MOTM

Hi,

Does anyone know how to patch existing MOTM modules to create the 
Shepard Function "Barber Pole" effect? Or any other non-repeating 
patches? I like listening to my synths play themselves...

Richard.

Hey Richard -

I'm not sure about the Shepard Function (maybe requires delay with 
feedback) but I'll share a few of my favortie tricks for getting MOTM 
to play *ahem* himself.

1) Use the 101 S&H for well-known randomness.  This is a cool way to 
explore new timbres.

2) Use the 320 as the S&H IN.  Try all the waveforms and play with 
SHAPE and RATE on the 320 and LEVEL and SPEED on the 101.  Seemingly 
endless variety of patterns emerge. This could even be more fun with 
a quantizer (hint hint Paul and I know the MiniWave has a quantizing 
trick up its sleeve).

3) Use a 300 into A IN of the 120 and the 320 SIN into B IN and put 
the 120 into CROSS mode.  Vary RATE on the 320.  Don't forget to try 
the WHITE OUT of the 101 as B IN as well!  Mayhem!

4) Use a sequencer: UEG, Mobius, or software.  Total fun and much 
music results.

Have fun!

Mike

--- In motm@y..., phaeton777@y... wrote:

> Hi,
> 
> Does anyone know how to patch existing MOTM modules to create the 
> Shepard Function "Barber Pole" effect? Or any other non-repeating 
> patches? I like listening to my synths play themselves...
> 
> Richard.

Oh, and I forgot to mention chaos patching.  Put cables where you 
don't think they belong, particularly where you think they might feed 
back.  There are a couple of great examples in the News section of 
Paul's Web site.

Mike

--- In motm@y..., "Mike Marsh" <mmarsh@s...> wrote:
> Hey Richard -
> 
> I'm not sure about the Shepard Function (maybe requires delay with 
> feedback) but I'll share a few of my favortie tricks for getting 
MOTM 
> to play *ahem* himself.
> 
> 1) Use the 101 S&H for well-known randomness.  This is a cool way 
to 
> explore new timbres.
> 
> 2) Use the 320 as the S&H IN.  Try all the waveforms and play with 
> SHAPE and RATE on the 320 and LEVEL and SPEED on the 101.  
Seemingly 
> endless variety of patterns emerge. This could even be more fun 
with 
> a quantizer (hint hint Paul and I know the MiniWave has a 
quantizing 
> trick up its sleeve).
> 
> 3) Use a 300 into A IN of the 120 and the 320 SIN into B IN and put 
> the 120 into CROSS mode.  Vary RATE on the 320.  Don't forget to 
try 

> the WHITE OUT of the 101 as B IN as well!  Mayhem!
> 
> 4) Use a sequencer: UEG, Mobius, or software.  Total fun and much 
> music results.
> 
> Have fun!
> 
> Mike
> 
> --- In motm@y..., phaeton777@y... wrote:
> > Hi,
> > 
> > Does anyone know how to patch existing MOTM modules to create the 
> > Shepard Function "Barber Pole" effect? Or any other non-repeating 
> > patches? I like listening to my synths play themselves...
> > 
> > Richard.

>Does anyone know how to patch existing MOTM modules to create the
>Shepard Function "Barber Pole" effect? Or any other non-repeating
>patches? I like listening to my synths play themselves...

For those who don't know what this is about:

http://www.crowncity.net/ratcave/Audio/Audio.html


Guess I should rename the page to something more specific. I'll add that to
my list...


-- 
Terry Bowman, KA4HJH
"The Mac Doctor"

Shepard tones require 8 or more phase locked triangle and sawtooth waves
driving 8 oscillators and amplifiers.  MOTM and no other modular that I know
of has phase locked LFOs, though Doepfer has a dedicated Shepard Function
generator, model A-191.  The magazine Polyphony (now Electronic Musician)
had a design and maybe even a kit ages ago to create the phase locked
control voltages, but you still needed 8 VCOs and VCAs to complete the
effect.

The effect is not limited to infinite pitch effects, you can use if for
infinite phasing and other effects as well.

John Loffink
microtonal@...

>
> Does anyone know how to patch existing MOTM modules to create the
> Shepard Function "Barber Pole" effect? Or any other non-repeating
> patches? I like listening to my synths play themselves...
>

P*IA sold a kit back in the 80s that generated 8 triangle and 8 
sawtooth waves that were phase locked 45 degrees apart. I still have 
one (somewhere). It's conceptually simple to generate these waves 
digitally. Going from memory, the circuit worked like this...

A sawtooth wave is just a counter going up (or down) that rolls over. 
A triangle wave is created by XOR-ing the most significant bit of the 
sawtooth wave with the other bits. To get the phase offsets, just add 
a constant to each sawtooth. The P*IA kit used an 8 bit counter, so 
the offsets for each sawtooth were: 0x00, 0x20, 0x40 ... 0xE0.

The biggest limitation I found was with the 8 bit resolution of the 
waves. There was quite a bit of zipper noise, particularly when the 
VCAs were closing down (I was using SSM-2020 chips for VCAs). I'm 
sure somebody could build one today with 12 bit (or better) 
resolution. Perhaps a future MOTM module?

At 8:40 AM -0500 3/6/01, Microtonal wrote:
>Shepard tones require 8 or more phase locked triangle and sawtooth waves
>driving 8 oscillators and amplifiers.  MOTM and no other modular that I know
>of has phase locked LFOs, though Doepfer has a dedicated Shepard Function
>generator, model A-191.  The magazine Polyphony (now Electronic Musician)
>had a design and maybe even a kit ages ago to create the phase locked
>control voltages, but you still needed 8 VCOs and VCAs to complete the
>effect.
>
>The effect is not limited to infinite pitch effects, you can use if for
>infinite phasing and other effects as well.
>
>John Loffink
>microtonal@...
>
>>
>>  Does anyone know how to patch existing MOTM modules to create the
>>  Shepard Function "Barber Pole" effect? Or any other non-repeating
>  > patches? I like listening to my synths play themselves...
>>
-- 
------------------------------------------------------------------------
Scott Juskiw                                            scott@...