'Custom' in that during my most active DIY speaker years from '56 - '89 I learned that sealed often didn't work all that well down low in most homes/apartments in my locale [greater metro Atlanta], so experimentally found a vented tuning that worked much better overall using basic TL/horn design theory.
For the record, TTBOMK, Don Keele's is the original T/S theory EBS: [Thiele #9.5]: Vb = 2.6*Vas, Fb = 0.52*Fs, 0.625 Qts': [Qts] + any added series resistance [Rs]: http://www.mh-audio.nl/Calculators/newqts.html
No, sealed is just a pressure vessel, so it's strictly for vented alignments and didn't mean for you to literally try his math [or 'my' Altec X-Bass that I'd long since forgotten about posting], just the 'shelf' concept as my customs requires you to learn about mass loaded [vented] TL, horn design to do them.
That said, with such a low Qts, the basic vented concept should work in your app.
Regardless, without knowing any room dimensions, floor plan with speaker, listening positions, basic building structure details, etc., can't really recommend any ~ optimum sealed alignments other than making it with an over damped ~0.4 Qtc' since the room tends to increase it and provide access to reduce its net Vb if required to change the Fc:Qtc ratio.
For the record, TTBOMK, Don Keele's is the original T/S theory EBS: [Thiele #9.5]: Vb = 2.6*Vas, Fb = 0.52*Fs, 0.625 Qts': [Qts] + any added series resistance [Rs]: http://www.mh-audio.nl/Calculators/newqts.html
No, sealed is just a pressure vessel, so it's strictly for vented alignments and didn't mean for you to literally try his math [or 'my' Altec X-Bass that I'd long since forgotten about posting], just the 'shelf' concept as my customs requires you to learn about mass loaded [vented] TL, horn design to do them.
That said, with such a low Qts, the basic vented concept should work in your app.
Regardless, without knowing any room dimensions, floor plan with speaker, listening positions, basic building structure details, etc., can't really recommend any ~ optimum sealed alignments other than making it with an over damped ~0.4 Qtc' since the room tends to increase it and provide access to reduce its net Vb if required to change the Fc:Qtc ratio.