physics questions?

Question

1. Why do the same notes on a trumpet and on a saxophone sound different when both are played with the same pitch and loudness? Explain.

2, A loudspeaker produces a musical sound by means of the oscillation of a diaphragm. Does the loudness of sound produced depend on the frequency of oscillation, the amplitude of oscillation, the kinetic energy of oscillation, or all of these? Explain.

3.Which is a more objective measurement - sound intensity or loudness? Defend your answer.

4. How is an electronic organ able to imitate the sounds made by various musical instruments? Explain.

5. Why does your voice sound fuller in the shower?

6. How many octaaves does normal human hearing span? How many octaves are on a common piano keyboard?

Thanks a million =)

Answer 1

Just a minor addition to question 2... I'd argue that it's a combination of all 3.

Two reasons. First, isn't "loudness" defined as a perceptual thing? Our ears don't have a flat frequency response - i.e. different frequencies *sound*, to us, louder than others even if the amplitude is changed.

Secondly, and even if you ignore that, what I'd class as making the difference between a loud and quiet sound is the pressure difference between the successive "peaks" and "troughs" of the sound wave... i.e. the "amplitude" (as the first fabulous answer said) of the sound wave.

I'd say that amplitude *of the sound wave* will be a function of both the speed and the amplitude of the cone... and so is the frequency. i.e. keep the amplitude constant and vary the kinetic energy of the oscillation of the speaker cone and the frequency will change. If you step slowly into a pool, the ripples you make are reasonably small, whereas if you take a running jump (i.e. high kinetic energy)...

Answer 2

I will only answer the parts of this question that I think I know. The sound difference between saxophone and trumpet, or any other instrument for that matter, involves several factors. First of all, the acoustic envelope plays a major part. The acoustic envelope refers to the specific characteristics of a sound as it first begins and as it ends. This envelope is unique from instrument to instrument. However, if the envelope is removed, by digital means for an experiment for example, many instruments sound quite similar. Secondly, instruments produce different overtones based on their acoustical contruction - shape, materials from which made, etc.. When you hear a note, that is the fundamental pitch of the sound. Many other pitches are contained within that sound and differ from instrument to instrument. The listener only recognizes the fundamental as the sounding pitch, but the other overtones in their varying strengths greatly affect the sound and allow the listener to identify different instruments.
As for loudspeakers, loudness would be measured in amplitude. I am fairly sure that this is affected by the amplitude of oscillation. Amplitude, in this case, would be kinetic anyway, I believe. Don't quote me on that.
Electronic organs reproduce sound in much the same way as I described before, the overtones. If you can determine the overtone structure produced by a specific instrument and reproduce it digitally, the sound produced will sound basically like the instrument you are trying to imitate. This is obviously easier said than done. Most trained musicians can quickly tell the difference between syths and real instruments, although some patches are getting rather good. Much of this identification goes back to the acoustic envelope.
I would have to look up the range of normal human hearing, I think it's something like 20 hertz(cycles per second) to 20,000 hertz. Do a quick google search for that one. A piano contains 7 octaves. Hope this helps.

Answer 3

1. Because in addition to the fundamental frequency (the 'note') each instrument produces a different set of harmonics or overtones at different intensities. This give sound 'colour'.

2. Loudness is proportional to amplitude.

3. Sound intensity. The human ear is more sensitive to sounds within a certain band of the audible frequency range, around 3000Hz, from memory.

4. By blending in various intensities of harmonics - back to question 1.

5. Reflection of sound waves from the tiled surroundings.

6. 32Hz to 20,000Hz for someone under about 18 years of age - that's about 9 octaves. 7 octaves on a normal piano keyboard.

That's got to be worth 100 points :-)

Answer 4

I am currently a student in college taking the course Physics 4 with Calculus. I found high school Physics to be incredibly easy. It is easy for many high schoolers. AP Physics is also easy. If you like science and math, then you should have no problem taking preAP Physics. It is far easier than college Physics with Calculus.