Can Somebody Help Me Design a Cab? Please :)

Discussion in 'Amps and Cabs [BG]' started by deadinameadow, Jun 17, 2018.

  1. I've recently ordered an Eminence Kappa 15LFA driver and i would like to build a cabinet that is perfect for this speaker, only i don't understand any of this haha.

    I've been looking at graphs and numbers and things that i really dont understand because I am new to this.

    I am going to buy a 4x10 cabinet one of these days (hopefully very soon) and this single 15 is going to be paired to it. I also am looking into a 500w head (anybody have experience with the Ampeg Portaflex 500?;)) I've never built anything before lol WINISD is all gibberish to me

    The most confusing part is the HPF that Eminence says must be used with it, what does this even do for me?:roflmao:

    I know that there's a lot of experienced people on here so thank you to anyone who can help:bassist:

    This link contains ALL the information on this speaker: "Eminence Kappa-15LFA 15" Low Frequency Driver 8 Ohm" from!
    Pbassmanca likes this.
  2. mmbongo

    mmbongo Regular Human Bartender Supporting Member

    Aug 5, 2009
    Jeez man, I'm going to try not to be negative here..but jeeez. I'm not sure where to start! You've never built anything before, and you don't understand frequency graphs, tunings, or HP filters. So not only do you need to learn carpentry, you also need to learn acoustic engineering.

    PLUS, a 4x10 is a very poor match with a 1x15. That just does not work well.

    Just how dead set are you on building something yourself?
  3. Lol I mainly bought the speaker as a replacement on my vintage 2x15, not realizing it might not sound good. I don't have it yet, so I'm not necessarily set on anything yet
    Pbassmanca likes this.
  4. mmbongo

    mmbongo Regular Human Bartender Supporting Member

    Aug 5, 2009
    Well the biggest hindrance is the carpentry part....when you say you've never built anything do you mean that literally or you've just never built a speaker box before?
  5. Very little experience, but recently graduated so some math is fresh in my head lol
    funkinbottom likes this.
  6. buldog5151bass

    buldog5151bass Kibble, milkbones, and P Basses. And redheads.

    Oct 22, 2003
    With all due respect, you don't know carpentry, you don't know acoustics. If you want to build something, build a fEARful flatpack to start.
  7. I've considered this also, my only problem there is that those cabs are designed for those speakers. Would I need to modify the fearful to be more specific to this speaker?
    I have friends and family also with varying levels of experience that I can have help me. Along with the local luthiers and music stores.
  8. buldog5151bass

    buldog5151bass Kibble, milkbones, and P Basses. And redheads.

    Oct 22, 2003
    Building a bass cabinet is a lot more than building a box and cutting a hole for a driver. It is designed for the driver(s) and tuned for the desired sound. With no experience and not understanding what you are doing, the odds of being happy is pretty slight. You are better off returning that driver.
  9. You're not wrong by any stretch, but a workable solution is absolutely doable even to a newcomer. Half of getting everything done is convincing yourself that you can do it. You're not helping this guy out by telling him he's made crap decisions. Let them get messy, take chances, and make mistakes.

    OP, flowery talk aside, you've recognized you've made a rash decision with regards to the kappa15lfa. If it hasn't shipped yet, maybe try seeing if you can cancel the order or if you can ship it back - call them in the morning. If you're out of luck, at least you tried.

    But here's the good news - you maymget the chance to learn some carpentry AND get your feet wet with amateur speaker design. Luckily, eminence publishes recommended cabinet designs for their drivers, this one is no different. That'll give you realistic looks at a few different basic designs, find one that might look good to you. From there, it's a bit of math to get a cabinet with a form factor that matches your needs and the internal volume that the driver needs. From there, you learn the carpentry - and I hope you either have tools or know a guy who does, because that can be another money problem, and look into different materials - MDF is cheap, but heavy as all get out, everybody here recommends half inch plywood, the good void free stuff - but that has a premium attached to it. This is all a very cursory glance, and unfortunately I'm hitting the field for the next two weeks.

