Technical info

Here you can find information partly for organizers and partly for those more generally interested in technology. There are many interesting technical aspects in this project, and also a lot that is good to know for organizers.

The project combines and unites old and new technology. The organ and the cabinet, from the 60s and 70s, must work together with today’s effect modules and self-built computers.


The organ is placed on a podium in the center of the room. All around, 4 Leslie cabinets are placed in the corners of an imaginary square. It can be the corner of the room, but the distance to the organ itself should not be more than about 5m.

For smaller rooms, no additional amplification is required, but you may need some kind of additional speaker next to each cabinet. Important is doick that you keep the feeling of 4 separate sound sources.

The audience can be both inside and outside the square. The sound experience comes through regardless.


The organ that I have used so far and plan to use is my Hammond B3, a vintage organ from 1971. It is the most classic of all Hammond models, and the design of the furniture with its turned legs is almost iconic.

I have owned this organ since 2010 and it was the one I used the most in concerts and recordings. These days it is mostly in the studio, but on special occasions, such as this, it gets to go along.

However, the concept and setup are not dependent on a specific organ.

Hammond B3 -71


The Hammond organs and Leslie cabinets of the time were constructed with completely different specifications to what we have today, for example in terms of signal levels and the design of contacts between the organ and the Leslie. It has also varied and evolved over the years, meaning that organs and leslies from different genres can have completely different connection types. I have modified my organs and the leslie so they are compatible, both with each other and with more modern standards.

Cabinet control

The rotating elements in a leslie cabinet are driven by two different motors, where one has a faster and the other a slower speed. With relays you control which motor is active and then which speed the spinner has. If no engine is running, everything is at a standstill.

In my cabinets, I have built in digitally compatible relays that can be controlled with any type of switch. One of the sub-projects before the concert at Katalin was to program an Arduino computer to be able to control the cabinet more dynamically. The organ’s joystick is connected to it, which in turn has different programs that can be run with different parameters to affect the rotation of the cabinet.

In addition to that, I have also built an app that can be run in a computer where I can then also control the rotation directly via a touch screen.