Changing mics in mid-production

[henrytj]

Hello new to this site and forum.

I am helping out on a no-budget movie project. I have been made the boompole holder. No problem there as I am looking to expand my movie production experiences.

The production is about half done shooting wise. I am new to working with this group of people. For sound they have been using a cheap shotgun mic taped to the end of a boompole. The reason I say "cheap" is because this is one of those camcorder accessory mics that is mean to mount on the camera hotshoe. It connects by a 1/8" TRS connection. Their cable run is about 15' and unbalanced. I have done some research and asked some friends some questions. So on loan from other friends I have a better mic (Azden SGM-1X) and a 20' XLR balanced cable. I have offered this for use on this project. But, on of the people on the project raised the concern that it might be a bad idea to change mics in the middle of production.

So, that is my question here. Is it a bad idea to change mics in mid-production because the mics have a different sound to them from shot to shot.

I can understand this concern. We would be going from half the footage shot with a cheaper stereo mic using unbalanced cabling to a more expensive mono mic using balanced cabling. If their is a sound difference, can it be matched easy enough in editing?

I am new to this in a way. I took film production courses 25 years ago back in college. I did other things with my life since then and only recently getting back into movie making. So although I have some background, it was from a long time ago with different technology.

 

[Alex H.]

Seems to me that you're in a catch 22. You can switch now and have horribly unmatched audio, or you can go for continuity and stay with what's really the worst possible mic you could have used (or close to it).

Honestly, your post audio is already challenged, even if you stay with the mic you've been using. Dialog is never recorded in stereo as this will cause you problems when trying to mix centered dialog in post. It presents problems of phase cancellation and background noise.

Normally, continuity is the absolute best you can strive for. Different mics can be EQd in post to match closely, not always perfectly, but that assumes that the two mics are both good mics and (in the case of dialog) neither is a stereo mic. It's pretty common to have a mix of shotguns, hypercardioids, and lavs throughout the course of a mixed soundtrack.

Your best solution might be pretty complex: switch now, get the best dialog you can for the remainder of the shoot, and ADR the stuff that was shot with the cheap stereo mic. That's going to be a genuine PITA, but is the only way to fix the damage already done.

 

[henrytj]

Thanks, and I was afraid that this would be a difficult situation.

I think the mic that they are using now is the Azden SMX-10
http://www.fullcompass.com/product/335630.html

Where the mic loaned to me for this kind of use is the Azden SGM-1X
http://www.fullcompass.com/product/262912.html

Most of the shooting is being done in a bowling alley with lots of fluorescent light fixtures and I think the balanced cabling would help with EM noise. But, they as you pointed out, are worried that switching mic and cabling would result in too great of a difference in sound once shots are edited together. So I have offered the use of the mic setup that I have, but I don't want to push it.

Thanks again.

Added to post: BTW, I came into the production already in progress, so they had been shooting a couple months before I got involved.

 

[Alan H. Chang]

Question:
Do you have any kind of mixer or a separate pre-amp unit to send a line level to the camera?

Switching out the 1/8" TRS cable for an XLR cable would not make a difference if you are still using the SMX-10 microphone. Since it is a stereo mic the XLR cable will still act as an unbalanced stereo cable, thus introducing and picking up RF and EMI signals. Any possiblity of borrowing a mixer would greatly help the workflow. This way you can use your mic with the mixer and send a line level to the camera rather than a mic signal.

For continuity purposes, it's good to keep the same microphone from shot to shot. Majority of the time, however, using the same microphone throughout the entire production isn't always the best solution. It's just like having to use a camcorder and to always shoot medium shots. Not the case. Different lenses are in use and how much DOF considered for the shot to work well with the given environment of situation. Switching microphones from time to time is very noticeable on Hollywood feature films. You can hear it. What is decided on set depends on the setting. These two mics have about the same characteristics and I wouldn't worry much about it. Maybe your pals are worried about the looks of having a different mic or cable on the pole.

Trust your guts and first instincts. Then ask yourself if it's necessary to change for a specific cause. Your ears are your best friend.

 

[Alan H. Chang]

Oh,

No matter what microphones you use the results are entirely depended on your microphone placement and boom techniques. Always mic placement and boom skills. Style over substance.

 

[henrytj]

Question:
Do you have any kind of mixer or a separate pre-amp unit to send a line level to the camera?

No. THis is a $0 budget (bunch of friends doing it) project. and I am new to the group.

Switching out the 1/8" TRS cable for an XLR cable would not make a difference if you are still using the SMX-10 microphone. Since it is a stereo mic the XLR cable will still act as an unbalanced stereo cable, thus introducing and picking up RF and EMI signals. Any possiblity of borrowing a mixer would greatly help the workflow. This way you can use your mic with the mixer and send a line level to the camera rather than a mic signal.

