Subwoofer frequency ranges?

Archived from groups: rec.audio.tech (More info?)

"Brian" <bclark@es.co.nz> wrote in message
newsfki41h5kiamh5tu43ptln6v3isan1bh5d@4ax.com

> I'm currently trying a 100 watt sub woofer with a frequency range of
> 28Hz to 200Hz

> Would I gain much by replacing the sub woofer with another sub
woofer
> that has a frequency range of 20Hz to 200Hz.

If nothing else, you'll probably get more competent performance in the
28-50 Hz range from the subwoofer that works well down to 20 Hz, than
from a subwoofer that gives up the ghost at 28 Hz.

> I would gain the missing 20Hz to 28Hz but is there much that uses
this
> frequency range?

Other than very large pipe organs, very few instruments generate
fundamental tones below 32 Hz. However, there are percussive
transients and environmental sounds that have potentially audible
content at lower frequencies.

> The sub woofer is for music and movies.

Some movies have some really strong low stuff in their sound tracks.

Archived from groups: rec.audio.tech (More info?)

Eiron wrote:
> Brian wrote:
>
> > Would I gain much by replacing the sub woofer with another sub
woofer
> > that has a frequency range of 20Hz to 200Hz.
> > I would gain the missing 20Hz to 28Hz but is there much that uses
this
> > frequency range?
> > The sub woofer is for music and movies.
>
> Telarc CDs use that frequency range and lower.
> Check the specs carefully. 20Hz at -10dB isn't necessarily better
> than 28Hz at -3dB.

But it's doubtful that it's any worse. Consider that at a minimum,
the asymtotic rolloff rate is 12 dB/octave. 20 Hz is 1/2 octave
below 28 Hz. If it is a second-order alignment, 3 dB down at 28 Hz
will also give you 9 dB down at 20 Hz. Now, this assumes maximally
flat 2nd order aligment.

If it's a reasonably aligned vented system, 10 dB down at 20 Hz
could also mean 3 dB down at 24 Hz.

And given the sorts of alignments that one is likely to find in
many subwoofer implementation, i.e., slightly underdamped, 4th
order or higher alignments, -10 dB at 20 Hz is likely to have
its -3dB frequency lower than 28 Hz.

Not that it REALLY makes a lot of difference, despite claims to
the contrary.

Archived from groups: rec.audio.tech (More info?)

Wouldn't it be possible for ole Bri-Bri here to get a bit more
capability to at least half-way between 28 and 20 Hz if he experimented
with subwoofer locations "close-ish" to the wall or corner of the room?
Ideally, this could be helpful if the sub is a sealed design, but
sealed is not exactly common for consumer retail subs. If you are
really desparate, I suppose you could temporarily stuff the vent of
your sub and then try some wall/corner-loaded locations. None of this
is "ideal" to be sure, but I just thought it would make for some
intriquing and quick DYI options. Then you can play some movies and
really sample if it [4-8 more Hz] really makes a difference for your
particular uses.

As for "really strong stuff" in movie soundtracks, I've never really
seen claims of that nature quantified anywhere. Surely it is there,
but how much and how low? If there is "strong stuff" going on around
24 Hz, almost certainly there will be even "stronger stuff" going on at
30 Hz. So it's rarely ever clear if that extra "8 Hz" perceptibly
gives you more, even though technically it *is* more.