DIY Hydrophone

[@fynn7972]

Thank you so much for this. I wanted to buy one, but I think I'm going to build it now that I know how to do it. Thank you so much for this.

[@GeorgeVlad]

Great stuff Felix, excellent introduction to a bit of field recording DIY.

[@felix_blume]

many thanks George Vlad!!!

[@LordGryllwotth]

Do you know if you had a airpocet behind the piezo it would perform better? In this summer I will try and make one.

[@thekarmafarmer608]

Outstanding! Great video.

[@Jandodev]

Exactly what I needed!

[@mymodularjourney]

Awesome. I’ll take a stab at building one myself.

[@pierpa_76pierpaolo]

It works so well but it is very strange that there is no pre-amplifier for the piezo record (otherwise the 'audio is very weak.......). Here in the video there is no reference to various pcbs but only two connections, a piezo and two wires.

[@felix_blume]

Some other version of hyrdophone and piezo include some preamp, you're right... but the tutorial here is for a very "basic" hydrophone, only with a piezo (without preamp). I hope it helps!

[@nowgotnougat7871]

Hey Felix, thanks for the tutorial. Do you recommend an impendance adapter while using those mics with a handheld recorder (zoom h5)? If yes which one?

[@felix_blume]

You can use it directly on the Zoom H5, but you could use an impedance adapter too. I'm using the HOSA adapter, model MIT 129, but I can't be sure how much it's better or not than the zoom H5 directly.

[@TheErilaz]

The problem with piezo guitar pickups and piezoelectric crystals is that they are not well matched to typical audio inputs. By their nature they can generate a lot of signal, but they cannot drive a 50 kilohm typical line input. The pickup needs to work into a much higher impedance, typically 1 megohm or so. So what to people do? They go and plug a piezoelectric disks output directly into the line input of their recorder, typical impedance 50k, or the plug-in-power mic input of their recorder, typical impedance about 7k, and they start to bitch and moan that this damn thing sounds tinny. Which is does ! But they don't understand why! The reason why these devices often sound tinny is because the piezo sensor presents its signal through a series capacitance which is small, typically 15nF or less. When wired to a normal 50 kilohm line input this forms a high-pass filter, which eliminates the bass. Solution: github.com/Supermagnum/piezoelectric

[@MitchellMaichak-ze7mr]

The sound of " Sleepin' wit da fishes " !!!

[@thejawshop-AdventureRecording]

Very nice. I might just try this. Thank you

[@SonicIdentifications]

Great video. Might it also be possible to use hot glue as filling instead of silicone? :)

[@felix_blume]

It should work too, even if as the hot glue is more "solid" than silicone, it could change a bit the sound and the resonance of the piezo. But should definitely work! Try it and let us know!

[@MarkAlark22]

Hey Félix, i'm not sure I understand what's happening at 1:23-1:35. What exactly are you taping on the outside of the lid?

[@felix_blume]

Hi Marc. I'm taping the piezoelectric sensor, so it won't move while filing the lid with silicone. The full list of things you need to buy/use are at the beginning of the video, and on our website saralana.xyz/hydrophone or felixblume.com/hydrophone/

[@MarkAlark22]

@@felix_blume Cheers!

[@tone77]

So good. Thanks for sharing

[@davidmorley9916]

What size mic cable did you use,enjoyed the video thanks

[@famisheddendon]

How do i revord the same qualitu audio you did at the start, do i need a preamp?

[@felix_blume]

On the video, we've been connecting the hydrophone to a MixPre Recorder (by Sound Devices). But it should work with most of the recorders (including handy recorders)

[@ruxandracalin2627]

Hi @Felix - the copper foil - what's the thickness you recommend? Is 0.1 mm too thin? Thank you

[@felix_blume]

I think it should be enough.

[@areusmartinez8343]

Gracias por compartirlo 🙌

[@ZloyVorchun]

Снимали в тропиках? Песни птиц для нас совсем непривычные!

[@felix_blume]

filmed in Brazil, indeed.

[@proartwork7189]

Gracias Hermano!

[@vks002]

Hey! thanks for the video. I have been trying out various methods to make a piezo waterproof but have failed. I tried coating it with rubber paint , it didnt work. I then used nail paint and still doesnt work. The issue is that after painting it something it keeps giving a reading even when there is no vibration. I am not sure if the rubber film you showed will change this but because it is expensive in my country I cant but it for trial. Do you have any suggestions on what else could I experiment with? One other issue I had was that if I pack the peizo in a cap like you do, its sensitivity decreases a lot. My use case if to detect tiny droplets of water falling inside a tank to detect leakage.

[@felix_blume]

Hello. I would recommend to use "pastidip" to cover the piezo, it's not the same as in the video but it's the one which works better. I think it will fix your problem. About the sensitivity, you can try to put the piezo on a metal part (or in a small metal box) and it could help. Another option is to use 2 piezo, on a symetrical cable (3 pin XLR) so you will avoid interferences and have more signal. I hope it helps!!! Have fun!

