Answer:
If a key is pressed on a piano, the frequency of the resulting sound will determine the ___PITCH_____, and the amplitude will determine the _____LOUDNESS___ of the perceived musical note.
Explanation:
The frequency of a vibrating string is primarily based on three factors:
The sounding length (longer is lower, shorter is higher)
The tension on the string (more tension is higher, less is lower)
The mass of the string, normally based on a uniform density per unit length (higher mass is lower, lower mass is higher)
To make a shorter string (such as in an upright piano) sound the same fundamental frequency as a longer string (such as in a 9' grand piano), either the thickness of the string must be increased (which increases the density and the mass) or the tension must be decreased, and usually it's a bit of both.
Thicker strings are often stiffer and that creates more inharmonic partials, and lower tension is associated with other problems, so the best way to make a string sound lower is the make it longer, but it is not practical to make a piano from strings that are all the same density and tension, because the lowest strings would have to be ridiculously long. Nine feet is already a great demand on space for a single musical instrument, and of course those pianos are extremely expensive and difficult to move.
And alsoBesides the pitch of a musical note, perhaps the most noticeable feature in how loud the note is. The loudness of a sound wave is determined from its amplitude. While loudness is only associated with sound waves, all types of waves have an amplitude. Waves on a calm ocean may be less than 1 foot high. Good surfing waves might be 10 feet or more in amplitude. During a storm the amplitude might increase to 40 or 50 feet.
Many things can influence the amplitude.
What is producing the sound?
How far are you from the source of the sound? The farther away the smaller the amplitude.
Intervening material. Sound does not travel through walls as well as air.
Depends on what is detecting the wave sound. Ear vs. microphone.
