ ↓
02600 ***************
02700 * *
02800 OSCIL * *
02900 U3 * P6 *
03000 * *
03100 * * COMPILE;
03200 ********* INSTRUMENT GLISS;
03300 | OSCIL(P4,MAG/P2,P5);
03400 ↓ OSCIL(MAG*P7-MAG*P3,MAG/P8,P9);
03500 ***** OSCIL(U1,MAG*P3+U2,P6);
03600 * OUT * OUTA←OUTA+U3; END; FINISH;
03700 * A *
03800 *****
03900
04000
04100 In order for this instrument to perform glissandos, a third function
04200 must be defined for P9 (the "shape" of the glissando). A straight
04300 line slope will suffice for a simple glissando. After typing in the
04400 instrument definition set up the three functions.
04500
04600 ARRAY F5,F6(512); <F1 is already present.
04700 SEG(F5);0,1 .8,7 1,12 1,90 0,100;<Envelope
04800 SEG(F6);0,1 1,100; <Slope
04900
05000 In the preceding, the ARRAY declaration is needed only when some new
05100 function names are to be used.
05200
05300 The following will play a glissando up two octaves, from C to C*4.
05400
05500 PLAY; GLISS 0 1 C 2000 F5 F1 C*4 1 F6; FINISH;
05600
05700 If P8←.5; (while P2 remains at 1) two glissandos will be heard.
05800
05900
06000
06100 This instrument may be used for a dramatic demonstration of
06200 "foldover", the phenomenon which occurs when a frequency exceeds the
06300 upper limit of one half the sampling rate. (See Mathews' book for a
06400 technical explanation.)
06500
06600 For this purpose it is best to use a Sine wave in P6.
06700
06800 SYNTH(F1); 1 1 999;
06900
07000 PLAY; GLISS 0 1 1000 2000 F5 F1 4000 1 F6;FINISH;
07100
07200 This first note will slide up from 1000 hz to 4000 hz.
07300
07400
07500 PLAY; GLISS 0 1 1000 2000 F5 F1 9000 1 F6;FINISH;
07600
07700 Due to "foldover" (at 10000/2 hz.) this note will slide up to 5000 hz
07800 and return to the 1000 hz level even though 9000 hz was given in P7.
07900 The general rule for "foldover" is that any frequencies which exceed
08000 one half the sampling rate will be heard at (SRATE-F) hz.
08100
08200
08300 Try this one!
08400
08500 PLAY; GLISS 0 1 0 2000 F5 F1 30000 1 F6; FINISH;
08600
08700
08800 This same instrument may be used to produce a vibrato by putting a
08900 sine wave into P9, setting P8←1/7; (the vibrato rate will be 7 times
09000 per second) and making P7 some very small amount different from P3.
09100
09200 PLAY; GLISS 0 1 C 2000 F5 F1 C+2 1/7 F1; FINISH;
09300
09400 (It is assumed that F1 is a sine wave.)
00100 Various types of noise and other random fluctuations are
00200 produced by the two random number unit generators. These are called
00300 RANDH and RANDI. RANDH (H=hold) produces in effect a function made
00400 up of horizantal lines at various levels with a perpendicular jump
00500 from one level to the next. There are two inputs to RANDH. The
00600 first (left hand) gives the range, plus or minus, of random
00700 selection and the second (right hand) gives the rate (per second) at
00800 which the selections are to be made.
00900
01000 Care must be taken with the number in the first input. If
01100 the number 100 is given, the output of RANDH will fluctuate between
01200 +100 and -100. Thus if a range of 100 to 200 is desired, the input
01300 number should be 50 and the number 150 must be added to the output.
01400
01500
01600 MAG*P7 MAG*P8
01700 P4 MAG/P2 | |
01800 | | ↓ ↓
01900 ↓ ↓ ***************
02000 *************** * *
02100 * * OSCIL * RANDH * U2
02200 * * U1 ***************
02300 * P5 * |
02400 * * |
02500 * * |
02600 ********* MAG*P3 |
02700 | | _____________|
02800 |________ _↓___↓_
02900 | \ /
03000 | \ + /
03100 | \_/
03200 | |
03300 ↓ ↓
03400 ***************
03500 * *
03600 OSCIL * *
03700 U3 * P6 *
03800 * *
03900 * * COMPILE;
04000 ********* INSTRUMENT NOISE;
04100 | OSCIL(P4,MAG/P2,P5);
04200 ↓ RANDH(MAG*P7,MAG*P8);
04300 ***** OSCIL(U1,MAG*P3+U2,P6);
04400 * OUT * OUTA←OUTA+U3; END; FINISH;
04500 * A *
04600 *****
04700
04800 ARRAY F2(512); <F1 is already present.
04900 SEG(F2);0,1 .8,7 1,12 1,90 0,100;<Env.
05000
05100
05200
05300
05400 The following will produce white noise.
05500
05600 SRATE←25000;MAG←512/SRATE;SPEED←2;
05700 PLAY;NOISE 0 .5 C*8 1000 F2 F1 P3 P3*4;FINISH;
05800
05900 Actually P8 (given as P3*4) can probably be left at a number
06000 like 4000 for noise purposes. As P7 is changed the apparent
06100 band-width of the noise will be changed. As the band-width gets
06200 narrower the center frequency becomes more apparent. Thus if P7←P3/16
06300 and P3 is up in the range of C*8, something of the effect of blowing
06400 across an open tube will be produced. The pitch is clear -- but
06500 quite windy.
