Hydrophone Recording

Question

Hey Folks,

I have to record a variety of underwater movement and I'm in the process of doing some experimentation. I currently own 2 dolphin ear pros, but I'm not totally happy. I'm wondering if anyone can share their experiences and maybe share what sort of movement is most useful.

I have access to a pool and a lake.

Best,
Michael Raphael
http://rabbitearsaudio.com
http://sepulchra.com/blog/

Answer 1

Hey, I'm not sure if this'll help, but, I've had to do the same sort of thing in the past, while some sounds we got with the hydrophone turned out well, alot of those effects we needed were achieved by processing sounds recorded above water.

Some things we tried.

-Different sizes of hoses for bubbles and bursts.

-Balloons filled with air(or water), being released underwater

-Use a hose and spray it underwater at different pressure levels.

-Different objects sort of "slicing" through the water(a rake, long sticks, cheese grater, potato masher, nets, etc)

-Low pass filter some wind sounds and mix with rumbles and bubbles to get some underwater ambiences.

-Use a sampler, Load a bunch of sounds of different size streams, rushing water, bubbles, and fizzy sounds, make whooshes by playing with the level with an amplitude envelope, maybe some filter sweeps to give a sense of motion

I read something Rob Nokes said about hydrophones, basically he likes to use hydrophones arranged in some sort of an array to make the sound longer and fuller.

Answer 2

from what I've read the DPA 8011 is one of the best hydrophones available but B&H says its been discontinued!

some recordings with one here: http://devsnd.blogspot.com/2010/05/underwater-recordings-from-dpa-8011.html

one thing it could be maybe interesting to record is underwater vocalisations?

Answer 3

Recording props (well, anything) underwater to create sounds never turns out the way you expect it. In my experiments with my H2a, one "DUH!" moment was how water's density, as a medium, really tamps down the vibrations of objects. From dipping cymbals in water to running a thumb across a comb, I found that submerged small objects that create fine vibrations to create sound weren't that interesting.

Turbulence is a classic conundrum; you want the turbulent sound but don't want air bubbles on the actual mic, due to rumble. Try sweeping things like rakes, hairbrushes, and swim fins underwater. Danny's suggestion list is stellar, as was his frank assessment that sometimes creating turbulence that is recorded in-air and filtered in post can produce great effects.

On your own blog, Michael, you've done some interesting stuff with recordings and machinery (specifically engines). What about the sound of a pool cleaning robot? Or some underwater RC toys? Compressed air shot underwater? Bilge pumps? Any marine products catalog would surely yield some interesting ideas...

One of the most fascinating water sounds I ever heard was when I was staying in a floating hut made of bamboo in Thailand. The hollow ends of the bamboo lapping just at the waterline made the most amazing (and, uh, intestinal) sounds. Anything that interacts with the waterline - cupping, lapping, slurping - will make focused and interesting sounds underwater.

Answer 4

I just returned from a recording trip where I experimented a lot with a pair of H2a hydrophones. Here's a couple things that worked for me:

• Pool: Position a hydrophone directly above the flow of water coming out of the pool jet. Should yield mild to strong turbulence and bubbles.
• Ocean / Lake: Position the hydrophone near something that will react with the water in some way, ie. a pier piling, a large rock, a buoy, etc. The water action against that object should create some interesting movements that you would be unable to capture in the air.

Above all, what I learned is that it takes a LOT of experimenting to really find something that works well. But hey, that was what made it so much fun!

Answer 5

I used a DPA 4060 and a condom filled with air to waterproof the mic. It worked pretty well... It positionned the mic approximately 10 cm under the surface of the water. However I only used that to record motor boats and splashes for I didn't need much sensitivity because even under water it makes a lot of noise... The audio material resulting was good enough to be usable...

Hope this helps.

Peace.

Sam.

Answer 6

i tried to record a underwater sounds in my bath, with prepared cheap dinamic mic Audiotechnica covered in a celophane bag and scotchtape over it haha - and the record was awfull - very noisy. But know after some cleaning it sounds not so bad.

If i would buy any real hydrophone...