[sdiy] Bar Graph Driver as Quantanizer

Thu Feb 5 01:08:02 CET 2009

Agreed about keeping it in spectrum analysis. Too many things flying around and it just looks like pseudo-random patterns (not unlike what you see on the MySpace music player :[ ).

Cool stuff indeed! There was another video on the side of the page (http://www.youtube.com/watch?v=rA3AUjyZgps&feature=related), where a guy had used an Arduino board and some PWM to get some interesting results. It's another can of worms if I want full RGB color (might stick with the monochrome for now), but some "delay"-ish fading effects would be nifty.

_Kyle

--- On Wed, 2/4/09, Amos <controlvoltage at gmail.com> wrote:

> From: Amos <controlvoltage at gmail.com>
> Subject: Re: [sdiy] Bar Graph Driver as Quantanizer
> To: lightburnx at yahoo.com
> Date: Wednesday, February 4, 2009, 2:41 PM
> saw something that looks like the digital version of what
> you're describing
> (at least in one of its multi- modes...)
> http://www.youtube.com/watch?v=0d9_KZcxsGs&feature=related
> 
> If I had such a thing, I'd leave it in spectrum
> analyzer mode all the time,
> I think...
> and yes a DIY analogue version would be much cooler. :-)
> 
> -Amos
> 
> On Wed, Feb 4, 2009 at 4:19 PM, Kyle Stephens
> <lightburnx at yahoo.com> wrote:
> 
> > Just waiting for the 3914s to arrive to start
> experimenting!
> >
> > One good point Roy brought up was that the 3914 puts
> out currents not
> > voltages. Would the Schmitt triggers clear that up, or
> need I use an LED
> > (say, an opto-FET switch tied to a 1 volt voltage
> reference) to get back to
> > voltages?
> >
> >
> > _Kyle
> >
> >
> > --- On Mon, 2/2/09, Tim Parkhurst
> <tim.parkhurst at gmail.com> wrote:
> >
> > > From: Tim Parkhurst
> <tim.parkhurst at gmail.com>
> > > Subject: Re: [sdiy] Bar Graph Driver as
> Quantanizer
> > > To: lightburnx at yahoo.com
> > > Date: Monday, February 2, 2009, 12:57 PM
> > > Hey Kyle,
> > >
> > > I've been thinking about various applications
> for the
> > > 3914, and I've found a
> > > few on the interweb, but I've been so swamped
> with
> > > other Magic Smoke
> > > business that I really haven't had a chance
> to try any
> > > of them out! Of
> > > course, you have the various audio level and
> voltmeter
> > > applications, along
> > > with Ian's 5 Pulser and Grant's Analog
> Tracking
> > > Generator. I was also
> > > thinking you could do a sequencer (with voltage
> control of
> > > stage and
> > > direction), a quantizer, and a three 'window
> > > generator' where you put in a 0
> > > to 10V ramp and get out three voltages that rise
> and fall
> > > at evenly spaced
> > > intervals (apply those voltages to three VCAs and
> you could
> > > smoothly fade
> > > between the three VCA outputs). The 'window
> > > generator' is somewhat related
> > > to Grant's design, but with multiple outputs.
> Other
> > > than that, I was
> > > thinking of enhancements like adding trigger outs
> at each
> > > stage and maybe
> > > some other goofy stuff like that. If you do knock
> together
> > > a 3914-based
> > > quantizer, let me know how it works out!
> > > Tim (Servo) Parkhurst
> > > On Sat, Jan 31, 2009 at 10:02 PM, Kyle Stephens
> > > <lightburnx at yahoo.com>wrote:
> > >
> > > > After I sent off the email, I thought of the
> 3x LM3914
> > > idea too after I had
> > > > some more time to ponder :)
> > > >
> > > > Just took a look at the Oberheim (available
> here if
> > > anyone else is curious:
> > > >
> > >
> http://www.crowncity.net/ratcave/Electro/Oberheim/Mini_Seq.jpg),
> > > and I
> > > > know about the MFOS quantinizer, and
> there's one
> > > by Scott Stites too (
> > > >
> > >
