Am Sonntag, 31. Mai 2009 schrieb Nick Copeland:
I get the click too, and also a bit of aliasing noise
on my system but that
could just be me, did not test it widely.
The original keyboard did have a bit of keyclick however it was not as
pronounced as the Hammond and as such never got picked up as a character of
the sound. Apart from that, the Hammond was popular also with jazz
keyboardists, the Vox only ever really penetrated the rock market.
The Vox had the same multiple contacts under each key and again, pressing a
key slowly would sound each harmonic separately, not noticeable really when
playing - you have to like move the key with a micrometer screwguage to be
able to hear them. Each key also had a separate generation PCB that did the
master oscillator division, waveform extraction from the master clock and
this probably also had a key grooming circuit to reduce noise, especially
shelving noise from the contacts (which was a large part of the Hammond
sound). Most of the click I got from Connie only noticable on note_off
rather than note_on but both of these could be improved with a grooming
I'm just working on this problem. It clicks because I switch the signals on/off
without every smoothing at random moments of the sine wave. I've changed the
timing to switch at zero crossings and the clicks go away.
Also, as with all frequency division circuits it was
equally tempered scale - every note is an integral division of the master
clock which I understand ran at 2MHz and some notes were up to 1.6 cents
out. There are kind of two issues with emulating that, firstly the midi
tables here are for ET pitch rather than integer division, and then each
wave I think is separately generated thus has no phase relation since each
voice here looks like a separate phase accumultor. The phase accumulation
probably has little effect since your frequency tables are going to be very
accurate although purists might argue that ET scaling vs. an organ divider
circuit is audible when playing chords.
I've got the schematics from http://www.reinout.nl/?page_id=80
and there I
found that the (early?) Vox had twelve individual LC oscillator boards for the
chromatic notes - the freq can be modulated via the vibrato signal. Each board
has six astable multivibrators to divide down six octaves. These seven octaves
are routed to the keys. So you're able to tune the "connie" ET or even
Werckmeister - that's cool.
My next version will have a modified freq generation. The mixture is created
from a buffer holding one cycle and sampled at different frequencies. So the
harmonics are in tune with the 8' stop. This reduces the clicking and also
reduces the CPU load quite a lot - so Connie will be more eeepc friendly.
The vibrato is perhaps a bit slow too and although the
original be modified
by a surface mounted pot I am sure that House of the Rising Sun, another
Vox classic, had it run faster than this? The pot wasn't very accessible
admittedly, and it was generally glued with that red paste to stop it from
travelling however there were a few that had this pulled out to a panel
mounted pot to be configurable, maybe only on the later Italian models
after Jennings had sold the rights.
The next Connie version will have an drawbar for an adjustable vibrato.
Perhaps just out of interest more than
anything, the current rights to Vox and Continental is held by Korg Inc of
Japan, not that they have done anything with rights to the organ. If you
ever saw one of these keyboards it was pretty spectacular: reverse
white/black keys, bright orange panel and the still quite futuristic Z Bar
frame. They should re-release it.
I have owned a couple of these over the years, an original very rare
Jennings handbuilt with laquered wooden key action, extremely light touch,
and then later the Italian plastic keyed dual manual Super. The latter
actually had the original Z Bars (the Jennings model only came as is) but
the sound was not quite as warm as the handbuilt ones.
Date: Sun, 31 May 2009 00:15:13 -0500
Subject: Re: [LAU] Connie, an organ template for JACK
Really like the sound of it. Has a bit of a harsh tick sound when
pressing a key. Not sure if that's supposed to be a "key click" or if the
audio generated for a new note is just sent as-is without fading it in.
Check it, yo!: Martin Homuth-Rosemann was sayin:
sorry, just realized that the hammond discussion mentioned below was
here and not at LAD, so please allow this kind of "crosspost":
this is my first post to LAD. The discussion about a hammond simulation
"Fons could you make us...", Beatrix and some research for writing a
(german) wikipedia article (stub) about the Vox Continental inspired me
to hack a quick organ program that simulates the internal signal flow
of the "Connie" with JACK MIDI input and JACK audio output.
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