Recording Car Audio 🚗
Cars are a major part of everyday life, so there is clear value in being able to capture their sound. I recently recorded my 2015 Vauxhall Corsa, which I found to be a challenging but rewarding experience. I will detail the setup and recording process here.
When getting into sound design and audio recording, I thought that recording a car would be unfeasible for me due to the fact that many professional car recordists suggest using microphones that have a substantial price tag. These microphones can get the job done well, but I think it is important to note that you can get great results with much more affordable equipment, so people should consider cost to be less of a barrier for recording car audio than they might initially expect.
There are three primary categories of sound you may want to capture when recording a car:
Foley sounds
Onboard driving sounds
Exterior driving sounds
Foley sounds
The easiest is the foley sounds (e.g. the sound of the doors, the gearstick, etc). These are easy to capture with any portable recorder and your microphone of choice. This category is fairly self explanatory, though one thing I would note is that some of these sounds are worth capturing from both inside and outside the car (for example door slams, boot/trunk opening, etc).
Onboard driving sounds
A typical recording session for onboard driving sounds would involve recording at least three perspectives: engine, exhaust and interior.
For the engine and exhaust microphones, you are likely to want to use the smallest microphones that you can, as this will be very useful for mounting them securely. Lapel microphones are great for this purpose due to being very light and small. On top of that, they typically have very thin cables which are easy to fit through tight spaces as needed. It is worth noting that lapel mics typically use low voltage plug-in power and not 48v phantom power, which means not all audio recorders can directly support them. In my case I used a Zoom H6, and its XY module has a stereo minijack input which can record two lapel microphones if you use it with a stereo breakout cable.
I used an affordable Audio Technica ATR3550x lapel mic (worth around £30/$37 new) for the exhaust. I taped this a bit above the exhaust on the back of the car. I used gaffer tape which is plenty strong enough, and while this didn't peel any paint, it did leave a residue which needed a bit of a scrub to get off! Painters tape may be a better option if you can get that. I think that having the exhaust microphone far from the edges of the car means it is fairly unlikely to be hit by strong winds as you drive, but it is better to be safe than sorry. I didn't particularly trust the tiny wind cover that was included with the mic, so I instead used a foam cover intended for a pencil condenser microphone and taped it down. I found that this needed more gain that I expected, so in hindsight I think I could have gotten away with the mic being a bit lower down.
A lapel microphone would also be a good choice to capture the engine sound. In my case I went for a gooseneck microphone instead, specifically a Behringer TA5212 (also worth about £30/$37 new). It's a little tricky to see in the photo, but I tucked the microphone between the car's metal frame and a foamy material that was below it. I previously tried positioning it slightly higher up, but this prevented the bonnet from closing (or "hood" as non-Brits might call it). Due to the construction of the microphone, I was able to point the mic towards the engine. To run the cable to the recorder, I had to pass it through the passenger window which I left slightly open.
I positioned two audio recorders on the passenger seat. The Zoom H6 is my primary recorder, and it was recording the engine, exhaust and dashboard signals. I also used a Zoom H1n to capture a stereo interior perspective. I would have used the H6's XY module, but the H6 disables the XY mics when a mic is connected to its minijack input (which the lapel mic was in my case).
The driving sounds are significantly affected by the location you record them in. You'll want to avoid busy roads as much as possible. I'd also pick a day and time that would have less traffic, such as a Sunday afternoon which is what I went for. If you drive in a low gear, you can achieve a high RPM without needing to go particularly fast, so I was able to capture a wide range of sounds without needing to leave my town. I went to a long and straight road which was far enough away from housing to avoid annoying the locals!
I also went to a long stay car park in my town to capture some stationary recordings. It was fairly quiet there apart from infrequent traffic on a road nearby.
While finding a spot away from busy roads, you might encounter another issue: birds! It is quite ironic that on a typical day I find that traffic noise ruins my attempts to record birds, but while I was recording a car I had to deal with intrusive birdsong. I even inadvertently captured a call of a Green Woodpecker from the exhaust mic, which is a bird I have spent a lot of time and effort trying to record!
Exterior driving sounds
As well as capturing on-board sound, it is useful to capture an external perspective too. I opted to capture a range of manoeuvres, including:
Parking (forward and reverse)
Setting off (forward and reverse)
Driving past the microphone
I primarily used the Zoom H6's XY capsule to capture the external sounds. I placed it down on a small tripod at the edge of the car park in a position where I could drive beside it to capture pass-bys. When recording in public like this, I'd recommend leaving a label on the recorder which says "audio recording in progress" in case people are unsure what it is.
As well as the manoeuvres, I also captured an exterior perspective of some revving sounds with the car in neutral. For these revving sounds, I parked the car parallel to the edge of the car park and placed the Zoom H6 a couple of metres in front of the car pointing towards the engine, and the H1n a couple of metres behind the car pointing towards the exhaust. I then recorded some short rev "bursts" as well as some prolonged loops at a few different RPMs. Compared to when the car is in motion, it is considerably easier to maintain a consistent RPM when the car is parked. Though, a downside of this method is that the engine will theoretically sound different when it is under load. Something which could be considered as either a positive or a negative of recording while stationary is that you won't capture any sound of the road surface, which you may or may not want depending on how you intend to use the sounds. I'd recommend recording the car both in motion and stationary if possible.
I am very pleased with the recordings I captured, and I compiled them into my 2015 Vauxhall Corsa sound library.
Additional reading
Here are some related resources that I found insightful:
An interview with Pole Position Audio's Max Lachmann for Asoundeffect
Lots of useful tips from Max Lachmann and Bernard Lohr in this talk at GDC
There are some informative interviews where Mark Mangini talks about his approach to car audio here and here
Some surprisingly good results are shown in this video, captured using iPhone earphones!