From bruce@ashbysolutions.com Tue Jan 29 05:18:02 2002
Subject:Re: Multiple unit modeling

Galen,

>Attached is page 5.1 of Line 6's Vetta (Guitar amp modeling) manual. I have also cut and pasted it below for those of you who can't open your attachment.

Actually, the attachment didn't make it. I forgot to mention that I had removed attachments from CWSG postings as an anti-virus measure. Most of the modern computer viruses are based on attaching a document or executable to an email, which then spreads itself around when an unsuspecting user opens the file. (It's so much more efficient than waiting for users to make floppies.) The size of this group would almost guarantee the spreading of such a virus, so I elected to strip off all attachments from files. It has already saved us a couple of times.

All,

>Is it technologically feasible for a Hammond clone manufacture to produce a unit that not only modeled *The* B-3 sound, but (like the approach taken by the Line 6 engineers) model a number of different Hammonds?
>Further, would the result be cost prohibitive to the end user?
>
>Or, do we essentially already have the equivalent of this when we, for example, switch from a factory "Theater" patch to a "Church" patch and so on?

This was my reply to Galen's original letter on the topic:

Many of the modern clones (CX-3, VK-7, V3) already have the ability to sound like a range of Hammonds. Using my CX-3 as an example, I see that there are settings for "clean" and "vintage" tonewheels, adjustments for overtones (with respect to the "perfect sine wave" that a tibia voice is supposed to create), crosstalk, key click, bass treble, and two different amp models. That should be sufficient to model almost any Hammond from 1940-1974, road-warrior to living-room-fresh, IMHO. I believe that the VK-7 has similar capabilities.

Despite the folklore, the differences in the Hammond/Leslie design throughout the years is not that great. Mostly, the changes were in filtering on the buss bars (to eliminate that awful key click!), the change to continuous response on the drawbars vs. rachet-style, the change from Jensen to Atlas drivers, and gradual feature enhancements, as can be seen in the BV -> B-2 -> B-3, or the 21H -> 22H -> 122. The rest of the tonal differences can be attributed to component aging and unit-to-unit variations. Ex: There is more difference in the vibrato circuit of a B-3 vs. A-100, than between a 1962 and 1969 B-3.

I'm often amused at the lengths that guitar amp modelers will go to both model tiny subtleties between model years -- and to convince the buyers that such subtleties are important as Hell to their sound. I completely disagree. I've owned a 1959 Tremolux, a 1964 Deluxe Reverb, and a 1970 Deluxe Reverb -- all similar designs. There are clearly differences in sound between the three. However, I've heard a 1968 Deluxe Reverb, and it is NOT tremendously different from a 1970. In fact, I'm not sure if it's different at all, neglecting the difference in tube age/manufacture between any two samples. The goal in the design was to MINIMIZE the effect that different capacitors and transformers had on the sound, not to depend on them for the proper operation of the amp.

Every Hammond has a slightly different sound, but it's not due to year of manufacture as much as it is to the random sample of components used, and the way the organ has been treated in its life.

And, a few additional comments that just occurred to me:

My earlier comments about mimicking many different vintages of Hammond probably cause some of you to comment, "Yeah, but I can still tell my '58 B-3 from my CX-3," or something of the same vein. Very true. And I can probably tell the difference between a Line 6, Johnson, Fender, or Vox modeler and a vintage amp in a blindfolded test. Modeling is an inexact process, given the current levels of CPU horsepower available for the task. But they're close enough to be worth the effort, IMHO.

Regards,

-BW

--
Bruce Wahler
Ashby Solutions™ http://music.ashbysolutions.com
CloneWheel Support Group moderator
978.386.7389 voice/fax
bruce@ashbysolutions.com