Best way to record audio from a boat?
 

This summer I'll be filming the next tubing video for my site, www.fansn.com. As you can tell from the last video, all audio is completely overshadowed by the droaning noise of the boat engine. What i'm trying to figure out is a way to record audio of the tubers, to hear what their saying, the splashing, etc.

My idea is this. On the back of the boat, about a 4ft light pole extends vertically. The filmer is usually sitting in the back seat next to this pole, with a extension cord connected from the camera to the top of the pole, where a shotgun microphone will be attached pointing towards the tubers.

What would be your suggestions for a cheap, durable microphone for this situation? I don't want anything overly nice since there will be a ton of bumping, and the chance of the thing flying off into the water. Also, what microphone would also be the best for picking up the audio from the tubers (and the tubers only) from about 60ft away?

Also, if there is a better way to do this then what i'm thinking here, what would you recommend?

Thanks!

60 feet is an incredibly long distance for any conventional mic - shotguns aren't like a camera lens and don't magnify sounds the way a telephoto lens magnifys images. While they can have more apparent sensitivity than other types it's mostly only apparent instead of real because their rejection of off-axis sound lets you increase the recording level a bit more than you otherwise might but this is all relative. Even shotguns work best when they are only 1 or 2 feet away from the sound source so I'd be very surprised of this plan worked very well.

You might want to google for "parabolic microphone" and see if you can come up with some DIY ideas for one. Birders and wildlife filmmakers use them to reach out and capture distant sound and they are used to eavesdrop on conversations from a distance. You can make one out of an old Snow Saucer and a cheap Radio Snak microphone.

Another thought, although a bit risky to the gear, is to go wireless and enclose the mics and transmitters in those heavy duty baggy kind of things snorkelers sometimes put cameras in and put them on the tubers.

Even a parabolic mic will have problems in this situation due to the close proximity and high sound pressure level of the engine to the microphone. I think wireless on the tube (or tuber) is your best bet. A trick that I have seen is one of those tiny Pelican cases (with the clear top) with a waterproof lav fed through a hole sealed with silicon caulk. The case interior was padded to protect the transmitter, and the whole deal floated if dropped. They do make waterproof wireless systems if you happen to have a budget, or you could rent one for the day of the shoot.

Can you modify a life jacket to hold a wireless? Some lavs are said to be highly water resistant; the transmitter might go into a waterproof pouch which would be transparent to RF.

Wireless might be to risky and expensive. You guys however did give me the idea of using the iRiver mp3 player to do this. What i think i'm going to do is mount it on the largest tube, least likely to flip over. Waterproof it (and maybe shock proof it a bit with padding) and have a cheap microphone angled towards the tubbers. The tubers themselves are knocked in the water waaaay to much to risk it, but this should work i believe

Thanks guys, don't know why i didn't think of that in the first place!

An independent cameraman here encased a Lectrosonic in a small Pelican case and strapped it onto a surfer. He said he got great audio from the guy when he went through a tube up on the North Shore.

I'm planning to make a pair of waterproof pouches for my ATW-101's to cover kayak fishing and other activities where getting dunked is a real possibility. These pouches are originally intended to protect marine VHF radios and seal up nicely. The modification consists of a short wire with the right TA5 plug and socket on each end, sealed through the bag, so that the mic doesn't have to be fed through a the bag's clamped opening.

Sending the wire through the clamped seal of the pouch not only strains the mic wire but also violates the integrity of the seal -- and will cause it to leak. By sending a patch cable through the wall of the bag and sealing it with 3M 5200, it's a foolproof connection.

How are you going to waterproof the microphones themselves?

If he uses Contryman B6 mics with the caps on, he won't have to waterproof them. They already are.

Ty Ford

Good point.

I use Countryman B3's. They're about as close to waterproof as you can get. I heard about a demo where a Countryman rep used one to stir his coffee.

Makes for an expensive stirring stick. And they're actually too small to get the sugar off the bottom of the cup efficiently. But I guess he made his point! :-)

Done it with B6s, but not B3s.

Ty Ford

I was considering covering the end with a cut-off piece of a latex glove and securing with with a dental floss wrap. I think that's what the cameraman did when he rigged the surfer with the wireless unit.

Even tho the mic is water resistant I noticed that if the screen gets a drop of water on it the audio gets muffled. The latex cover will help prevent that from happening. And it'll provide a little extra security as well.

All this tech talk aside, with tubing aren't you just gonna get a lot of screaming?

:-)

Yes, a single drop of water can obliterate the audio if it lands on the screen.

Ty

How about noise cancellation?
 

I have no experience with this, but would it be possible to separately mic the engine noise, and use that track to cancel a lot of the engine noise from the track that has the sound you want to keep?

I am a complete novice with noise cancellation. Correct me if I am wrong.

not possible.

Try an electric outboard motor. Quieter, but probably not quiet enough.

Ty Ford

Trojan non-lubricated condoms work very, very well for keeping mics dry. Doing that right now in Hawaii on a small shoot. Stretch em' tight, use Blaxx hair bands to hold it on, with a tiny bit of Vaseline to assure there is no leakage at the cable side. This works for the wireless as well, if you need to waterproof it. Just be sure the condom doesn't make the transmitter antenna coil or lie next to the mic cable. Carefully lay the antenna so it is to the side of the transmitter and you won't kill your distance too much.

Yes, it is possible to do that but as it requires accurate knowledge of the difference between the channels in both amplitude and phase it would probably be necessary to separate into several bands in the frequency domain, difference each bin separately and then recombine the bins before going back into the time domain. Adaptive filtering might also work using the motor only channel to "train" the filter. A DSP guy could probably come up with other schemes as well but practically speaking if you aren't trained in the theory and implementation of DSP these techniques are unavailable to you.

Another technique which is available is to go into the frequency domain, find which bins contain the interfering noise (engine) and suppress those bins before going back into the time domain. A module which does this is available in Sound Track Pro and they demonstrate it at their website http://www.apple.com/finalcutstudio/..._2_restoration with this very application (suppressing the sound of a boat motor). You might want to have a look (or rather listen) to see what you think. Quicktime is required.

Haha thats the best part! That and the roaring noise of the tubes riding across the water, 10x better than any sound picked up on the boat.

The Countryman's are definitly out of budget for this, but wow do they look amazing. I think I'm going to try out the condom idea, even though keeping a stockpile of condoms next to my camera equipment will be a hard one to explain to my family...

As far as equiping it on a tuber, i think I'm going to strap the iRiver on the top back of a lifejacket of the middle tuber, with the condomphone sticking out of the top shoulder area (I figure it's the least likely area to hit the tube itself).

Also, what's a cheap microphone you guys would recommend? (I'm pretty sure i'll be using iRiver 790 for recording)