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Best neodymium 15" replacement?

Discussion in 'Amps and Cabs [BG]' started by basss, Nov 29, 2003.


  1. basss

    basss

    Aug 27, 2001
    NYC
    I'm looking for a 15" driver with a neodymium magnet for a cab I'm putting together. The cab is about 3 cubic feet with 2 3" round ports. I would like it to function as a stand alone in a box with a tweeter. I have found these on the web.
    P.audio sn15 b
    P.audio sn15mb
    B&C 15hpl76
    B&C 15hpl76w
    Eminence Deltalite 2515
    Would any of these work well for bass? Any other suggestions? Thanks
     
  2. First, rule out the Eminence 2515 entirely. This is a junk driver compared to the others, and it requires an enormous amount of cabinet volume for both vented and sealed boxes. Totally useless for electric bass, IMO. This driver is only useful for a PA system or other non-bass application.

    The two PAudio drivers require smaller cabinet volumes of 1.8 cubic feet or less. Except for the SBB4 alignment, they tune far too high. Even in SBB4, they begin to roll off above 100 Hz.

    This leaves B&C as the best choice. The decision is efficiency vs low frequency extension, a classic case. The "W" driver is -3dB less efficient, has more bottom, and requires a larger cabinet. To fit your existing cabinet, the non-W model (15HPL76) requires 2.5 cubic feet tuned at 39 Hz, with an F3 of 74 Hz. Sensitivity calculates at 97.6 dB, not at all bad for a 15" driver.

    If you are not constrained to using Neo drivers, there is a wide range of 15" drivers to choose from. You need to calculate the exact internal volume of your cabinet. Then deduct about 0.2 cubic feet for the driver displacment. If there is bracing, deduct its volume also. Sort my spread sheet by driver size (15") and cabinet volume until you find a match for your existing cabinet. You will have to spend time correctly tuning the cabinet. Guessing is not an option here.
     
  3. I'm not so sure I would be looking at a neodenium spkr.A good friend of mine works for a music store that sell ampeg and he was told the neodenium speaker deteriorates much quicker than a standard speaker.The magnet is lighter and doesn't take the heat very well.Take it for what it's worth.
     
  4. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    pfffftt. That's just means that Ampegs's neo's are crap. I know lots of people using neo's for both Bass and PA applications, including myself, and we ALL think that everyone should use em....

    I looked into those P.Audio neo 15's after using the 10's with success in a mid/high cab. Bgavins right, they're better suited as PA drivers than bass drivers. They don't go low at all.

    B&C are excellent. Every cab I've heard with B&C components in it has impressed me no end. Epifani Ultralights use B & C, though not the same ones available over the counter.

    Quesion - is this driver going to be used as a replecement speaker for an existing cabinet? Or do you intend building a cabinet from scratch?
     
  5. basss

    basss

    Aug 27, 2001
    NYC
    bgavin-
    Thanks! Thats exactly the info I was looking for. I will check out the B&C driver.
    Petebass-
    It's for an old cab that I am rejuvinating- its already built.
    Do you guys know where to buy B&C drivers? Also what is a good choice for a tweeter?
     
  6. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    What are the dimensions of the cab?

    I just want to make sure that B&C neo's will work in that size cab?
     
  7. basss

    basss

    Aug 27, 2001
    NYC
    Cool, thanks! The internal dimensions are 18 x 18.25 x 13.25.
     
  8. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    That's about 63 litres. That's small for a 15.

    Of the 2 B&C neo's the HPL 76 would work better in that cab BUT it's -3dB at 74Hz. That's not all that low for a 15.

    The HPL 76W goes deeper (-3dB at 42Hz ) but it needs a cab that is 118 litres, roughly double the size of you cab.

    What speaker was in it before?
     
  9. basss

    basss

    Aug 27, 2001
    NYC
    I don't know- it was an unmarked speaker with a ripped cone. The cabinet is sound and looks well constructed.
    I think I read in another post that you can stuff the cab with fiber filler and effectively increase the volume by 30%. Is this something I would want to try for this situation?
     
  10. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    I ran a bit of a simuulation for the HPL 76 driver through WINisd pro.

    Stuffing the cab will effectively bring the cab size out to 81 litres, so that's what I used. I found that by tuning the cabinet to 54Hz, it produced a relatively flat frequency response that was -3dB at 55Hz, Group delay peaks at that frequency too and is an acceptable 10ms. This cab won't fit into the design criteria of any of the established allignments but hey, it seems to work in theory.

    That's much better than -3dB at 74Hz, but it's still going to be a "Punchy" 15 rather than a swampy/warm one. Is that what you're after?

    Just bear in mind that it will be possible to bring this speaker to it's excursion limit, by feeding it frequencies below 54Hz when driven hard. For reference, your low E has a fundamental of 41Hz, A string is 55Hz. Lots of commercially available cabs have this same problem........
     
  11. basss

    basss

    Aug 27, 2001
    NYC
    Couple questions-
    What would happen if I lowered the tuning frequency? Could I play lower frequencies before reaching the excursion limit? What would I be loosing if I did this? I play 5 string so I'm a little concerned about this.
     
  12. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Your 5th string has a fundamental of 31 Hz. The above calcs create a box which is -18dB at 31 Hz.

    If I change the tuning frequency to 31 Hz, we are now -12dB at 31Hz which is better, and excursion limits will be harder to reach. However, the cab is now -3dB at 80Hz. So all that's happened is the cab starts to loose bottom end sooner but at a softer slope.

    I'm trying, but it's looking to me like you may have to consider other non-neo drivers at this stage. Sorry if that's not what you wanted to hear.
     
  13. This is why one has to look at the entire picture when choosing a driver. The Deltalite 2515 has an awfully short Xmax, plus it requires huge cabinet volumes. Not acceptable on several fronts.

    My spread sheet has a column labeled FPX. This stands for Full Power Xmax, and has a "Y" in the column if the driver will accept full rated power without exceeding Xmax. Most of the JBL meet this requirement.

    Take a long look at the Selenium 15SW1P, as it meets a whole lot of requirements, including FPX, makes a lot of noise, small cabinet, good tuning, reasonable F3 in both SBB4 and QB3. In short, a 1st Class driver.
     
  14. bben

    bben

    Feb 28, 2002
    Santa Fe, NM
    I don't have any specific suggestions, but the task of trying to back-fit a new driver into an existing cab is almost always dodgy, as the well-informed discussion here points out. And looking for neo really limits the choices.

    If I had a cab that size and were determined to stuff it I would consider a 12" driver. I think part of the reason for the resurgence in 12" cabs is that they work pretty well with a low B string in a reasonable size cab, unlike many 15" cabs and/or drivers.

    In the long run, personally I believe in picking the driver first, and building a cab to fit it, not the other way round.