Heat, from Pro Tools HD

HEAT (Harmonically Enhanced Algorithm Technology) is a software add‐on for Pro Tools HD
software that adds euphonic qualities of analog consoles and outboard gear to the Pro Tools mixer.
Developed with legendary analog/digital designer Dave Hill of Cranesong, HEAT is sonically superior
to the analog emulation plug‐ins on the market. Also, HEAT is not a plug‐in, but rather it is built right
into the Pro Tools mixer, where it changes the sound of the entire “board” and easily manipulated
with a global control. HEAT is separate add‐on option for existing customers, and ships
for free with new HD systems. HEAT will be available for TDM systems only.

Usage

Drive
The Drive control introduces a non‐linear processing, emulating magnetic recording tape combined
with harmonic information commonly found in analog gear.
Turning the Drive control counter‐clockwise emulates a tape based non‐linear distortion (odd
harmonic, starting with the third and fifth. As you increase the level on tape, or in this case the Drive
control level, the harmonic content increases and higher frequency odd harmonics are added. The
result is a sound that fattens up the bottom and midrange of a recording and smoothes high
frequency transients as you increase the process.
Turning the Drive control clockwise has a more aggressive effect, while adding an even harmonic
series commonly found in triode tube circuits to the aforementioned odd harmonic series. This can
give the effect of prized tube microphones and other tube based analog gear.
It should be noted that the harmonic structure changes with signal level and the amount of process
being applied, just like it does in a tube and the analog world.

Tone
As with tape, there can be loss of high frequencies with respect to low frequencies if driven far
enough, as the high frequencies start compressing sooner then the low frequencies. Under the
hood, these losses are compensated for, and in the process adds detail, and can add some
brightness, depending on the program material and its level. Moving the Tone control away from its
default position will accentuate or de‐accentuate the amount of detail and brightness.
The effect of raising the tone control is different, depending on which direction the Drive control is
turned in and the amount and character of the harmonic content is changed by this control in a nonlinear
fashion, unlike what a tone control in an equalizer would do.

How to Use
The process is level and program dependent. Although quite frequently a generalized setting will
work for many sources, some settings that will work best for one source may not have the desired
effect for another source. If you need a general‐purpose setting try adding two steps of the Drive
control (in either direction).
Because we are not used to a musical device that changes harmonic content with a knob it will take a
little ear training. It is good to be aware that the human ear loves a little harmonic generation. Once
you are used to how the program material sounds with some processing, turning the process off can
take the life out of your program material, even if you did not realize it was turned on.
The amount of process can result in subtle changes or drastic changes depending on what the
program is like, and how it was recorded. In this way, the difference between processing an analog or
digital recording can be subtle or drastic. It may be easier to hear in material that is more open as
opposed to material that is very dense. The amount of low frequency information added will also
affect how we hear the process.