MOTM

What does tap-tempo mean for an LFO?  I understand the implications (I
think?) for a delay module, where it echos when you tap, but what does it do
for an LFO?  Does it restart the cycle at each tap?  Would it "learn" the
rate from the tap-tempo?  (I think that would be difficult to do in analog.)

--PBr

> -----Original Message-----
> From:	Charles Stella [SMTP:cstella@...]
> Sent:	Wednesday, May 17, 2000 11:17 AM
> To:	motm@egroups.com
> Subject:	[motm] LFO Tap and Division
> 
> Hello all. A friend of mine recently purchased an Electrix FilterFactory
> andI was showing him how to use filters and the various controls. While
> this unit pales in any comparison to MOTM it did have a couple of cool
> real-time performance features. There is a tap tempo for the LFO, and a
> button that flips through various ratio divisions of the LFO. So you can
> quickly skip from 1:1, 2:1 etc  through 1:4. Has anyone experimented
> with these types of effects with MOTM Modules? Or is this a yet to be
> released module(s)? Regards, Charles.
>

> Hello all. A friend of mine recently purchased an Electrix FilterFactory
> andI was showing him how to use filters and the various controls. While
> this unit pales in any comparison to MOTM it did have a couple of cool
> real-time performance features. There is a tap tempo for the LFO, and a
> button that flips through various ratio divisions of the LFO. So you can
> quickly skip from 1:1, 2:1 etc  through 1:4. Has anyone experimented
> with these types of effects with MOTM Modules? Or is this a yet to be
> released module(s)? Regards, Charles.

the joys of digital LFOs.  i personally don't like the electrix stuff.  it
seems very "gimmick" and not designed for integration into a professional
studio setup for "creation" but more for post production and dj doodling.

-steve

In a message dated 05/17/2000 2:52:52 PM, velure@... writes:

<< i personally don't like the electrix stuff.  it
seems very "gimmick" and not designed for integration into a professional
studio setup for "creation" but more for post production and dj doodling. >>

I like the stuff for what it is; very inexpensive and MIDI-friendly simple 
effects devices.  It is quite good for live electronic music performance as 
well.

Ivan

> What does tap-tempo mean for an LFO?  I understand the implications (I
> think?) for a delay module, where it echos when you tap, but what
> does it do
> for an LFO?  Does it restart the cycle at each tap?  Would it "learn" the
> rate from the tap-tempo?  (I think that would be difficult to do
> in analog.)
>
> --PBr

OK, let's take a stab at this. You'd need a digital counter to time the
taps. That would be converted into a control voltage, by a ROM table/DAC or
some other means. The LFO receiving the control voltage would have to be
precision tuned to a known starting frequency, and could have no FM going on
other than the tap CV input.

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

>> What does tap-tempo mean for an LFO?  I understand the implications (I
>> think?) for a delay module, where it echos when you tap, but what
>> does it do
>> for an LFO?  Does it restart the cycle at each tap?  Would it "learn" the
>> rate from the tap-tempo?  (I think that would be difficult to do
>> in analog.)
>>
>> --PBr
>
>OK, let's take a stab at this. You'd need a digital counter to time the
>taps. That would be converted into a control voltage, by a ROM table/DAC or
>some other means. The LFO receiving the control voltage would have to be
>precision tuned to a known starting frequency, and could have no FM going on
>other than the tap CV input.
>
This has me thinking down a similar path. I have a Roland MC-303 Groovebox.
OK, you can stop laughing now. The groovebox has a tap tempo feature, and
I've used it live as a tempo controller for my MAQ, and for delys that sync
to MIDI clock. I'm thinking I could send the MIDI output of the groovebox
to a MIDI/CV converter that has a clock output, send that to a clock
divider, and then send the subdivision output to the 320 LFO. Would I want
to go the the Sync or the CV input? What would be cool would be to have the
MIDI/CV provide the base tempo, and the Rate knob provide the subdivision.
This'd be kind of like how oscillator sync works, only in the sub-audible
range. I'm going to have to play with this when I get a chance.

