20 REM BASSOON.BAS   CALCULATES look-in ADMITTANCE AND PRESSURE FOR  Conical
21 ' bore at points 50 mm apart.
22 F = 140: REM INSERT FREQUENCY HERE.

24 SCREEN 12
25 CLS
30 DEFINT N: PI = 3.14159
40 NS = 52: REM NO. OF SECTIONS, EACH SECTION 100 mm. LONG
50 DIM D(NS): REM D(N) IS THE DIAMETER OF THE Nth SECTION, BEGIN 4 mm START
55 D(0) = 5.148: REM BEGINS WITH CYLINDER 50 MM LONG FOR REED, THEN 4mm diam
56    ' expanding as cone to 40 mm.
60 DIM P(NS), PWR(NS)
80 FOR N = 1 TO 52
85 D(N) = 4 + .6923 * (N - .5): REM AFTER 52 SECTIONS, 40 MM DIAMETER LARGE END
90  NEXT N
102 PRINT "FREQUENCY ="; F
108 PRINT "DIST      r      ANGLE      G           B      R eff  PRESS   PWR"
109  T$ = "####   .#####   ##.####  ###.####   ###.####  .####  #.####   ##.###"
120 G = O: REM BEGINNING G, CLOSED END
130 B = 0: REM BEGINNING B CLOSED END
135 P = .5: PREL1 = 1: REM STARTING PRESSURE IN REED CAVITY
150 FOR N = O TO NS
170 K = F / 55704! / (1 - 3.34 / D(N) / SQR(F)): REM PROPAGATION CONSTANT
180 LF = 1 - .00556 * SQR(F) / D(N): REM LOSS IN REFLECTION VECTOR FOR 50 mm LENGTH
190 R = SQR((B ^ 2 + (1 - G) ^ 2) / (B ^ 2 + (1 + G) ^ 2))
200 DET = 1 - G ^ 2 - B ^ 2
210 AN = ATN(2 * B / DET): IF DET > 0 THEN AN = AN + PI
220 AN = AN + 100 * K: REM ADDS SECTION ANGLE FOR 50 MM MOVEMENT
230 R = LF * R: REM REDUCES REFLECTION VECTOR
240 DEN = 1 + R ^ 2 - 2 * R * COS(AN)
250 G = (1 - R ^ 2) / DEN
260 B = -2 * R * SIN(AN) / DEN
265 PREL = 2 / SQR((G + 1) ^ 2 + B ^ 2): REM PRESSURE RELATIVE TO INCIDENT
267 P = P * PREL / PREL1: P(N) = P
268 PWR(N) = P * P * G * D(N) ^ 2: REM PRESSURE SQUARED * ABSOLUTE ADMITTANCE
270 PRINT USING T$; 50 * N; R; AN; G; B; (1 - R) / (1 + R); P; PWR(N)
273 IF N = 25 THEN GOSUB 610
275 IF N = 52 THEN GOTO 400
280 G = G * D(N) ^ 2 / D(N + 1) ^ 2
300 B = B * D(N) ^ 2 / D(N + 1) ^ 2
302 PREL1 = 2 / SQR((G + 1) ^ 2 + B ^ 2)
305 NEXT N
400 GOSUB 610
500 CLS : WINDOW (0, 0)-(NS, 1.1): LINE (0, 0)-(NS, 0)
505 LOCATE 2, 15: PRINT "PRESSURE DISTRIBUTION AT FREQUENCY = "; F; " Hz"
508 PSET (9, 1.01), 3: LOCATE 3, 16: PRINT "LOSS DISTRIBUTION"
510 FOR N = 0 TO NS: PSET (N, P(N)): NEXT N
515 FOR N = 1 TO NS: PSET (N, 5 * (PWR(N) - PWR(N - 1))), 3: NEXT N
520 WHILE INKEY$ = "": WEND
530 END
610 PRINT "PRESS ANY KEY FOR MORE"
620 IF INKEY$ = "" THEN GOTO 620
630 PRINT "DIST      r       ANGLE     G           B      R eff  PRESS"
640 RETURN