# Sound Waves, Resonance, and intensity

1. Mar 15, 2008

### babybeth09

"If two flutists play ther instuments together at the same intensity, is the sound twice as loud as that of either flutist playing alone at the intensity? Why or why not?"

I know that the answer has something to do with the sensation of loudness being logarithmic in the human ear, but I guess I don't really understand the concept.

Any help is greatly, greatly, greatly appreciated!

2. Mar 15, 2008

### dst

The sound will be 1dB louder, I think (using the original as a reference). Either way, it will not be twice as loud. You already gave the correct answer.

Last edited: Mar 15, 2008
3. Mar 15, 2008

### babybeth09

Thanks!

4. Mar 15, 2008

### Snazzy

Well, the equation for the sound level is:

$$\beta=10log[\frac{I}{I_o}]$$

Where $$I_o=10^-^1^2\frac{W}{m^2}$$

So you can just plug in values for varying intensities and see.

5. Mar 15, 2008

### babybeth09

Cool - thank you guys. It's good to have some help because my teacher just gives us the assignment without doing much lecturing or anything, then won't really help us at all, so you guys are life savers!

6. Mar 16, 2008

### Claude Bile

A doubling in intensity is about 3 dB as a rule of thumb.

Claude.