Greg Hill says Hey!

Soundwave ConceptsGreg Hill is by far one of the most influential minds in vehicular audio these days. His contributions are lengthy and include the Real Racing series for iOS devices, the Red Bull Racing F1 team’s driving simulator, and iRacing, among many others. I am humbled by the opportunity to hear his thoughts, and honored to share them with the world.

TTA: First off, I’d like to ask a bit about your involvement with the Real Racing series. I am a bit of an iOS addict, and the Real Racing games are certainly quite unique to the device. However, I know that there are some serious hardware limitations of the device.

Creating audio content for the smartphones and handheld devices presents a few limitations that are akin to the titles of the early 90’s. So you have to revisit how you did it back then, yet being aware that the tiny tech squeezed into these units is hugely impressive and fast!

TTA: Given the variety of cars in Real Racing, and the unique sounds for each car, how did you overcome the memory and runtime processor limitations?

I usually start by drafting a wish list of sounds (engines, transmission, tyres, surface, damage, environmentals etc), and then I have to pare everything down to fit within the memory that’s allocated to audio. Lossy compression helps a lot too!
Generally speaking car game audio gets a reasonable slice of the memory; it is a well recognised aspect of the driving experience. The solution for a large variety of engines was to have separate sonic models for both the Player and Ai vehicles. The Player car is always going to be the most important, so it has to contain the most elaborate and convincing set of sounds. It is also helpful that only one Player car is ever running at any one time thus reducing the footprint on memory. However, there are potentially dozens of Ai buzzing around you, so the number of spawned Ai at any single time is capped to the nearest few fore and aft. The Ai engine sounds are also limited in size, number and resolution, with only the simplest versions of acceleration and deceleration hooked to physical parameters.
I really push for genuine deceleration samples for all my racing titles and this includes iOS based titles with hardware limitations. Deceleration is an important characteristic of the engine sound and to me it is effectively half the character – why leave it out? It upsets me that some AAA racing titles – running on more powerful platforms than mobile gadgets – fake deceleration by applying low-pass and volume ducking to the acceleration sounds. For high end simulations like iRacing I also include ‘steady’ engine sounds for neutral throttle inputs with little or no engine load inertia, but more on this later.

TTA: Were you running a simple loop-based sound set, or did you come up with a new solution to matching RPM and sound?

We trialled a few loopless systems for engines but ended up coming back to simple loop-based sound sets. We found it tracked the physical parameters more accurately and was just more suited to the platform; loopless works more efficiently on the higher end hardware. Each engine ended up being a set of 8 to 10 looped samples crossfaded and pitched along an RPM scale for both acceleration and deceleration. The Ai used around half that number of samples. The same crossfaded-loop technique was used for transmission whine and also the tyre/surface sounds; the scaling for these was either velocity or rotational speed.

TTA: Also, I notice that there is a change in sound from internal and external views. Were you able to make this change through DSP or was it a change in sample?

Both views are using the exact same engine samples. It sounds a bit different due to volumes tweaks of certain sounds to make them sound more onboard plus we added the onboard transmission sounds – these helped a lot! It would be nice to add extra sets of dedicated onboard samples, but it’s probably overkill on this platform at this stage.

TTA: Next, I’d like to ask a bit about iRacing. iRacing is a very unique platform in that it’s definitely a simulator and not a “game.” Correct me if I’m wrong, but I’d expect that the client expects very realistic audio, as opposed to “enhanced” or “hyper-real” that we hear in games. Did you find this kind of demand challenging?

Yes, it is challenging on two counts really:
1. The demands on realism from the iRacing team and the sim racing clients.
2. Having to deal with the old audio system.
iRacing have great demands on realism, any suggestion of “enhance” or “hyper-real” is taking your life into you own hands! I am kidding of course, but they are pretty serious when it comes to authenticity. For example, the amount of preparation that goes into the data collection of sounds is immense. There are no sound-a-likes in iRacing, the engine sounds are all genuine real-world counterparts. Recording sessions are predominantly done at the track. Chassis dynamometers with knurled rollers often make too much noise and those hydraulic hub dynos are quiet but don’t decelerate. Most importantly, at the track the car is actually moving over the road surface so the residual sound, modulation and the correct proximity effects are all there to be captured. Track recording does however present a whole range of other issues but we have developed some nifty techniques to overcome most of these.

Anyway, with regard to the old audio system in iRacing I am currently working on updates with the team engineers. This new system will allow me a greater hands-on involvement in the implementation and tweaking of new and existing sounds. We are also planning additional sounds and sonic events that will really take it to a new level. Hooking more sounds up to the physical parameters of the sim will provide a greater sense of connection for the sim racer. The fidelity will improve a lot as well. This update is very much anticipated by everyone and I am no exception – I can’t wait!

