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<div class="moz-cite-prefix"><br>
right, but no I won't forget that, it's on the list (and
implementation ideas) :-)<br>
And the percussion mode of course, is also on the list. That
definitely adds some of the sound characteristic.<br>
<br>
- Steve<br>
<br>
Am 11.02.2017 um 17:09 schrieb bill bigrig:<br>
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<div id="yui_3_16_0_ym19_1_1486811626097_41243"><span
id="yui_3_16_0_ym19_1_1486811626097_41242">don't forget key
click.</span></div>
<div><span>Rig</span></div>
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<div dir="ltr"><font face="Arial" size="2"> On Saturday,
February 11, 2017 7:29 AM, Tom Wiltshire
<a class="moz-txt-link-rfc2396E" href="mailto:tom@electricdruid.net"><tom@electricdruid.net></a> wrote:<br>
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On 11 Feb 2017, at 14:08, Gordonjcp <<a
moz-do-not-send="true"
ymailto="mailto:gordonjcp@gjcp.net"
href="mailto:gordonjcp@gjcp.net">gordonjcp@gjcp.net</a>>
wrote:<br>
<br>
> On Sat, Feb 11, 2017 at 11:42:18AM +0000, Tom
Wiltshire wrote:<br>
>> <br>
>> On 11 Feb 2017, at 11:03, Gordonjcp <<a
moz-do-not-send="true"
ymailto="mailto:gordonjcp@gjcp.net"
href="mailto:gordonjcp@gjcp.net">gordonjcp@gjcp.net</a>>
wrote:<br>
>> <br>
>>> What you absolutely must do is ensure that
all the notes you generate start in phase.<br>
>> <snip><br>
>>> This is something you'd need to do on a
tonewheel emulation, too.<br>
>> <br>
>> <br>
>> Why? The Hammond tone generator is free-running
and the pitches are fed straight to the busbars. While
the frequencies themselves might have a fixed phase
relationship, it's not related to note onset in any way.<br>
>> <br>
>> Or am I misunderstanding what you meant?<br>
>> <br>
> <br>
> Okay, pull out the 8' bar and play C3. Holding
that down, play C4, on and off a few times. You'll hear
it key on and off, great.<br>
> <br>
> Now pull out the 4' bar as well, and play C4
again. What's the phase relationship between the
fundamental of C4 and the 4' stop of C3? Can you see a
situation where you might end up with the two
cancelling?<br>
> <br>
> If you were generating all 91 tones, you'd just be
gating them on and off. But in a typical software synth
you'd generate each voice individually with fixed
polyphony. If you're not careful with it you could
easily end up with some notes out of phase with others
and odd random shifts in tone colour as a result.<br>
<br>
Aaah! Yes, ok, absolutely! I see what you mean. Thanks
Gordon.<br>
<br>
This is a very good point he's making - since the
Hammond uses the same tone generator for every/any note,
there's no danger of phase cancellation. The same is
true in the TOG organs/synths. Any "voice based"
implementation needs to ensure that it copies this
effect. This isn't too difficult if all the voices are
produced on the same DSP, but it makes
processor-per-voice implementations a bit awkward to do.<br>
<br>
I'd be inclined to run NCOs simulating the correct
Hammond pitches for the driving/driven gear
combinations, and then use shifted versions of the phase
accumulator to generate the waveform indexes for the
required number of octaves. With only a dozen notes,
that's not a lot of work.<br>
To adjust the pitches for the standard TOG division
frequencies would then be a case of tweaking the twelve
frequency increments.<br>
<br>
Tom<br>
<br>
<br>
<br>
<br>
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