Frequency -- True meaning?

E

EvolutionNine

EvolutionNine
Joined
Aug 29, 2012
Location
Olympia WA
So this goes out to anyone really but I wanted to point this over to West, Horace111, Rajsta vibe, and Mr. Flech.



So I was reading up on reading music, should have payed attention in music :/


Anyhoo I was wanting to know if this sounded correct:

Frequency = (how many times the molecules in the air vibrate per second)

So if we are having a crap load of SB peaking between 43-63Hz, in that case I am assuming that the air molecules are vibrating(Alternating) between 43-63 times a seconed?

Please let me know if that is right. I think that is crazy. If that is right then it explains why you feel the SB more than you hear it.

Anyhoo Good night everyone..

Cheers
 
Last edited:
It is not air molecules vibrating; that is known as temperature.

Frequency (in this context) refers to the number of peaks or troughs in the sound wave which passes a particular point. A sound wave is actually a moving difference in air pressure.. imagine pushing your hands through sand, you build up a pile of sand on front of your hands, and a hollow area behind. This is exactly what happens when a speaker cone moves in the air, it crushes the air molecules tighter together in front (increase in pressure), and they spread out in the area behind the speaker (lower pressure). This pressure difference moves through the air. If the speaker cone moved just once you get an impulse (a single wave) which means there is no real frequency at all. However, if the speaker is vibrating back and forth 50 times a second, you get 50 pressure waves moving away from it (at the speed of sound) across the room, and this is measured as frequency, and your ears detect it as a tone.
Going back to the sand analogy, the individual bits of sand may be vibrating (temperature), but it is not so relevant in this example. (temperature and pressure are linked in the real world but not particularly when dealing with sound and speed of sound).
You can also think of frequency a bit like throwing a rock in the lake. The impact point is the speaker, and the ripples spreading out are like the pressure waves travelling at the speed of sound. You just count the number of ripples passing any point to get the frequency.
 
As I see, you are in a philosophyc trip.
Sub (infrasonic freqs) is used by certain animals, e.g. Elephants and Whales, to communicate in long distance.
They discovered elephant emitting vocalisation on spectrum of 14/24hz and at a pressure of 90dbs.
Elephants like walking subwoofers! Lol

And just to give you some more entertainment, I found a pleasant reading on this article 4 short page long http://freq.uenci.es/2012/01/13/thought-waves/?wpmp_tp=0

Have fun!
 
Air molecules vibrate due to the temperature... when you heat something you transfer energy into it which causes the molecules to vibrate. More vibration = hotter. Sound, which I already pointed out, is changes in air pressure (density of molecules within a given space). Think of cars in a traffic jam, they sit and idle and vibrate (like atoms/molecules with temperature). Every so often the lights change and a few cars get to jump forward a bit. This frees up a gap behind them, which fills with more cars, which creates a gap behind them, and so on, so the gap moves through the entire traffic jam as a wave, exactly like how a sound pressure wave moves through the air. It's not related to the individual cars vibrations. The only difference with the traffic jam is that the cars are always going in one direction, with air it just moves together and apart.

The reason we feel sub bass, and hear higher frequencies is due to the design of the ear. It detects changes in air pressure. When the pressure fluctuates, at a rate of ~25-18000hz it is perceived as a tone by the brain. Higher and the ear doesn't really respond. Lower, and you feel the air vibrations instead (this also has to do with the amount of energy required to create a wave of a particular volume at a particular frequency... its easier to shake your hand in a lake and create a lot of small ripples than it is to plunge a table up and down in the water to make big fat waves. So to produce a high enough amplitude (the height of the wave = volume) it takes more energy for low frequencies (ever wonder why a guitar amp is rated 30w and a bass amp at 300w?)
 
Last edited:
Back
Top Bottom