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JBL E-140 in sealed 1X15

Discussion in 'Amps and Cabs [BG]' started by Corwin81, Apr 13, 2004.


  1. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    Has anyone ever used a E-140 in a sealed cab? I've got one coming along with a Mesa Diesel 1X15(has an EV in it). I was planning on making a cab the same size as the Diesel(to make stacking easy), but sealed for the JBL. How well would that size work?

    I'm assuming the Diesel would handle the lows while the JBL handles the punch since it'd be higher in the air. I'd be using 4 and 5 string basses although I mainly only go as low as the D note on the B string, but sometimes use the B.
     
  2. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
  3. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    I ran it through WinISD Pro.

    Firstly with a Qts of only 0.17, and an EBP of 168, this speaker is screaming to go into a vented enclosure. Ideally I'd put it into a cab that's 33 Litres (1.165cu.ft) and tune it to 66Hz. This will give you a -3db point of 88Hz.

    But if it must be sealed, put it in a cab that's 22 litres (0.777cu.ft). That'll give you a Qtc of 0.07 and a -3dB point of 130 Hz.

    Both cabs will yield good excursion results, JBL's are good like that. Both can handle their full power rating (200w) without hitting X-max and distorting. Both cabs also yield good group delay results.
     
  4. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Wow Pete, those are tiny enclosures...

    I don't even know if the E-140 would fit in a 22 litre box...you're kind of locked in to a minimum height and width due to the frame dimensions and even if you allow extra volume for the air that the speaker proper will displace, the cabinet might not be deep enough for the frame and magnet structure to fit inside...
     
  5. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    I realised that after I posted. But making the sealed enclosure larger strangled the speaker's performance.

    Say we bring it out to 40 litres, which is still pretty small but similar in size to the vented design. -3dB point is the same, but the low end roll off isn't quite as steep, so it will produce a bit more low end. But suddenly we have excursion problems. The speaker is now good for the full 200w for everything above 82Hz. It will distort at frequencies below that, which it will inevitably receive from a 4 and 5 string bass player. In the 22litre enclosure, the excursion stayed within X-max at 200w all the way down to 25Hz.

    I guess you could always put it in an enclosure shaped like an ice cream cone :)
     
  6. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    Weren't some of the 2X15 Fender Bassman and Dual Showman cabs sealed? I know some had JBL D-140s and E-140s in em. If I had the volume of one of those halved for a 1X15, would it blow the speaker if used on bass? It'd only get 50W when split with the Mesa cab.

    or if anyone has an 8 ohm EV 15L they wanna trade for it? :D
     
  7. Nightbass

    Nightbass

    May 1, 2001
    Seattle, WA
    I was composing a reply on this and said everything you just said... :)

    A couple of years ago I ran into the same problem with JBLs and BassBox Pro. The program was recommending an impossibly small box. So I talked to an engineer at Eminence about it and he told me that the low-cost box model programs fall apart at the extremes, and that Eminence and JBL have their own proprietary in-house modeling programs that deal with these drivers. He said to just ignore what BassBox, WinISD, and BoxPlot come up with and use common sense.

    The Super Bassman was about 45 x 30 x 11 and used the D-140, so you're right, if the volume of the Mesa clone is about half of that, you'll be fine. The internal volume of sealed cabs is nowhere near as critical as it is for vented cabs, and sealed cabs are more forgiving across the board.

    What I'd do is build a Mesa clone with the driver mounted at one end of the baffle, just like the original Mesa, leaving room for a couple of 4" round ports. Then if it sounds crappy you can simply cut round holes, pop in plastic ports, and tune the cab to whatever sounds best to you.

    Nightbass
     
  8. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    The volume is close, I'd just have to put a bit of insulation inside to make it think it was a tad bigger.
     
  9. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    I didn't trust WinISD either, until I took the time to learn to calculate these things manually using formulas from text books. The current Pro version certainly checks out. Even Bgavin's spreadsheet suggests very small cabs for the E140.

    Is the D140 is the same as the E140. I did a net search on it and came up blank. And it's not mentioned in the JBL's driver parameter .pdf file (which can be found Here.

    Sorry I didn't realise you wanted the cab to be about 90 litres or so. I can work, again it's better ported. But sealed can work if it's only getting 50w. -3dB at 133Hz, with a rolloff which is shallower again, a typical characteristic of enlarging the enclosure on sealed cabs. As an example, this design is -10dB at 57Hz, where the 22 litre cab was -10dB at 76.

    At 90l, it'll handle 50w right down to 37Hz, but will only handle the full 200 down to 87Hz.
     
  10. Nightbass

    Nightbass

    May 1, 2001
    Seattle, WA
    JBL told me to use the E140-8 specs for the D140F, but I'm not so sure about that. The closest thing to the D140F would actually be the 130A. The 130A has a smooth curvilinear cone like the D130, copper voice coil, and a paper dome.

    The D140F has a ribbed cone, coated surround, copper voice coil, gapped magnet, and aluminium dome.

    The 130A specs are in the JBL T-S docs.
     
  11. Andertone presented specs exactly match the JBL 130A driver in another thread here.

    Perhaps the F was just the musical instrument version of the 130A.