Not what I suggested. I offered to switch to the XLR mic and XLR cabling that I have available to me.

As far as I know, a mixer is not available.

For continuity purposes, it's good to keep the same microphone from shot to shot. Majority of the time, however, using the same microphone throughout the entire production isn't always the best solution. It's just like having to use a camcorder and to always shoot medium shots. Not the case. Different lenses are in use and how much DOF considered for the shot to work well with the given environment of situation. Switching microphones from time to time is very noticeable on Hollywood feature films. You can hear it. What is decided on set depends on the setting. These two mics have about the same characteristics and I wouldn't worry much about it. Maybe your pals are worried about the looks of having a different mic or cable on the pole.

Trust your guts and first instincts. Then ask yourself if it's necessary to change for a specific cause. Your ears are your best friend.

Well, my "instincts" are guesswork right now.

Maybe I should explain my situation a bit more. Right now I am out of work and live in poverty. I took movie making courses 25 years ago, but haven't tried to do anything with that until recently. Now I am trying to explore that road not taken back then. Last year I was a background extra in several big budget movies shot here in Pittsburgh. It reminded me how much I loved the movie courses I took. So I have been trying to get involved in any productions I could. This mean student and no-budget projects. I would love to do special effects, or DP (Ive done still photography for most of my life), or direct, or even write. But when I meet up with these young people, some just out of, or still in, one of the several media schools here, you can see that everyone wants to be the camera operator, or the DP, or director in general. Geez, from how they competitively talk you'd think they would get into a shoving match, if they could. But, almost no one wants to do sound. So I started doing boompole holding as almost no one else wanted to do it.

Now, even on the first two projects that I did boom-pole holding, I never got to monitor the audio. The producer/director/camera-man always hogged the headphones. So I did some research and at my own cost bought a Behringer HA400 headphone amp/splitter. Bought some parts at Radio Shack, soldered together a 9v battery connector and power connector together, and velcroed it to the side of the box. Now, the camera operator, myself, and two other people can monitor the audio. So recently for the first time I could actually hear the audio while holding the boom-pole. Plus I bought the cheapest full earcup headphones that I could find.

After helping some friends paint their house, they gave me one of the painter's poles that I have rigged with hardware so that it can hold a mic. Some other friends helped me to get the mic (Azden SGM-1X) and some cables and connectors. Right now I am using a $15 Hoya impedance matching adapter to go from XLR to 1/8 TRS mini-plug into a camera.

I didn't intend to do sound, but that is what is not being done and what is needed. So,... that's what I'm doing, and trying to learn about as best I can.

Next on my list is something like a 2-channel Beachtek box, but I have been outbid on every ebay auction for a used one, and I can't afford new.

So that is my minimal equipment situation. Sorry for the long post, but I just want to headoff the "why don't you just buy this $1000 item, or that $500 'cheap' thing?"

 

[Gohanto]

First, "boom-pole holding" almost demeans the job. Boom operator just sounds better to me since the job involves a lot more than just "holding" obviously.

You're on the right track though, and I think what's best would be to run some tests comparing the two mics and see what the differences are. Nice job rigging a system that lets you monitor the audio. It's sad how many films are done without letting the boom op even hear what he's doing.

On the XLR cable, it's only balanced if the input jack on the camera is as well. While you mentioned the jack is 1/8" TRS, it is likely a stereo input jack instead of a balanced one, which means that nothing is truly balanced in that setup. Then again, the build quality and general shielding of an XLR cable is probably going to be better than your currentl 1/8" cable even without it being balenced.

And do you have an shock mounting between the mic and the boom pole you're using?

 

[Noiz2]

This kind of stuff drives me crazy, not you these filmmakers. Since your just about done I would stay with what your using. The reason is, if they are doing their production like this you can bet post will be worse. So matching in post is probably not an option. Also they are probably not going to really "mix" this so switching from stereo to mono will probably be a problem. If it were a film that was going to an audio post I would say go with the best but in this case I would minimize the issues later. Any real post would end with the dialog all mono and centered but I would bet that they will leave the dialog as stereo so any switch to mono is likely to stick out like a sore thumb. And then it will have been "your fault".
Cheers
SK

 

[Alan H. Chang]

Henry,

I apologize if I had crossed your line. I didn't mean any harm. By switching out the 1/8" cable with an XLR cable and adding an adapter, the signal might improve (big MIGHT). The cable will still act as unbalanced, but with better shielding. As Noiz2 pointed out, the stereo mic will work okay since that was the mic used in the first place. Switching from stereo to mono will be noticeable. You're on the right track. Good thinking with the Behringer HP amp, doesn't cost an arm and a leg.

