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Hi,

I have done some research into this but am still looking for some more techniques to each my students. What I basically want are some cut and dry approaches to matching ADR to a scene so that it will sound like it is in the same space within the frame. I know that with exteriors, you have to EQ the voices to thin them out. What else do you guys recommend.

Thanks.

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11 Answers

The best dialog mixers in the world struggle with matching ADR to the production track. One of the reasons for this is that there are so many variables that occur during filming that are not easily remedied or recreated in post-production, ie. generator hums that fluctuate and resist EQ notching, broadband noise from a variety of light buzzes, traffic wash, etc. Even with the best tools at their disposal, it is a time consuming process whose results rarely escape the discerning ear.

Interiors can be as difficult to match as exteriors. The interior recording comes with its own set of challenges, not least of which being strange reflections and/or resonances that cannot be recreated with current plug-in technology (or old-school technology, for that matter).

The best thing you can teach your students is how to train their ears for this type of work. It really comes down to patient use of traditional filters and compressors - there are no short cuts or magic bullets.

A few techniques you may find useful:

  • Capture an impulse response (IR) of the various locations during filming that can be used in post-production to help the ADR match the track. May be of limited use but it's worth having just in case.
  • Use noise reduction technology, ie. CEDAR, Izotope RX, WNS, and Z-Noise.
  • Record the ADR in the same way it was originally captured, ie. if you're trying to match lines filmed on a rooftop, try recording the talent outside - this way you immediately avoid having to make your interior ADR sound like exterior production. Of course this has to be executed with caution due to exterior noise, but sometimes it makes more sense to match the realism rather than fight it.
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Awesome you mention that... just three weeks ago I brought the talent outside to my backyard with my laptop and mbox2 because recording exterior dialog inside just sounded way too boxy and I knew it would be near impossible to get it to sound right. –  Syndicate Synthetique Feb 16 '11 at 6:57
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Matching the energy of the performance is very important too. Even if you have to ask the actor to run on the spot for a minute to energize them it can be worth - no amount of mixing will make a performance match if the energy doesn't match the action... –  user49 Feb 16 '11 at 9:30
    
@Tim, +1 for that insight. –  Jay Jennings Feb 16 '11 at 17:26
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If you've got the information and access to the right microphones, then using the same mic as was used for the scene will get you 80% of the way there. If you don't have the exact model of microphone, then using something within the same class will be your best alternate (i.e. don't use a dynamic cardiod if the production used a condenser hyper cardiod). With that information, it isn't all that difficult to get a similar perspective match by ear. Just move the mic around until you're getting something close to the quality of the production audio.

From there, work with your reverbs/eqs on the dialogue track as needed. Get it to sit comfortably against the room tone/ambience, and you're pretty much there. I'm oversimplifying this last part a bit, but if you get the microphone and it's placement right, you'll find that you're only going to need some mild processing to make it work.

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I've had great success using compression to squash the ADR, since this tends to happen with production. Load up something like a C1 with a pretty harsh compression, and adjust the threshold in A/B comparisons with the production until it feels balanced. This goes without saying that all the other listed techniques work well too, and many are needed after the compression, such as EQ and such.

Also, Charles Maynes has mentioned that mixers like to use something called Magic Spectrum - essentially maps the frequency response from one sound to another. There are a variety of plugins which do this but he mentioned that this plugin seems to behave the best with dialogue-related sounds.

Interior and exterior matches are hard, although I vouch for one which is even harder still: matching ADR to interior car scenes.

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I learned the hard way that the key to being able to match well is having good ADR tracks to work off of. Make sure they're recorded on a stage, NOT in a booth. As Shaun said, matching mics will aslo be a big help.

I would recommend doing several things to practice:

  • Record good quality ADR and match with environments interior and exterior.
  • Record poor quality ADR (not sync'd properly, recorded in a booth, etc) and have them match up.
  • Record wild lines for a scene and have them match/replace obscured lines.

I think it would be more helpful to cover difference scenarios and learn how to deal with them.

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Some great advice here so far. The biggest rookie error in recording ADR that I hear is microphone placement. The dialog on set is recorded with a 416 on a boom 6 feet away from the actor, but it's adr-ed in a booth, recorded like a voice-over with the actor standing 6 inches away from a U87.

Using the same mic as production and getting some air between the actor and the mic is key to matching. Otherwise the mixer will have to wrangle it with EQ, verb, and delay for quite some time.

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Ask the production sound mixer to make full notes. Then match the microphone, height, distance and angle. Sometimes you have lavs that have been mixed in with the boom mic, and these can often have phase problems.

If you do not have sufficient information to match the equipment and the placement then get hold of the best quality condenser that you can, and use some heavy eq, this will get you close with an awful lot of practice.

Recording ADR is comparatively easy, but mixing it with production dialogue is an advanced skill that only a comparatively few re-recording mixers have.

Sometimes it easier to eq the production dialogue to match more closely what you recorded in the ADR suite. The audience are rarely concerned with reality, and dialogue is normally recorded artificially close anyway.

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Don't forget to mix in production room tone underneath if you're only flying ADR to replace certain lines. If you are doing ADR for the whole scene, then you won't really have any matching problems (since you're blowing away all the production sound), but you'll want some ambience mixed in there as well to help sell it.

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For me the most important part of making ADR work is getting a good performance from the actor. If the actor speaks too softly or doesn't scream when supposed to, it doesn't work no matter how close the character in sound matches the production sound. If you need to hit the actor to make him scream, then get someone to hit him! If you need to push and shake the actor then do it. Imperfections in the ADR make it sound more like the production sound.

I use a lot of reverb on all dialogue, production sound and ADR, to make it rounded and nice and to give a bit of stereophonic/5.1 life to the scene. The ADR normally gets a little more reverb than the production sound, typically a mono convolution reverb to match the early reflections you hear in the production sound.

I have no rules about EQ'ing other than just tweaking all bands until it matches the production sound. The production sound may have some pretty mean EQ'ing as well, especially with lavs hidden under clothes. You may want to tweak the production sound just before and after the ADR line to match the ADR, if they are too far apart in character.

If you have access to a big recording stage, then use it and try to match the microphones from the production sound. But often you are stuck in a small booth, and then you'll have to use the microphone that sounds best in that booth. There is no need to use a 416 or MKH60 in a small booth, it will only make you unhappy.

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http://www.boomlibrary.com/boomlibrary/products/outdoor-impulse-responses

This could also help for Exterior scenes when ADR is recorded in a studio.

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See also this sticky from the DUC - lot of repeated info from here but good advice nonetheless: http://duc.avid.com/showthread.php?t=270918

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Keeping in mind all the ideas presented here, and in similar ADR threads, I'd like to ask for some opinions.

I'm working on a short film at the moment which absolutely requires ADR. The location was here:

alt text

One of the actors is not available for ADR due to a falling out. The other two are not very experienced with ADR.

My intention after the reading I've done here is to record ADR at this location again, due to it being almost impossible (I assume) to make studio recorded ADR sit alongside the audio from the actor who isn't available anymore, let alone make it sound like it's outside in a space like that.

Is this the best approach I have?

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