    For now, though, shoot the guys you bought the speaker from an email, and call customer service first thing in the morning and see if you can cancel the order. If not, start looking this stuff up on Google and searching threads on TB. You'll get so much information you'll get confused, and then you'll think it makes sense, just remember - you CAN get through this, just put everything into tiny steps and go from there. The results won't be like what agedhorse or greenboy could do, bit there's no reason you can't make one that works decently with a good bit of reading and some decent tools.
    Brad Johnson, AstroSonic, G-Z and 3 others like this.
  10. buldog5151bass

    buldog5151bass Kibble, milkbones, and P Basses. And redheads.

    Oct 22, 2003
    I applaud OP for trying it, but I wouldn't advise someone who has never driven a car to go out and drive 75mph on the interstate.
  11. I'm trying to return before it ships, I was initially going for the Beta 15a and changed my mind last minute. But I may just try and get the original speaker fixed, since I'm probably incapable of building a box lol
    buldog5151bass likes this.
  12. One of these days though, I will build a cabinet and it will be awesome. Just need to do more research I guess
  13. Can somebody post some good thread links that cover the basics and whatnot of this topic?
  14. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    This is a very common scenario here on TB. And my default recommendation is typically to spend at least a month or so doing your homework before you buy anything. Try working through the Amp Forum FAQ tech link section for starters (AMPS FAQ!! Info on OHMS, Allsize RIGS-OverUnderPowerCabs DIY TechTalk-Links), and then pick a few dozen external links from there, and so on.

    I'd also suggest buying your plywood from a vendor who can do the panel cuts for you, especially the first time around. The last time I did this it cost me $20 for all the cuts for two 115 cabs. Good luck, and have fun. Yel_wink.gif
  15. Rick James

    Rick James Inactive

    Feb 24, 2007
    New Jersey
    The BFM Simplexx 15 can be used with a Kappa 15 LF. You can make it with a high frequency horn or without. You don't want to pair it with a 410, you don't want to pair any 115 with a 410. A 110 or 210 would be OK.
    All you need to know is this: it takes years to learn how to design speakers. It's worth it to learn of you plan on making it your profession, but not if you just want to make a cab for the sake of making a cab.
  16. How do I find the perfect replacement speaker? My cabinet is from the 70s, no information on it anywhere, I'd rather buy a driver that would be the best replacement in this cabinet than build a new one but if I can't get this returned then idk, but I need to find the dimensions and all that of my cab but idk what to do with that info once I have it. Idk how to calculate the tuning of the port or what the current speakers specs are

    Attached Files:

  17. To find a suitable replacement speaker for that cabinet, you need to be able to define the cabinet. Measure the internal dimensions H x W x D= Airspace. Are there any ports on the back? Another thing; putting a new/modern speaker with much different characteristics than the original speaker is not likely to bode so well for the working old speaker, even if it is designed to work with the cabinet's airspace. You will probably be replacing the other old speaker in short order!
  18. CRich0205


    Feb 17, 2013
    You don’t need to find the dimensions go measure it. If you’re considering building a cabinet you will need a tape measure. You can always out the new speaker in and listen to it. You might like it. I built a sealed 212 with eminence beta 12a2s last year that sounds killer. It’s not as hard if you go with a sealed cab design.
    funkinbottom likes this.
  19. I have thought about it restoring this cab and holding onto it forever, I'd probably try for neodymium magnets if I could afford it
  20. funkinbottom

    funkinbottom Supporting Member

    Apr 23, 2006
    Northern CA.
    You said you recently graduated so some math is fresh in your head. No sweat, you got this. It might involve some engineering, but it certainly isn't brain surgery. Go to Eminence site, look up your speaker. Scroll down and you will see recommended volume for sealed and vented cab. It is usually listed in cubic feet. Also click the cabinet designer link and it shows you different volume cab simulations and how that speaker reacts. Tells you the # of vents, and diameter and length of vents.

    PM me if you want some reading material and I'll email you pdf file.
    Last edited: Jun 17, 2018
    RobTheRiot, Pbassmanca and Sanchan like this.
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