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Message started by bnew63 on 02/06/07 at 20:50:03

Title: booming 12" WO
Post by bnew63 on 02/06/07 at 20:50:03

Refresh my memory(or lack there of),if the sub has a boomy sound to it do I reduce the size of the compression chamber?
I built a 12" version of a WO and having biult two others(an 8 & 6" version)this one seems quite boomy compared to the others.
Any suggestions

Thanks Brian

Title: Re: booming 12" WO
Post by JRock on 02/06/07 at 21:04:19

Boomy is a result of a larger compresion chamber or a small sealed chamber.  Try reduceing the volume of the compression chamber- if it doesn't work, its the Sealed section.

Title: Re: booming 12" WO
Post by bnew63 on 02/07/07 at 00:07:08

Thanks Jrock

could I use sand bags in the compression chamber to remove volume?This would be a temporary experiment to find the right volume needed.
I hope its not the sealed chamber,it would be more difficult to expand.I could turn the driver around,but I think I would open up a whole new can of worms.


Brian

Title: Re: booming 12" WO
Post by gexter on 02/07/07 at 02:06:55

I don't see why turning the driver around would be a problem. this would serve a dual purpose.
I would also try some sandbags to the CC.
if it works you may want to move the driver closer into the CC if your changes work.
the things heavy enough why keep a sand bag in it.

PS A 12" WO is always cool

Title: Re: booming 12" WO
Post by bnew63 on 02/07/07 at 03:05:27

Gex
The sand bags would only be temporary to calculate how much I need to decrease the CC.
I cheaped out and made this one from MDF so it's heavy.
Getting the 12" drivers to fit was a squeeze so I'm hoping I won't have to move them

  Brian

Title: Re: booming 12" WO
Post by gexter on 02/07/07 at 03:57:23


bnew63 wrote on 02/07/07 at 03:05:27:
Gex
The sand bags would only be temporary to calculate how much I need to decrease the CC.
I cheaped out and made this one from MDF so it's heavy.
Getting the 12" drivers to fit was a squeeze so I'm hoping I won't have to move them

  Brian


Ya I know, It was a rather stupid thing to say on my part.
Did you ever calculate the sealed area for that sub before you built? or just build it to Steves specs except for the height of course.
I see why you are reluctant to move them.
are you going to flip them around?
I had used insulation foam to take up space once. lined the CC with blue stryo. Even with styro/wood glue I felt that it may rattle loose after time.
Vibration and the glue hardens and becomes brittle and it falls off. It was  a Temp thing only.

Title: Re: booming 12" WO
Post by bnew63 on 02/07/07 at 15:34:42

Gex
I built it to Steve's specs with added width.I can't remember how much wider I made it as I made it over a year ago and just getting around to tweeking it.
Good idea on the styro,I think that's what I'll use.A good grade silicon should take the vibration and hold it in place.

 Brian

Title: Re: booming 12" WO
Post by gexter on 02/08/07 at 03:17:06

Good Idea
silicon will stay flexible. It can be a bad word around here although It never been an issue with me.
"The dreaded foam surround decay syndrome"

Title: Re: booming 12" WO
Post by 60_and_up on 02/21/07 at 15:37:26

Do not adjust the baffle further back in the chamber to reduce its size as a short cut, or you will increase the Q of the box to well over 1.0 (boom boom)



^ quoted from the plans.

Title: Re: booming 12" WO
Post by 60_and_up on 02/21/07 at 15:39:00

When selecting woofers for this enclosure, you can model a regular 4th order single reflex box to determine the rear (sealed) chamber. If it wants less air space than you have already built (gee you made the box first?) simple add bracing to the sealed chamber until its internal volume matches the requirement of your woofer. Do not adjust the baffle further back in the chamber to reduce its size as a short cut, or you will increase the Q of the box to well over 1.0 (boom boom)

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