Using the EVB3’s Integrated Rotor Cabinet Emulation

The Hammond story can’t be fully told without discussing the rotor cabinets, manufactured by Leslie. In fact, playing the B3 organ without a rotor cabinet is viewed as something of a special effect these days.

The EVB3 not only simulates the speaker cabinet itself, but also allows you to change the listening position by placing virtual “microphones” in different locations.

Some of the speaker cabinet models are mathematically simulated, and others use an actual recording of the spatial characteristics of the speaker. The latter is known as an “impulse response.” Detailed information on impulse responses can be found in the Space Designer section of the Logic Studio Effects Help.

If you’re unfamiliar with the concepts of the Leslie rotating speaker cabinets, see The Leslie Cabinet.

Basic EVB3 Rotor Speaker Controls

The “basic” Leslie rotor parameters are available in both the closed and open lid interfaces of the EVB3. These provide quick access to the Leslie speaker simulation.

The advanced rotor speaker controls are discussed in Advanced EVB3 Rotor Speaker Controls.

Figure. Basic Rotor Speaker parameters.
  • On/Off button: This enables and disables the Leslie cabinet simulation.
  • Rotor Speed buttons: These switch the rotor speed in the following ways:
    • Chorale: Slow movement.
    • Tremolo: Fast movement.
    • Brake: Stops the rotor.

MIDI Control of the EVB3 Rotor Speaker Speed

The Speed Control pop-up menu allows you to define controllers that are used to remotely switch the rotor speed buttons. You can choose from the following:

  • ModWheel: This setting makes use of the modulation wheel to switch between all three speed settings. Brake is selected around the modulation wheel’s center position, Chorale is selected in the lower third, and Tremolo in the upper third of the modulation wheel’s travel.
  • ModWhl Toggle: Switches as soon as the modulation wheel moves away from the centered position. If the modulation wheel passes the center position when moved from a high to low position, no switching will occur. This caters for Roland keyboards with combined Pitch Bend and Modulation controls.
  • ModWhl Temp: Switches as soon as the modulation wheel passes the center position, regardless of whether you have moved the modulation wheel from high to low or from low to high positions. This caters for Roland keyboards with combined Pitch Bend and Modulation controls.
  • Touch: Switches with aftertouch on messages. No switching occurs on aftertouch release.
  • Touch Temp: Switches with aftertouch on messages. A second switch occurs with aftertouch release messages.
  • SusPdl Toggle: Switches when you press the sustain pedal. No switching occurs when the sustain pedal is released.
  • SusPdl Temp: Switches when you press the sustain pedal. A second switch occurs when you release the sustain pedal.
  • CC #18 and CC #19 Toggle: Switches when you press controller 18 or 19. No switching occurs when either controller is released.
  • CC #18 and CC #19 Temp: Switches when you press controller 18 or 19. A second switch occurs when you release controller 18 or 19.

Note: All entries (except ModWheel) in the Speed Control pop-up menu switch between Tremolo and the speed set with the Rotor Speed buttons—either switching between Chorale and Tremolo, or switching between Brake and Tremolo. If the Tremolo Rotor Speed button is selected, you will switch between Tremolo and Chorale.

Advanced EVB3 Rotor Speaker Controls

The “advanced” Leslie rotor parameters are visible only when the EVB3 “lid” is open. These provide access to parameters that may be useful for specialized sounds, or when you are creating realistic emulations.

The microphone parameters are discussed in Setting the EVB3 Microphone Parameters.

A number of additional, advanced parameters are found in Extended Leslie Parameters in the EVB3.

Figure. Advanced Rotor Speaker parameters.
  • Rotor Fast Rate slider: Adjust to set the maximum possible rotor speed (Tremolo). The Tremolo rotation speed is displayed in Hertz.
  • Acc/Dec Scale slider: The Leslie motors need to physically accelerate and decelerate the speaker horns in the cabinets, and their power to do so is limited. Use the Acc/Dec Scale parameter to determine the time it takes to get the rotors up to a determined speed, and the length of time it takes for them to slow down.
    • Set the slider to the far left to switch to the preset speed immediately.

    • As you drag the slider to the right, it takes more time to hear the speed changes.

    • At the default position (1) the behavior is Leslie-like.

  • Horn Deflector field: A Leslie cabinet contains a double horn, with a deflector at the horn mouth. This deflector makes the Leslie sound. Some people remove the deflector to increase amplitude modulation and decrease frequency modulation. You can emulate this with the EVB3 by using the Horn Deflector field to switch the deflectors on and off.

Setting the EVB3 Microphone Parameters

The EVB3 features a pair of modeled microphones that are used to “pick up” the sound of the Leslie cabinet. These are essentially used to specify the listening position.

Figure. Microphone parameters.
  • Mic Distance slider: Determines the distance of the virtual microphones (the listening position) from the emulated speaker cabinet. Use higher values to make the sound darker and less defined. This is typical of microphones when positioned farther from the sound source.
  • Mic Angle slider: Use to define the stereo image, by changing the angle of the simulated microphones between 0 and 180.

Extended Leslie Parameters in the EVB3

The following Leslie parameters are found in the Extended Parameters area, accessible by clicking the disclosure triangle at the lower left of the EVB3 interface.

Figure. Leslie extended parameters.
  • Dry Level slider: Adjusts the level of the dry signal, which can also be useful if the “Switches to dry sound” option is selected in the Brake pop-up menu (see below).
  • Horn/Drum Brake Position sliders: Allow you to set an exact stop position for the Leslie horn or bass rotator, respectively. Because the original Leslie could not do this, sometimes a horn was aimed at the back of the cabinet when it came to a halt, which resulted in a less than desirable sound.
  • Reverb buttons: Allow you to patch the reverb effect before (Pre) or after (Post) the rotor effect.