The rotary speaker is also known as Leslie speaker, due to its inventor Donald Leslie. He created and manufactured the Leslie speaker which refined the sound of Hammond organ and popularized Electronic music. The rotary speaker was first used for the electronic reproduction of organ instruments.

The sound in the listener’s ear is altered by the Doppler effect, the directional characteristics of the speaker and the phase effects due to air turbulence. The Doppler effect raises and lowers the pitch according to the rotation speed. The directional characteristics of the opposite horn arrangements perform an intensity variation in the listener’s ear. Both the pitch modification and the intensity variation are performed by speaker A and in the opposite direction by the speaker B.


UVI Rotary


Earlier this year, a plug-in version of the rotary speaker effect caught my attention. It was Rotary by UVI. Taking its name and inspiration from these classic spinning speakers, Rotary represents the modern evolution of this classic design, delivering both a faithful reproduction of the original cabinets and providing a highly versatile and customizable musical tool for today’s artists and audio professionals. A simple and intuitive interface provides for a workflow that’s both fast and inspiring, while precise stereo mic placement and deep back panel controls allow for a huge range of tonal possibilities. Rotary can add another dimension to any sounds or instruments (even vocals), enhance harmonics and create a sensation of movement and depth.

In the next tutorial, I will guide you through its interface and show you how it sounds on different instruments. Within Soundbridge, I’ll start by adding a fresh instance of the Rotary on the roads piano chords that I have previously made.



The interface


At first glance, we can see a large speed slider that dominates the lower part. It is a 3 position selector. If you set it to the left, the Chorale mode will be dominant and this mode rotates the speakers relatively slowly by producing a gentle, dreaming effect. On the other hand, if you ser the Speed slider to the right, you’ll engage the Tremolo mode. This will produce a rich shimmering sound. The Speed slider can also be set to the middle which stops the rotation completely. Below we can turn up the Drive know in order to add subtle harmonics or more obvious distortion if set to the upper level. It is possible to control high frequencies with the Horn parameter and low frequencies with the Drum parameter. In the end, there is an output parameter that needs no further introduction.

In the upper part of the interface, we can change the model of the cabinet by clicking on the drop-down menu. Furthermore, we have the Distance parameter which changes the distance of the microphones from the cabinet. This has a profound effect on the sound. The last 3 parameters are the Width, which controls the stereo spread of the microphones. The Angle, which controls the left/right rotation of the microphones and lastly the Skew parameter which controls the distance skewed by the microphones.


Practical examples


After the introduction with the parameters and functions of this awesome plug-in unit, let’s move to the practical audio examples. First, let’s listen to the initial Rhodes piano chords again unprocessed and after that processed with the Rotary and a bit of reverb to add more sense of space.


~Rhodes piano – Unprocessed

~Rhodes piano – Processed with Rotary


Now let’s hear it on the acoustic guitar. Again first unprocessed and then processed with UVI Rotary.


~Ac. Guitar- Unprocessed

~Ac. Guitar- Processed with Rotary


Finally, let us hear how those two instruments sound in the full mix.



~Full Mix


Feel free to download the complete project here.