Hey everyone,

We've been lurking for a few years now, so for starters we would like to thank the community for all the priceless bits of information we've learned from the forum!

For our first post, we've been wondering how this segment is recorded as it seems quite challenging. Has anybody here run into something similar on the job? We figure there must be a lot of post wizardry at play? Let us know your thought!

It's probably recorded as live at the time in the car . Yes it sounds as if they have added a few effects to the voices but I don't think they have re-recorded the vocals ... these guys are pros!
Hopefuly the link below will show the kind of rig it was recorded on . Right at the beginning of the video in the OP ,you can hear James go off mic as he turns his head to the side.
https://pbs.twimg.com/media/CF8DSFbWAAAFa4v.png

There do appear to be continuity problems with the traffic in the background - guessing they run through the song more than once and edit together the best bits?

As for that camera and mic rig picture, that's intense! It sure obscures a LOT of visibility. Seems like it shouldn't be street legal!

It's not streetable. But they don't drive the car. They put the car on what's called a "process trailer" and pull the trailer. Out in traffic. Which is legal. Look down this thread for some more pix.

Basically the only thing that's real in a motion picture is some of the dialog. All of the other sound is added in post, from that barking dog in the distance, to the traffic noise, to the heel clicks, to the crowd noise in the diner (aka "walla"), even the dialog in a wide shot (ADR in post), ... all of it is added in post. That's the process of sound design. Sound designers create the entire sonic world of the picture. Every sound is motivated by the picture, and is there to support the story. This can require hundreds (that's right, plural) of layers in the DAW (almost always ProTools).

Unfortunately for Carpool Karaoke, unless they can nail it with a single long continuous take (very difficult under the circumstances) the traffic noise bleeding into the mics will give away the cuts. If they had a Hollywood sound budget, they could probably fix a lot of that too.

We did a car-karaoke shoot recently and basically copied James Corden's MO. Plant mics in ceiling (mostly CUB-1s), 5 or 6 GoPros, wireless feed of mics to a chase car, with headphone feeds for creatives etc in the chase car. We were able to play music to the car stereo via wireless from the chase car, as well has have a wireless earbug for the driver w/ talkback from the director, but we ended up doing what Corden does and just playing the music thru the car stereo speakers (loud), and the talent sang over it. They synced up the hero music tracks to the location sound in post to get some bass and clarity, and that was about it. It worked out very well as you've seen if you've seen Corden's videos.

James Corden's carpool karaoke - how is it really filmed?

The traffic noise wouldn't give away the edits because you can smooth the edits over in post . Whilst some feature films do re-record 100% of the dialogue and add all the sound fx and action noises , there are still alot of films particulary in the TV world where they use 100% actuality sound (because of budget restraints). There is a trend nowadays even in Hollywood for producers/directors to use as much actuality sound as they can.
I don't buy the fact that James is really driving the car . It's the kind of thing producers say to help keep the magic of the film but in reality , there is no way any insurance company is going to let anyone drive around Hollywood in a car plastered with cameras and lights and microphones whilst singing his heart out and negotiating traffic !

But the car isn't plastered with anything and the traffic noise is hugely attenuated by having the windows up (and is drowned out by the music most of the time anyhow). With current filmmaking equipment this kind of thing is not the huge deal it once was. The cameras have huge dynamic range, so lighting is very optional (we also used a moonroof with clear glass to get more light in). Corden's shoots have a very offhand feel to them (as with Seinfeld's "Comedians in Cars..." ) which is their point. I have many years of experience with process trailers, and the initial "take off" and stop of a rig like that is a jerky complex operation involving a lot of walkie chatter and cops etc, and Corden (and my shoots) had none of that. As James says, they drive quite slowly on a preplanned route (with Michelle Obama he just drove round and round the oval driveway in front of the White House). On public roads they have front and back vehicles and everyone listens on wireless headsets. If it was more of a deal than this the vibe they want would not happen.

This side of the pond we use low loaders for traveling shots, it can get bloody cold on them for winter nightshoots
Driving shots always were dodgy with actors driving and being unable to see much of the road because of the camera and lighting rig
Many cant drive....
Smaller devices really help and modern car acoustics and sound insulation are much improved
I worked on a documentary tv series about learner drivers, some of that was hilarious but also deadly
Car stuff always takes ages, almost as long as fight sequences ,and just as boring.
One of the first car tv drama series I worked on was about Police patrol cars in Liverpool, that was mostly night shoots, luckily the dialog was studio shot with with back projection front and side

They seem to be a lot more lax on road safety in the States , there's no way my company , a major uk broadcaster would let the talent drive . On low budget independants, producers may be prepared to chance their arm. I personally have been recording broadcast drama dialogue for over 30 years on low loaders and A frames. I'm envious of the way the Americans like to help their industry by letting stuff like James' car pool karaoke go ahead. It probably wouldn't be allowed over here.James' car still looks suspiciouly high off the ground to me . Also how come no shot from the back seat looking forward ?

Probably dpa4060's taped to the dash or pinned to the headlining. A friend of mine did a shoot where they were driving and talking and they just used GoPro's and the audio was fed back to a chase car via radio where it was recorded. The quality of the singers means that it shouldn't surprise you with their vocal sound. These people genuinely do sound great, it teaches that it's not the gear that makes them sound good, though it can help.

There are a lot of ways to skin the cat re mics for this, once you realize that it's going to sound like they are inside a car no matter what you do. I had a wrestle with the agency on the last one of these I did --they were sure they wanted lavs on everyone (4 people), and I know from experience that that's not a great way to go. Rumpled clothes (from sitting, leaning over), seat belts, head turns, and no time at all ahead with the talent to wire them anyhow--these are usually one-shot deals with very busy famous people. Having the mics overhead (front) or on the seat backs (back seat) sounded great, and recorded as isos let them remix to their heart's content. I hate working off process trailers--lots and lots of clanking chains, groaning metal, squeaking brakes, walkie chatter, noise when they hit (or bottom out ) on bumps. The whole Corden (and Seinfeld) vibe is kind of guerilla, they don't want all of that stuff.

Sun visors are good locations for DPA 4060s
Your mixer/recorder/radio must have low frequency attenuation, a lot of road noise is LF rumble, this must be cut steeply
Roger