## Math help--Hydrophone voltage output scale

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A prototype app is using a hydrophone

http://www.aquarianaudio.com/h1c...

The datasheet says under Specifications

which is confusing to us...a uPa is less than a butterfly wing beat.

So, off to Google and I found an explanation from another manufacturer site:

http://www.ondacorp.com/tecref_t...

Let's see if it pastes decently here...

Converting the Hydrophone Sensitivity into MKS units

In the future, Onda Corporation is going to use the units Volts/MPascal since these are the most appropriate for the types of hydrophones we sell. However, the legacy units which we have inherited are the crazy dB with respect to 1 Volt per micro Pascal, which carry over from early work done with microphones in air. These units are about 240 dB from where we want to be typically. The following figure shows how a conversion is accomplished, including how one accounts for the impedance of the media when calculating the conversion from volts squared to intensity. Note that we assume the media is water, as other fluids could cause damage and void your warranty.

But I don't see where the -238.5 is plugged in there.  How do we use our -190 to get our V/MPa ?

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

does this help?  http://www.sengpielaudio.com/cal...

(Possum Lodge oath) Quando omni flunkus, moritati.

"I thought growing old would take longer"

In the first equation:

GV:= (10^(G/20))*(V/((10^(-6))*Pa))    // If I didn't miss or add a paren

It appears they plugged -238.5 in for G.

Edit: If I didn't miss something (which I probably did!) I get 316 V/MPa.

David

Last Edited: Thu. Feb 23, 2017 - 05:47 PM