Is this alright for a port, bit of an odd design!

Boscoe · 25th November 2010, 06:48 PM

Okay I've got this design for a sub and i've designed thje port into the encloure (see pics) is this okay? I've designed this sub of a port with the same surface area (on the front) as is in my WinISD model so will this be okay as i have kept the length of the port the same.

So what i want to know is:

Is this design of port okay?

Can I change the width and height of a square port as long as it is the same surface area?

Thanks
Boscoe

sreten · 07:50 PM

Hi,

It should be OK, the arrangement is quite common but with one or two
strips front to back to allow the two surfaces to reinforce one another.

And yes you can essentially vary the shape of a rectangular port,
though here going full width is by far the easiest of the options.

rgds, sreten.

planet10 · 25th November 2010, 08:06 PM

This should wotk fine. I almost always do it this way (althou as sreten points out, usually with a port spacer to reduces resonances of the unclamped ends).

The high aspect ratio port will, as a generalization, start rolling off a bit sooner, and a bit slower as it effectively puts some resistance in the port. This usually gives a better end result, despite the common wisdom of some, that the port will compress sooner. I find more control & finese than in a typical low aspect ratio port.

And at least one of the beta testers of my CHR-Ken found that bass was deeper than in a same volume box he had with the same driver but conventionally ported.

dave

Boscoe · 25th November 2010, 09:18 PM

Okay nice thanks for clearing that up.

Top Shelf · 28th November 2010, 03:12 AM

+1 to Dave, I use that Box/port design quite frequently. Very easy to build. Not too hard to change the port length (shorter)either. Good luck.

THORNSPAWN · 28th November 2010, 03:38 AM

I use this design too only mine has 2 15s one on each side magnet to magnet.

Richard Ellis · 28th November 2010, 04:15 AM

This approach was commonly used in the early days of ports as it was simple to build. More precisely it is the mass of air we are concerned with....as is determined by the volume of the port.

__________________________________________________ ______Rick........

25th November 2010, 06:48 PM	#1
Boscoe diyAudio Member Join Date: Feb 2010 Location: England	Is this alright for a port, bit of an odd design! Okay I've got this design for a sub and i've designed thje port into the encloure (see pics) is this okay? I've designed this sub of a port with the same surface area (on the front) as is in my WinISD model so will this be okay as i have kept the length of the port the same. So what i want to know is: Is this design of port okay? Can I change the width and height of a square port as long as it is the same surface area? Thanks Boscoe

25th November 2010, 07:48 PM	#2
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, It should be OK, the arrangement is quite common but with one or two strips front to back to allow the two surfaces to reinforce one another. And yes you can essentially vary the shape of a rectangular port, though here going full width is by far the easiest of the options. rgds, sreten. __________________ There is nothing so practical as a really good theory - Ludwig Boltzmann When your only tool is a hammer, every problem looks like a nail - Abraham Maslow Last edited by sreten; 25th November 2010 at 07:50 PM.

25th November 2010, 08:06 PM	#3
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	This should wotk fine. I almost always do it this way (althou as sreten points out, usually with a port spacer to reduces resonances of the unclamped ends). The high aspect ratio port will, as a generalization, start rolling off a bit sooner, and a bit slower as it effectively puts some resistance in the port. This usually gives a better end result, despite the common wisdom of some, that the port will compress sooner. I find more control & finese than in a typical low aspect ratio port. And at least one of the beta testers of my CHR-Ken found that bass was deeper than in a same volume box he had with the same driver but conventionally ported. dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

28th November 2010, 03:12 AM	#5
Top Shelf diyAudio Member Join Date: Apr 2010 Location: Midland, Ontario	+1 to Dave, I use that Box/port design quite frequently. Very easy to build. Not too hard to change the port length (shorter)either. Good luck. __________________ JEREMY M_________________________________ I like it loud, BUT NOT TOO LOUD!.... Hey do you hear that high pitched ringing sound ?

28th November 2010, 03:38 AM	#6
THORNSPAWN Sound with Style diyAudio Member Join Date: Mar 2010 Location: Geelong, Vic	I use this design too only mine has 2 15s one on each side magnet to magnet. __________________ Australian Frugel horns and flat pack kits now available at http://www.soundwithstyle.com.au


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25th November 2010, 09:18 PM	#4
Boscoe diyAudio Member Join Date: Feb 2010 Location: England	Okay nice thanks for clearing that up.

28th November 2010, 04:15 AM	#7
Richard Ellis diyAudio Member Join Date: Sep 2006 Location: Mar del Plata, a BIG seasonal getaway city, can see the Ocean from our residence.	This approach was commonly used in the early days of ports as it was simple to build. More precisely it is the mass of air we are concerned with....as is determined by the volume of the port. __________________________________________________ ______Rick........

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