Bass Cabinet Build

Discussion in 'Amps and Cabs [BG]' started by KJP1990, Feb 1, 2014.

  1. KJP1990


    Jan 23, 2013
    Hey Low-end heads,

    I am contacting you guys about a bass cabinet I am going to be building within the next month or so. I bought an Ampeg PF500 head that I plan to pair with a single cab (to start). I am well aware of the mixed reception of this head but have also been reading a lot about how the problems have been sorted out on Ampeg's side which was good enough for me to believe in the great bass amp makers.

    Now to the niddy-griddy, I have some plans to kinda copy the PF115 head that Ampeg makes that usually gets pair with this cab (in pictures). I am going to use a 15" 4 ohm speaker Eminence Kappa ProLFC 600W speaker instead of a 450W one that is used in the PF115. Is this a good idea with no driver speaker. I play in a 90's cover band ranging from Tool to No Doubt and I need to cover a good amount of bases (basses?) of tone range.

    My bass is an Ibanez SR370 with an active EQ that I fiddle with to dial in the tone I want..

    and if you're still reading (Sorry for the Wall of Text) here is a link to the guitar cab I built in the spring, the bass cab of course will be different port wise and interior wise:
  2. Link to Kappa Pro 15LFC Datasheet

    For starters, this is a 4 ohm driver.
    With most amps, this is the lowest impedance they will support.
    This appears to apply to the PF500 as well.

    You will not be able to use a 2nd cab.

    A single 15" is probably not going to be enough noise for your requirements.
    If you examine the response chart, you will see it is good to about 1500 Hz before a very steep roll off.

    IMO, skip the 4 ohm driver, and use the 8-ohm equivalent, so you can add a 2nd cab.
    Please observe the Chart for the Kappa Pro 15LF2 is the same response level at 1w input power.
    There is nothing to be gained, and much to lose, by choosing the 4-ohm driver.
  3. KJP1990


    Jan 23, 2013
    If I use the 8ohm speaker doesnt that knock the wattage of the amp down to 350? I could add a tweeter to bring the watts up to 500 I am worried about blowng it out..
  4. 1n3


    Sep 13, 2007
    KJP1990 -

    Your gearpage link doesn't work.

    The Kappa Pro 15LFC is not a full-range speaker. You probably wouldn't like the sound.

    Watts are not the most important speaker spec, and running at minimum amp impedance is not always the best option.

    Adding a tweeter won't make the cab impedance 4 ohms, unless you put it in parallel with a woofer without a crossover or high-pass filter (don't).

    Frankly, it doesn't sound like you're ready to design a cabinet. Suggest you study more, or use a proven design.
  5. Bemis


    Apr 28, 2013
  6. edpal

    edpal Banned

    Oct 3, 2007
    I agree with all commenters above - go with the 8 ohm speaker, not the 4. Better to have headroom or safety on your speaker than to red-line the speaker just to squeeze out those extra watts. And not to dismiss the joy of DIY, but since you aren't building anything new or exotic your time and money might be better spent buying one that is built.

    Two 4 ohm loads in parallel would give you a 2 ohm load. In series would give you 8. But yeah, bad idea.
  7. KJP1990


    Jan 23, 2013
    I understand series and parallel but bass cabinets are very different than guitar cabinets as far as filling them goes..

    I was only looking for advice on what to fill it with not the design.. There are plenty of designs both on line and stuff I can go and test out and see what is inside other cabs.

    I am looking to go for something portable to begin with. I don't want to be bringing around a 4X10 or something bulky..
  8. makohund


    Dec 12, 2002
    Yes, very. Step one is dismiss the notion of "filling a cab" with speakers.

    You can get away with that for guitar, but not bass.

    First choose your goals. Then design "type" (ported, sealed, horn, etc).
    Then the speakers that should get you there. THEN design a cabinet specifically for those speakers.

    A long way around would be to start with a finished cab (or design). Then using the specs of that cab, choose speakers that would match the cab to get what you want.

    So... are you asking whether that particular driver would be a good choice to design/build a single 15" cab for, or are you asking whether it would be a good replacement for the stock speaker in a PF115 (of which you intend to build a clone)?

