A Big'un - the Audio Nirvana Super 15

[Bob Brines]

Originally Posted by mondogenerator

....Couldnt you reverse eng to guesstimate, scott? Im not sure there are any secrets any longer!

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.

Bob

[Bigun]

are we sure that we even want a vent ?

[Scottmoose]

Originally Posted by Bob Brines

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

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).

[mondogenerator]

right. Ok. My mistake. Sometimes i regret writing. Anything. Lol

[Bigun]

Originally Posted by Scottmoose

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.

[GM]

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

[Bigun]

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

[planet10]

Originally Posted by Bigun

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

[GM]

Originally Posted by Bigun

Damping - adding resistive ports to the back panel could be experimented with as the back panel will be removable & replaceable

'Sounds' like a plan!

GM

[Scottmoose]

Yep, that's going to be favourite.

Originally Posted by GM

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 ).