Use some waterproof ear buds and wire them to your machine if you can. My Excal has a ctx connection for my headphones. I made some water proof buds with the same connector type for my CTX because,..well.... headphone volume basically sucks in the water on the CTX. With the buds they SCREAM. If this is all to much work to have to mod your machine and then try to solder angel hair connections to a new plug maybe you need to get some of the mentioned swimmers ear stuff. If that doesn't help maybe you need to stay out of the water as much as I hate to say that to you. Hearing is pretty important in life and I wouldn't suggest you jeopardize it for anything.