AudioMotors – Review

Thanks to David Nichols @ Track Time Audio for reviewing this.

When Varun asked me if I would like to review Audiogaming’s “Audiomotors” engine granular synthesis tool, I excitedly agreed as it’s a product I was looking into for my own purposes as well. Audiogaming supplied us with a Protools plugin on  version 1.0.2 which does have some new features over 1.01, which is the version you still get if you download the demo. I’ll highlight some of the changes in this review as I go.

First things first, purchasing and installation is very simple. The plugin comes in .dpm, VST, and AU flavors, and all are included with purchase. Purchase also includes documentation in .pdf’s and two sample cars to play with. There is a free trial available as well, which is full-function but generates an audio “beep” every ten seconds or so.

Adding the plugin as an insert functions like any other plugin that runs on a sample. For the audio below I used one mono channel outputting to a bus, recorded on a second audio channel. Performance-wise, this plugin is not cheap in the CPU department; running this on a 2007 Macbook Pro did require me to close every other program while running (though I attribute that to my old laptop!) Other than that, though, the plugin was rock-solid. When Audiomotors first came out, I took a look at it on Nuendo (I’m guessing build 1.0.0) and it was not quite as stable. Unfortunately I only have a .dpm version to review in 1.0.2, however it does feel rock solid now [Ed: AudioGaming sent us a newer version post this review, which is a lot more stable and less power hungry].

The most important step in using Audiomotors is selecting the pieces of the sample to pick grains from, as well as decide how to play those grains back. The “Freeze Size” knob controls how far away from the current RPM it will select grains to pull from. Using a smaller number will create a smoother transitioning sound, but makes a held RPM sound much worse as the “loop” becomes shorter and shorter. Too long a freeze size and it starts pulling grains that it can’t pitch shift fast enough. Additionally, using the “Trim Begin“ and “Trim End“ allows you to narrow the range of the sample where grains can be pulled from, and the “Adapt” comes in handy when using non-engine sounds (it’s essentially a grain smoothing function). “Transpose” and “Randomize” both refer to output pitch, which is calculated after the grain selecting process. Hitting the button in the bottom-right (says “Stop” in the photo) starts playback and allows adjustment of the real time control parameters to dial in playback behavior. Running in RPM Mode uses the RPM tracking function to scroll through the grains. There is also “Scratch Mode” which skips the RPM tracking parameters all together and just scrolls through by pitch. This is toggled be the dropdown in Scratch Mode. When running in RPM mode as in the photo below, a giant RPM knob appears and turning it will simulate scrolling through an engine’s RPM, and handle the pitching automatically. New to 1.0.2 is the “Accel. Control”, which automatically scrolls the RPM up (accelerating the engine) or down (negatively accelerating the engine). This becomes awesome later.

I started by playing with some of my samples out of my Kickstarter-backed recording session. Sample 1 is from a loop-based recording, where RPM of the car was held at 500 RPM intervals. You can see in the photo below the main window, a spectrogram, how Audiomotors automatically tracked the engine RPM based on the “engine control” functions, with the red line. The tracking function actually worked exceptionally well, and much faster than any similar program I’ve run into, even on non-car source.

I chose this sample over a straight power pull as I wanted to test one of the weaknesses of granular-style engine reproduction, which is “holding still” on an rpm. As you can hear in the output sample, it still struggles to hold still at an unmoving RPM and sound good. In transition, it sounds wonderful. At the top of the RPM range, though, you can hear some engine character jumps as playback skips between flat-rpm sections of the sample. What this shows is that Audiomotors will be a bit picky about the recordings that are fed to it. The best possible material will have a linear increase in RPM over a long period of time.

In theory, you can use Audiomotors on any sound that is cyclical in nature. For Sample 2, I used another of my recording session’s samples, this time of a contact microphone attached to part of the transmission to capture the whine of the gears. The output does have some interesting artifacts from where the gears are engaging and disengaging, which you can hear in the source, as Audiomotors correctly finds the RPM but selects grains from both the engaged and disengaged sounds.

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Where the power of Audiomotors really shines though is once you start adding automation, especially to either the “scratch” or “rpm” controls. You could, in theory, have cars of two different cylinders running at the same automated RPM and create dysharmonic sounds. Or, you could sync multiple mic positions across different recordings, as seen in “Use Case” on the Audiogaming’s main page. You could even mix-and-match different engine components together – ever wonder what a Mustang exhaust sounds like with a Corvette intake?

For a person like me, this plugin is very interesting and fun to play with, and does leave a lot of room for experimentation. So should you buy it? You probably already know if this would be for you or not. At a nearly $300 USD pricetag, it’s rather steep on it’s own. (There is bundle pricing if you also pick up Audiogaming’s AudioWeather)  For me, I’d really want to see Audiomotors do a better job at a non-moving RPM. It would be wonderful it I could use this to make a steady loop out of a recording that features no steady-state RPM – as it stands, it doesn’t quite produce satisfactory results. However, if you find yourself doing a lot of work with cars in film where you want lots of dynamic engine snapshots, you could get this plugin, a couple samples from say Pole Position, and Waves Doppler and you’d be ready to make a full-on custom car system for your film for under $1,000 USD.