boputnam
09-06-2003, 05:25 PM
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 project ;) was on the misbehaving Thread that Don quarantined due to it containing near pornographic JBL lore :eek:, 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... ;) )?
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 project ;) was on the misbehaving Thread that Don quarantined due to it containing near pornographic JBL lore :eek:, 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... ;) )?