bass guitar DIY speaker

Discussion in 'Archived Threads 2001-2004' started by Brian Womble, Nov 28, 2001.

  1. Brian Womble

    Brian Womble Extra

    Aug 25, 2001
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    Hi, I am want to attempt to make a bass guitar speaker. i have decided on a driver: the Eminence Kappa-15LF.
    Impedance- 8 ohm
    Power Rating- 400W rms
    Resonance- 39Hz
    Usable Frequency Range- 35Hz - 3kHz
    Average Sensitivity- 1W @ 1m 101 dB
    Magnet Weight- 95oz.
    Gap Height- 0.375", 9.52mm
    Voice Coil Diameter- 3", 76.2mm
    Thiele-Small Parameters:
    Resonant Frequency 39Hz
    Impedance (RE) 5.4 ohm
    Coil Inductance (Le) 1.27 mH
    Electromagnetic Q (Qes) 0.41
    Mechanical Q (Qms) 6.08
    Total Q (Qts) 0.38
    Compliance Equivalent Volume (Vas) 159 liters 5.6 cu.ft
    Peak Diaphragm Displacement Volume (Vd) 471cc
    Mechanical Compliance of suspension (Cms) 0.15mm/N
    BL Product (BL) 18.6 T-M
    Diaphragm Mass inc. Airload (Mms) 105 grams
    Equiv. Resistance of mech. suspension loss(Rms).28N*sec/N
    Efficiency Bandwidth Product (EBP) 97
    Voice Coil Overhang (Xmax) 5.5mm
    Surface Area of Cone (Sd) 856.3cm2
    Impedance at Resonance (Zmax) 86 ohm
    the question i have is sealed or vented??? the box can be 3 cu. ft. MAX. if it is sealed, do i stuff it, what does stuffing the box do? I want solid extension to 40Hz, lower is better but i can EQ some at 33Hz. my amp is rated 100 watts RMS. thanks in advance!!!
  2. KevinP

    KevinP Auditioning

    Jan 11, 2000
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    The Kappa 15LF will do best in a 4.6cuft ported enclosure tuned to 42hz. This will give you flat response down to about 72hz and a 3db down point of 42hz. The low E on your bass is centered at 41.203 hz so this setup would be ok but that 3db down would require twice as many watts to be as loud as one octave up. Got a five string you say? That low B is down at 30.868 hz. This setup would be 12.4 db down, AND would be below the tuning of the enclosure. Below tuning your speaker is unloaded by the box, meaning it might as well be sitting on a table flapping in the breeze, VERY easy to damage with that 33hz eq you spoke of. In the 3cube max sealed response will be down MUCH sooner, flat to about 300hz 3db down at 75hz. Low E, -9.7db, low B -15.
    Now, this all is not to say that this speaker would not sound good to you as a low frequency (you must use something on the highs) bass guitar speaker, just that by hi-fi standards it probably would not.
    Check out Winisd @ this program will get you used to what happens to a speakers frequency response in different boxes. (the Kappa 15LF is in its database) Its not the last word in box design programs but its a GREAT starting point.
    Hope this all helps,
  3. jeff lam

    jeff lam Screenwriter

    Jun 4, 2001
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    San Jose, CA
    Real Name:
    Jeff Lam
    Good to see there are several other bass players also around here. I personally have an SWR 15" combo and it's great!
  4. Jack Gilvey

    Jack Gilvey Producer

    Mar 13, 1999
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