06600
06700 The SRATE (sampling rate) must be increased for noise
06800 production since very high frequencies are essential. At SRATE←25000
06900 the high frequency cut-off will be at 12500 hz.
07000
07100 If P8 is set to a low number (e.g. 8) individual random
07200 pitches, instead of noise, will be produced at that rate.
07300
07400
07500 If the random unit generator is replaced by a RANDI the
07600 random function produced will be made up of a series of slopes
07700 (I=interpolating) up and down from one random point to another. In
07800 the case of noise production there is little difference between RANDI
07900 and RANDH. However RANDI is necessary for getting such things as
08000 random vibrato. The following will produce an acceptable, "human"
08100 sounding vibrato.
08200
08300 PLAY; NOISE 0 1 C*2 1000 F2 F1 P3*.01 16; FINISH;
08400
08500 The random rate of 16 per second (in P8) is considerably
08600 faster than the human vibrato rate of 5 to 8 per second. In this
08700 case however since the full band-width (in P7) is only seldom
08800 attained and the heard effect is that of a rate much slower than 16.
00100 Frequency modulation allows for the production of a wide
00200 variety of tone colors using relatively little compute time. The
00300 INTRP unit generator is really just a combination of an OSCIL and an
00400 ADD box. The left input represents the output when the function (P10
00500 below) is at zero and the right input represents the output when the
00600 function is at 1 (peak amplitude). No time input is given with
00700 INTRP. The speed of stepping through the function array is always
00800 taken as being P2, i.e. the note duration. In this case P10 will
00900 contain an envelope which will control the changes in frequency
01000 modulation. For a full explanation of FM see John Chowning's AES
01100 Journal article on this subject.
01200
01300
01400 P9*P7*MAG P8*P9*MAG
01500 | |
01600 ↓ ↓
01700 ***************
01800 * *
01900 * P10 * INTRP
02000 * * U2
02100 * *
02200 * *
02300 * *
02400 * P9*MAG
02500 P4 MAG/P2 | |
02600 | | ↓ ↓
02700 ↓ ↓ ***************
02800 *************** * * OSCIL
02900 * * OSCIL * * U3
03000 * * U1 * P11 *
03100 * P5 * * *
03200 * * * *
03300 * * *********
03400 ********* MAG*P3 |
03500 | | _____________|
03600 |________ _↓___↓_
03700 | \ /
03800 | \ + /
03900 | \_/
04000 | |
04100 ↓ ↓
04200 ***************
04300 * *
04400 OSCIL * *
04500 U4 * P6 *
04600 * *
04700 * * COMPILE;
04800 ********* INSTRUMENT FM;
04900 | OSCIL(P4,MAG/P2,P5);
05000 ↓ INTRP(P7*P9*MAG,P8*P9*MAG,P10);
05100 ***** OSCIL(U2,P9*MAG,P11);
05200 * OUT * OSCIL(U1,U3+P3*MAG,P6);
05300 * A * OUTA←OUTA+U4; END; FINISH;
05400 *****
05500
05600
05700
05800 The following functions should be set up to test the FM instrument.
05900
06000 ARRAY F1,F2,F3(512);
06100 SYNTH(F1); 1 1 999; < A sine wave.
06200 SEG(F2);0,1 .9,4 1,8 1,72 .8,88 .5,95 0,100; < Envelope
06300 SEG(F3); 0,1 1,100; < An upward slope or ramp.
06400
06500 The following will produce a shift from a pure sine tone to a
06600 highly modulated tone over a period of 2 seconds.
06700
06800 PLAY; FM 0 2 100 1000 F2 F1 0 10 100 F3 F1; FINISH;
06900
07000
07100 To reverse the procedure, i.e. change from the modulated tone
07200 to the pure tone, reverse the values of P7 and P8.
07300
07400 P7←10; P8←0; PLAY;FM;FINISH;
07500
07600
07700 Change F3 (the ramp) to make the modulation emerge only in
07800 the mid-part of the note.
