Requirements:
VST

32 or 64 Bit Windows Vista or higher/ OS X 10.8+
(64 Bit Windows 7/8/10/OS X 10.9+ recommended)

4 Gigabytes of Ram
(8 Gigabytes recommended)

Intel Core 2 DUO @ 3GHZ or higher recommended.

Firewire or PCI-based Audio Interface recommended

*Plugin may work with older hardware, but performance will be affected
* Plugin currently designed to work at a sample rate of 44.1kHz
AU

32 or 64 Bit MAC OS X 10.9 (Mavericks) or later
(little endian CPU)

4 Gigabytes of Ram
(8 Gigabytes recommended)

Intel Core 2 DUO @ 3GHZ or higher recommended.

Firewire or PCI-based Audio Interface recommended

*Plugin may work with older hardware, but performance will be affected
* Plugin currently designed to work at a sample rate of 44.1Khz
AAX

64 Bit MAC OS X 10.9 (Mavericks) or later/64 Bit Windows 7/8/10

Protools 11/12

4 Gigabytes of Ram
(8 Gigabytes recommended)

Intel Core 2 DUO @ 3GHZ or higher recommended.

Firewire or PCI-based Audio Interface recommended

*Plugin may work with older hardware, but performance will be affected
* Plugin currently designed to work at a sample rate of 44.1Khz

Adam Monroe's Tremolo is a free vst and au effects plugin conceived as a companion piece to Adam Monroe's Mark 73 Electric Piano. There are many free tremolo effects plugins to chooose from, but I wanted to design my own, with both traditional amplitude tremolo and stereo panning. The idea was to implement both "vertical" and "horizontal" oscillators, and to be able to easily tweak these values via knobs.

I wanted to make a simplified, streamlined GUI, with direct access to the plugin's parameters. The user can adjust both the speed and depth of the plugin's tremolo, and the speed and depth of stereo panning. Both effects are routed to a mixer, so the user can adjust the wet/dry signal.

Sample rates can be easily adjusted. This has the added effect of either slowing down or speeding up the tremolo, depending on your chosen sample rate.

The values for depth and speed of tremolo and panning effect are quite large. With the depth values set at maximum, the plugin utilizes full-spectrum sine wave oscillation for tremolo/amplitude modulation and full stereo panning for the "panner."

This tremolo plugin is provided for free as a compliment to Adam Monroe's Mark 73. The decision was made to implement a separate plugin for two reasons: Firstly, to provide tremolo to Kontakt users, and secondly, to be provide functionality with other plugins.

A Tremolo plugin vst or audio unit effect isn't that difficult to program. Originally, I intended to make a non-parameterized, version to go a long with an upcoming Wurlitzer sample library that would mimic the traditional "vibrato" oscillator of a Wurlitzer 200a. Having accomplished this, the decision was made to make an independet plugin, as the tremolo effect sounded nice with my Rhodes sample library.

Stereo panning was added to make the piano more robust/useful. Technically speaking, the tremolo sine wave is half the length of the panner sine wave, so that with all knobs being equal, the Tremolo effect should pan at 2:1 ratio with the panner effect. However, in practice amplitude and stereo modulation are different sounding enough for ratios to become difficult for the ear to quantify. By varying speed and depth, the user can produce all kinds of unique relationships between the two oscillators. Adding a parameter to change oscillators from sine waves to square or triangle waves was considered, but for practical purposes it is my feeling that sine waves produce the best tremolo effect.

The length of the Tremolo and Panning sine waves are 18,000 and 36,000 points respectively, so that the slowest possible oscillation can occur at 2.45 and 1.225 Hz (or lower if selecting a higher sample rate) up to 100x (about 245/125 Hz). With the speed set at maximum, it becomes difficult to discern the tremolo effect.

This plugin was coded in native C++ for both VST and AU versions. The majority of build time was spent teasing out Apple's Audio Unit and Cocoa frameworks. By default, Audio Units are designed o process audio data independently, one channel at a time. For the stereo panner, this is a limitation that had to be overcome.

A bit of time was also spent making 3d models and artwork for the GUI. The entire build process took less then a week. As such, the decision was made to make the plugin free.