Altec 828 horn flare without a rear enclosure

[jocelys1]

Hi,

Could we design an Altec OB (sort off, for want of a better word), with the speaker basket sealed off like the Klangfilm Bionor, shown here.

What does this sealed off rear do ? Is it similar to an aperiodic enclosure ? GM (who else) has explained this in a post on diyaudio here, but I didn't understand it.

Quoted from diyaudio.com:

Right, damping the vent is for fine tuning the cab, damping the driver is required to make it ~aperiodic and to do that requires the cab be tuned above Fs since adding stuffing lowers Fb, so tuning to ~Fs/Qts with a cab Vb = ~sealed max flat and stuffed with 1-1.5 lbs ft^3 fiberglass acoustic insulation works well, ergo as Vb rises above this point the vent area rapidly increases to where it becomes baffle size and why either using a stuffed to suit open back cab or just a flat baffle with insulation stapled loosely over the back of the driver has historically been the DIYer's default aperiodic alignment.


Will this work for a 416 or 515, used with the 828 flare ? Will it reduce excursion, which seems to be the main problem in an Altec OB ?

thanks,
Sunil