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The 8" speaker, and the evil machinations of my mind...

Discussion in 'Amps and Cabs [BG]' started by kalipigeon, Jun 29, 2007.

  1. So I play bass, bassVI (sorta baritone?), and guitar, and often with the same band on the same set. You can imagine the fun this has made for me in the speaker cabinet venue. I like some of the rigs I've seen with 4x10 +1x15 (or 18) for bass, and was thinking that I might be able to get away with some sort of 4x8 and 2x12 (or 2x15) setup that would let me play bass with decent roundness and still have the guitar have some sparkle when I'm using it.

    I know, I know...get a Henry 8x8, don't build one, or get 2 amps...I'm a poor student, people! Also, I like to tinker, so I wanted to try building something so I have a summer project to work on. Ok now that the intro is out of the way...I'd like to take some 8's (6's are too weak on midbass response from what I've seen) with decently high sensitivity (95-100 dB/W/m) and build a multi-purpose set of cabs for my Ashdown ABM 500 EII RC. Can anyone recommend a low cost , high efficiency driver for this use? I'm expecting to make up some bass with larger speakers in the lower cabinet, but the top cab will be 8s of some kind I think. I know 8's can do this, the new Fender cabs with 1x8 and 2x8 in them in the acoustic/jazz lines have some great bass and nice upper mids for both bass and guitar.

    Sorry for the long, meandering post, but I figured if anyone could help, it would be someone here. I'm looking at the Eminence Acoustinator 8" series for their high end sparkle, as well as their pro audio Alpha 8A or Alpha 8M-RA drivers ($44 each at MF...). Any other suggestions for efficient drivers that can handle some medium excursion at good efficiencies would be greatly appreciated.

    N.B. I'd prefer 75-150 watts per driver...want a final cab in the 400-500 range if I can.
  2. funny, i too am thinking homemade 4x8 + 2x12. i think i would run a 2x8 and a 1x12 on either side of the drummer and use seperate channels to drive each size speaker. i cant really suggest any specific drivers as, like i said, am still in the planning phase, so good luck and keep us posted!
  3. brisonic


    Jan 1, 2006
    san diego
    This sounds like a cool project with proper driver protecting crossovers. If you really want 8s, that will require a bit more scouring. May i suggest a browse through www.diyaudio.com?
  4. joelb79


    Mar 22, 2006
    Lansing, Michigan
    I would say you could get much better quality for just below building one yourself by ordering one of Don's fine 8" creations from www.lowdownsound.com

    Just my $0.02, i've thought long and hard about building my own cabs for a while but when I totaled out all the parts and the finishing supplies on top of the hours of labor to make it 100% right, it didn't make sense.
  5. TimmyP


    Nov 4, 2003
    Indianapolis, IN
    Get an Acmebass LowB2 or LowB4 cabinet with the head of your choice (I like a bridged Crown K1 driven by an Eden WP100). It will sound great with bass and acoustic. Add a processor with cabinet simulation for the electric guitar tones and you are set.
  6. frettiyeti


    Jun 30, 2007
    this is what i made.........very small very powerful....could use 10 inch forward firing for guitar......im gonna change forward driver as it lacks high end......but 450 watts per channel in a cab you can carry with one hand.....i dont know why they dont produce dual firing cabs similar to this........
  7. That's a cool design frettiyeti, does it give you noticably more volume/cut than a single driver cab the same size?

    Along those same lines, the Alpha 8M-RA drivers from eminence roll off at 400 Hz, but have a sensitivity of 100 dB/W/m which seems to be nearly unheard of in an 8. Apparently they have a closed back setup which makes them pre-tuned to maximum sensitivity at the expense of some low end. I'm wondering if I can take your "box with 2 baffles and a center divider" idea and maybe make a small chambered 4x8 that fires forward with a hidden 15" (C2515 basslite or some similar driver) in the bottom that gets most of the cabinet volume since the 8's don't need it according to Eminence. I could even wire it to have multiple jacks for 3 options of play.

    1. 8 ohm - 4x8
    2. 8 ohm - 1x15
    3. 4 ohm - all 5 drivers

    maybe add a switchable 100 W piezo tweeter for when i'm only using the 15 and it would be a powerful, lightweight cab with only slightly more volume than a 1x15 cab.

    I like how you feed my evil designs with new ideas...keep them coming please, I'm getting excited to start plotting size and materials costs.
  8. frettiyeti


    Jun 30, 2007
    yes it really adds to the vol......but they are two different tones....that is part of the fun.......running stereo amp also makes it so if you are using more sensitive speakers for mids and highs you can just adjust manually dont have to worry about attenuation resistor demons to install....also if you need an amp.......i got that one new from roaddog music for 149 bucks nib 3 yr warrenty....most charge 399 for same amp....it was 269 minus a 120 rebate again im a poor bastard so this allowed me to make a new cab with out having to feed the cat to the dog...peace
  9. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    The problem with using car audio subwoofers is that they are too sub-bass oriented, have too little midrange and are too insensitive. If you want to get to band level SPL you need a lot of car audio subwoofers and a lot of power. Better off to use a more efficient pro audio woofer which requires a greater cabinet volume to operate efficiently in the low register.

    Maximum sensitivity and absolutely ZERO low end! The MR in Alpha 8MR stands for midrange and thus must be crossed over at no lower than 500Hz with a 2nd order filter.

    You won't need more than one of the Alpha 8MRs, though two vertically aligned wouldn't hurt. Do NOT use four in 2x2 configuration because that is far more sensitivity and midrange power handling than you need or want and side by side drivers cause comb filtering (basically poor off-axis response).

    I wouldn't use a single piezo tweeter due to the poor power handling and sensitivity but a short array of piezos can be very effective.

    Using a 15" woofer plus an 8" midrange is a good combination. To make the cab sufficiently sensitive you need to give the 15" a lot of cabinet volume. The Alpha 8MRs don't need a subenclosure because they're closed back. I would strongly recommend checking out this design, it is absolutely ingenious and ticks all your boxes:


  10. Thunder Pulse

    Thunder Pulse

    May 12, 2007
    Link? Nothing relevant comes up in a quick Google search
  11. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

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