what is the down side to 1box both ported & sealed

busterno1 · 30th April 2010, 06:49 AM

I am looking to build a new sub

I am looking at is the exdusaudio shiva-X2 . in the applications for the driver it has a sealed & ported box both 70lt .

I was wondering what is the down side to making the ported box for h/t then sealing up the port for listening to music . or is it alright to do this ? thanks

Volenti · 30th April 2010, 03:20 PM

This is fine, just use a big chunk of foam or similar to plug up the port for music.

pacificblue · 3rd May 2010, 06:05 PM

Usually the right volume for a closed box is to small for a BR box and leads to impractical sizes for the BR tube. The right volume for a BR box is usually too big for a closed box resulting in too low Q and weak bass. A volume in between will result in suboptimal performance for both setups.

If you decide for the volume the BR box needs, you could apply a Linkwitz transform when you close the port to get the best of both worlds.

David_Web · 3rd May 2010, 06:49 PM

It's gonna be hart to tune it low enough to not get boom in room with that size box and still keep the port under 1m. If you make the port smaller to shorten it then you won't get much output before it chokes.

I can't seem to get an advantage with the ported box over sealed.
Maximum output level is around 3dB above sealed, and below 24Hz sealed wins. Mainly due to small port. But 100cm2 already has 60cm of length at 20Hz tuning. Tune it higher and you get a big hump.

Not sure you need LT when sealed. Maybe around 5dB boost at 20Hz to get it flat in room.
But it depends on room and what you want.

Brett · 8th May 2010, 07:50 AM

Quote:

Originally Posted by busterno1

I am looking to build a new sub

I am looking at is the exdusaudio shiva-X2 . in the applications for the driver it has a sealed & ported box both 70lt .

I was wondering what is the down side to making the ported box for h/t then sealing up the port for listening to music . or is it alright to do this ? thanks

Why bother? There is so little music with output around the 25Hz tune of the ported 70L box that it will likely make zero difference when listening to music. No need to plug it.

30th April 2010, 06:49 AM	#1
busterno1 diyAudio Member Join Date: Mar 2003 Location: brisbane queensland	what is the down side to 1box both ported & sealed I am looking to build a new sub I am looking at is the exdusaudio shiva-X2 . in the applications for the driver it has a sealed & ported box both 70lt . I was wondering what is the down side to making the ported box for h/t then sealing up the port for listening to music . or is it alright to do this ? thanks

3rd May 2010, 06:05 PM	#3
pacificblue diyAudio Member Join Date: May 2008	Usually the right volume for a closed box is to small for a BR box and leads to impractical sizes for the BR tube. The right volume for a BR box is usually too big for a closed box resulting in too low Q and weak bass. A volume in between will result in suboptimal performance for both setups. If you decide for the volume the BR box needs, you could apply a Linkwitz transform when you close the port to get the best of both worlds. __________________ If you've always done it like that, then it's probably wrong. (Henry Ford)

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30th April 2010, 03:20 PM	#2
Volenti diyAudio Member Join Date: Aug 2003 Location: Australia	This is fine, just use a big chunk of foam or similar to plug up the port for music.

3rd May 2010, 06:49 PM	#4
David_Web diyAudio Member Join Date: Sep 2008	It's gonna be hart to tune it low enough to not get boom in room with that size box and still keep the port under 1m. If you make the port smaller to shorten it then you won't get much output before it chokes. I can't seem to get an advantage with the ported box over sealed. Maximum output level is around 3dB above sealed, and below 24Hz sealed wins. Mainly due to small port. But 100cm2 already has 60cm of length at 20Hz tuning. Tune it higher and you get a big hump. Not sure you need LT when sealed. Maybe around 5dB boost at 20Hz to get it flat in room. But it depends on room and what you want.