File: rotary.c

package info (click to toggle)
bristol 0.60.10-3
  • links: PTS, VCS
  • area: main
  • in suites: wheezy
  • size: 15,652 kB
  • sloc: ansic: 124,457; sh: 10,579; makefile: 111
file content (735 lines) | stat: -rw-r--r-- 19,956 bytes parent folder | download | duplicates (3)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735

/*
 *  Diverse Bristol audio routines.
 *  Copyright (c) by Nick Copeland <nickycopeland@hotmail.com> 1996,2012
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, see <http://www.gnu.org/licenses/>.
 *
 */

/*

b3 intertia control alterations do not reset as expected
30.3, 64bit, -no-jack-midi option

observed behaviour:
Altering the intertia control from minimum to maximum gives expected
result, but when the control is returned to minimum, the interia is
apparently not altered

steps to reproduce:
1. configure inertia to minimum value, leslie on, slow speed, mode
separate.
2. save profile, exit
3. start new bristol session, load saved profile
4. play chord of your choice
4. switch leslie to fast, observe spin-up is within 4 or 5 seconds
5. alter inertia to maximum, observe spin-up is very slow
6. reset inertia to minimum

notice that the spin-up is very slow. It does not return the the speed in
step 4.

bristol needs to be restarted to return to normal.

As an aside, even at minimum inertia, I can't get the leslie to spin up
quickly enough when compared to real B3 performances I've heard. Is there
some other parameter that I need to alter?

 */

/*#define DEBUG */

#include <math.h>

#include "bristol.h"
#include "rotary.h"

/*
 * Used by the user interface in the effects rack.
#define EFFECT_NAME "leslie"
#define SHORT_NAME "Leslie"
 */

#define SPEED		0
#define INERTIA		1
#define DELAY		2
#define REVERB		3
#define FEEDBACK	4
#define OVERDRIVE	5
#define CROSSOVER	6
#define FLAGS		7 /* Sync on rotations. No rotation bass. On/Off. */

#define OPNAME "Leslie"
#define OPDESCRIPTION "Rotary speaker simulator"
#define PCOUNT 8
#define IOCOUNT 3

#define LESLIE_IN_IND 0
#define LESLIE_OUT_IND 1
#define LESLIE_OUT2_IND 2

static void newValvify(float *, int, float);
#define ROOT2 1.4142135623730950488
static float pidsr;
static int stopped = 0;

/*
 * Reset any local memory information.
 */
static int destroy(bristolOP *operator)
{
#ifdef BRISTOL_DBG
	printf("destroy(%x)\n", operator);
#endif

	bristolfree(operator->specs);

	cleanup(operator);
	return(0);
}

/*
 * This is called by the frontend when a parameter is changed.
static int param(param, value)
 *
 * Too many of these parameters are integers, and this is obscuring the min
 * and max rotary speeds, especially the max speed. They should be made into
 * floats, additionally changing the speed to have 3 values:
 *	High, Low, Stopped
 */
static int param(bristolOP *operator, bristolOPParams *param,
	unsigned char index, float value)
{
#ifdef DEBUG
	printf("checkParams(%i, %i)\n", param, value);
#endif
	switch (index) {
		case SPEED:
			param->param[index].float_val = value * value * value;
			param->param[index].int_val = 532 - value * 512;
/* printf("speed is %i\n", param->param[index].int_val); */
			break;
		case INERTIA:
			param->param[index].float_val = value / 2;
			break;
		case DELAY:
			param->param[index].float_val = value;
			param->param[index].int_val
				= value * (LESLIE_TBL_SZE - 24) + 1;
/*			param->param[index].int_val * LESLIE_TBL_SZE; */
/*printf("delay is %i\n", param->param[index].int_val); */
			break;
		case REVERB:
		case FEEDBACK:
			param->param[index].float_val = value * 0.9;
			break;
		case OVERDRIVE:
			/*
			value = 0.5 - value;
			param->param[index].float_val = 1.0 + value * 10;
			if (value < 0)
				param->param[index].float_val
					= -1 / (1.0 - (value * 10));
			*/
			param->param[index].float_val = 1.0 - (value * 0.5);
			break;
	}
	return(0);
}

