The R&D that goes to producing 'that sound' is immense. I strongly believe its why Roland and Korg (VK7/8, BX/CX) threw the towel in after the Hammond New B3 and XK3 was released and why Yamaha and all the other major players stopped trying years ago. There is only so much a General manufacturer like Roland, Yamaha, Korg, Ketron etc. can assign to ANY specific area of R&D, particularly one with almost infinite variables*. Hammond developed the award winning long loop tone-wheel sampling method for the new B3 and passed the technology down to lower models, no other major manufacturer has been able to do this.


So in all honesty if Hammond is truly an important part of your sound you have only two NEW options:

1) Hammond XM2 & a real Leslie
2) KeyB module (no Leslie required)

The ventilator you own is only slightly above average, just like the simulator on a modern Hammond it is Two Dimensional (listen through headphones). The worlds only true Three Dimensional simulator is found on the KeyB - you absolutely do not need a Leslie. Pitch and amplitude are manipulated and the result is a staggering 3d real rotation in a stereo image - its just astonishing. (on the module you can plug in other equipment e.g. a guitar to run through the sim.)

Lastly, as a Ketron Audya owner, if you just need occasional Hammond lead or pad sounds, I would personally suggest you use the samples (the main B3/Jazz samples on your Audya are taken from a KeyB Duo actually) The Leslie sim is not KeyB though and Ketron uses a somewhat unique 'morphing' effect to shift from Slow to Fast. As a Hammond player I do not find the Classic B3 samples on the Audya at all offensive but would never use the built in drawbars and effects dedicated to that section myself.


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*
A Hammond & Leslie combination is probably the most complex of sounds to reproduce - far more so than analogue synths, Wurlitzer Pianos or Hohner Clavinets, Even a high end Grand Piano is easier to reproduce because for the most part these instrument follow a set of specific rules and variables. The core Hammond sound is far from pure sine-waves; many other variables come into play, each one is unique. for instance here are a few (but not all)

1) cross talk (the amount of 'harmonic noise' that occurs due to the hundreds of tiny lacquered copper wires at the rear of the contact system. every single tonewheel Hammond is slightly different and this 'natural' crosstalk is almost impossible to replicate with any degree of authenticity.

2) Tube overdrive. This is not 'distortion'. overdrive occurs when the signal passing through a valve begins to 'clip' creating warm, even-order, harmonics. Its naturally occurring and unique to tube technology.

The list could go on for ages, but would also include keyclick, chorus/vibrato, percussion, Tonewheel flutter, Hum, Acutronics Reverb and of course Leslie simulation. None of these (particuarly a Leslie Speaker) is easy to reproduce.