 

[SMuir]

My first impulse was to advise you to use the better of the two mics, but Noiz2's point about the unlikelyhood of any substantial audio post-production has made me rethink that position.

While its quite possible to degrade a clean recording to match one made with consumer gear, its the kind of task that requires a deft touch during post-production. Sadly, most zero-budget films wind up skipping audio post, instead expecting the picture editor to rough-in the levels in FCP while listening to playback on a pair of $10 computer speakers. In my experience, this almost never works out in the film's favour. Unless you know that someone involved with post-production can match the two mics, you're safest bet is to stick with the old mic.

As for the Beachtek box, have you considered the DIY option? I can't say that I've built one myself, but it seems that a ballanced-to-unballanced adapter circuit would be a pretty simple matter. Add a passive level control and you'd be in business. A consumer camcorder's plug-in power bias voltage may complicate matters, though.

 

[henrytj]

First, "boom-pole holding" almost demeans the job. Boom operator just sounds better to me since the job involves a lot more than just "holding" obviously.

Sorry, no insult intended. On a different forum I read one post saying that a true "boom operator" was someone who operated something more complex that is used in television studios where there are actual controls that have to be manipulated. So I use the term that I did so as not to misrepresent myself as being something that I am not. But maybe I will start using your abbreviated "boom op" if that is okay.

You're on the right track though, and I think what's best would be to run some tests comparing the two mics and see what the differences are. Nice job rigging a system that lets you monitor the audio. It's sad how many films are done without letting the boom op even hear what he's doing.

Thank you. Its a nice and inexpensive setup. Each time I first offer to use it with a new group of people, they are a little uncertain, but once they try it, they like it. The HA400 only comes with an AC power adapter, but with a couple Radio Shack parts and sticky velcro dots its easy to rig a makeshift battery supply.

On the XLR cable, it's only balanced if the input jack on the camera is as well. While you mentioned the jack is 1/8" TRS, it is likely a stereo input jack instead of a balanced one, which means that nothing is truly balanced in that setup. Then again, the build quality and general shielding of an XLR cable is probably going to be better than your currentl 1/8" cable even without it being balenced.

And do you have an shock mounting between the mic and the boom pole you're using?

Yes, the Azden mic came with a hot shoe shock mount. So I had to get a carriage bolt, some nuts, and a couple inches of rubber tubing, to rig a way to have the mic clip hold the shock mount.

BTW, there's a person on ebay that machines and sells adapters that go from painter's pole threading to mic attachement threading. Before I showed up the group I am working with now were literally gaffer taping the mic to the end of a painters pole.

 

[henrytj]

On the XLR cable, it's only balanced if the input jack on the camera is as well. While you mentioned the jack is 1/8" TRS, it is likely a stereo input jack instead of a balanced one, which means that nothing is truly balanced in that setup. Then again, the build quality and general shielding of an XLR cable is probably going to be better than your currentl 1/8" cable even without it being balenced.

I was hoping that the Hosa (MIT-156) impedance matching transformer would keep the XLR mic side balanced. Maybe I was wrong about that.

 

[henrytj]

Thanks everyone for your considerate replies.

My plan now is to not push the issue of the better mic at the current location and continue using the setup that they have been using. But, there is talk of starting a new scene at a pizza shop. If we do, then maybe I will push for using the better mic and cabling at the other location as the ambient sound will be different anyway. Then I can try out the new mic without it causing editing problems at the current bowling alley location.

Thanks again. I will probably be posting other questions as well. In fact I can think of a couple and will start new threads for each.

Henry

 

[Noiz2]

M
As for the Beachtek box, have you considered the DIY option? I can't say that I've built one myself, but it seems that a ballanced-to-unballanced adapter circuit would be a pretty simple matter. Add a passive level control and you'd be in business. A consumer camcorder's plug-in power bias voltage may complicate matters, though.

A small capacitor will block that. If you know how to solder, or want to learn, you can save a bundle, and end up with something you know how to repair if the need arises.

