From bruce@ashbysolutions.com Wed May 12 05:11:41 2010
Subject:Re: sample over synth

Hi Paul,

All in all, I have to agree with your sentiments. I'm a stickler for a
real Hammond and Leslie, or the closest thing I can find to it. That's
why I use a BX3, and I use and sell the Ventilator. That said, there
are a lot of alternatives that will get you 80-90% of the way there. On
my CloneWheel Page (http://clonewheel.ashbysolutions.com), I have a
section called "Hammond Sounds for Alternative Tastes." This was an
article I originally wrote for the TheatreOrgans Hammond page,
discussing how to use various synths to get a "real Hammond sound." I
haven't kept that page up, mainly because no one else contributed to the
knowledge base, but there are some pointers there that can easily be
applied to any synth that can create a sine wave, or has a 'Hammond'
voice built in. It's handy for players who don't use a Hammond sound in
every song.

The biggest problem with sampled sound (vs. modeling) is that each of
the tonewheels in a real Hammond were tuned chromatically -- not just
the notes, but EVERY harmonic. So, no matter what notes or chords are
played on a Hammond, all of the notes and harmonics have been
chromatically adjusted to minimize phase and 'beating' issues. This
isn't true of a sampled instrument, unless one wants to sample all 91
tonewheels and recreate the sounds by additive synthesis. (The New B3
does something like this.) In the case of most 'simple' samplers, a
Hammond sound will use say, 20-25 samples across the keyboard, and
transpose the other notes from the nearest sample. This leads to a
noticeable 'beating' effect on certain chords and/or drawbar
combinations; in some of the worst cases, it also adds a phase-shifter
effect to the sound, which often sounds bizarre through a Leslie or
sim. This was true of early clones like the XB2 and XK2. Some players
hardly noticed the problem; others hated it.

Beyond that, there are the aspects of key click, leakage, etc. which
aren't equal across the keyboard of a real Hammond. I sample of say,
Middle C with a drawbar combination of 88 8842 253 will have a certain
relationship of these artifacts. If that same sample is used to create
Middle D, all the artifacts will be duplicated. In a real Hammond,
these elements are more random, note to note. Also, the tonewheels in a
Hammond have slip-clutches to prevent the mechanical system from seizing
up from lack of oil. This means that a few of the wheels may turn just
a little bit slower than the rest, or stick once in a while, changing
the phase relationship between wheels and adding a little more
randomness to the sound.

And finally, there is the issue of foldback. 91 tonewheels isn't enough
to cover 61 keys on 9 drawbars, and a real Hammond repeats lower octave
harmonics when it runs out of 'real' tonewheels. This is rather
difficult to simulate using sampling -- not impossible, but it requires
many more samples.

As you say, though, lack of these subtleties doesn't necessarily prevent
a player from using a "great Hammond sound" in a performance. They're
more like icing on the cake.

Regards,

-BW

Bruce Wahler
Ashby Solutions.com^(TM)
bruce@ashbysolutions.com
http://music.ashbysolutions.com

On 5/11/2010 7:44 PM, Paul Cunningham wrote:
> Come on Tony, don't be like that.