Underwater Audio – Part II

Diving on deep wrecks can be very rewarding, but it can also very boring during deco.

Sometimes you can do your decompression on a wall or reef that is nearby but that is not very often. Most often, you are just hanging around a down line or anchor line “watching the blue go by.”

For example, on our recent dive on Deep Throne, Drew & I had about 90 minutes of deco for 12.5 minutes on the structure.

That is just the price you pay for deep dives. There really aren’t any ways around it.

I’m often asked “what do you do when you are staying there for so long?” Well, the answer is usually “not much.” Sometimes you get a visitor or two swimming by, but it is often pretty boring.

Hence, the desire to find something to pass the time.

I know some cave divers that bring iPhones in special housings and watch TV or movies with subtitles on. On some of these dives, deco times stretch into hours.

For really long dives, they build an underwater “habitat” that is dry that you can get into and read books, watch movies on iPads etc. while you do your decompression. Below are photos of one being setup.

Deco in caves is a little different because there is generally no current and often there is a place to literally sit or lay down while you do your deco. Hence, it is easier to watch something on an iPhone in a waterproof case.

My ongoing side project is to find a way to listen to music on deco.

First Generation Solution

There are plenty of underwater audio players but they are generally meant for swimmers and not for functioning at depths for scuba.

My first solution involved a “special” iPod Shuffle that was “water-proofed” by H2O Audio by (I think) putting some “goo” into it to help make it waterproof.

I’m pretty sure they stopped making them. The units for sale on their website are all refurbished. I detailed my experience with these in one of my posts on equipment testing over at Catalina late last year.

Essentially, it worked but had some major limitations:

• The company originally had a depth spec of something like 150 feet but now they say it is only 10 feet although I have taken it deeper
• Therefore, I had to “stash” the player on the downline or anchor line at a “reasonable” depth. This wasn’t a show stopper, but wasn’t ideal.
• The headphones were near impossible to put on when I got to the depth where the player was stashed. This was due both to wearing dry gloves and the small headphones.
• Therefore, I went with a detachable headphone solution and put the headphones under my hood before I left the boat and connected them to the extension cable on the player when I got to the depth it was stashed at.

Overall, it worked, but it was far from ideal.

Second Generation Solution

I needed a better solution and started thinking about having something custom built.

H2O Audio used to make a couple different cases designed for scuba but they don’t manufacture it anymore and they are almost impossible to find. Below is one model that was designed for 300′ and housed an iPod.

These units also included a separate amplifier to boost the sound for underwater use.

My plan was to have Martin at Tecme.de custom build a Delrin case. It would be very simple and wouldn’t allow for any control of the music or volume once it was sealed, but it would allow me to listen to music while diving.

The key with this is that the interface between the headphone cable and the housing needs to go through a “gland” that clamps down on the cable and doesn’t allow water into the case.

The other complicating factor is that I needed headphones that were “bulkier” and designed for underwater use. Luckily, Mel Clark offered to ship me a spare pair she had from her H2O Audio Player.

One key factor in getting a good seal on the cable gland is that the minimum diameter of the cable can’t be too much smaller than the larger part that has to fit through the gland. I sent the dimensions to Martin and he had a gland that would work.

I decided to have him build a case big enough to house an iPod nano.

I got the case, gland, etc. from Martin and assembled it for testing.

Test 1 – No Player

My first test was to assemble the unit without a music player in it and take in on a dive with some tissue paper inside to see if I could find any leaks. I took it on the Deep Throne to 300′ and it worked great.

Test 2 – Music!

This past week when I went diving on the Pipe Horse @ 240′ deep (stay tuned for a full dive report), I took my audio player and tested it out. Everything worked very well and it was really nice listening to music on deco. I had the volume a little too low since it gets muted as you go underwater so anything that is loud at the surface won’t be as loud in the water.

The obvious limitations are that I can’t skip songs or adjust the volume under water but I can live with that.

Next Generation

This system worked really well but was somewhat bulky and large.

Therefore, I’ve asked Martin if he can produce another tube that has a thinner wall and is shorter and smaller diameter to accomodate only an iPod Shuffle.

Stay tuned…