[@vks002]

@@felix_blume Thanks for the suggestions. I will certainly try that out. Can you tell me more on the 2 piezo solution. How do I connect two of them? I am using a microcontroller to sense the signal which runs on a battery so I cant use amplifiers or signal conditioners as they will hog batteries.

[@felix_blume]

@@vks002 To connect 2 piezo, you need to connect both "-" polarity to the ground, and then the "+" of one piezo to the "+" signal of your XLR cable, and the other piezo to the "-" signal of your XLR cable. If you don't have an XLR input it won't work I guess

[@crazydiydaniel7835]

Hi @vks002 did you ever get this to work for leak detection? I'm trying the same thing.

[@Superkuh2]

Is this reciprocal? Could you use it as a (low power) underwater speaker?

[@felix_blume]

Well, you could use a piezo as a speaker, indeed, and probably underwater with this method. But I guess the frequency response will not be very good, and the volume probably very low.

[@Ma_X64]

It's better to use balanced cable but of course you need to double your piezo-sensors and connect them properly to get a para-phase signals.

[@felix_blume]

indeed, it's a good way to get more signal, using 2 piezo sensors

[@searchiemusic]

piezos are already high enough impedance that you're loosing signal no matter what length of wire you run, so idk how high we're setting our quality needs here, if i was really spicy about it maybe a DI transformer wouldn't be too hard an addition, spensy though

[@Ma_X64]

@@searchiemusic balanced cable is about eliminating the induced noise. Also I have a practical experience of using such a scheme and it works good. Of course or is better to have in-place preamp but not mandatory.

[@디옹윤-i5f]

If I use balance cable, do I have to connect hot to A piezo's center/ cold to B piezo's center/ ground to copper foil?

[@Ma_X64]

​@@디옹윤-i5f Good question. You can actually be using different variants but the one where you solder piezos metal bodies back to back and connect the Gnd to it, appears the most practically useful. (hot and cold wires are connected to piezos centers, yes) Signal wires turnes to be surrounded by Gnd so the humming sound will not bother you when you touch the device. *If you want to pick-up the difference in signals in two places, then just solder each sensor with Gnd and signal wire. You also can play around connecting good coupled resistors in parallel to piezos: say, 15-5 MOhm.

[@delunamoon]

Hi Felix When I do this project I have some questions, please tell me what is your copper foil type thickness. Because I’m very worry about if the size is too thick that it will affect the signal. Look forward your answer Thanks your answer

[@felix_blume]

I would recommend to use a copper tape, which is much easier to use and very thin. But in any case, I don't think the copper foil could affect your signal.

[@luthfiemazhar4895]

hi felix, what is the purpose of copper foil? edit: ah its for shielding.. thanksss

[@atokenbeast3927]

Do i have to use a 1/4 jack? couldnt i just cut one end off an XLR cable?

[@felix_blume]

Yes, XLR Cable works too, then you have to connect pin 1 and 2 only

[@escuchaespontanea]

Hey Félix! Great video! I have a question: what is the function of the washers? Thank you! I already suscribed to your channel ✌🏼

[@felix_blume]

They give some "weight" so the hydrophone is not floating... but you could anything else to give some weight.

[@escuchaespontanea]

@@felix_blume Great! Thank you!

[@Umapena]

Oi, Felix, você por acaso não vende um hidrofone desse? Eu to procurando um pra um projeto de arte mas não encontro, ou então recomenda onde comprar? Obrigado!

[@felix_blume]

Você pode me escrever aqui felixblume.com/contact

[@laodeofficial1604]

Can i buy your hydrophone

[@cleciorimas]

Ao invez de silicone, posso usar cola quente?

[@felix_blume]

Acho que a cola quente pode ser muito dura... o silicone tem a vantagem de ser menos duro. Mas talvez funcione da mesma forma, ten que testar!

[@theo_dec]

Hello, is an aluminum foil can replace the copper foil for electromagnetic interference protection ?

[@felix_blume]

I'm not sure... I've been trying and it didn't work so well with aluminium... But I would recommend a copper foil tape, which is much more easy to manipulate (and cheaper).

[@yDeathAngely]

@@felix_blume why do you need the foil at all? Because you never solder anything to it. Is it for shielding?

[@TheErilaz]

@@yDeathAngely It's for shielding. Any metal box or foil that is conductive works. Just check with a ohm meter that there actually is conductivity if layers is used.

[@TheErilaz]

@@felix_blume Aluminium or copper, it really does not matter. Just be aware that the aluminium or copper foil or tape may be covered with some stuff that hampers the conductivity. A ohm meter will absolutely discover that.

[@alvarobyrne]

please tell me where to buy plasti film, thanks in advance

[@felix_blume]

You can find a local reseller on Plastidip website plastidip.com/