07900
08000 SEG(F3); 0,1 1,50 0,100; < Makes a pyramid.
08100
08200 PLAY;FM;FINISH;
08300
08400 Try several of the variations suggested in Chowning's article.
00100 ********** APPENDIX XXX NOT COMPLETE!!!XXX ************
00200
00300 The main program for sound generation is currently called MUSIC.FAI
00400 or MUSEXP.FAI (EXP=export). The export version is designed to run on
00500 a standard PDP10 DEC system (which has a "FAIL" compiler.)
00600
00700 The main program must be loaded with two subroutine packages which
00800 are called MUSF4.F4 (OR MUSEXP.F4) and MUSIO.FAI (or EXPIO.FAI.) The
00900 FORTRAN routines are for the creation of function arrays and for
01000 organizing the output of sound samples to tape or disk after they
01100 have been computed. The FAIL routines are for fast output of blocks
01200 of samples.
01300
01400 The STANFORD version can play sound from core or write all samples on
01500 an external device for playback with another program. The latter
01600 method is always used for sounds longer than about 10 seconds.
01700
01800 See SCORE.LCS[UP,DOC] for information on longplaying features (RCDFLG
01900 and BIGBIT) and much other information.
02000
02100
02200
02300 ************** FILTER SETTINGS **********
02400
02500 The filter switches are near the floor roughly behind the
02600 PDP6. For the purposes of the tests described in this document the
02700 setting for channel 1, the right hand switch, should always be at 5K.
02800 This means that frequencies higher than 5000 hz will be suppressed.
02900 For later experiments with NOISE and FM it may be desired to change
03000 the setting to 12.5 K. If this is done however sound run by other
03100 users at the lowest sampling rate (10000, SPEED 3) will always
03200 include the sampling tone of 5000 hz. The switch at the top of the
03300 cabinet should be left at 5 K.
03400
03500
03600
03700 ************ LOCAL SPEAKERS ***********
03800
03900
04000 To hear sound produced by the D-A converter from the small
04100 speaker associated with your TTY console hit the 'ESC' key followed
04200 by the '4', and then the 'U'. (ESCAPE 4 U).
00100 ********* SOME INFO RE. THE 'FUNC' PROGRAM ***********
00200
00300 CRUNCH: Any two functions already in a single .DAT file may be
00400 "crunched" together. Also, a function may be created by either the
00500 SEG or SYNTH routines and then if instead of typing "F" for FINISH
00600 the letter "Z" is typed the program will jump immediately to "crunch"
00700 mode. At this point the new function may be combined with any
00800 function found in the file presently in core. Note however that once
00900 this new function is processed by any of "crunch" options its
01000 original form cannot be regained without going back to ordinary SEG
01100 or SYNTH mode.
01200
01300 PLOTTING: If "SP" (=see on the plotter) is typed single functions
01400 can be drawn on the Calcomp plotter. The size asked for is in
01500 inches. "SA" (=see all on plotter) will plot all the functions found
01600 in a single file. "SX" (=see all on the XGP) will draw all functions
01700 from a single file in the proper size for printing by the XGP. In
01800 order to use "SX" you must!!! follow the next steps exactly!!!
01900
02000 Before running FUNC type: A DSK PTP <CR>. This will cause the
02100 instructions FUNC sends to the plotter to be written in a
02200 file on the disk.
02300
03000 When the FUNC program finishes then type R X <CR>.
03100 This runs a program called X which converts plotter
03200 information to XGP commands.
03300
03400 X will ask you 5 questions. You should answer as follows:
03500
03600 PLOT.BIN <CR> (the file name)
03700 <CR> (plot slice?)
03800 5 <CR> (shift 5 inches)
03900 <CR> (use default value of 11".)
04000 1 <CR> (1 inch from the left)
04100 Y (yes, delete the plot file)
04200
04300
04400
00100 Information re. WAVES. To run it type R WAVES.
00200
00300 This will allow you to display the actual wave shapes of sound
00400 computed using RCDFLG←-1;. The MUSAA.DMD file thus produced is read
00500 by WAVES.
00600
00700 You may display up to 3072 samples at a time but since only 1024
00800 separate positions can be shown at once, larger numbers will cause
00900 some samples to be skipped over (but with no great loss.) After each
01000 group of samples is displayed a <CR> will move on to the next group.
01100 If a number is typed, that will set the extent of the next group. If
01200 the number -1 is given, the program will automatically cycle through
01300 all available samples by groups of the last given number. (When no
01400 more samples are to be found it will end with an error message.) In
01500 order to make the program go backwards type any number less than
01600 -2 for the number of samples you wish to back up.
01700
01800 This program should be of use in seeing the wave shapes produced by
01900 amplitude and frequency modulation as well as seeing the effects of
02000 foldover, etc. Composite waves from more than one voice may be
02100 displayed but as the complexity increases it may prove rather
02200 difficult to glean useful information from what is seen.