Sounds of an Upgraded Turbo GTR - Headphones Recommended

Thanks for the feedback! While I don't know exactly what questions to ask quite yet, I'm sure there will be some.

Here are some things that have come up thus far from your reply alone.

The wide range of sound levels the car is capable of producing makes it challenging to tune the gains so that audio recorded from each POI is significant enough to come through in normal driving but doesn't clip during pulls. Using a 6-channel recorder has made it both easier and more difficult in certain ways but allows for much better tuning flexibility of each input gain.

I am not sure whether under-gaining then adjusting later in post is the proper workflow or whether it is better to reduce post work by adjusting the gains as close to clipping as possible so it sounds close to ideal without much post processing. I can hypothesize that doing the latter introduces risk of clipping the captured audio in certain situations. My Photoshop RAW experience tells me under-gaining it would be ideal if the same concept of preserving details that can be brought out in digital post processing applies. What would the pros do?

Being that I wasn't exactly sure what was needed, the mics used for the different POIs were omni lavs that I purchased off Amazon based on widest range of frequency response. As with anything else audio, the published numbers alone aren't indicative of other factors and the sound quality varies for each model even though the numbers are very similar.

I ran a standard TRS cable to the engine bay mic and used a wireless setup for the exhaust since that was more convenient and got decent sound for an initial experiment. My next test is to integrate a 3D/ASMR binaural mic in the cabin and blend that in for more depth since I felt the onboard X/Y 120 degree mic capsule didn't provide enough of that. The POI mics are sufficient but by themselves, are very one dimensional if that makes any sense. Would the cardioid mics be even more focused and flat sounding or, if configured correctly, provide additional depth?

Would running two mics at each POI, whether it be omni lavs or cardioids, one on each bank of the engine bay recorded in stereo help provide better imaging?

So what we do do for compartmentalized audio channels is isolate the subject you want to hear. Sounds simple-- no pun intended but it can be tricky. Cardioid mics work like the name suggests the sound capture field looks like a heart with the pointed tip pointed away from the mic end. You can talk right next to a shotgun mic (super cardioid) and it wont pick your voice up but will pick up anything its directly pointing at. That is how Isolation is used with mics.

As far as gain, try to keep it as close to 0db as possible at peak. What auto gain does is compress the gain before it clips and boosts it when its quiet. lets take a recorded gunshot as an example. Auto gain will make it sound like a sharp crack but manual gain if used correctly will add substantial depth and even extend that duration of the sound event.

The equipment you have should be ok, the main thing that will affect the final product is adjusting your levels to the correct range (without clipping) 0db and making sure that your interface has the ability for channels to be manually adjusted.

I'm a better operator then teacher so lmk if this makes sense.

Can't believe it's been three months since I posted the last video. With summer travel out of the way, I finally circled back around to getting something better (GoPro Hero 10) for video and tested out a slightly different configuration for audio capture. For this test, I am still using the lapels for engine bay and exhaust with two now under the hood. The two under the hood added some noticeable depth through the headphones. The driver side channel doesn't seem to be picking up as much detail as the passenger side. Maybe I need to use the same brand of mics for both sides next time.

Also started using the binaural microphones in the cabin which adds some more depth. The cabin mic is really a fine balance between too much and too little because it will push things over top causing the audio to clip if gained too high. Too little and it doesn't make enough of an impact. I think it's the lower frequencies causing the clipping so maybe I need to start learning how to use the crossover feature in Premiere Pro to filter or level out the frequencies causing those thumps.

After figuring out that I didn't want to deal with a clunky DSLR for POV video recording, the GoPro really is the best option. Night driving makes it challenging in my parts of town where people don't like artificial light. This video was recorded in 4k/30 and I'll need to do a higher FPS video next to see if the footage is usable without too much post editing. Not sure I want to do a daytime video yet until I figure out a more discrete way of mounting the camera. Having a GoPro mounted six inches in front of my nose isn't weird at all to other drivers.

Any feedback welcome...

It has been a while since I've uploaded videos to YT and wanted to share a couple that were uploaded including one from a private track day this past Saturday at Bandimere Speedway.

DA was about 8,500ft. Some were quoting as high as 9300ft at the track but I don't have the data to support that. Not the best conditions but still managed a personal best of 147mph in roll racing. The best 1/4 mile pass was [email protected] Awesome event either way with 15 total passes which included missing the first three hours of the event and sitting out almost two hours to cool the car down. The car ran flawlessly and was in the [email protected] range all day long.

As for the videos, the sound signature of the car has changed somewhat with the HKS 4" exhaust system swapped out for a quieter Garage Whifbitz system. I will eventually finish that exhaust write up one day but it is as quiet as stock cruising around town and there is no more trumpet sound at WOT even with catless downpipes. Although subjective, it's just a very satisfying sound similar to an open wastegate turbo car not often heard from a GTR at the stock motor power level.

Relevant to this thread -- I also switched to three matched lav microphones for more consistency in both sound signature and resolution. Per @livinlrg05's suggestion, I picked up a pair of Rode matched cardioid mics. Just haven't figured out how exactly they'll be integrated into the setup yet but they sure do sound good in testing so far!

On with the videos...

Over the weekend I hooked up the Rode M5 cardioid mics for a quick cold start test just to see how they handle a car as the audio source. The audio was just so-so for an initial test. Ended up blending in the audio from the iPhone 13 Pro and the X/Y stereo capsule mic on the audio recorder in post. Perhaps the setup will end up being used in a stationary setup for flybys in the future. Conveniently integrating them into a moving car the way the lav mics are setup where I can just plug in the recorder and go is going to be more challenging as they're not very discrete in comparison.