____________________________________________
Dave Trenkel : improv@...
Minus Web Site: http://listen.to/minusmusic
Minus MP3's: http://www.mp3.com/-minus-
____________________________________________

This makes me think:  instead of having a groovebox & midi to cv converter
to create tap tempo for an MOTM LFO, what about having some sort of
dedicated external controller that could perhaps be integrated into a larger
controller with joysticks etc.?  I have no idea what this would take, but it
seems like a good idea to me.

tomr
----- Original Message -----
From: <improv@...>
To: <motm@egroups.com>
Sent: Wednesday, May 17, 2000 4:55 PM
Subject: RE: [motm] LFO Tap and Division


> >> What does tap-tempo mean for an LFO?  I understand the implications (I
> >> think?) for a delay module, where it echos when you tap, but what
> >> does it do
> >> for an LFO?  Does it restart the cycle at each tap?  Would it "learn"
the
> >> rate from the tap-tempo?  (I think that would be difficult to do
> >> in analog.)
> >>
> >> --PBr
> >
> >OK, let's take a stab at this. You'd need a digital counter to time the
> >taps. That would be converted into a control voltage, by a ROM table/DAC
or
> >some other means. The LFO receiving the control voltage would have to be
> >precision tuned to a known starting frequency, and could have no FM going
on
> >other than the tap CV input.
> >
> This has me thinking down a similar path. I have a Roland MC-303
Groovebox.
> OK, you can stop laughing now. The groovebox has a tap tempo feature, and
> I've used it live as a tempo controller for my MAQ, and for delys that
sync
> to MIDI clock. I'm thinking I could send the MIDI output of the groovebox
> to a MIDI/CV converter that has a clock output, send that to a clock
> divider, and then send the subdivision output to the 320 LFO. Would I want
> to go the the Sync or the CV input? What would be cool would be to have
the

> MIDI/CV provide the base tempo, and the Rate knob provide the subdivision.
> This'd be kind of like how oscillator sync works, only in the sub-audible
> range. I'm going to have to play with this when I get a chance.
>
> ____________________________________________
> Dave Trenkel : improv@...
> Minus Web Site: http://listen.to/minusmusic
> Minus MP3's: http://www.mp3.com/-minus-
> ____________________________________________
>
>
>
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In a message dated 5/17/2000 12:16:08 PM, Moe writes:

>OK, let's take a stab at this. You'd need a digital counter to time the
>taps. That would be converted into a control voltage, by a ROM table/DAC
>or
>some other means. The LFO receiving the control voltage would have to be
>precision tuned to a known starting frequency, and could have no FM going
>on
>other than the tap CV input.

And I bet Crow could whip a 1U module (tap tempo) pretty quickly. Then one 
could plug the output into the sync in of the 320 for example. Not a bad idea 
for a module (though of somewhat limited interest amongst MOTM buyers, and 
few people would want more than one). Possibly it could have a mic input and 
a footswitch input.

JB

Hi all,

Dave>I have a Roland MC-303 Groovebox. OK, you can stop laughing now.

I'm not laughing... this is a very good machine to drive your modular.
It has a nice enough sequencer and the arpegiator is great. You can pick
it up for 225UKP NEW in the UK right now. I just wish it could send out
midi controller information. And the software is a little buggy in
record mode, it is best to make a copy of your track you are working on
to the next location just in case it decides to rewrite snippets your
masterpiece. Oh, and the drum sounds aren't bad either.

You can hear it driving my modular in some of the short samples on my
wavefolder page.

Regards,

Tony Allgood  Penrith, Cumbria, UK

Modular synth circuits, TB303 clone and Filter Rack

http://www.techrepairs.freeserve.co.uk/projects.htm

On Wed, 17 May 2000 jwbarlow@... wrote:

> And I bet Crow could whip a 1U module (tap tempo) pretty quickly. Then one 
> could plug the output into the sync in of the 320 for example. Not a bad idea 
> for a module (though of somewhat limited interest amongst MOTM buyers, and 
> few people would want more than one). Possibly it could have a mic input and 
> a footswitch input.

  Tap-tempo acquisition is not difficult to do.  Some years ago I made a
similar device that used 4 taps to set a rate.  There are several "small,
but useful" PIC things I'd like to cram into a module.  MIDI<>sync, a
gate-to-trigger thing (to do cute stuff like generate a trigger on the
rising, falling or both edges of a gate), this tap-tempo thing and a
digital noise generator that Does Not Suck(tm).

Crow

/**/

>   Tap-tempo acquisition is not difficult to do.  Some years ago I made a
> similar device that used 4 taps to set a rate.  There are several "small,
> but useful" PIC things I'd like to cram into a module.  MIDI<>sync, a
> gate-to-trigger thing (to do cute stuff like generate a trigger on the
> rising, falling or both edges of a gate), this tap-tempo thing and a
> digital noise generator that Does Not Suck(tm).
>

I always thought that the Emu noise circuit Did Not Suck, and it was
digital. What esoteric, exotic, or cool things do you have in mind for
yours?

