Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums > LAB Subwoofer Forum

What is it which makes a subwoofer "omnidirectional"?

(1/13) > >>

Mike Henderson:
Hey guys, I am thinking of getting this sub for my garage:

https://av.loyola.com/products/audio/ev ... or-kw.html

Can you guys tell me exactly what it is which makes a sub omnidirectional please?

I have this one:

https://av.loyola.com/products/audio/ev ... i-sub.html

which is omnidirectional too but instead of trying to find another one, I am thinking might best to get the dual 18" version but these 2 subs look totally different in design which is why I am asking the question.

Tim Weaver:

--- Quote from: Mike Henderson on May 16, 2021, 09:37:29 am ---Hey guys, I am thinking of getting this sub for my garage:

https://av.loyola.com/products/audio/ev ... or-kw.html

Can you guys tell me exactly what it is which makes a sub omnidirectional please?

I have this one:

https://av.loyola.com/products/audio/ev ... i-sub.html

which is omnidirectional too but instead of trying to find another one, I am thinking might best to get the dual 18" version but these 2 subs look totally different in design which is why I am asking the question.

--- End quote ---


In this house we obey the laws of Physics!


It's not the mic of the kickdrum, it's the size of the wavelength.


Size doesn't matter. Until it does.

David Morison:

--- Quote from: Mike Henderson on May 16, 2021, 09:37:29 am ---Hey guys,

Can you guys tell me exactly what it is which makes a sub omnidirectional please?


--- End quote ---

All sounds have a characteristic called Wavelength, which is inversely related to frequency. Therefore low frequencies = long wavelengths.

If the source of a wave is much smaller than the wave itself, then the source will not be able to control where the wave goes, and it spreads out pretty much in every direction.

The wavelength of 100Hz is about 3.4m (and 30Hz = 11.4m), whereas common subwoofers might only be 0.5-0.6m wide (or tall if laid down), therefore the subwoofer definitely falls into the category of "small relative to the wavelengths being produced".

Wiki link if you want to get academic about it.

Cheers,
David.

PS: The links in your post don't work so I've no idea what subs you were referring to, but the general relationship between size & directivity applies to all subs, unless you move the goalposts by adding other sound sources to creat cancellations in the direction of the "unwanted" sound.

Mike Henderson:

--- Quote from: David Morison on May 16, 2021, 10:41:01 am ---PS: The links in your post don't work so I've no idea what subs you were referring to, but the general relationship between size & directivity applies to all subs, unless you move the goalposts by adding other sound sources to creat cancellations in the direction of the "unwanted" sound.

--- End quote ---

Sorry, these links should work:
https://av.loyola.com/products/audio/ev-eliminator-i-sub.html

https://av.loyola.com/products/audio/ev-eliminator-kw.html

Matthias McCready:
Mike,

David is correct it has to do with Wavelength.

--

Fun experiment for you. Play some pink noise and use a low-pass so that you are only getting information under 200hz. Now place a normal speaker (not a sub) on a stick.

While your eyes are closed have a friend spin the speaker around, and see if you can hear when it is aiming directly at you vs away.

Navigation

[0] Message Index

[#] Next page

Go to full version