I kind of stumbled across a pretty neat way to get some rather groovy Pulse Width Modulation in the WAV channel which I thought I would share. I am not claiming to have invented this or anything but I haven't seen it being widely discussed so I hope its useful for someone. This is a demo track I recorded, badly and too loud, using this technique to give you and idea what it sounds like.
http://www.lazerscale2010.com/track.php?id=823
The Pulse channel has (for all intents and purposes) 3 step PWM at 12.5%, 25% and 50% which is really useful but the WAV channel is a fair bit more powerful.
Step 1 - Instruments
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Make a new WAV instrument (00) and name it PWM0, make a second WAV instrument (01) and call is PWM1
Go to your chain and put note on all steps from 0 to F using instrument 00. I used the blues scale at octave 5, it seems easier to hear the effect at this pitch.
Clone the chain, in the cloned chain change all the instruments to 01
So we should now have
Chain 00 with notes in octave 5 on every step from 0 to F using instrument 00
and
Chain 01 with notes in octave 5 on every step from 0 to F using instrument 01
Step 2 - Synth
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Go to instrument 00, check synth 0 is selected, hold select and press up once and left once to get to the synth editor.
The top row of numbers represent the first 16 steps (left half) of the first frame of the wave editor, the bottom row of numbers represents the second (right half).
In the Top left you can see "WAVE 00"
The first 0 of the represents the wave, the second 0 represents the frame. If you hold B and Press up and down, you can cycle through different waves (probably all look like sawtooths), hold B and press Left and Right to move through the frames.
Go back to 00. Dont hold B or A, just use the D pad to move all the little pixels to the very bottom of the grid so boths rows of numbers are "0"s. Go to the left most pixel, press down once and the pixel should jump up to the top of the table giving you
F00000000000000
Along the top. This is going to be the first frame of out PWM wave.
We are now going to copy this frame.
Hold Select - Tap B Twice
This selects the whole frame.
Release Select and Tap B. This copies the Frame.
Hold B press right once, This will move you to the Second Frame of Wave one, you should see "WAVE 01" in the top left.
Now hold Select, press A to paste frame 01 over Frame 02.
now move the second pixel to the top of the table so you should have
FF0000000000000
Along the top row.
Repeat this process, copying frame 2 to frame 3, editing the frame to read,
FFF000000000000
and repeat all the way to frame 16 where the left half of the table will be at the top and the right hald at the bottom, giving you a 50% squarewave.
Quick note DO NOT, repeat DO NOT edit ANYTHING on the synth screen or you will have to do this step again.
Step 3 - Tables
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Go to the instrument screen for instrument 00, leave everything as is except
Change PLAY to MANUAL
Change AUTOMATE to ON
change TABLE to ))
Enter table 00
at step 00 enter F0F
at Step 01 enter F0E
etc
down to Step F00
This is manually specifying the frames for our instrument, incrementing one frame each time the intrument is played.
Now go to Instrument 01, set it to the same setting as instrument 00, make sure it is synth 00, but set the table to 01, go into table 01 and enter the opposite of table 00.
IE
Start at Step 00 F00
and finish at Step 0F F0F
Now go out to the chain screen and play your two phrases, you should head the PWM Start at the 50% phat Frame and close down to the thin frame by the end of the phrase, then open up again through the second chain!!
Its can obviously be fiddled around with and improved upon but I thought the was fun to work with.
I have included a .sav for LSDJ I think 3.9.6 if you cant follow my probably garbled instructions.
http://lazerbeat.com/lazerbeat/dropbox/lsdjPWM.sav
Last edited by Lazerbeat (Jun 29, 2010 4:16 pm)
