Conference napalm::commusic_v1

	Eventide, Ibenez, and MXR are the only ones I know of
	who make Harmonizer/pitch transposers.

	The Ibenez works by having to delay lines in parallel
	while one is sampling the input the other is clocking
	out at a rate that is front panel controlled (your pitch
	shift) then the latter line goes to sample and the former
	does what the latter did. (???) Is that clear??

	Eventide has a new one that is supposedly glitch free.
	I don't know if I've ever heard the MXR, but I think
	it would sound the same as the Ibenez. Which is not great.

	$$$$$
	Ibenez - ~$500
	MXR    - ~$1100
	Eventide - ~$4500

	I don't know how you would control a keyboard with it though.
	(If that's what you asked, I can't see your original note now
	bad planning)

	John Wlaont
	err. that's Walton

If that's the way it works, the delays aren't in parallel they're in serial.


INPUT------|
           V
	********
	*      *       Signal
	*DELAY *--------------------|
	*      *                    |
	********                    V
	   ^			********    
IN CLOCK---|			*      *    
				*DELAY *------OUTPUT
		OUT CLOCK------>*      *    
				********    
				
THAT WOULD be pretty glitchy.  That's not what I want.  I want something
that plays chords automatically.  I tell it I'm in F major, and when it
hears me play an F it plays an F major chord; if it hears an E it plays
a C major chord.  like that.

TOm

	No it's like this...

input  **********      #######
------>* memory *------# VCA #----------
       **********      #######		|
	     ^		    ^		|
	     |		    |		|
	     |		    |		|
input  **********      #######		|
------>* memory *------# VCA #----------X-------> output 
       **********      #######
	 ^   |		^   |
	 |   |		|   |
       CLKA CLKB       CVA CVB

	CVA and CVB are 180 degrees out of phase. I don't know the waveform
	but would think it's roughly a square wave. As CLKA runs at input
	clock rate ~Nyquist frequency = 11KHz -> CLKB will run at a rate
	equal to CLKA(degree of pitch shift). When the CV's change the
	CLK's exchange rates. 
	  You have parallel circuits performing alternate tasks 180 out
	of phase.


	John

	   Sorry about that.....I got lost, like off the track/road
	by a mile.....
	   But, to answer your question about getting your keyboard
	to play notes only in a specified key in response to notes
	from an acoustic source.....did I get that right????
	   I don't know.

	   If your going to use say an acoustic guitar or a violin
	or a trumpet I don't think you've got much of a chance (I
	hope I'm wrong) frequency-to-voltage converters aren't great
	for that stuff PLL's though might do it. You would need to 
	some kind of dynamic expansion in order to keep your source
	signal dynamics within the dynamic range of your curcuitry,
	also most front-ends for these applications 'like' to have
	a clean square or pulse wave, locked on the fundamental,acoustic
	instruments have a nasty habit of containing harmonics that
	tend to fluctuate in energy. That is, during the course of
	the note the second/third harmonic will gain enough energy
	over the fundamental and the PLL will lock on that, Kind
	of like a yodle not unpleasent, but you can't always anticapate
	it.

	   Anyway I've got some specs on chips of the expander,
	F-V and V-F types if you would like copies of them.

	A guy from PRIME (yow!!!) gave them to me!!!

	Send E-NET mail if you want them (mail-stop) and I'll get
	it out on inter-office as soon as I can.

	John

Thanks.  I have more data books then I need.  to build NORAD.
Tom

I know what you mean about harmonics.  Last year I built a simple circuit
that followed a pitch at the pitch or one or two octaves below.  The 
movers lost it.  Maybe that's all a harmonizer is.  I should build it
again with PLL's to get parallel chords.
         9V power|\OP AMP *******
                 | \      *CMOS *
LINE IN----------| /------*F/F  *********|
                 |/       *******        |
                                         > voltage divider OPAMP
                                         <                 |\
                                         >                 | \
                                         ------------------| /---OUT
                                         >                 |/
                                         <
                                        ___
                                         _
TOm

	Here's a good one for frequency offsets (+,-)....

	
input	     Voltage        output
-------> PLL --------> VCO ----------------->
	 ^                        |
         |                        |
         --------------------------
	  signal feedback loop

	In the feedback loop you can put dividers (F/F) or an OP-AMP
	to drive the VCO to frequencies other than the input. Also
	put conversion circuitry in the Voltage line.

	John

Anyone out there ever heard of Zappa's Electro-Wagnerian Emancipator?
I don't know much about it, but it sounds like a harmonizer, and was
probably done with fairly old (early 70's) technology.

I've often wondered what it would take to build one of these beasts, and
have filled the bacls of envelopes with chicken scratches about PLL's,
Schmitt triggers, filters and whatnot. The ultimate problem as a musician
and composer was getting beyond the simple octave or triad sounds produced.
If you want to get into modal harmonies and the like, it's probably just the
thing, but otherwise I suspect you'd need some more hands to work the conttrols,
and then why not get back to keyboards. My instrument is the trumpet, and I'd
like to play with some of the sounds that I hear coming from John Hassel, where
the trumpet is more of a controller than a melody instrument. So I can see a 
need or desire to do this. Would a guitar synth help?

