2
$\begingroup$

The short version is: should I be worried about bass transmission through water into my neighbors' hulls?

I am renovating a small houseboat (12x30 ft) to live on. It is one large room, and I plan on putting my reasonably large hifi system into it (260W/channel at 8Ω). One side of the boat is glass windows, the other is a plywood wall with an ~8" cavity with studs. The floor is a plywood floor, and the hull is a fiberglass shell with marine ply inside.

I am familiar with audio transmission/reflectance/resonance in, say, an apartment context, which can be roughly modeled as adjacent resonant cavities. How will transmission differ through water? Will I have higher transmission at bass frequencies? The houseboats adjacent to mine have thick concrete hulls (say, 6-12"), so maybe the point is moot and I should be only worried about transmission over the surface of the water, which I know is highly reflective.

tl;dr am I going to pwn my neighbors with bass through the water or should I be more worried about the glass wall and transmission through the 12 ft of air separating the boats? What other factors may contribute that I may be missing?

Thank you for your help.

| improve this question | |
$\endgroup$
  • 1
    $\begingroup$ But you are not worried about any effects on the fish? $\endgroup$ – Solar Mike May 13 '17 at 16:32
  • $\begingroup$ +1: I find it very commendable of you to ask for factors that you are missing, before doing this. $\endgroup$ – MrYouMath May 13 '17 at 16:47
  • $\begingroup$ I'd agree that transmission thru the air is a strong path -- windows tend to resonate at low frequencies, for one thing. Plus if you ever want the windows open, well... :-) $\endgroup$ – Carl Witthoft May 14 '17 at 11:25
1
$\begingroup$

As @SolarMike pointed out the acoustic waves might harm the fish because the sonic speed in water is approximate $1484 \frac{\text{m}}{\text{s}}$ (at $20° \text{ C}$), this is quite high compared to the sonic speed in air which is approximate $330 \frac{\text{m}}{\text{s}}$. This might lead to the disorientation of the fish population close to your boat. The worst case scenario would be that your hi-fi system destroys the lateral line system (something like the ear of humans but not quite the same) of the fish population, which will lead to a permanent loss of the ability to orient and possibly to their death.

For example, when underwater drilling is carried out it is necessary to create a curtain of air bubbles, which locally reduces the sonic speed, in order to protect the fish from taking harm.

For the other questions, you can simply replace the sonic speed of air with the sonic speed of water and the physics should not change.

| improve this answer | |
$\endgroup$
  • $\begingroup$ I think it's equally important to consider the boundary condition -- basically Snell's Laws for the acoustic transmission of the boat vs. the water. If you could get a very large difference in "n" that would reduce emissions. I suspect that's the primary reason the "air bubble" approach works. $\endgroup$ – Carl Witthoft May 14 '17 at 11:27
  • $\begingroup$ The air bubbles change the volume fraction of air in water and at the same time act as insulators. $\endgroup$ – MrYouMath May 14 '17 at 12:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.