This month Pole Position Production is introducing a dyno sound library.
To kick off this new type of sound library, Max Lachmann and Robin Olsson shared how to record and use these special new vehicle libraries.
Max, this month Pole Position are introducing “dyno” game asset sound libraries. First, for those new to dynamometer car recordings, can you explain what a dyno is?
A dyno is intended for use when you map the engine on a car, and measure a bunch of things like torque and horsepowers. You remove the tires and connect hubs instead, that applies resistance on the axles. For our purposes it means we have the car running with load on the engine, but still being stationary.
And how do you record cars on a dynamometer?
Recording cars on a dyno is very different from recording cars on a track. The wheels are removed, and instead two huge hubs are connected to the axles. These hubs are controlled by a computer, and you can set it to perform certain runs, in our case that means sweeps (ramps) or steady RPMs. All runs can be performed with and without load on the engine, and also to any given amount of time for each run. So it gives a lot of control compared to a track recording. But it comes with other challenges too. There is no speed wind noise or tyre noise, but instead you have the whining noise from the hubs, which especially is audible on the lower RPMs. You also need to use big fans for cooling the engine, which the speed wind takes care of on a track. Another big challenge is that most dynos are indoors, which affects the sound a lot. We spent a lot of time and effort in treating the room and the hubs, to make it have as little impact as possible on the recordings. Besides the control of the maneuvers, another benefit with dynos is that you can place microphones a couple of meters behind the car, which is not as easy on a track. But on the downside, you don’t get any passes by etc, so the material is mostly intended for onboard representation of the car.
Pole has recorded hundreds of cars on tracks. Why did you record cars on a dyno instead?
In this particular case it was the customer who required a dyno session. And since it’s a method that often has been used in the past, it was exciting to get to try it out. The recordings are very easy to work with if you need to make game assets like loops or ramps, since they are very precise and controlled. So if you are a modder or a sound designer with less experience or small budgets, this is very useful material.
One would imagine that recording a car indoors on a dyno would sidestep field recording challenges like wind, intrusive sounds like aircraft and birds, and so on. What did you have to keep in mind, and what different challenges did you have to navigate when doing the dyno recordings?
It is correct that many challenges you face on a track recording are not valid on a dyno recording, but instead other challenges are introduced. But also opportunities. You don’t need to consider weather, disturbing noises from the surroundings, road surface and so on. But instead you need to deal with the acoustics of a room, and the noise from the hubs and the fans. And instead of having to gaffer the microphones on the car, you can use microphone stands, which also gives you the possibility to adjust spacing and angle between microphone and source in a more precise way. One thing to keep in mind though, is that dynos are not a “natural” way of driving a car, so it comes with a risk of damaging the engine among other things.
With all this in mind, what are the pros and cons of dyno and track recordings?
The pros are definitely the very controlled environment and maneuvers, which makes it quick to work with the material, and the possibility to adjust microphones to precise positions. The cons are the introduced noise from the room and hubs, and the lost opportunity to get all the exterior perspectives from passes by and all of that.
Robin, you wear many hats at Pole Position. In particular, you have expertise creating vehicle assets for game audio projects. Can you tell us a bit more about that part of your job?
For these recordings our focus was on getting the needed assets to make vehicle sounds in a game. This particular client needed ramps, steady RPMs, idle and start/stop sounds. So when the recording is done, my job is to choose what takes and mics to use and mix them accordingly. For this game they used granular synthesis mainly for the accelerations and decellerations, then fading over to loops when coasting. So using the steady loops made with the dyno recording is great. Usually when we make loops for games we cut a ramp into smaller pieces and then flatten the pitch straight, this process comes with its own problems. While the fundamentals will be flattened, the noise will be pitched the other way. The steadies on the dyno make that part easier, also you can get both on and off load steadies. It’s sometimes hard to convince the owners to let us record steady RPMs with full load on higher RPMs. Stationary high RPMs can be straining on the engine and for an owner it can be scary.
To be able to use the steadies together with the ramps, the RPM of the loop is needed. We use the same program that flattens pitch to get the mean frequency of each steady and then translate that to RPM.
While the core of your work is editing these assets, you were also involved in the dyno recordings themselves. How did you record the cars to help get the job done back at the studio?
We had a very good idea of what we needed to get out of the recording. So I aimed to instruct the technician to “drive” the cars in the best way possible to get exactly what we needed: ramps of different lengths and then steadies that are long enough to use for loops (somewhere around 5 and 10 seconds). Also a few extra start idle stops to have for variations. We did ramps on different gears, but apparently that did not matter much because the load was the same regardless of what gear the was in.
Usually you use Pole’s existing track libraries to create game assets from scratch. By contrast, the dyno libraries are specifically prepared for game audio sound designers and modders. Can you talk a bit about the benefit of these new dyno libraries?
Ramps are very similar to use as from our other recordings, the big difference here is that there are a few more mics at different distances from the exhaust to choose from. But one big thing are the steadies, we have included markers with the mean frequency of each section of steadies and these are very easy to loop and then have a ballpark rpm to use for loops in games. Some tuning is most often needed to get the right transition between loops.
This month Pole is sharing an Aston Martin Vantage S dyno recording. Can you tell us a bit about that vehicle?
It has a big V12 that sounds amazing. When that car revved the engine the air inside the room shifted quite a lot. The amount of torque and weight of that engine was amazing and quite alarming to have roaring through the RPMs while still being totally stationary. While it still has a stock exhaust, it sounds really good. Very often with more modern cars and stock exhausts, there is just air and noise coming out and not so much tonal information.
What other dyno libraries are in the pipeline?
In total we recorded 10 vehicles on the dyno, that means we will have 9 more released in the coming months! Everything from a Lamborghini Huracan to a smaller Fiat Abarth and Porsche 964 Cup.