/*
 * Reset any local memory information.
 */
static int reset(bristolOP *operator, bristolOPParams *param)
{
#ifdef BRISTOL_DBG
	printf("reset(%x)\n", operator);
#endif
	if (param->param[0].mem)
		bristolfree(param->param[0].mem);
	if (param->param[1].mem)
		bristolfree(param->param[1].mem);

	param->param[0].mem = bristolmalloc0(sizeof(float) * HISTSIZE);
	param->param[1].mem = bristolmalloc0(sizeof(float) * HISTSIZE);

	param->param[1].int_val = 5;
	param->param[3].float_val = 0.7;
	param->param[6].float_val = 0.01;
	param->param[7].int_val = 1;
	return(0);
}

static float table[TABSIZE];

static void
rotate(bristolLESLIElocal *local, float *history, float *ib, float *obl,
float *obr, int count, float scan, float feedback, float delay, float reverb)
{
	float volleft, volright, freq1, histout, value, depth, scanp, scanr, rev;
	int histin, i, revout, revout1, revout2, revout3;

	volleft = local->Vol1;
	volright = local->Vol2;
	freq1 = local->Freq1;
	histin = local->Histin;
	histout = local->Histout;
	scanp = local->scanp;
	scanr = local->scanr;
	revout = local->Revout;

	/*
	 * Reverb should be a function of the rotational speed? We have two totally
	 * distinct delay lines, one for the treble rotor, and one for the base
	 * rotor, and should use them. Range is about 300.
	 */
	if ((revout = histin - TAP1) < 0) revout = histin - TAP1 + HISTSIZE;
	if ((revout1 = histin - TAP2) < 0) revout1 = histin - TAP2 + HISTSIZE;
	if ((revout2 = histin - TAP3) < 0) revout2 = histin - TAP3 + HISTSIZE;
	if ((revout3 = histin - TAP4) < 0) revout3 = histin - TAP4 + HISTSIZE;

	for (i = 0; i < count; i++) {
		history[histin] = *ib;

		/*
		 * Some doppler
		 */
		if ((histout + 1) >= HISTSIZE)
		{
			value = history[0] * (histout - ((float) ((int) histout)))
				+ history[(int) histout]
					* (1.0 - (histout - ((float) ((int) histout))));
		} else {
			value = history[(int) histout + 1]
					* (histout - ((float) ((int) histout)))
				+ history[(int) histout]
					* (1.0 - (histout - ((float) ((int) histout))));
		}

		/*
		 * Some tremelo, and for now put doppler in both sides.
		 */
		rev = history[revout1] * 0.8
			+ history[revout2] * 0.36
			+ history[revout3] * 0.62;

		obr[i] += *ib * volright + value * reverb
			+ (history[revout] + rev) * volleft * feedback;
		obl[i] += *ib * volleft + value * reverb
			+ (history[revout] + rev) * volright * feedback;

		history[revout] += (value + rev) * feedback;
		history[histin] += rev * feedback * 0.5;

		++ib;

#ifdef DEBUG2
		printf("in %i out %f step %f depth %f\n", histin, histout, freq1,
			histin - histout < 0? histin + HISTSIZE - histout:histin - histout);
#endif

		if (++histin >= HISTSIZE) histin = 0;
		if ((histout += freq1) >= HISTSIZE) histout -= HISTSIZE;
		/*
		 * Revout should be made into a 4 tap delay line, potentially with dual
		 * taps (ie, 8 tap), with feedback returned to first tap.
		 */
		if (++revout >= HISTSIZE) revout = 0;
		if (++revout1 >= HISTSIZE) revout1 = 0;
		if (++revout2 >= HISTSIZE) revout2 = 0;
		if (++revout3 >= HISTSIZE) revout3 = 0;