> http://mypeoplepc.com/members/scottnoanh/birthofasynth/id15.html),
> > > but
> > > > like you said, there's fun to be had.
> > > >
> > > > Hmm. What have you wrung out of the 3914 so
> far? I got
> > > wind of it through
> > > > an Ian Fritz design, the 5pulser (
> > > >
> http://home.comcast.net/~ijfritz/sy_cir8.htm<http://home.comcast.net/%7Eijfritz/sy_cir8.htm>
> > ).
> > > >
> > > >
> > > > _Kyle
> > > >
> > > > --- On Sat, 1/31/09, Tim Parkhurst
> > > <tim.parkhurst at gmail.com> wrote:
> > > >
> > > > > From: Tim Parkhurst
> > > <tim.parkhurst at gmail.com>
> > > > > Subject: Re: [sdiy] Bar Graph Driver as
> > > Quantanizer
> > > > > To: lightburnx at yahoo.com
> > > > > Cc: "Synth-DIY"
> > > <synth-diy at dropmix.xs4all.nl>
> > > > > Date: Saturday, January 31, 2009, 8:55
> PM
> > > >  > On Sat, Jan 31, 2009 at 8:00 PM, Kyle
> Stephens
> > > > > <lightburnx at yahoo.com> wrote:
> > > > >
> > > > > > Some musings...
> > > > > >
> > > > > > While looking at the LM3914, a
> bar/dot graph
> > > driver, I
> > > > > realized that it's
> > > > > > basically a quantinizer. With a
> few tweaks
> > > and a
> > > > > stable voltage reference,
> > > > > > it'd serve as such. I think...
> Help me
> > > here if
> > > > > otherwise.
> > > > > >
> > > > > > Datasheet's here for
> reference:
> > > > >
> http://www.national.com/ds/LM/LM3914.pdf
> > > > > >
> > > > > > One big question, is how could I
> use just 2
> > > chips(*)
> > > > > for several octaves
> > > > > > (vs. 1 chip per 10 notes...?).
> Some kind of
> > > dynamic
> > > > > reference voltage
> > > > > > offset...? Not unless that's
> not a
> > > completely
> > > > > unreasonable solution. The
> > > > > > datasheet says you can chain
> together up to
> > > 100
> > > > > outputs. With 12 discrete
> > > > > > keys per octave, that's 100/12
> =
> > > effectively 8
> > > > > octaves.
> > > > > >
> > > > > > (*) At least 2 chips would have to
> be
> > > employed anyway,
> > > > > as they only have 10
> > > > > > outputs each. So, call it 2
> chained ICs for
> > > 20 total
> > > > > outputs, 12 of which
> > > > > > would be used for 12
> "bits" of
> > > > > resolution/levels of quantification.
> That's
> > > > > > assuming the "just 2
> chips"
> > > configuration is
> > > > > possible, otherwise it's just a
> > > > > > step-after-another progression.
> > > > > >
> > > > > > There's also the LP3943, which
> has 16
> > > outputs to
> > > > > start with. It's a low
> > > > > > power IC though - has that any
> share of
> > > potential
> > > > > issues?
> > > > > >
> > > > > > Datasheet:
> > > http://www.national.com/ds/LP/LP3943.pdf
> > > > > >
> > > > > >
> > > > > > The 3194 has a 'bar' and
> > > 'dot' mode;
> > > > > bar is 'from ground up,' with
> each
> > > > > > output giving a fixed voltage,
> which when
> > > summed would
> > > > > give you the
> > > > > > quantinized CV.
> > > > > >
> > > > > > Switch to dot mode, which triggers
> the
> > > output
> > > > > designated closest to the
> > > > > > input voltage, and you got a
> voltage
> > > controlled event
> > > > > generator; between
> > > > > > your preset step range (dunno the
> exact
> > > hysteresis
> > > > > thereof...), gate 'a'
> > > > > > fires, next step gate 'b',
> etc.
> > > > > >
> > > > > > On the note of hysteresis, I
> looked it up in
> > > the
> > > > > datasheet just now and it
> > > > > > said there isn't any built in,
> and
> > > there's a
> > > > > fadeover of 1mV or more between
> > > > > > outputs (apparently less if the
> next
> > > "step"
> > > > > isn't on the same IC, for
> > > > > > chained circuits). I'm not
> sure how to
> > > address
> > > > > that... A comparator, or a
