Cab Size

Discussion in 'Amps and Cabs [BG]' started by Jammin'John, May 17, 2005.

  1. Happy MurphDay

    Happy MurphDay

    Mar 9, 2004
    This is probably not the response your looking for, since I've never built a cab, but in most cases, if it is ported they can take more wattage and give deeper lows. And because your using 8's, *usually* the smaller the speaker, the less bass. So I'm going to take a stab and say to port the cab

    I don't know how to determine cab/port size, and I've never built a cab, so take my thoughts softly
  2. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Aside from personal practice at low volume the Beta 8 is not suitable for electric bass. To determine the optimal cabinet download the WinISD freeware at linearteam.
  3. Petebass


    Dec 22, 2002
    QLD Australia
    I wouldn't use it for bass either unless you've got a larger diameter speaker working with it to take the lows.

    The Beta 8 has an EPB of 161. Greater than 100 suggests a ported cab will work better, but this isn't a hard and fast rule. Each speaker will need about 18 litres (0.64cu.ft) and the port should be tuned to 58Hz. This will give you a -3dB point of about 85Hz. The problem is the small X-max probably won't let you get that low. The speaker's suspension will simply run out of travel and bottom out.

    The better option might be to run a crossover to keep the lows away. Do this and a sealed cab is certainly back on the cards. But only if you've got a 12 or 15 to take the lows.
  4. timinator


    May 8, 2005
    See if you can find any stats on what SWR puts into their 8x8 cab. I know it's a lot different than what you're building, but that thing smokes and I tried out an Ampeg 4x8 a few years back that was cool, too.
  5. The xmax is 3 mm....I thought that is a lot

    36.348 cm high 58.812w 22.463d
    dual ports 7.62 dia. 12.763 long

    I want to use 2 of 'em on top of a 1x15 cab no crossover

    Bad idea...........?

    Would a small sealed box control cone excursion ?

    Is a crossover necessary ?

    It says Performance optimized
    for midrange use between
    400 Hz and 4kHz in multi-way
    systems. Also suitable for
    vocal P.A., keyboards, club
    systems, stage monitors,
    and bass guitar.

    I just wanted a simple small box to put on top of a 15" :D

    A delta 12 only has an xmax of 1.6 and is used for bass.
    Even a delta 15 ....................2.7............................
    This little 8 has an xmax of 3.............
    Do I have to get a 2x10 ? :crying:
  6. Masher88

    Masher88 Believe in absurdities and you commit atrocities

    May 7, 2005
    Cleveland, OH
    Definately Crossover!!!! :D The 8's will just bottom out trying to produce lows that they can't handle...that's what your 15" is for!
  7. Petebass


    Dec 22, 2002
    QLD Australia
    On top of a 15 sounds promising, but a crossover is a must for this speaker. The x-max travel is part of the equation. The other part is the suspension compliance (stiffness). A Delta 12 may only have 1.6mm x-max, but the suspsnsion is likely stiffer and therefore requires more watts before it is maxed out.

    I suggested sealed because it's easier to build and it will result in a smaller cab. The benefits of porting lie in the low frequencies, so a crossover makes porting less necessary in this instance.

    I'd go for 2x8's in a 22 litre cab (0.76cu.ft) sealed, crossed over at 400Hz. And I'd make my own crossover. It's not hard, it's cheap, it's fun, and it allows you to experiment with different crossover points.
  8. Chef

    Chef Moderator Staff Member Supporting Member

    May 23, 2004
    Columbia MO
    Staff Reviewer; Bass Gear Magazine
    So...what would be a good 8" speaker?
    I have both an swr baby blue 2x8, and an swr henry 8x8, and they both have plenty of bass. I believe both are ported...
    Low Down Sound make some killer 8" based cabs, maybe call Don and buy your drivers from him...?
  9. Petebass


    Dec 22, 2002
    QLD Australia
    Both SWR and Ampeg would have had 8" drivers made for them to their specs. Or perhaps chosen suitable 8" drivers from a manufacturers OEM catalogue. When you're talking garden variety over-the-counter speakers, 8" are very disappointing.

    The only ones I've found which "might" do the job are the Fostex FE208E, FE206E, and FF225K. Now I say "might" because I haven't done the proper math on them yet, and they all look like they're going to have X-max limitations. But nothing else I've seen even comes close.

    Out of curiosity, what are the sensitivity ratings on your 8" loaded cabs?