DIY hydrophone

A simple tutorial to do an hydrophone (aquatic microphone), step by step.








do it yourself following each step below.



Materials:

1. Mic cable (mono)
2. Thermofit
3. Piezoelectric sensor (on our video we used a 1″ piezo)
4. Plastic lids or “feet” for chairs or tables (with a diameter about 1cm bigger than piezoeletric’s diameter)
5. 1/4″mono jack plug
6. Iron washers
7. Rubber coating
8. Copper foil
9. Solder
10. Silicon
11. Electric tape

Tools:

1. Cutter
2. Scissors
3. Drilling machine
4. Drill
5. Hole saw (with a diameter a bit smaller than piezoelectric diameter)
6. Cutting plier
7. Soldering iron
8. Ruler
9. Permanent ink pen
10. Lighter




step 1: plastic lid preparation








  • Choose a plastic lid with a diameter about 1cm bigger than piezoeletric’s diameter. In our video we used a 1″ piezo (25mm)

  • With a ruler mark the center of the plastic piece

  • Make a hole with the drilling machine and the hole saw. (The hole saw diameter should be a bit smaller than piezoelectric diameter)

  • On the side of the plastic lid make a hole with the drill. It’s where the mic cable will pass through.




step 2: copper foil








We will use the copper to protect the hydrophone from electro-magnetic interference.

  • Measure the plastic lid height

  • Cut the copper foil as a strip with the same height.

  • Take the copper strip and internally cover the lid.

  • Fix the copper ring with electrical tape

  • With scissors cut a hole on the side of the ring Note: it exist a self-adhesive copper foil which could be better for this use (and easier to work with)




step 3: piezo and cable soldering








  • Position the piezo centered outside of the lid. The terminals must be seen inside the hole.

  • Fix it with electric tape. It will be removed on step 5.

  • Before soldering put 2″of thermofit on both sides of the cable.

  • Pass the mic cable through the lid and copper holes and solder it on piezo’s terminals : ground on the external part, positive on the internal part of the piezo.

  • Solder the 1/4″mono jack plug on the other side of the cable.

  • After soldering, reposition the thermofit and get it hot with the lighter.
    Note: it would be possible to use a stereo cable to have probably better shielding. You should then connect ground to the copper foil, positive on the center and negative on the external part of the piezo.




step 4: silicon and iron washers








  • Fill half of the lid with silicon.

  • Put 2 iron washers inside it. (In order to give some weight to the hydrophone)

  • Fill the rest of the lid with silicon.

  • Cut a copper foil circle, with the same diameter as the lid.

  • Put the copper circle on the top of the silicon, so it will get glued._ Wait until the silicon dries (about 30 minutes)
    Note: you could put some weight on top of the copper foil, so it will get straighter.




step 5: rubber coating








  • Carefully remove the electric tape from the piezo.

  • Dip the lid in the rubber coating can and take it out very slowly.

  • Let it dry for around 30 minutes and repeat this step 2 or 3 times.

  • For a uniform rubber layer, you can turn the lid upside down while drying




step 6: Listening

  • Try your hydrophone and share your recording

  • Enjoy !!




TUTORIAL DONE by Sara Lana & Félix Blume

Other nice hydrophone tutorials where we learned to construct ours:

If you want to buy some, here are a few links :

  • Aquarian is one of the famous constructor of very good and cheap hydrophones, already very famous

  • Dolphin Ear is doing very good hydrophones too (a bit more expensive)

  • Cold Gold has a lot of different models of contact mic and hydrophone, at very good prices (including some piezo and copper foil for DIY mic)

  • Jez Riley French is doing and selling a few models of contact and hydrophone since a long time now (at a good price too)

  • Crank Sturgeon sells different models of contact mic (some are waterproof) done by himself

  • Monkey Sound is doing and selling a few nice models too

  • Geophone by LOM Audio. It is not an hydrophone, but it’s a very nice tool for contact recording

  • Ambient sells ones of the best hydrophones, but with a much higher price



Missing a link to a nice DIY tutorial or another nice way of buying an hydrophone? Contact us!

https://saralana.xyz/about & https://felixblume.com/contact