Folded Horn Subwoofer
Country: United States
Date: November 2008
What are the advantages of having a
In order to have true horn loading in a subwoofer, the horn must be
monstrously long, opening up to at least 5 feet square at its large
end. Folding the horn reduces its size. But whether folded or not, a
horn loaded subwoofer that has good response down to 30 to 50 Hz, must
be massive in size. A folded horn that can accurately reproduce bass
this low (and after all, that is what a subwoofer is supposed to do),
will be at least 4-5 feet wide, by 5 feet high and 4 to 5 feet deep.
This size is needed because the wavelength of sound at low frequencies
is very large.
If the speaker system in question claims to have folded horn loading,
and is a lot smaller than the above dimensions, then it is just a
useless sales gimmick. Basic physics dictates that for horn loading
(folded or not) to have any effect at all at the low frequencies a
subwoofer is intended to reproduce, the horn must be very large.
As an example, the famous Klipschhorn folded horn speaker sold for
decades was about the size listed above, and even then it had to be
placed in the corner of the room so that the walls of the room acted
as an extended horn, Even so, its bass response was only barely
equivalent to a modern (and far smaller) ported system.
But to directly answer your question, the advantage of a folded horn
(over a non-folded horn) is reduced size. There is no other advantage.
Compared to a non-horn loaded subwoofer, a folded horn woofer will be
massively larger, and have some minor sonic problems as a result of
the sound waves having to navigate the folds in the horn. A true horn
speaker (folded or not) does have the advantage of higher efficiency.
This has nothing to do with sound, but only means a lower power is
needed to produce the same volume as compared to (say) a more standard
Having said all that, rest assured that a true folded horn subwoofer
will have a hard time fitting on your parent's living room! Anything
smaller, means the folded horn is just a useless gimmick. Basic
physics dictates that, in order to work, low frequency horns are huge!
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Update: June 2012