Recording field audio of car engine/exhaust/etc

Question

Ok so to jump right into it, a couple of friends and I picked up an 2014 Audi RS7 and plan to make a commercial/teaser-esque video of it. I have three GoPro hero4 black editions so the video portion of this is more than set. Now for the question, GoPros aren't notoriously known for the best audio, but I'm looking to get professional sounding engine & car sounds, like deep rich sounds from the exhaust that I'm going to overlay over the video audio.

1.) What would be the best way to record these sounds, harnessing the ultimate sound quality to then later piece together. Currently I have a Azden shotgun mic for my DSLR, but only one of them. And if need be I have a Blue Yeti microphone if i could use that too.

2.) What is recommended for movie level sound quality(obviously not movie because we don't have thousand dollar microphones)?

3.) Placement on the car/in the engine bay etc?

4.) What other microphone(s) should I get?

5.) Any help is welcome!

Answer 1

I strongly disagree with a lot of Dave's recommendations, based on my experience recording vehicle sounds for racing games, advertisement and sound engineering:

1. an engine under load doesn't sound like an engine revving while standing still at all.
2. "patching in after the fact" will be loads more work than recording audio and video at the same time. Expect days of editing the sound to match the picture.
3. Engine bay mics are standard practice. Do it! Just watch out not to place them on very hot components: on the engine block or the exhaust parts.And check that your mics can withstand 50-80 deg Celsius.
4. Air intake sound, turbo whine, the wastegate whistling... lots of cool noises in the engine bay, especially in high performance vehicles like the RS7.
5. Using only the exhaust sound will result in a very one-dimensional character. Mixing engine bay with exhaust produces the most hollywood-like and impressive results.
6. Yes, Hollywood sound is often larger-than-life. The picture is as well, so this is expected. The question is not about making a documentary.
7. In-motion audio is most reliably produced by putting mics on and in the car you are recording. Sound from a chase car is pretty much worthless above 50 km/h (I've done that, with an electric car, with a full Rycote Blimp with thousand dollar mics. You hear mainly wind). A chase car driving ahead of the subject can produce usable results for specific overtaking scenarios, but again this is rather limited.

Taping lavalier omni mics to the back of the car, with these little furry wind protection balls will produce very usable and consistent exhaust noise. There will be something missing, because part of the exhaust noise can be captured only about a meter behind the tailpipes, which can only be captured on a dyno. Combine that with mics in the engine bay and roadside mics for passbys and you can create stunning results.

Answer 2

I know this is almost 5 years old... However, I stumbled upon something that supports EMV's answer. RØDE made a hot lap recording of a GTR and also showed a setup for consumers without a massive budget.

Setup with iPhones and SmartLav+:

Pro setup hot lap:

RØDE Racing: http://www.roderacing.com/

Answer 3

I am both a car enthusiast and audiophile and have seen this question posted a few times elsewhere as well.

First off, forget the GoPro built in audio its OK at best but on any thing moving at speed is going to be mainly wind noise and some engine crackle in the background.

The shotgun you have will do just fine and all you really need to do is capture the audio in a static situation (unless you want audio of the car passing buy). The way I would go about this is to shoot the video and patch in some dummy audio of the engine after the fact. FWIW it will much easier to capture the engine noise with the car not moving and you will get the tone you are looking for. An engine revved up while parked is pretty similar to when its under load. In this case you can use any mic you like, a condenser, small or large diaphragm will work as will the range of popular dynamics. Cars have a pretty high SPL output so you don't need something super sensitive. You should keep in mind (although this is a newer car) exhaust is a dirty thing and you should keep the mic out of the direct line of the tailpipe as well as the spray of gasses that come out.

Im not sure why you would put a mic in the engine bay and I would not for a few reasons.

1. Its extremely hot in there and you can damage the element
2. There is not a ton of noise in there on modern cars, you will hear some valve tapping and lots of air moving around

Most of the audio you want is going to come out of the tailpipe and thats where I would focus my efforts. The key is to try and record on a day with not a lot of wind so you can reduce issues from it. Since you are just going for audio you can chose a day that may not be great for video recording.

I have owned and driven a wide variety of cars and frankly the movie car audio you often hear is a poor representation of what engines really sound like. the vast majority of cars dont make some fancy air compression release noise when they shift (fast and the furious). Cars dont shift 25 times in a 1/4 mile drag race.

To get good in-motion audio you will need a chase car (something quiet, an electric if you can get it). You will have a wind issue but you can get a variety of wind screens for this which may help. I have tried this a few times and never gotten a solid result so I wont offer much more than that.

This is a great documentary that has some great audio of car engines. Magnus is a very nice guy and if you reach out to him may offer some advice on how he captured such good audio of his cars.