Sound: Speakers Woofers vs. Tweeters

[JoshMG]

Why are speakers that are used to produce low notes such as woofers bigger than speakers used to produce higher notes such as tweeters?


The idea that I have is that, lower notes have higher frequency which is harder to hear so in order to hear it has to be produced my a bigger instrument.

But I'm not sure if it's right.

 

[tiny-tim]

Woof! Tweet!

Why are speakers that are used to produce low notes such as woofers bigger than speakers used to produce higher notes such as tweeters?

The idea that I have is that, lower notes have higher frequency which is harder to hear so in order to hear it has to be produced my a bigger instrument.

But I'm not sure if it's right.

hi JoshMG!

i don't really know anything about woofing and tweeting, 'cos I'm only a goldfish … but i do know some sea bass …

so i think it's the same reason why bass organ pipes and bass fiddles are so large!

 

[CaptainMarvel]

Firstly, lower notes have lower, not higher, frequencies.

Looking at the equation:

wavespeed = frequency * wavelength

Since all sound waves travel approximately at the same speed (340 metres per second) this means that low notes must have long wavelengths.

In Summary:

LOW NOTES = LOW FREQUENCY = LONG WAVELENGTH

Because of these long wavelengths and the fact that the bass part of the spectrum takes more energy to reproduce than any other part, large amounts of air need to be moved to recreate a bass note.

Large speakers have a greater mass and therefore more inertia which means they cannot move fast enough to produce high frequencies. Although small speakers are capable of vibrating slow enough to match bass notes, they won't push enough air at low speeds to be audible, so a large surface area is required to produce the lower-range sounds. Hence big woofers!

Hope this helped.