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

In a message dated 00-05-23 10:42:42 EDT, you write:

<< and a
 digital noise generator that Does Not Suck(tm). >>



crow,
i`d love to see a source of uncorrelated ( say 3 or 4 ) random triggers 
derived from such a noise source. any chance ?
best,
dave v.

On Tue, 23 May 2000 davevosh@... wrote:

> crow,
> i`d love to see a source of uncorrelated ( say 3 or 4 ) random triggers 
> derived from such a noise source. any chance ?
> best,
> dave v.

  Uncorrelated?  That would require good old shot noise to be truly random
between concurrent triggers.  In a PIC, I can rig several long feedback
shift registers and thus create pseudo-random noise by instructing the
regs to shift at a rate of 40KHz, but unless the seed number can be set by
some sort of "real-world random" for each register, the triggers would
actually be correlated by the finite (long, yes, but still finite) shift
register bit patterns.

  Hm, now this has me thinking.  I have methods I've used in the past to
get fairly "true random" seeds that involve detecting the error in
thermocouple cold-junction compensation servo loops, but that might not be
the best solution here (as I'm not trying to build a process controller
here). What might be of more use to us however is some way of setting
specific random seeds by hand and then load/start the registers.

  A "random" sequencer for triggers is what I'm arriving at here.  Some
way to set a seed with a load jack/pushbutton, a clock rate switch to run
it at 40KHz for audio uses or select a manual shift clock from a VCO or
whatever.  I'll have to puzzle over it a bit to see if what I'm thinking
actually works the way I want it to.

  And here I just wanted to use my PIC part that I use to replace the
flimsy digital noise chip Prophet-5s used.  Now look what it has become.
;)

Crow

/**/

On Tue, 23 May 2000, Dave Bradley wrote:

> I always thought that the Emu noise circuit Did Not Suck, and it was
> digital. What esoteric, exotic, or cool things do you have in mind for
> yours?

  I can't speak for the Emu noise circuit, but the Prophet-5 used an
MM5837 which was pure crap. "SchksshhhSchkshhhSchkshhh..."

  The first cool thing is a set of shifters as long as your arm.  The
second thing is a manual noise clock for trigger fun.  I'll have to figure
out just what I want this weekend. :)

Crow

/**/

Use PIC with ADC, measure Zener Diode noise (amplified).

Paul S.

----- Original Message -----

From: The Old Crow <oldcrow@...>
To: <motm@egroups.com>
Sent: Wednesday, May 24, 2000 4:13 PM
Subject: Re: [motm] LFO Tap and Division


>
> On Tue, 23 May 2000 davevosh@... wrote:
>
> > crow,
> > i`d love to see a source of uncorrelated ( say 3 or 4 ) random triggers
> > derived from such a noise source. any chance ?
> > best,
> > dave v.
>
>   Uncorrelated?  That would require good old shot noise to be truly random
> between concurrent triggers.  In a PIC, I can rig several long feedback
> shift registers and thus create pseudo-random noise by instructing the
> regs to shift at a rate of 40KHz, but unless the seed number can be set by
> some sort of "real-world random" for each register, the triggers would
> actually be correlated by the finite (long, yes, but still finite) shift
> register bit patterns.
>
>   Hm, now this has me thinking.  I have methods I've used in the past to
> get fairly "true random" seeds that involve detecting the error in
> thermocouple cold-junction compensation servo loops, but that might not be
> the best solution here (as I'm not trying to build a process controller
> here). What might be of more use to us however is some way of setting
> specific random seeds by hand and then load/start the registers.
>
>   A "random" sequencer for triggers is what I'm arriving at here.  Some
> way to set a seed with a load jack/pushbutton, a clock rate switch to run
> it at 40KHz for audio uses or select a manual shift clock from a VCO or
> whatever.  I'll have to puzzle over it a bit to see if what I'm thinking
> actually works the way I want it to.
>
>   And here I just wanted to use my PIC part that I use to replace the
> flimsy digital noise chip Prophet-5s used.  Now look what it has become.
> ;)
>
> Crow
>
> /**/
>
>
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>

In a message dated 00-05-24 17:16:35 EDT, you write:

<< 
   A "random" sequencer for triggers is what I'm arriving at here.  Some
 way to set a seed with a load jack/pushbutton, a clock rate switch to run
 it at 40KHz for audio uses or select a manual shift clock from a VCO or
 whatever.  I'll have to puzzle over it a bit to see if what I'm thinking
 actually works the way I want it to.
  >>



crow,
this sounds like it might be interesting.
on what you were saying earlier about PRBS length, you are certainly correct 
but with a long enough sequence, the desired "random" effect might be 
produced.
best,
dave v.