> > > > > > specific output-voltage referenced
> Schmitt
> > > trigger,
> > > > > per output??
> > > > > > (x12 is kinda steep). How many
> cents off
> > > would ~1mV
> > > > > bend a VCO anyway?
> > > > > >
> > > > > > Any other thoughts on this? And
> again, is it
> > > even an
> > > > > effective, let alone
> > > > > > feasible idea? Just wana scope
> things out
> > > before I hit
> > > > > the breadboard.
> > > > > >
> > > > > >
> > > > > > Also: a grateful if belated thank
> you to
> > > everyone who
> > > > > responded about my
> > > > > > MS-20 filter clone questions!
> > > > > >
> > > > > >
> > > > > > _Kyle
> > > > > >
> > > > > > (whoops, meant to send this to
> Kyle AND the
> > > list...)
> > > > > Hey Kyle,
> > > > >
> > > > > The 3914 is an interesting chip.
> I'm putting
> > > together
> > > > > some 3914 based stuff
> > > > > for a "Making Music With the
> 3914" book
> > > I want to
> > > > > write... some day. In any
> > > > > case, I haven't made a quantizer
> with the
> > > little
> > > > > buggers yet, but my
> > > > > thoughts are: Use three chips - the
> first is the
> > > Octave
> > > > > Quantizer and is set
> > > > > up to quantize to the nearest whole
> volt value,
> > > and
> > > > > subtract the ouput of
> > > > > that from the input so that you're
> left with
> > > a CV that
> > > > > varies from 0 to 1V
> > > > > (e.g., 1.23V in = 0.23V out, 3.75V in =
> 0.75V
> > > out). The 0
> > > > > to 1V signal goes
> > > > > into the Note Quantizer made from two
> 3914s
> > > chained
> > > > > together (and adjusted
> > > > > so that you're only using the first
> 12
> > > outputs). All of
> > > > > the 3914 outputs
> > > > > drive 40106 schmitt trigger inverters.
> This makes
> > > it so
> > > > > that the selected
> > > > > 3914 out goes high, and should
> eliminate any
> > > problems with
> > > > > the 'fadeover'
> > > > > causing more that one out being on at a
> time.
> > > Combine the
> > > > > output of the
> > > > > first 3914 (the Octave) with the output
> of the
> > > Octave
> > > > > Quantizer and the Note
> > > > > Quantizer, and Bob's yer uncle,
> you've
> > > got a
> > > > > 3914-based quantizer.
> > > > >
> > > > > To sum it up; one chip quantizes to the
> nearest
> > > octave,
> > > > > another two chips
> > > > > quantize to the nearest note within one
> octave,
> > > and then
> > > > > you combine the
> > > > > outputs. In theory, you should be able
> to get 10
> > > octaves
> > > > > with three 3914s,
> > > > > four 40106 inverters, a handful of op
> amps, and
> > > maybe a
> > > > > couple of voltage
> > > > > reference chips or zeners. You'll
> probably
> > > also need
> > > > > several trimmers and /
> > > > > or precision resistors for setting up
> voltage
> > > dividers.
> > > > > Might be easier to
> > > > > go with the standard
> Counter-D/A-Comparator type
> > > of
> > > > > quantizer, but where's
> > > > > the fun in that? ;-)
> > > > >
> > > > > (If you want a potentially quicker
> solution,
> > > check things
> > > > > like the Oberheim
> > > > > mini-sequencer, or I think Ray Wilson
> has a nice
> > > updated
> > > > > version complete
> > > > > with a PCB for purchase)
> > > > >
> > > > >
> > > > > Tim (proud owner of a tube full of
> 3914s) Servo
> > > > > --
> > > > > "A nation cannot prosper long,
> when it
> > > favours only
> > > > > the prosperous." -
> > > > > Barack Obama
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > > --
> > > "A nation cannot prosper long, when it
> favours only
> > > the prosperous." -
> > > Barack Obama
> >
> >
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at dropmix.xs4all.nl
> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >