Underwater Speaker?

[MilitantMedic]

So I take it the Fletcher Munsion Curve is altered by immersion in water?

 

[O2BBubbleFree]

So I take it the Fletcher Munsion Curve is altered by immersion in water?

Since the Fletcher Munson curves deal strictly with sound propogation through air, it doesn't really apply...

But in general, yes, sound propogates differently in water than in air.

 

[markfm]

It might be tempting to put a little RF speaker in an immersion bag (like the ones they make to hold VHF FM radios -- it's basically a super ziploc). It's not like it needs to submerge to 100', correct? If the speaker could be put in to even 5' or so depth that might be fine.

 

[MilitantMedic]

3dent,
Actually the Fletcher Munson Curve has nothing to do with wave propagation through air. It deals with human perception of loudness of differing freqs. Nothing at all to do with air or water for that matter. (BTW it was said in jest as well)

 

[O2BBubbleFree]

3dent,
Actually the Fletcher Munson Curve has nothing to do with wave propagation through air. It deals with human perception of loudness of differing freqs. Nothing at all to do with air or water for that matter.

What I was trying to say is that since sound propagates differently in different media, and the curve was constructed using sound in air only, it is only applicable to sound in air. For instance, low frequencies propagate much better in water than in air. If the curves had been constructed using sound in water, they would be skewed to the lower frequencies. Even using headphones, where the distance from speaker to eardrum is minimized, there's a significant difference in sound quality in water versus air.

For example, some of the newer underwater MP3 players use bone conduction, which eliminates the sound in air v. water problem. However, at least one of the older models that used headphones had built-in equalization. It sounded like crap out of the water, but acceptable in the water.

(BTW it was said in jest as well)

Jest you wait 'til I get my hands on you...

I figured that, but thought that this was a good opportunity to emphasize to others reading this thread that your music (or whatever) is going to sound significantly different underwater than it does in air.

As I've mentioned in other threads, at work we put together a system to broadcast messages underwater. We had an amateur sound engineer alter the message files to enhance the underwater intelligibility. BTW, if you’re diving and hear something along the lines of “This is the Coast Guard. You have entered a restricted area. Surface immediately”, I recommend you follow their instructions...