In a lot of commetaries, the sound sort of goes up and down, depending on when the commentator is speaking. Then there's more than a few, that have the same level of volume the whole movie, and you can always hear the speaker(s) breathing or doing something or another, for maybe the entire movie. And also, a few have the volume up way too loud, the whole movie, and thus, some comments may be hard to make out.

Does anyone know how these things are recorded, and why the differences? Any commentary experts out there? I'm just curious about this, for some reason.

it just has to do with the studios, microphones, and audio engineer...some are better than others in all three instances. Some group commentaries might be held around one large microphone, while others give each person a mic. with commentaries that are edited together, its a good chance that a whole other setup is in place to record dialogue.

A commentary usually recorded in a screening room with the commentator sitting in the front of a microphone while watching the movie. If you're curious, you can check some video commentaries such as those in Jerry Maguire where they also do a video shot the commentators while recording.

About sound quality, I think it's more of a microphone and mixing factor. So if the volume is too loud, it could be because of the mixer didn't set the level of the commentary and film sound volume properly.

Are you talking about how the volume of the film is raised when no one is talking? That's so there will be something to listen to when there's a dead part of the commentary. In some cases, it's because whoever's talking wants us just to watch a certain part, so turning up the volume helps with that.

It's like how on a radio talk show, you'll hear the theme song lead in, and then the host will speak. The music volume goes down when the host starts talking. It's just a standard practice when it comes to combining speech with a background track.

Also keep in mind that some commentaries aren't really done in one go. For example, Frank Darabont mentioned on his The Green Mile commentary that they did quite a few passes. So this may be an example of editing all the comments together.

I know the Scorsese commentary on Gangs of NY seems to be cobbled together. Audio quality just seems to shift mid sentence.

Very interesting, thanks.

I was thinking more along the lines of what Drexl explained in regards to the volume stuff...the volume of the film itself during commentary.

One group commentary you can see (but not the whole length of the movie...you get prompted as to when you can use the "multi-angle" feature to see it) is in Mallrats. I have a feeling that there's others out there you can view fulltime so to say. Is Jerry Maguire that way?

One point that I think is being missed is that the film audio you hear isn't laid down with the commentary as it's being recorded. What typically happens is the film's main audio track is mixed with the commentary afterwards, and the level is raised to full volume during lulls in the commentary track, which is most likely done by programming an automated console or digital audio workstation software (i.e. it's not usually a dude sliding a fader control anymore). Sometimes, the film audio isn't mixed with the commentary, in which case you may only hear faint audio from the headphones people are wearing, or perhaps a small speaker in the room where the film is being played for the commentators. I almost kind of prefer the latter, because if I'm watching the film with the commentary track on, it's a little jarring to have loud sound effects, etc. come up to full volume when nobody's speaking, only to go back to just the commentator's voice when he/she has something to say. It's especially annoying on films like STAR WARS Episode III where it's a pretty loud film, and the guys doing the commentary are pretty quiet, mumbly types. I often go to sleep listening to commentaries since you don't really need to see the film, and it sucks that when I set the volume loud enough to hear the commentary, it's "daytime loud" when the film audio comes back up to full. Hard to strike a balance in those cases.

Yeah, I think the ones where you always hear the speaker(s) are the best.

The commentary on the first Austin Powers film is the only time that I know of where the film's audio track was off completely. It was so nice to just listen to the commentators instead of hearing them compete with the film. Why can't that be done on all commentaries? They could certainly bring the film's soundtrack back if a certain piece of dialogue or music is discussed. But otherwise, just keep the damn film silent. We know what's happening in the film since we can still see it, but why do we have to listen to two audio tracks at the same time?

Hmm...didn't know that. I thought what you heard in the background while there was talking would be whatever sound the commentators were listening to, and then occasionally if there was silence someone would fade the audio back to regular volume. I guess that makes no damn sense. Laff....

Nah, the audio the commentators are listening to is typically isolated, but often you can hear the headphones in quiet bits, and some people who come in to do commentaries don't want to sit there wearing headphones for two hours, so you can hear the monitor speaker they're listening to.

I suppose part of the reason producers mix the main audio under the commentary (and sometimes AROUND it) is to give you the full experience of watching the film along with comments from the director, et al, as if they were in the room watching it with you.

I really prefer the commentaries where all the people are recording together and there's little or no film audio (although you might miss it more than you think if it wasn't there at all). Too many commentaries are cobbled together from the comments of a few different people, and often no more than two of them were actually in the room together. The commentary on the T2 Ultimate Edition DVD has to be the absolute worst in that regard, but I really love ones like the one on the Clerks X DVD where everyone is obviously there and interacting with each other. Having the video there is very nice as well.