Does water pressure affect the speed or frequency of sound under water and how?

Answer 1

A few things to think about, or confuse you. I assume you are talking about in the ocean.

As you go down in depth, the water pressure increases due to the weight of the water. Water is "relatively incompressible", IF the temperature does not change. As you go deeper, the water also gets colder. This temperature change will have a greater effect, because there is a change in density and the water molecules are closer together. Since there are more molecules per volume, sound (energy) will decrease more rapidly, since there are more water molecules to go through and impart energy on per distance traveled.

Of course if you are assuming no temperature change, then that is all irrelevant. Sound travels very well underwater.

P.S. Water is relatively incompressible due to its properties, but it can be pressured, otherwise water would not move through piping. Water pressure in an enclosed space goes up quickly with only a small amount of water addition. Example; If you have a 10,000 gallon filled and sealed water tank, with no change in temperature and no gas in the tank, introducing an additional 1 gallon of water to the tank will increase its internal pressure about 100 psig.

Answer 2

The higher the pressure the smaller the wavelength, and the farther the sound can carry ( not LOUDER.... but farther)

A whale can sound near the surface and its call only travels a short distance underwater, yet if the whale dives down a few hundred feet, the sound can carry a half an ocean away.

Same goes for the Doppler effect. Most underwater listening devices are DEEP WATER, and can hear ships/submarines pass from great distances, and tell in what direction they are travelling..

Answer 3

The speed of sound is the square root of the change in pressure per change in density. Since water is (almost) incompressible, this means that the speed of sound will not change, no matter the pressure.

Answer 4

The speed of sound in water does depends on pressure (hence depth), temperature and salinity. Mackenzie derived the following equation based on these variables:

Speed = 1448.96 + 4.591T - 5.304 x 10^-2T^2 + 2.374 x 10^-4T^3 + 1.340 (S-35) + 1.630 x 10^-2D + 1.675 x 10^-7D^2 - 1.025 x 10^-2T(S - 35) - 7.139 x 10^-13TD^3

where,
T = temperature in degrees Celsius
S = salinity in parts per thousand
D = depth in metres

There are equations too...
http://www.npl.co.uk/acoustics/techguides/soundseawater/

Answer 5

no because pressure does not affect the properties of water (water is incompressible).
I think however that the temperature of water affects speed.

Answer 6

No ... water is not compressible