		/*
		 * The output buffers get a filtered volume fraction, plus a phase 
		 * component.
		 */
		if (--scanr <= 0)
		{
			scanr = scan;

			volleft = (1.0 - table[(int) scanp]) * 0.5;
			volright = (1.0 - table[(int) ((scanp - 80) < 0?
				scanp - 80 + TABSIZE:scanp - 80)]) * 0.5;
			/*
			 * Freq1 will initially define a length of the delay chain. Then
			 * we interpolate the changes we need to make to histout to move
			 * to this depth.
			 */
			freq1 = delay - table[(int) ((scanp + 50) >= TABSIZE?
				scanp + 50 - TABSIZE:scanp + 50)] * delay;

#ifdef DEBUG2
			printf("scan %3.0f: ddepth %f, tbl %f", scanp, freq1,
				table[(int) ((scanp + 50) >= TABSIZE?
					scanp + 50 - TABSIZE
					:scanp + 50)]);
#endif
			/*
			 * Get the current depth
			 */
			depth = histin + scan - histout < 0?
				((float) histin) + scan - histout + HISTSIZE
				:((float) histin) + scan - histout;

			freq1 = (depth - freq1) / scan;
#ifdef DEBUG2
			printf(" adepth %f, step %f\n", depth, freq1);
#endif
			if ((scan > 400) && (scanp == (TABSIZE>>1) + local->toff))
				--scanp;
			if (++scanp >= TABSIZE)
				scanp = 0;
		}
	}

	local->Vol1 = volleft;
	local->Vol2 = volright;
	local->Freq1 = freq1;
	local->Histin = histin;
	local->Histout = histout;
	local->Revout = revout;
	local->scanr = scanr;
	local->scanp = scanp;
}

extern void butter_filter(float *, float *, float *, float, int);

/*
 * Leslie will operate in several separate modes, potentially not all 
 * exclusive:
 *
 * Crossover bin to horn on/off (probably bad idea - we have to emulate speaker
 * type 12 inch and bullet horn).
 * No bin rotation.
 * Sync/noSync horn to bin.
 *
 * Also, valvify should be progressively high end damped as it cuts in more.
 */
static int operate(bristolOP *operator,
	bristolVoice *voice,
	bristolOPParams *param,
	void *lcl)
{
	bristolLESLIE *specs;
	bristolLESLIElocal *local = (bristolLESLIElocal *) lcl, *local2;
	register float *source;
	float *dest1, *dest2, *tbuf = local->tbuf;
	int nSpeed = local->nSpeed, Speed, Delay, count, inertia = local->inertia;
	register int i;
	float Feedback, Reverb;

	((bristolLESLIElocal *) lcl)->toff = -25;
	local2 = (bristolLESLIElocal *) (lcl + sizeof(bristolLESLIElocal));
	((bristolLESLIElocal *) local2)->toff = 10;

	specs = (bristolLESLIE *) operator->specs;

	count = specs->spec.io[LESLIE_OUT_IND].samplecount;
	source = specs->spec.io[LESLIE_IN_IND].buf;
	dest1 = specs->spec.io[LESLIE_OUT_IND].buf;
	dest2 = specs->spec.io[LESLIE_OUT2_IND].buf;

	if (tbuf == 0)
	{
/*printf("mallocing tbuf %i\n", sizeof(float) * count); */
		local2->tbuf = (float *) bristolmalloc0(sizeof(float) * count);
		tbuf = (float *) bristolmalloc0(sizeof(float) * count);
		local->tbuf = tbuf;
	}

	/*
	 * operational parameters.
	 */
	if (param->param[7].int_val == 0) {
		/* This is stopped. Put in a very slow rotation, it will spin down and */
		/* eventually stall facing us (more or less facing). */
		Speed = 16383;
		stopped = 1;
	} else {
		if (stopped == 1) {
			nSpeed = 168;
			stopped = 0;
		}
		Speed = param->param[SPEED].int_val +
			(127 - (voice->baudio->contcontroller[1] * 127));
		if (param->param[SPEED].int_val == 532)
			Speed = (532 - (voice->baudio->contcontroller[1] * 512));
		else
			Speed = param->param[SPEED].int_val
				+ (127 - (voice->baudio->contcontroller[1] * 127));
	}
	Feedback = param->param[FEEDBACK].float_val;
	Reverb = param->param[REVERB].float_val;
	Delay = param->param[DELAY].int_val;
	/*
	 * Reverb was moved out of the rotary for being weak - it was only intended
	 * for doppler effects so now going to fix the values.
	 */
/*	Reverb = 0.7; */
/*	Feedback = 0.4; */
/*printf("Rev %f, Delay %i\n", Reverb, Delay); */

	if (nSpeed != Speed)
	{
		if (nSpeed == 0) {
			local->tinc = 0;
			nSpeed = 138;
		}
/*
printf("ns: %i s %i i %i b %i t %f\n",
nSpeed, Speed, inertia, param->param[3].int_val, local->tinc);
*/
		/* 
		 * The inertia algorithm needs to change.
		 */
		if (nSpeed < Speed) {
			if ((param->param[3].int_val) ||
				(++local->inertia >= local->tinc))
			{
				local->inertia = 0;
				if ((local->tinc -= param->param[INERTIA].float_val) < 0)
					local->tinc = 0;

				if ((nSpeed += 1) >= Speed)
				{
					nSpeed = Speed;
					local->tinc = 0;
				}
			}
		} else {
			if (++local->inertia >= local->tinc)
			{
				local->inertia = 0;
				local->tinc += param->param[INERTIA].float_val;

				if ((nSpeed -= 1) <= Speed)
					nSpeed = Speed;
			}
		}
	}

#ifdef DEBUG
	printf("leslie(%x, %x, %x, %i)\n", source, dest1, dest2, count);
#endif

	/*
	 * Put in some distortion
	 */
	newValvify(source, count, param->param[OVERDRIVE].float_val);

/*printf("leslie %i\n", param->param[7].int_val); */
/*
	if (param->param[7].int_val == 0)
	{
		for (i = 0; i < count; i++)
			*dest2++ = *source++;
		return;
	}
*/

	/* 
	 * crossover should be made configurable?
	 */
	if (local->crossover != param->param[6].float_val)
	{
		float c;

		local->crossover = param->param[6].float_val;

		if (local->crossover == 0)
		{
			local->crossover = (float) 1.0 / CONTROLLER_RANGE;
			param->param[6].float_val = local->crossover;
		}

		pidsr = M_PI / sqrt(M_E);

		/*
		 * Configure a lowpass butterworth
		 */
		c = 1.0 / (float) tan((double) (pidsr * local->crossover));
		local->a[1] = 1.0 / (1.0 + ROOT2 * c + c * c);
		local->a[2] = 2 * local->a[1];
		local->a[3] = local->a[1];
		local->a[4] = 2.0 * (1.0 - c*c) * local->a[1];
		local->a[5] = (1.0 - ROOT2 * c + c * c) * local->a[1];
		local->a[6] = 0;
		local->a[7] = 0;

		/*
		 * And a highpass butterworth.
		 */
		c = (float) tan((double) (pidsr * local->crossover));
		local2->a[1] = 1.0 / (1.0 + ROOT2 * c + c * c);
		local2->a[2] = -(local2->a[1] + local2->a[1]);
		local2->a[3] = local2->a[1];
		local2->a[4] = 2.0 * (c * c - local2->a[1]);
		local2->a[5] = (1.0 - ROOT2 * c + c * c) * local2->a[1];
	}

	bristolbzero(local->tbuf, count * sizeof(float));
	bristolbzero(local2->tbuf, count * sizeof(float));

	/*
	 * The butterworth filters do not like having zero inputs, they head into
	 * max CPU land.
	 */
	tbuf = source;
	for (i = 0; i < count; i++)
		*tbuf++ += 1;

	/*
	 * Put together a low pass and high pass for the crossover.
	 */
	butter_filter(source, local->tbuf, &local->a[0], 2.0, count);
	butter_filter(source, local2->tbuf, &local2->a[0], 2.0, count);

	/*
	 * Dest1 is probably also the source pointer, so clean it up.
	 */
	bristolbzero(dest1, count * sizeof(float));

	/*
	 * Rotate the horn.
	 */
	rotate(lcl + sizeof(bristolLESLIElocal), param->param[1].mem,
		local2->tbuf, dest1, dest2, count, nSpeed,
		Feedback, Delay, Reverb);

	if (param->param[7].int_val == 3)
	{
		/*
		 * No rotation on the bass drum.
		 */
		tbuf = local->tbuf;
		for (i = 0; i < count; i++)
		{
			*dest1++ += *tbuf;
			*dest2++ += *tbuf++;
		}
	} else {
		if (param->param[7].int_val != 2)
			inertia = nSpeed * 1.13;
		else
			inertia = nSpeed;

		rotate(local, param->param[0].mem,
			local->tbuf, dest1, dest2, count, inertia,
			Feedback, Delay, Reverb);
	}

	local->nSpeed = nSpeed;
	return(0);
}

static void
iSnewValvify(register float *busData, register int count, register float valve)
{
	register float div, *busData2 = busData;

	if ((valve == 0) || (valve == 1))
		return;

	div = 1/valve;

#ifdef DEBUG
	printf("newValvify()\n");
#endif

	for (; count > 0; count--)
	{
		/*
		 * The upper output is flattened, and the lower output is extended to
		 * imitate logarithmic valve distortion. Gain levels are corrected to 
		 * prevent clipping where possible.
		 *
		 * The positive compression would be better emulated with a tanh()
		 * function.
		 */
		if (*busData > 0)
			*busData++ = *busData2++ * valve;
		else
			*busData++ = *busData2++ * div;
	}
}

static float lpf = 0; // need to bury in a local structure

static void
newValvify(register float *busData, register int count, register float valve)
{
	register int div, i;
	register float s;

#ifdef DEBUG
	printf("newValvify(%f)\n", valve);
#endif

	if ((div = (int) (valve * 3.0f)) >= 2)
		return;

	for (i = count; i > 0; i--, busData++)
	{
		 switch (div) {
		 	case 3:
		 	case 2:
				return;
		 	default:
				s = *busData * -0.00390625f + 8.0f;
				*busData = (s * s * s * 0.00390625f - 8.0f) * 256.0f;
				break;
		 	case 1:
				s = *busData * 0.00390625f + 8.0f;
				*busData = (s * s * 0.0625f - 8.0f) * 256.0f;
				break;
		}
		*busData -= (lpf += (*busData - lpf) * 0.0001);
	}
}

static void
buildSineTable(float *table)
{
	int i;

	for (i = 130; i < (TABSIZE + 130); i++)
		table[i - 130] = (float) sin(2 * M_PI * ((double) i) / TABSIZE);
}

/*
 * Setup any variables in our OP structure, in our IO structures, and malloc
 * any memory we need.
 */
bristolOP *
leslieinit(bristolOP **operator, int index, int samplerate, int samplecount)
{
	bristolLESLIE *specs;

	*operator = bristolOPinit(operator, index, samplecount);

#ifdef BRISTOL_DBG
	printf("leslieinit(%x(%x), %i, %i, %i)\n",
		operator, *operator, index, samplerate, samplecount);
#endif

	/*
	 * Then the local parameters specific to this operator. These will be
	 * the same for each operator, but must be inited in the local code.
	 */
	(*operator)->operate = operate;
	(*operator)->destroy = destroy;
	(*operator)->reset = reset;
	(*operator)->param= param;

	specs = (bristolLESLIE *) bristolmalloc0(sizeof(bristolLESLIE));
	(*operator)->specs = (bristolOPSpec *) specs;
	(*operator)->size = sizeof(bristolLESLIE);

	/*
	 * These are specific to this operator, and will need to be altered for
	 * each operator.
	 */
	specs->spec.opname = OPNAME;
	specs->spec.description = OPDESCRIPTION;
	specs->spec.pcount = PCOUNT;
	specs->spec.iocount = IOCOUNT;
	specs->spec.localsize = sizeof(bristolLESLIElocal) * 2;

