Hey out there...
I'm just finishing some refitted cabinets that mimic the L65, but for LF use the LE14A, 8-ohm, with foam surround mounted to front of cone (well, some LE14's just do that...).
Much of the info about this little small format projectwas on the misbehaving Thread that Don quarantined due to it containing near pornographic JBL lore
, and it has not yet been restored, so...
The cabinet is an old Altec ModelNine, gutted, with new baffle fitted for LE14A, LE5-9 and 075 or 077. Approx. 3.22 cuft. Box is completely lined with 1-in batting (not on baffle back).
I've tested three different ports. The old JBL plans for this size cabinet and the LE14A+LE20 calls for 4-in diam 3-in duct. One of Giskards old posts elsewhere called for a 8-in duct. Considering the "virtual volume" added by the batting might take these little suckers closer to effective 4 cuft - looking at the chart Giskard posted a few days back (not yet restored, same-same) a 4 cuft cabinet calls for a 2.5-in duct.
Of the three (er four, = no duct):
1) my wifey likes no duct, but to me that is a bit boomy and I worry about LF phasing/cancelling. Valid concern, or was the original L100 ductless port right...?
2) 2.5-in sounds good, better than..
3) 3-in, which sounds better than...
4) 8-in which seems a bit muted LF.
¿How do I test the Fb of the cabinet empirically, removing subjectivity (which will, of course be add-back, later...
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