From bruce@ashbysolutions.com Mon Jan 29 05:57:49 2007
Subject:Re: Double triggering - how is it meant to be like?

Hi Andreas,

[This is a rather long post ...]

>Could someone please explain to me which kind of double triggering a
>real hammond does, i.e. how to achive it, how does it sound, and so on.
>
>I browsed the whole message archive and found lots of contradictory
>statements about that issue :(
>
>As far as I understand, some clones (VK-8, CX-3, XK-3) do sort of
>double triggering in a more or less realistic way and some people like
>it, some don't...

No one is trying to simulate "double triggering" itself. Everyone is trying to simulate the fast action of the Hammond keyboard, using the limited tools that are available in a modern MIDI keyboard. In the process, double triggering happens. Let me explain the differences in the keybeds, and I think that you will understand a little better.

The Hammond keyboard has nine contacts, Ideally, they should all close at the same time, but because of the real-world issues (spacing of the buss bars, angle of the key to the switches, etc.) they do not: The first contact closes at about 1/3 of the key travel, and if one continues to press a key very slowly, the other harmonics are added one at a time. This results in a bit of randomness when playing the Hammond Organ, especially on fast passages, because some of the keys will be pressed all the way (resulting in all nine switches closing) while others will not.

None of this is possible in a standard MIDI keybed. 99% of the requirements for a MIDI keyboard controller in 2007 are for velocity sensing, and this can be accomplished by calculating the time between the closure of two switch contacts. To give the most accurate measurements, the first switch should be triggered almost as soon as the key is pressed, while the second switch should be triggered almost at the bottom of key travel. This is the "reality" of a modern keybed -- two switches, one near the top, the other near the bottom.

Traditional organ notes are not velocity-sensitive, so only one switch is absolutely necessary to trigger a note. Thus, given the modern MIDI keybed, the choice is whether to trigger nearer the top (CX-3, VK-8, C1) or nearer the bottom (Electro, VK-7). Each method is NOT a perfect copy of the Hammond B-3, and each method has advantages and drawbacks:

-----
Top-switch Triggering --

- faster action, able to play faster riffs
- closer to the "feel" of a real B-3
- prone to double-triggering on staccato techniques

-----
Bottom-switch Triggering --

- slower response than on a B-3
- stable over a wider range of playing styles (staccato vs. legato)

It would be possible to develop a different keybed with both of the switches located nearer to the middle, but the testing and tooling costs are very high. My suspicion is that the costs are so high that ALL of the clone manufacturers would have to commit to using ONE keybed to make the effort profitable -- and of course, this is unlikely.

Regards,

-BW

--
Bruce Wahler
Online Music Sales
AshbySolutions.com™ http://music.ashbysolutions.com
978.386.7389 voice/fax
bruce@ashbysolutions.com

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