-seymour-

 PIPA::JANZEN               * Integrated Circuits *           27-SEP-1985 09:04 
 Note 47.7                      -< SAD1024 ? >-                          7 of 7 

The Reticon Analog Signal Processing Integrated Circuits data and
applications book (Spring 85) which just arrived from East REgional Office
35 Congress St., Salem, MA, 01970, (617)7457400, does not have this part,
but does have more up-to-date versions of the same function.
The application notes are about pitch transposers and reverbs and signal
processing filters.
The pitch transposer articles are in reference to tape recorders that can
play at different speeds without changing the pitch of the speaker on the
tape..
Tom

    One harmonizer that was not mentioned (and is perhsps the best all 
    around harmonizer for the money) is the Digitech IPS33 "Intelligent 
    Pitch shifter". It sells betwee $600 and $700. It has midi in/out/
    through jacks, and has about 100 to 200 memory locations. Half the 
    memory is full of factory presets, and the other half is for user-
    defined patches. This unit must be tuned to the instrument you are 
    using, and offers pitch shifting in any of the modes. I believe it 
    produces up to three or more harmonics around the input. There are
    notes on the IPS33 in the guitar notes files, and possibly in the 
    Music notes as well. An Eventide unit with comparable features
    (like midi) sells for around $5000. I'm sure there are differances
    in sound quality, construction, and circuitry, but the differance
    in price is tremendous (let's face it, most people would be wasting
    their time looking at an Eventide, unless they plan to sell their
    car to get one, but the Digitech unit is quite affordable).
    
    Some of the multi-effects units include a harmonizer. The A.R.T.
    multiverb is one of their newer units that allows layering, and
    includes a simple but useable pitch shifter which allows you to
    produce one harmonic anywhere between -1 octave to +1 octave.
    I believe the Yamaha SPX90 also allows for pitch shifting.
    While these units may have usable pitch shifters, the IPS33
    really blows them away.
                                      
    Check one out !
    
    Mark
    

>    < Note 60.10 by ANT::JACQUES >
>                 -< Digitech IPS33 intelligent pitch shifter >-
>
>    One harmonizer that was not mentioned (and is perhsps the best all 
    >    produces up to three or more harmonics around the input. There are
If they are around the note in ratios other than positive integers,
    they are not harmonics.  
    
    >    notes on the IPS33 in the guitar notes files, and possibly in the 
>    Music notes as well. An Eventide unit with comparable features
>    (like midi) sells for around $5000. I'm sure there are differances
>    in sound quality, construction, and circuitry, but the differance
    >    in price is tremendous
    It is my suspicion that modern VLSI digital signal processors and DACs
    and ADCs are the same parts in most systems, especially the 32000
    series DSP chips, and information about DSP s/w is common now, so
    I wouldn't expect serious differences for this type of unit costing
    thousands; after all, it's less software than a microcomputer and
    less hardware as well.
    
>    I believe the Yamaha SPX90 also allows for pitch shifting.

    The SPX90 can pitch shift to one or two pitches simultaneously, with 
    feedback if desired, and delay to 2 seconds on the spx90II.  Using
    MIDI input changes the base note.
    In practice this would allow a sequencer to play it any interval
    you wanted in real time.  
    Sounds like a smart-shift function if you combine the
    right hardware.
    It shifts +/- 1 octave.
 > Mark
Tom    

    I know this is slightly off the track, but its notes-worthy.
    
    When I was in high school, my friends sister worked with Larry
    Fast's (solo albums, foreigner, p. gabriel) wife. Anyway,
    Larry Fast was at my friends house for a picnic, and I was
    gaping-mouthed in awe, and talked about keyboards.
    (My setup at the time was a PAIA organtua, and a CAT-SRM synth)
    
    He swore to me that the ONLY effect one ever needs is a harmonizer.
    (he had an eventide)
    Not that I believe him ((I think he has a fairlight or two now))
    but at the time the words were divine.
    

    I'm normally not in to making corrects but some of these are
    significant:
    
    > I believe it produces up to three or more harmonics around the input. 
    
    I'm not sure what you meant by "up to 3 or more", but the IPS
    is capable of producing two other pitches besides the original
    pitch.
    
    > An Eventide unit with comparable features (like midi) sells for 
    > around $5000.
    
    I'm not sure which unit you are thinking of but the Eventide H-3000
    is also comparable to the IPS-33 and sells for around $2,000.
    (IPS sells for around $600-$700 as Mark stated.)
    
    The H-3000 is also capable of doing most standard digital effects besides
    harmonization.
    
    The Eventide is definitely a higher quality unit, but the IPS-33
    is remarkable for its price.  I can't imagine too many people in
    here springing the extra $1500 for the Eventide unless you have
    a very serious studio.
    
    I've played with the IPS-33.  It tracks most keyboard patches
    flawlessly.  As for guitar, if you have good technique (you articulate
    each note well), it will also track nearly flawlessly.  If your
    technique is not so good, you'll have problems.
    
    Only crticism is that it's very sensitive to tuning.  Your guitar
    being slightly out of tune, or if you bend the string accidently
    you will get very obvious and undesirable glitches.
    
    I wrote a very extensive review in GUITAR (conference) somehwere.
    
    It's definitely a hot unit.
    
    	db