ref: a1330dd9e6d91aa52faa914a9f38eb5790edde8a
parent: 31fa53e75a84582474a35ef9582bab8afb508c39
author: robs <robs>
date: Sat May 16 13:46:56 EDT 2009
allow synth exp > 100dB
--- a/sox.1
+++ b/sox.1
@@ -3600,7 +3600,7 @@
effect.
.na
.TP
-\fBsynth\fR [\fB\-j \fIKEY\fR] [\fB\-n\fR] [\fIlen\fR] {[\fItype\fR] [\fIcombine\fR] \:[[\fB%\fR]\fIfreq\fR[\fBk\fR][\fB:\fR\^|\^\fB+\fR\^|\^\fB/\fR\^|\^\fB\-\fR[\fB%\fR]\fIfreq2\fR[\fBk\fR]]] [\fIoff\fR] [\fIph\fR] [\fIp1\fR] [\fIp2\fR] [\fIp3\fR]}+\fBsynth\fR [\fB\-j \fIKEY\fR] [\fB\-n\fR] [\fIlen\fR] [\fIoff\fR] [\fIph\fR] [\fIp1\fR] [\fIp2\fR] [\fIp3\fR] {[\fItype\fR] [\fIcombine\fR] \:[[\fB%\fR]\fIfreq\fR[\fBk\fR][\fB:\fR\^|\^\fB+\fR\^|\^\fB/\fR\^|\^\fB\-\fR[\fB%\fR]\fIfreq2\fR[\fBk\fR]]] [\fIoff\fR] [\fIph\fR] [\fIp1\fR] [\fIp2\fR] [\fIp3\fR]}.ad
This effect can be used to generate fixed or swept frequency audio tones
with various wave shapes, or to generate wide-band noise of various
@@ -3657,7 +3657,10 @@
.EE
See the
.B delay
-effect for further examples.
+effect (above) and the reference to `SoX scripting examples' (below)
+for more
+.B synth
+examples.
.SP
.B N.B.
This effect generates audio at maximum volume (0dBFS), which means that there
@@ -3688,10 +3691,10 @@
`s' appended to it.
.SP
\fItype\fR is one of sine, square, triangle, sawtooth, trapezium, exp,
-[white]noise, tpdfnoise pinknoise, brownnoise, pluck; default=sine
+[white]noise, tpdfnoise pinknoise, brownnoise, pluck; default=sine.
.SP
\fIcombine\fR is one of create, mix, amod (amplitude modulation), fmod
-(frequency modulation); default=create
+(frequency modulation); default=create.
.SP
\fIfreq\fR/\fIfreq2\fR are the frequencies at the beginning/end of
synthesis in Hz or, if preceded with `%', semitones relative to A
@@ -3736,8 +3739,8 @@
default=10 (trapezium), or sustain (pluck); default=40.
.SP
\fIp2\fR (trapezium): the percentage through each cycle at which `falling'
-begins; default=50. exp: the amplitude in percent; default=100, or tone
-(pluck) default=0.
+begins; default=50. exp: the amplitude in multiples of 2dB; default=50, or
+tone (pluck) default=0.
.SP
\fIp3\fR (trapezium): the percentage through each cycle at which `falling'
ends; default=60.
--- a/src/synth.c
+++ b/src/synth.c
@@ -230,7 +230,7 @@
if (chan->p1 < 0) /* p1 is position of maximum */
chan->p1 = 0.5;
if (chan->p2 < 0) /* p2 is amplitude */
- chan->p2 = 1;
+ chan->p2 = .5;
break;
case synth_pluck:
@@ -563,7 +563,7 @@
* | |
* 0 p1 1
*/
- synth_out = dB_to_linear(chan->p2 * -100); /* 0 .. 1 */
+ synth_out = dB_to_linear(chan->p2 * -200); /* 0 .. 1 */
if (phase < chan->p1)
synth_out = synth_out * exp(phase * log(1 / synth_out) / chan->p1);
else