The Yamaha AN1x Synthesizer mailing list

An1xers:

I must be having too much time on my hands. Yesterday I started 
recording An1X oscillator tones and looking at waveforms. I also 
started timing tests on LFO 1. I came up with the following table 
which is pretty good up to three significant digits, I reckon.

Note that since the LFO's don't lock to anything, it would be a waste 
of time using this table for synchronizing BPM. You would be best 
served using this as a reference for programming vibrato, tremolo, 
chiff, growl and other kinds of modulation things.


LFO 1 Setting	Rate (hz)
1	0.042
5	0.210
10	0.421
20	0.841
30	1.26
40	1.72
50	2.31
60	2.90
70	4.04
80	4.96
90	5.89
100	6.77
110	7.87
120	9.82
130	10.1
140	12.7
150	15.2
160	18.3
170	22.4
180	27.6
190	34.3
200	43.4
210	54.9
220	71.2
230	87.8
240	111
250	141
256	162

The waveforms were very interesting. I found a couple of surprises:

- All the waveforms were far more rounded than I expected even at an 
edge of 127
- The pulse wave (at edge of 127) was more lopsided than I expected. 
It had a sloping top line, looking more like a truncated saw, than a 
square. (I guess they wanted to give us the possibility of more 
overtones, should we need them.) I didn't play with pulse width, 
though that is my next test.
- The saw, pulse, saw2 and mix waveforms, collapse to a pure sine 
wave when edge goes to zero. The exception is the pulse wave under 
oscillator sync, which collapses to sine only when edge is zero 
AND sync pitch is minus 12. (I wonder if the slave is tuned up by an 
octave, or something? why?)
- The internal (1,2,3) waveforms would not collapse to sine under any 
circumstances. They appear (visually) to be stacked saw waves tuned 
to the harmonic series. I am not sure specifically which overtones 
they are tuned to, but I know it is not a simple octave relationship, 
as I could not collapse them to sine by playing with the sync tuning 
and edge. Each individual element would get more sine like, but not 
the combined waveform. 

My opinion:
I suspect (but I am not sure) that these are saw waves at an octave 
above and 1.5 octaves above. The difference between the waveforms 
(int1, int2, int3) lies in the relative volumes of the overtone waves.

I may be off base with these observations. I am hoping someone from 
the list may have an inside scoop (Gary?), or has done more extensive 
tests.

Anyway, I hope this info helps someone.

Cheers,

Jerry