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bvan 26th June 2006 05:29 PM

How to make sub 'faster'
Hi, complete diy newby here.

I'm wondering how one can modify a bought sub to be more musical/tight/fast.

I'm thinking of matching a sealed 12" sub(-3db@25hz) with some fast electrostatics. From my cursory reading it seems that Q is the issue? Is it all about "critically dampening" the sub or is there more to it than this? What numbers should I be aiming for?

What, if anything, could I as a novice do to tighten up the sub? I have friend who is an EE so if there is something to be done involving the PCB then please also let me know.

I should also say that I am happy to sacrifice some ectention(say 30hz) and lots of output to achieve my end.(I dont listen over 80db).

Thanks for any help.


richie00boy 26th June 2006 06:06 PM

It's not a lot really to do with Q, especially if the box is sealed. The factor is integration - the low-pass filter.

sreten 26th June 2006 06:24 PM

Re: How to make sub 'faster'

Originally posted by bvan

What, if anything, could I as a novice do to tighten up the sub?


Investigate the stuffing of the subwoofer. Depends on the driver
and the current type of fill and its density. increasing stuffing will
tighten bass though as said integration of the sub and the
electrostatics is also critical.


bvan 26th June 2006 06:57 PM

Thanks for that.

I have a BFD if that helps with intergration? I take it you mean that the subs and speakers roll-off slopes must be such that there are no holes or humps?

So increasing the stuffing inside the speakers would help? Why do manufacturers skimp on this i.e what is the tradeoff of putting too much dampening material in the enclosure?



richie00boy 26th June 2006 07:03 PM

If you stuff it too much it reduces the effectiveness of the stuffing.

bvan 26th June 2006 08:43 PM

last question,

what will happen if a take a saw to it and make it a bit smaller?



richie00boy 26th June 2006 08:50 PM

Q will raise making a peakier response and worse group delay, and low-extension will reduce. Power handling will be improved provided you have not reached the voice coil thermal limit.

Bear in mind that changing Qts from e.g. 0.7 to 0.9 is only quite suttle.

bvan 26th June 2006 10:05 PM

I think I found what I'm looking for! Will start from scratch:

A "critical Q" sub, Q=0.5, designed for music not HT.

What you guys think? look easy enough to build.

cheers for the help,


RobWells 26th June 2006 10:38 PM

Will add that the peerless drivers are meant to be fantastic drivers, just be wary of believing all on the critical q site. Esp. the measurement bits.


lndm 26th June 2006 10:49 PM

I wonder what exactly you mean when you say tight. A well designed woofer with a Q of 0.5 should indeed give you tight bass.

This bass might be accurate, gentle and articulate (for want of a good set of descriptive words). It will play well with most types of music.

However, if you listen to much rock music, or anything with a bit of sting, you might favour something different. Perhaps a system with a higher Q, and an amp with a high damping factor maybe.

FWIW, I use a low Q setup and find all music listening enjoyable.

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