    Although either way, the answer to both so far is "no" (based on impedence and frequency range).
  9. 1n3


    Sep 13, 2007
    Thanks. Looks like KJP1990 has the equipment and manual skills... a very good start.

    He mentioned bringing an 8 ohm speaker up to 500w with a tweeter. I made an assumption.
  10. edpal

    edpal Banned

    Oct 3, 2007
    Sorry, didn't mean to pound you on the ohms... you were completely right that it wasn't a very workable way to get what he wanted.
  11. Stumbo

    Stumbo Wherever you go, there you are.

    I suggest you go with the 8 ohm speaker and when you add the second 8 ohm cab, you'll get your 4 ohms total. Win-Win. Modular rig for small or large venues.

    +1 to picking a speaker then designing cab to optimize speaker function. WinISD is free cab design software. If your nice, lots of TB speaker/cab gurus will help you out. :)

    I also think you should take a look at fdeck's hpf/pre v.III. It'll protect the lowend of your speakers and give you a tighter sound.

    Post some pics/audio/video when you're done.:cool:
  12. KJP1990


    Jan 23, 2013

    Im looking for assistance in choosing a speaker for a ported cab much like the PF115. Or assistance in a different design all together as far as speaker arrangement. I am totally open to all ideas it just needs to be loud and portable. I built that 2X12 pictured in my original post (I fixed the link) bassed an older Mesa caninet my friend had. My dad and I are well prepared and skilled wood workers and craftsmen. I am just not as well versed in bass because it's my second instrument to guitar.

    So the meat of that is I am looking to build a bottom ported. An like the PF115 or something different but just as portable. I don't have the wood or the desire for multiple cabs though.
  13. So, loud, portable, ported, can handle some power, DIY. And, you're having some problems with designing. OK. Then, how about some designs that are portable (light), shelf ported, about 700 watts, plans are free, and all of the design work, and testing, and tweaking have already been done for you. They are called fEARful!
  14. KJP1990


    Jan 23, 2013
    I am looking at the fEARful stuff and this is EXACTLY what I was looking for. They even help you with what type of speakers to choose to put in them and how to wire them up (I already understood the wiring but this will make it fool proof).

    Are there any comparable speakers to the Kappalite 3012? That is a little expensive, part of the reason I am building instead of buying is cost savings..

    Now I just need help deciding what sizes to go with. Do any of you have a preference or experience with 12+6 cube, 12+6, or the 15+6 cabinets?

  15. The cab is designed around specific speakers. Using a different (cheaper) speaker would require a re-design, and would not have the same level of performance.
  16. KJP1990


    Jan 23, 2013
    Hmm.. How much of a redesign and I think it's a little silly that you can't use a different speaker with similar sound properties in any of those cabinets.. Isn't each one going to be a little different due to the builder?
  17. popcorn.
  18. makohund


    Dec 12, 2002
    Ah, ok then. Much easier question to answer. :)

    Fearful owner here, yeah they are loud low and portable. But they aren't inexpensive, and while they can get there with eq, they are far from a portaflex clone tonally without it. (Think agressive full PA with subs.) From that lineup I'd recommend a 12/6/1 with the alpha mid... for your budget & portability needs. Should keep up with most single 15s in a smaller footprint and happens to be the least expensive build.

    But if you are really after portaflex tone with no shaping besides a portaflex head, a Bassic 15 might be more your speed. Not a DIY design, though. Either buy one, or build a similarish cab of your own design. Or maybe a classic TL 606, altered for lighter build (1/2 inch ply) and a non-lf emi 3015 or faital in it.

    Note that if designing your own, there is homework to be done first. Study some other design/build threads, get some software to crunch the numbers (T/S parameters, volume, porting, etc), and so on.

    Best of luck. :)
  19. makohund


    Dec 12, 2002
    Like I said, for bass it is very important that a cab is designed for specific speakers, or vice versa. Ignoring that will lead to poor performance, and be a waste of time money & effort. It's not a guitar cab, you can't just stuff good sounding speakers in a box. Well, you can, but odds are the results will suck, even if using the best speakers on the planet.

    The performance requirements for reproducing bass and doing it well are a completely different universe. The interaction between the speakers and the box (air volume, port size/length, tuning), particularly in lower frequency ranges, are huge. For guitar they are relatively inconsequential.