[sdiy] trying to understand appregiators in late 70's synths
George Hearn
georgehearn at btinternet.com
Mon Jan 5 09:02:59 CET 2009
..I didn't mention MIDI clock synchronization in my last mail so I thought
I'd add my thoughts... I personally prefer it if the arpeggiator always
starts from 0 time when a key is pressed for the first time, keeping time
with the MIDI clock, but not necessarily beat synced to it, others may
prefer to have a hard synchronization with the MIDI clock, where arpeggiator
notes always play dead on MIDI clock pulses. This however I found gave a
bit of an un-natural feel when playing, others may hear it differently.
George
-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of George Hearn
Sent: 05 January 2009 01:10
To: synth-diy at dropmix.xs4all.nl
Subject: RE: [sdiy] trying to understand appregiators in late 70's synths
Interesting this said about arpeggiators on this thread. It is not too
difficult to code an arpeggiator I suppose but to get it to 'feel' right and
to respond in a musical way is very tricky indeed and commercial synths do
differ in how playable their arpeggiator is. I have just implemented one on
one of my designs. My code went through several iterations before it felt
just right and could keep a good rythumn whilst changing notes. It has
up/down/up+down/random modes and a choice of 1/2/3/4 octaves.
This is roughly how I did it.
1. Store up to 10 notes held down in a table as incoming note-on messages
are received. When a note-off message is received, find the corresponding
note and make the velocity=0;
2. Use a sorting algorithm to sort the notes in order of number ascending
(up mode) or number descending (down mode).
3. Loop through this table outputting the notes if( velocity!=0 ) at the
desired intervals N times where N is the arpeggiator 'range' in octaves,
each time transposing by N octaves.
4. At the end of the cycle, if the mode is 'up+down' use the sorting
algorithm to reorder the table of held notes. Then repeat the cycle.
The trick I found was to have a good system of remembering held down notes
in a table and then using a sorting algorithm to order this table. The
arpeggiator loop itself can then be very simple. Another handy hint is to
keep a variable in your code that remembers how many notes are held down,
you can use this to have special cases when the first note is pressed or the
last note released etc. Interestingly the system that remembers the notes
and sorts them by number/order received can be exactly the same one used for
deciding which note(s) has priority to play on a limitied voice synth, even
on a monosynth. Such was my experience anyways! G
-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Bob Weigel
Sent: 04 January 2009 22:38
To: Andre Majorel
Cc: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] trying to understand appregiators in late 70's synths
Sorry for not being clear there, but as to top posting it is just
something that I often do :-). ** (Below if you want to read my
philosophy on why I deliberately do this in most instances as a courtesy
to others. Sorry it didn't work out that way in this one..)
Anyway I was talking about Jupiter 4. Like I said I *just* got the
first Jupiter 6 I've ever had a chance to play with much on my bench.
The arpeggiator is more like the Polysix it seems in feel. And indeed
while sure it's on a clock, It's just different in how it interfaces. I
haven't analyzed exactly what it is they did different. But when I play
a JP4 it seems to almost...anticipate what I want it to do. And I can
do really complex things without it doing something that sounds like "Oh
crud did he hit the wrong set of things THERE!". hehe. Jp6 native
(without Europa) is pretty good but not as good in that way for me.
Closer to the way it was done in polysix and mono/poly. I should do a
recording of the two and let you guys hear what I'm talking about
probably. I'll play nearly identically as I can a passage on those
arpeggiators and upload it today if I get a chance. There is already
a sample of me playing some jp4 arpeggiation on the sounddoctorin.com
page in the sdstudio section. Hit 'studio map' and then the bank of
keyboards that is listed below with the jp4 in it. -Bob
** It frankly annoys me when people do not top post in most cases
because I have to re-sort through everything to figure out where the new
part of the post is which is sometimes extensive and sometimes people
weave things in between stuff and I miss it if I don't look carefully.
(ie. the logic works like this. I'm a busy guy and assume others are
too. I can't read every post. I look for things that I'm interested in
right now. I glance and if it's not something I currently have need to
read I quickly hit delete and move on. Others want to read that, they
don't hit delete. Great. We all have different interests no problem.
So optimally I like to see immediately the latest thing someone said in
a discussion. Even discussions I wasn't initially interested in *might*
have something tacked on that I am interested in. But if people bottom
post I just assume probably not and delete before I even see it often.
Just because it time averages out to my advantage that way.)
I'm one of those guys who works all the numbers and optimizes everything
:-). Most conversations are of limited nesting unless people get into
an argument where they're insulting each other or something and I don't
give a flying rip about how those things go :-) But when I top post
it's so that someone can glance and BOOM move onto the next post if it's
not something they are immediately interested in. Chances are they've
already seen the stuff below. Why would they want to take even 4
seconds to maneuver down and find what I said. Multiply that 4 seconds
by 30 posts a day for a lot of us and that's 2 minutes a day. Multiple
that by 365 and that's 700 minutes a year and so on.
The only time I recommend NOT top posting is when it's a thing that
requires some detailed interaction with the text below. I used to like
the vi editor because it was so quick to do a line by line reply in.
With the little >> 's instead of the lines that I still don't know how
to get rid of sometimes. But anyway I probably should have done that
kind of reply in this case to reduce ambiguity...I dunno.
Andre Majorel wrote:
>On 2009-01-03 20:16 -0700, Bob Weigel wrote:
>
>
>>Doug Terrebonne wrote:
>>
>>
>>
>>>The ultimate arpeggiator is the Europa Jupiter-6. Check out all
>>>the features here -
>>>http://www.synthcom.com/Europa/support/EuropaUserGuideV1.0.pdf
>>>
>>>I think the earliest synth with an arpeggiator was the
>>>Jupiter-4 in 1979. Anyone know of one earlier?
>>>
>>>
>>>
>>It's also one of the best in my opinion :-). Other arpeggiators
>>you have to hit right on the money or it's train wreck time.
>>Eg. Akai AX60 eg. Korg poly's etc.
>>
>>
>
>Because you top-post, when you write "it", it's not clear whether
>you're referring to the Jupiter-4 or Jupiter-6.
>
>How can the output of an arpeggiator be a train wreck ? I thought
>notes were produced according to the clock, not to when the key
>was pressed...
>
>
>
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