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You got it going on with this gizmo... :T

I was searching for "6 inch flared ports" and guess who comes up first and second on Google? lol... Home Theater Shack and then Subwoofer-Builder... wouldn't you know. :whistling:

How do you flare those things? Can we get a primer on this posted somewhere?
 

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Discussion Starter #27
Sides, top, bottom, edge bracing and door support are on.

Up to routing off the overhangs on the edges before gluing front and back.
Project has moved back outside for routing but weather is lousy here (flood warnings etc)


I was in too much of a hurry with the bottom panel and its at an angle.
Have worked out how to make a jig to allow the router to act as a milling machine to get it back to square. Should make for some good photos...
 

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Discussion Starter #31
A bit more progress....:bigsmile:



Soon be up to some measurements and listening impressions....
 

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I'm anxious to hear how this one performs too.
The press regarding bandpass boxes says there are response timing issues, but these can be addressed in a large ported design, so I'd think the same obstacle could be overcome in a bandpass box as well.

It's cool that you tried a enclosure that vents the front wave and the rear wave.
 

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Hey, this is the first bandpass enclosure I've seen with the usual DIY 15 and 18" drivers. I must have missed it, but what is the target application again? I thought I read the whole first post and most all of the posts afterwards, but apparently not.
 

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Discussion Starter #37
Thanks for the thumbs up guys.

looneybomber - Target application is for music and to add some "slam" to movies. It's not designed to go real low for movies though.

JohnF - love the picmod!
 

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Discussion Starter #38
Measured outside with REW (blue line)
WinISD prediction is the green line.


A bit peakier than I expected, and the frequencies seem to have drifted a bit..

More analysis>>

Initial impressions are that it's adequate but not exactly chest slamming.
Another bank of filters defined on the BFD should let me kick it a bit harder..:R
 

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Discussion Starter #40
The frequencies of the peaks were different to the design, so I thought that perhaps the volumes were out by a bit.

Since the port lengths were known, I adjusted the box volumes in WinISD till the peaks lined up with what was measured. What I wanted to know was if WinISD would show the height of the peaks correctly.

It seems that even if the tuning is spot-on, WinISD will show the lower frequency peak as about 6dB too low and the higher frequency peak as about 4dB too low (gaps between the blue and red lines)

This is a best case scenario. I took a fair amount of care working out the volumes, so I think the green line is a better representation of what, according to WinISD, was built.

Without doing a whole heap more boxes, it's hard to know where the truth lies.
It would be interesting to hear from anyone else who has been down a similar design / build road.

Meanwhile, the peaks can be chopped with a BFD, getting back to the plateau that is supposed to be there....
 
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