Rich Grise, but drunk wrote:
"... Accurate imitation of the Hammond sound with simple electronic
circuitry was difficult, because the subtly-changing phase relationships
between tonewheels could not be easily replicated...."

OK, fair enough. :-)

I guess a piano is even harder - they don't even reproduce well from a
live recording! :-)

I heard a decently accurate electronic piano sound long before I heard
anything remotely resembling the timber of a B3. Still haven't heard
anything that sounds exactly like a B3 (other than an A100 or another
B3).

--
If John McCain gets the 2008 Republican Presidential nomination,
my vote for President will be a write-in for Jiang Zemin.

On Wed, 28 Dec 2005 22:03:48 +0000, Joerg wrote:

Hello Rich,

It seems like, no matter how closely you try to mimic the waveform of a
real instrument,...


I have a feeling that this is exactly the problem. Engineers try to
mimic the output waveform instead of looking how the real instrument is
built. If they did that, they'd try to emulate all the individual parts
and pieces.

Regards, Joerg

http://www.analogconsultants.com

Yabbut, how many gyrators and phase shifters and stuff does it take to
model, for example, a bowed string? ;-)

Thanks!
Rich

On Thu, 29 Dec 2005 01:06:02 GMT, the renowned Rich Grise
wrote:

On Wed, 28 Dec 2005 22:03:48 +0000, Joerg wrote:

Hello Rich,

It seems like, no matter how closely you try to mimic the waveform of a
real instrument,...


I have a feeling that this is exactly the problem. Engineers try to
mimic the output waveform instead of looking how the real instrument is
built. If they did that, they'd try to emulate all the individual parts
and pieces.

Regards, Joerg

http://www.analogconsultants.com

Yabbut, how many gyrators and phase shifters and stuff does it take to
model, for example, a bowed string? ;-)

Thanks!
Rich

Whatever it is, if it has to come out of speakers it isn't going to
sound quite right.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

Hello Spehro,

Whatever it is, if it has to come out of speakers it isn't going to
sound quite right.


In case of a Hammond organ it might since it has a speaker. Of course,
it's a tube amp but that is a whole other matter which alone could make
this thread balloon.

It'll take a lot of gyrators and filters but considering that one can
buy a 400MHz DSP for less than a crate of beer these days it should be
feasible. In case of our piano the DSP still couldn't win. The piano
doesn't need power. Not even light since it has its own candles.

Regards, Joerg

http://www.analogconsultants.com

On Tue, 27 Dec 2005 18:59:56 GMT, Joerg
wrote:

Hello Jim,

Do it the way the original radio did it -- dynamotor. You can still find
them in the back room at a lot of military surplus electronics junk stores.


But then be prepared for some major restoration. The bearings of a lot
of these are nearly shot, mostly from sitting in an attic for decades.
It's like old pond pumps. They run fine for a few weeks and then the
racket increases, some weird noises appear, things get hot and they
seize up.

I restored an old Hammond organ. These generate the tones in a similar
manner. A motor (plus a start motor) and over a hundred pickup coils on
the long secondary shaft. 20 hours of hard work got it going again but
we have accepted the fact that some of the bearings are pretty much over
the hill. So it needs 2-3 starts to coax it to run without that mild
screeching in the background. Getting spare parts from a company that
went out of business 30 years ago just isn't going to happen.

Regards, Joerg

http://www.analogconsultants.com

what kind of bearings? - ball bearings are like tubes - thay have
numbers and substitutes. Bronze bearings are routinely made by
machinists. Babbit is hardest as it is poured in place but you might
be better off replacing them with something else like bronze. Bearing
technology is not all that complicated if you poke into the right
group of folks.

On Thu, 29 Dec 2005 02:13:05 GMT, the renowned Joerg
wrote:

Hello Spehro,

Whatever it is, if it has to come out of speakers it isn't going to
sound quite right.


In case of a Hammond organ it might since it has a speaker. Of course,
it's a tube amp but that is a whole other matter which alone could make
this thread balloon.

Don't some of them have rotating speakers?

It'll take a lot of gyrators and filters but considering that one can
buy a 400MHz DSP for less than a crate of beer these days it should be
feasible. In case of our piano the DSP still couldn't win. The piano
doesn't need power. Not even light since it has its own candles.

Regards, Joerg

http://www.analogconsultants.com

Sure, but can you flip a switch and be playing the flute or er-hu?


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

Spehro Pefhany wrote:

Don't some of them have rotating speakers?


That is a "Leslie" speaker. I have to service the one at my church.
The bearings are shot.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

"Rich Grise" bravely wrote to "All" (29 Dec 05 01:06:02)
--- on the heady topic of " 6v & 90v DC Power supply"

RG From: Rich Grise
RG Xref: core-easynews rec.radio.amateur.homebrew:90355
RG sci.electronics.design:535244


RG On Wed, 28 Dec 2005 22:03:48 +0000, Joerg wrote:

Hello Rich,

It seems like, no matter how closely you try to mimic the waveform of a
real instrument,...


I have a feeling that this is exactly the problem. Engineers try to
mimic the output waveform instead of looking how the real instrument is
built. If they did that, they'd try to emulate all the individual parts
and pieces.

Regards, Joerg

http://www.analogconsultants.com

RG Yabbut, how many gyrators and and stuff does it take to
RG model, for example, a bowed string? ;-)

RG Thanks!
RG Rich


One wouldn't use gyrators and phase shifters but rather wavetables.
In a nutshell, it is a sample (digital recording) of the real
instrument. Then it is digitally manipulated to add modulation, timbre
characteristics, and whatever other effects are required for the
instrument. This is calculated for each note and stored in a table in
memory, hence the name wavetable. Then this is read out to the digital
to analog converter. The resulting sound is hard to tell apart from
the real instrument. Another even more realistic and versatile method
uses digital building blocks to mimic each physical component. For
example in the case of the human voice, the nose, the mouth, windpipe,
etc. One can create totally non-existant instruments like a violin
that sounds like a flute or whatever else you could possibly imagine.
There is a program which does this but I'm drawing a blank now.

A*s*i*m*o*v

.... Guitar smashing doesn't bother me. Some "need" smashing. -Chet Atkins

http://www.rodgersinstruments.com/

featured on Made in America tv show,
amazing stuff.

I bet you can get replacement
bearings from searching on the web

http://www.mitatechs.com/organcom.html
http://www.tonewheelgeneral.com/
http://www.goffprof.com/