The iRacing engine sounds are very intricate and cover both the onboard and external views with multiple engine loadings (accel/steady/decel). The new system will include many extra sonic parameters and form the most complex and realistic sonic models I have ever produced.

TTA: iRacing is also, in essence, a MMO “game” with extremely long player exposure time to the sounds. Were there any difficulties in keeping repetitiveness at bay?

Just allowing a range of dynamics is an important way to control repetitiveness. Allowing some space and avoiding the annoyance of pushing every sound at maximum. I think it’s important to implement a small pool of sounds for each event so they can be shuffled – hearing the same skid sound over and over is not a great idea.

TTA: With your work with the Red Bull Racing Simulator, did you have any trouble sourcing the actual F1 car sounds? I know that F1 is under some heavy testing bans, meaning they’re extremely limited on where and when they can run the cars, and getting audio for a driver sim must be low on the priority list.

Lucky for me I recorded the still current V8 engine a couple of years ago before the testing bans. Sourcing F1 has always been extremely difficult, but there are some lucky people who own superseded F1’s and drive them at track days and I’ve scored a few recording sessions this way.

TTA: Also, did you have to implement the playback system as well on the driver rig? If so, what’s it like?

No, the sounds were delivered with rFactor Pro. So the sounds were pre-implemented.

TTA: I assume the realism and detail required on such a system from such a customer must be very high, since the system is used for driver training. Does RBR maintain communication and require updates with the new seasons?

I’ve not had any requests for sound updates. Next year may be different when the F1 engines change capacity and configuration.

TTA: What’s your favorite sounding car?

I have a few favourites, but I’d have to say the 1980 Ferrari 312 T5 F1 engine (see below). The array of harmonics in that engine is almost musical. Within the lower RPM range you can hear each cylinder bank pulsing like a contented cat purring. This car is the Gilles Villeneuve T5 and I was fortunate to record this car at Donington Park. I had about 10 minutes to hook it up with a small rig.Click to have a listen.

TTA: What advice would you give to someone who wants to record cars for a living?

I don’t think I could make a living from just recording cars alone, so I’m not sure I’m the one to ask? Recording is a crucial part of my involvement in the industry, but sound design and implementation of interactive sound is my major focus.
I suggest regular visits to this very website – there’s a lot to digest here! Also a genuine passion for cars, some mechanical knowledge and a relentless desire to push the boundaries to a new level.

TTA: Are you planning on attending GDC or similar conferences in the next year?

I’m always looking to attend the GDC, but unfortunately I just can’t get away from the studio. I sometimes hook up with the lads from FMOD and demo their Fmod Designer at conferences. I hope to be at the GDC in SF next year, where I can meet some of you then?

TTA: What’s the funniest thing that’s happened to you during a recording session?

I lost a car! Well it was more comical than funny, but there’s a lesson to be learned here. I was at Spa with 3 historic cars rigged up to record and they all headed out to the grid for the same race, no one told me the classes were put together and were all in the same race! I hadn’t turned the recording units on yet. Well there must have been more than 50 cars lined up and the 5 minute siren blows – nightmare begins. I don’t know why, but in my panic all the cars started to look the same. I had to plough through a field of cars, pit crews, stewards, corporate dudes, trolleys, umbrellas and media. Halfway down the grid I finally find one of the cars, open the door, start the recorder and the driver starts talking to me and want’s to have a chat – “sorry dude I’ve got 2 other cars to find”. Up near the back I find the second car, I fling the door open and the driver asks “where have you been?” I start the recorder and I said “have you seen the Cortina GT?”, “nope” he said with a giggle. The one minute siren sounds to clear the grid and an entourage of people start heading to the pits. By this stage I was in a complete panic running like a nutter back down towards the front of the field. The marshals are calling me off the track in a language I don’t understand, I’ve looked everywhere, I can’t find the car and I just give up! I stand at the pit wall out of breath with everyone staring at me and shaking their heads; I felt really bad. The cars take off on their warm up lap and everyone has to clear pit lane. And guess which car is sitting at the red lights at the exit of pit lane? You guessed it, that Cortina GT…press record!
I guess the moral is don’t get too overconfident and rig up 3 cars without knowing their whereabouts at a crucial time.

TTA: What’s the scariest thing that’s happened to you during a recording session?

During a dyno session at the Ducati factory in Bologna a tire delaminated, exploded and caught fire, well not really flames but enough smoke to fill the chamber, we were blinded and choking on toxic fumes. The bike must have been doing 300kph or more so it took ages for the tire carcass to stop rubbing against the wildly spinning roller. Kudos to the rider who managed to keep his composure throughout the drama.

TTA: And finally, where should readers go to get in touch with you?

Website and email is best.