A Big'un - the Audio Nirvana Super 15

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I decided it was time to open a thread to capture my experiences with this driver and the box I'm going to make for it.

It's a big driver. Until you have one in your hands, it's hard to imagine.

More about the driver here
Edit: the ferrite version is no longer available, I recommend the Super 12” Ferrite as the affordable alternative to the 15” Alnico. Also, I wouldn’t go smaller than 10”, where the Super 10 Alnico is my recommendation as the preferred option for a vented box design enclosure when smaller size is a priority.


Edit: this design eventually became an open back box with a light level of stuffing behind the driver. It's not an open baffle dipole in the traditional sense because the highs are mostly radiated from the front whizzer cone and the stuffing absorbs these frequencies behind the driver. The bass however is able to radiate backwards from what is essentially a U-frame, perhaps tending towards cardioid.
 

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A big driver deserves a big box. I requested plans for the 13.6 cu.ft. enclosure from the Common Sense Audio.

There will be no supporting woofers or tweeters, nothing other than a wire between the amplifier and the driver.

This is the real deal, a single full-range driver.

Sitting on the floor the driver has been gently breaking in and it sounds very promising.
 
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big one

Me too. I note the 1 mm xmax and go directly to my ancestry (AR, TL) and hope for the best on the bottom end...could be great! Chances are the 17mm Matsushita Philcos I enjoy so much in my basement have about that much, or little, xmax. Big boxes. Make them kiosks for art, visual that is. Bigger is better they say. And sit in the middle.
 
I think that Scott was referring to what the designer specified as opposed to what is really required. At least that would be my question.

You read my mind Bob :D

are we sure that we even want a vent ?

It depends what you mean by 'vent' but assuming you are talking about a hole in the box (irrespective of whether it has a duct or tube attached), and again assuming the published data is representative, I would say almost certainly not, unless it's tuned so low that it provides zero useful output. The cabinet is too small to be vented (at least, under the further assumption that a reasonably accurate response is desired).
 
I would say almost certainly not
exactly.

Looking at the AN15, the published Fs is already low enough, no need for a resonant port to extend it lower. And I already ruled out adding a 2nd driver, which a tuned port becomes, albeit with a mechanical cross-over.
 
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What?! No ~aperiodic vent to 'tighten up' this under-damped alignment? Also, FWIW, the pioneers of audio determined that from an acoustical loading POV of point source drivers that the cab's net Vb should be whatever raised its Fs 1.56x, be it sealed or vented, or ~15.15 ft^3 based on the published spec. No clue whether there's any audible difference between 13.6 and 15.15 though. My SWAG is it would be very room, signal source dependent.

GM
 
My local store stocks Baltic Birch in 2' x 4' sheets. With almost no cutting this makes for a Vb of 16 cu.ft. - less volume of the panels, the driver, and bracing. It's probably going to end up closer to the 13.6 than 15 but I figured this still allows an Fc around high 30's which is just fine.

Damping - adding resistive ports to the back panel could be experimented with as the back panel will be removable & replaceable
 
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frugal-phile™
Joined 2001
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are we sure that we even want a vent ?

I did the 1st pass on an An-Ken for the 15, constrained by the wxd restraints posted by an interested party and they would have needed to be 3m tall. Set that aside for now.

Thinking of a practical box that isn't an OB (which i have never been enamoured of), i was figuring a couple hundred litre, box damped like a boffle with a swiss cheese back (you need a back to make the box structurally strong).

dave
 
Yep, that's going to be favourite. :)

What?! No ~aperiodic vent to 'tighten up' this under-damped alignment? Also, FWIW, the pioneers of audio determined that from an acoustical loading POV of point source drivers that the cab's net Vb should be whatever raised its Fs 1.56x, be it sealed or vented, or ~15.15 ft^3 based on the published spec. No clue whether there's any audible difference between 13.6 and 15.15 though. My SWAG is it would be very room, signal source dependent.

GM

+1. Since the CSA plans were mentioned, I was largely just dreading they were going to be run as a BR (since their record isn't great when it comes to box alignments ;) ).
 
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