Is 200Hz LPF for a subwoofer too low? Would 300Hz make a difference?

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steveilee@gmail.com - 20 Sep 2007 20:58 GMT

Hi guys, I have a subwoofer amp (1000watts @ 2 ohms) that has a
variable LPF built in. The LPF only goes up to 200Hz.

With certain songs, parts of the beat are pretty quiet, but low parts
of the beat (below 200Hz I assume) rattle my teeth loose. It sounds
horrible.

I'm considering selling this amp at a considerable loss to get a
similar amp that has a variable LPF that goes up to 320Hz (1300watts @
2 ohms, if it even matters). Do you guys think that this will fix the
problem? Is it just certain low frequencies that cause extra rumble?

I'm not sure what 200-300Hz sounds like... is it more or less
impossible to get a thump in that freq range, in which case I should
blame my music for being defective and having beats in freq ranges
that are unable to cause thump?

Another thing I plan on doing is replacing my factory 8" door woofers
with something more serious and have a 200-350Hz band pass filter on
them, so they can complement my 15-200Hz thumper in the back. My
worry is that they will not create the follicle-massaging bass to
match the rear amp/sub.

Thanks in advance to any help you guys may have to offer.

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buddha73 - 20 Sep 2007 21:22 GMT

sounds like your sub can't handle low frequency's very well, and mos
subs you don't really want to run that high, lp around 80 is mor
common.

edit: lookin over your post again, is your box ported, do you have
subsonic filter

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steveilee@gmail.com - 21 Sep 2007 20:07 GMT

> sounds like your sub can't handle low frequency's very well, and most
> subs you don't really want to run that high, lp around 80 is more
[quoted text clipped - 12 lines]
> --
> Posted via a free Usenet account fromhttp://www.teranews.com

I have an Alpine Type-X (SWX-1243D) 1000watt 12" sub set to 2ohms.
I'm powering it with an Alpine PWX-1.1000 1000watt@2ohms amp.
Subsonic filter is set at 15Hz. Box is sealed, not ported. I was
just noticing that certain bass notes sound alot louder than other
bass notes... I figured it was a fault of the amp.. and maybe I needed
an LPF set higher than 200Hz... to 300Hz? Maybe it's just my music?

Any ideas?

Thanks.

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Mook Johnson - 21 Sep 2007 23:41 GMT

> I have an Alpine Type-X (SWX-1243D) 1000watt 12" sub set to 2ohms.
> I'm powering it with an Alpine PWX-1.1000 1000watt@2ohms amp.
[quoted text clipped - 6 lines]
>
> Thanks.

What is the volume of your box? Too small of a box will sound boomy like
this too. Try adding some polyfill from Walmart to the box to increase its
appearent size by ~10-20%.

Raising the crossover will not fix the overly booming problem. If you want
to see, just turn off the LP crossover and let the woofer play full range as
a test.

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Mook Johnson - 21 Sep 2007 20:21 GMT

> Hi guys, I have a subwoofer amp (1000watts @ 2 ohms) that has a
> variable LPF built in. The LPF only goes up to 200Hz.

You want most subs to only got to 100Hz max. 200 it pretty high and
considered high bass or lower midrange. Try downloading CoolEdit and making
a CD of test tones to here the different frequencies. Can also be good for
finding rattles.

> With certain songs, parts of the beat are pretty quiet, but low parts
> of the beat (below 200Hz I assume) rattle my teeth loose. It sounds
> horrible.

Check if it has a bass boost. If it does, turn that down to 0dB. That boost
will make the amphit hardest on a single note if its boosted all the way.
If that doesn't do it, turn the gain down until the bass notes are more in
line with the rest of the system. Once you have have that all sorted out
then you can goose the bass knob if you want more kick.

Before testing I'd turn the bass and treble (or EQ) on the radio to flat (0
boost 0 cut).

That way you get a refreence spot and you can adjust up or down from there.

<snip>

> Another thing I plan on doing is replacing my factory 8" door woofers
> with something more serious and have a 200-350Hz band pass filter on
> them, so they can complement my 15-200Hz thumper in the back. My
> worry is that they will not create the follicle-massaging bass to
> match the rear amp/sub.

Yup, no factory speaker is going to be able to keep up with a sub that can
handle 1000 Watts. The rest of your system needs to be upgraded if you want
it to keep up with the sub. You should get some highpass filters for the
other speakers so the don't struggle to make bass that your sub is more than
capable of providing.

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Mariachi - 21 Sep 2007 22:33 GMT

> Yup, no factory speaker is going to be able to keep up with a sub that can
> handle 1000 Watts.

> The rest of your system needs to be upgraded if you want
> it to keep up with the sub.

Unless you're one of those ghetto people who know nothing about sound
quality and only use a sub that rattles their whole car to pieces.

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