This sounds counter to everything I would normally say, but it's very easy to spend a lot of money on sound. It's also very easy to waste money. Buy a little dodad that will help this project out a bit but is some non standard xxx. And you just subsidized so and so's film but you haven't really done anything for your self. What I'm trying to say is that I would not go and buy something that may or may not improve the sound to some slight amount if it's not going to make a difference in the end. Not that I haven't done that. I have and that's why I'm recommending that you don't. The filmmakers in this case haven't spent any time figuring out how to capture decent sound. My experience is that if that's how they start out thats how they finish. Very few if any filmmakers hit some epiphany mid production and start making good sound decisions. So if you go and spend $100 or so on some box that may reduce the noise slightly I have no confidence that any improvement will be supported later, or even appreciated. And you end up with a box that is not something that you are likely to use in the future that gets to sit around and collect dust. From your description these guys are either very young and doing this for a lark or just have no clue. In either case it's a waste for you to spend money on it. Now if you have some future interest or need for doing sound then I would say buy stuff that will still be useful when your working on a project that cares. A good mic is not a bad purchase, a good portable mixer, or a portable recorder. They will all have uses in the future, a box to hook up to a camcorder that doesn't have XLR in's is something the guy who owns the camera should be buying, not you. You, hopefully, won't have a use for that in the future.

Now I'm all about supporting filmmakers who have no budget and really think through the flow to maximize $$$ on the screen. But a lot just don't care about sound and don't hear how bad their tracks are. They are hobbyists whether they admit it or not. I have no problem with them being hobbyists but I'm not going to underwrite their hobby.
Cheers
SK

 

[Steve House]

I was hoping that the Hosa (MIT-156) impedance matching transformer would keep the XLR mic side balanced. Maybe I was wrong about that.

Depends on where you put it. With a transformer doing the converting from balanced to unbalanced, the system is balanced up to the transformer. If you have it at the camera end of the cable, you're golden. If it's at the mic end of the cable, for all intents and purposes you're unbalanced all the way.

 

[henrytj]

This sounds counter to everything I would normally say, but it's very easy to spend a lot of money on sound. It's also very easy to waste money. Buy a little dodad that will help this project out a bit but is some non standard xxx. And you just subsidized so and so's film but you haven't really done anything for your self. What I'm trying to say is that I would not go and buy something that may or may not improve the sound to some slight amount if it's not going to make a difference in the end. Not that I haven't done that. I have and that's why I'm recommending that you don't. The filmmakers in this case haven't spent any time figuring out how to capture decent sound. My experience is that if that's how they start out thats how they finish. Very few if any filmmakers hit some epiphany mid production and start making good sound decisions. So if you go and spend $100 or so on some box that may reduce the noise slightly I have no confidence that any improvement will be supported later, or even appreciated. And you end up with a box that is not something that you are likely to use in the future that gets to sit around and collect dust. From your description these guys are either very young and doing this for a lark or just have no clue. In either case it's a waste for you to spend money on it. Now if you have some future interest or need for doing sound then I would say buy stuff that will still be useful when your working on a project that cares. A good mic is not a bad purchase, a good portable mixer, or a portable recorder. They will all have uses in the future, a box to hook up to a camcorder that doesn't have XLR in's is something the guy who owns the camera should be buying, not you. You, hopefully, won't have a use for that in the future.

Now I'm all about supporting filmmakers who have no budget and really think through the flow to maximize $$$ on the screen. But a lot just don't care about sound and don't hear how bad their tracks are. They are hobbyists whether they admit it or not. I have no problem with them being hobbyists but I'm not going to underwrite their hobby.
Cheers
SK

I should probably be more careful to not misrepresent the bunch I am working with at the moment. They are a great bunch of guys. Hell, they let me join in on their movie making adventure. Most around here don't seem to do that. They seem to work with only their film school budies and don't consider giving outsiders a chance.

Anyway, the group I am working with, many have some backgroung, be it either courses or some hobby project. Last year they formed when they did a silent short for the 48hm Film Project. They are basically making a more involved sounded feature version of their short. Like many such groups, their first investment was in better camera gear. Yes, their sound was more of an after thought, but that is where I am trying to help.

Also, I want to make my own shorts and demo reel footage. Years ago I was loaned a consumer miniDV camera, but made little use of it because the on-camera mic was not very good. So a XLR box (used if I can manage) would give me more options. (Actually more on this in another post.)

And more, in that I have been asked to video record a play in a few months. They have a guy doing sound, but he does musician/play kind of sound. If I can get a 2-channel XLR box then I can hopefully connect to his sound system (line in) on one channel, and record with the shotgun on the other stereo channel.

At the present, I can at least imagine several uses for a 2-channel Beachtek (actually I might like the SignVideo manufactured one better) XLR box.

 

[henrytj]

Depends on where you put it. With a transformer doing the converting from balanced to unbalanced, the system is balanced up to the transformer. If you have it at the camera end of the cable, you're golden. If it's at the mic end of the cable, for all intents and purposes you're unbalanced all the way.

Thanks. Yes, the transforming adapter is at the camera side of the cable run. From what I had read, I was hoping that what you describe would be the case.