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Discussion Starter #1
I'm thinking of building something different for the IXL18 driver. This bandpass design......


Preliminary details here

Large chamber 200 litres / 25hz / pair of 6inch ports
Small chamber 60 litres / 53hz / single 6 inch port

Output with 1000w applied....

Bandpass in Green
Compared to LLT sono in red (365 litres / 15hz)

what do people think?
 

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Looks very interesting but obviously with a different application in mind, I think four would make wicked club subs with that response range, good party sub
 

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Discussion Starter #5
I don't really need another sub, but was asked to do something with this driver, providing the chance to have some fun.

Since sealed and ported have been done to death, I figured a 6th order bandpass would provide the appropriate novelty.

With plenty of movies mixed with peak LFE around 30hz (to cater to the HTIB crowd I guess), the design should give a bit more slam than the traditional HT sub.

It should also work well for parties / disco etc.

Size is about the same as a sono (ie big), but that might not bother everyone.

I'll take plenty of photos and publish the panel sizes to make it easier for anyone who wishes to share in the madness.
 

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Discussion Starter #7
I was planning on a DIY filter.

In the past, I've built this Linkwitz-Riley 4th order high pass filter....

Frequency = 1/(2 * pi * R * C * sqr(2))
For our needs R=21K C=0.33uF should yield 16Hz
For other frequencies, use this calculator


Since a 2nd order is sufficient, I'll leave out one of the two stages. This is simple enough to make up on Veroboard.

For the power supply, I'll use a plugpak and Rod Elliot's Power Supply Project

What all of us would give for a simple commercial hipass for around $30 - $50 eh?
 

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Since we're on the discussion of more exotic enclosures.. Ever thought about an Aperiodic Bi-Chamber, or “ABC” Enclosure?

http://archive2.avsforum.com/avs-vb/showthread.php?t=735976

Apparently there is an alpha build of WinISD floating around that supports ABC designing.

From my post on AVSForum regarding ABC's:

To introduce the concept, An Aperiodic Bi-Chamber, or “ABC” enclosure has two chambers: a large chamber that is two-thirds of the entire net volume and houses the driver(s), and a smaller chamber that is one-third the total volume. The design uses three ports – all the same cross-sectional area and length – one venting each chamber and one connecting the two chambers. According to the Subwoofer DIY Page for “Dual-chamber Ported Systems” (http://www.diysubwoofers.org/prt/dual_chamber.htm): “The primary advantage of the [ABC] system over a simple ported system using the same driver is a further reduction in driver excursion, caused by the addition of a second port resonance within the passband of the system.” Besides being more efficient than a simple ported enclosure the other major advantage of an ABC enclosure is that you have two tuning frequencies.

As most of us already know Home Theater subwoofers lend itself to a lower tuned frequency 15 – 25hz where as musical subwoofers are better tuned higher around 29 – 40hz. With a dual tuned ABC enclosure you can get the best of both worlds having it dual tuned for both Home Theater and Music.

 

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Collo now that the drivers are down under is there any time frame for the build? Can we expect pictures soon? Or is it still in the planing stages?
 

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Discussion Starter #11 (Edited)
Still in the planning stages - things move slowly at Castle Collo!

I did however spend the day doing a fully detailed cutting list, which has been added to my site, (linked to earlier) so now I can order the sheets. The list is designed to be printed out to make construction easier.

Here's a sample....



Myn... I checked out the ABC design you linked to. Yes, I did wade through all those pages. The gems seem to be on pages 13 and 17 (at the moment). It appears that the design doesn't give more output down low than a conventional ported box of the same overall size. I like that the 6th order box can have each chamber tuned individually... maybe some other time for the ABC box!
 

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Discussion Starter #13
I remember reading somewhere that bandpass boxes took a bit of work. They weren't kidding!

 

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Nice work, Bill. :T
You can say that again, looking very good :T Im really interested to see how this turns out, bandpass boxes are interesting but on the fringe when compaired with ported and sealed designs

As far as im aware the advantage of bandpass is higher sensitivity in the band its designed to reproduce with the disadvantage of high group delay and size

Keep those construction photos coming, im sure you have more than that.... :waiting:
 

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How are you planing on getting to the driver when its finished in case it needs to be replaced etc? Looking very good and not as large as i thought it might be, interested to see completed photos and also Graphs

Good work collo
 

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Discussion Starter #18
There will be a door in the back panel


similar to this design...


It will be tight, but I'm fairly sure the driver can be installed by tilting it on an angle. If not, the door will get re-designed..:bigsmile:
 

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There will be a door in the back panel

It will be tight, but I'm fairly sure the driver can be installed by tilting it on an angle. If not, the door will get re-designed..:bigsmile:
Nice work.

You know the saying: "Better safe than sorry" ...I think is better to re-design the door right now before you do the finish job; maybe you can make one that it can be removed completely :huh:

EDIT: after looking at the picture, I think you're right ...maybe just using a bigger door to have enough space to avoid tilting the sub (I'm sure is heavy and you want to avoid any damage when moving, Right????)
 

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Discussion Starter #20
We can all sleep easy. I checked, and the driver fits through the hole OK.

 
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