	/*
	 * Now fill in the specs for this operator.
	 */
	specs->spec.param[0].pname = "speed";
	specs->spec.param[0].description= "rotation speed";
	specs->spec.param[0].type = BRISTOL_FLOAT;
	specs->spec.param[0].low = 0;
	specs->spec.param[0].high = 1;
	specs->spec.param[0].flags = BRISTOL_ROTARY|BRISTOL_SLIDER;

	specs->spec.param[1].pname = "inertia";
	specs->spec.param[1].description = "inertia of rotation changes";
	specs->spec.param[1].type = BRISTOL_FLOAT;
	specs->spec.param[1].low = 0;
	specs->spec.param[1].high = 1;
	specs->spec.param[1].flags = BRISTOL_ROTARY|BRISTOL_SLIDER;

	specs->spec.param[2].pname = "delay";
	specs->spec.param[2].description = "delayed signal";
	specs->spec.param[2].type = BRISTOL_FLOAT;
	specs->spec.param[2].low = 0;
	specs->spec.param[2].high = 1;
	specs->spec.param[2].flags = BRISTOL_ROTARY|BRISTOL_SLIDER;

	specs->spec.param[3].pname = "reverb";
	specs->spec.param[3].description = "reverberation signal";
	specs->spec.param[3].type = BRISTOL_FLOAT;
	specs->spec.param[3].low = 0;
	specs->spec.param[3].high = 1;
	specs->spec.param[3].flags = BRISTOL_ROTARY|BRISTOL_SLIDER|BRISTOL_HIDE;

	specs->spec.param[4].pname = "tuning";
	specs->spec.param[4].description = "speaker reverberation";
	specs->spec.param[4].type = BRISTOL_FLOAT;
	specs->spec.param[4].low = 0;
	specs->spec.param[4].high = 1;
	specs->spec.param[4].flags = BRISTOL_ROTARY|BRISTOL_SLIDER|BRISTOL_HIDE;

	specs->spec.param[5].pname = "overdrive";
	specs->spec.param[5].description = "poweramp overdrive";
	specs->spec.param[5].type = BRISTOL_FLOAT;
	specs->spec.param[5].low = 0;
	specs->spec.param[5].high = 1;
	specs->spec.param[5].flags = BRISTOL_ROTARY|BRISTOL_SLIDER|BRISTOL_HIDE;

	specs->spec.param[6].pname = "crossover";
	specs->spec.param[6].description = "crossover frequency";
	specs->spec.param[6].type = BRISTOL_FLOAT;
	specs->spec.param[6].low = 0;
	specs->spec.param[6].high = 1;
	specs->spec.param[6].flags = BRISTOL_ROTARY|BRISTOL_SLIDER|BRISTOL_HIDE;

	specs->spec.param[7].pname = "operation";
	specs->spec.param[7].description = "off HornBass HornBassSync Horn";
	specs->spec.param[7].type = BRISTOL_ENUM;
	specs->spec.param[7].low = 0;
	specs->spec.param[7].high = 3;
	specs->spec.param[7].flags = BRISTOL_BUTTON;

	/*
	 * Now fill in the IO specs.
	 */
	specs->spec.io[0].ioname = "input";
	specs->spec.io[0].description = "rotary speak input signal";
	specs->spec.io[0].samplerate = samplerate;
	specs->spec.io[0].samplecount = samplecount;
	specs->spec.io[0].flags = BRISTOL_AC|BRISTOL_INPUT;

	specs->spec.io[1].ioname = "left output";
	specs->spec.io[1].description = "rotary speaker left channel output";
	specs->spec.io[1].samplerate = samplerate;
	specs->spec.io[1].samplecount = samplecount;
	specs->spec.io[1].flags = BRISTOL_AC|BRISTOL_OUTPUT;

	specs->spec.io[2].ioname = "right output";
	specs->spec.io[2].description = "rotary speaker right channel output";
	specs->spec.io[2].samplerate = samplerate;
	specs->spec.io[2].samplecount = samplecount;
	specs->spec.io[2].flags = BRISTOL_AC|BRISTOL_OUTPUT;

	buildSineTable(table);

	return(*operator);
}