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Need some advice.. cab building and speaker choices.

Discussion in 'Amps and Cabs [BG]' started by Magneto, Jan 19, 2004.


  1. Hi,

    I have some questions about bass amp speakers, cabinet building, and wiring. Hopefully you can help point me in the right direction as I've been out of the loop for too long.

    1. It's been my experience that many of the 15" full range speakers that I've tried in various (past)bass cabinets did not reproduce mids and (especially) highs as well as smaller speakers. Some of the better ones back then were JBL,ElectroVoice, Cerwin-Vega, etc.. Some of the not-so-good ones were Peavey (I had some 15" Black Widows which were awful).
    In the past I decided to build all my own cabinets, and had been told that going with a 2-way cab with two- 15"s and a single 10 (or 12) inch, crossing the mid and high freqs over to the smaller speaker, the mid-bass and lows to the larger, might be the best option for me. Since many of the 10s and 12s reproduce mids and highs much better than 15 inchers, I could probably find a good crossover point to get the sound I wanted. I like the bottom end from 15 inch speakers, so I rarely consider 2-12, 4-12 speaker/cabinet arrangements. I used to own an older Fender Bassman 135 amp and cabinet, which had 4-12s set in an angled-in enclosure. It just never gave me what I wanted. I then switched to a 2-15 Peavey BW cabinet that wasn't any better. EVen with a good EQ, I just could not get the bright, tinny highs that I had heard with more expensive speakers.
    Also, by going with the 2-way 15" cabinet, this would allow me to use less expensive 15 inch speakers, because their mid-bass and low qualities are usually still quite good. I could always upgrade to better speakers in the future as my budget allowed. Or at least this is how I see it.

    2. Since those days, so much as changed. I see many bass cabinets with tweeters already installed, more bass heads with bi-amp capabilities, etc.. Since most biamped heads are more expensive, I settled on the idea of just wiring my cabs with passive crossovers.

    3. Choosing which speakers I want to build around is the hard part. I could go with individual cabinets (15 woofer + smaller speaker for mids/highs), or I could build a 2-15 cabinet with a 12" for mids/highs. With the first option, I could wire the individual cabs at 8 ohms, which when run together from an amp's parallel connections would give me a 4 ohm setup. Then should I decide to practice with a single cab, it would be running 8 ohms, which is not a big deal.

    There are so many other options, that I find myself spinning my wheels trying to decided which direction to head. How do you guys see it?
    What are some of the better larger full ranger drivers out on the market, and how would you build if you were going to "do-it-yourself"??

    Sorry about the long post, and thanks for taking the time to read it and share your ideas with me..

    Mag...
     
  2. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    I know what you mean about trying to limit your variables a bit. It sounds like you have been playing bass and building cabs a few years (as have I) and perhaps are not in your first 2 decades. I would start from the perspective:

    What am I willing to carry?

    I decided that the biggest box I was willing to pack was about 40#, but I didn't mind packing a few if needed.

    I decided that given the way technology had been moving, it was more cost effective to go biamp, and put the crossover in front of the amp instead of using passive in the cabinets (and it was also a lot easier to engineer since I just twist a knob to change crossover point). I bought the cheapest rig I could put together (used Yamaha preamp and QSC RMX power amp).

    Speakers have come a long way in the past 20 years. I had always liked the sound of 15's for bottom, but I found that I could get away with 12's of a modern design. I don't play a lot of highs (flatwounds and such) and so my needs there are pretty simple.

    I ended up with a pair of 4 ohm car audio subs (2.2' boxes tuned to 28 hz) crossed over at about 150hz and an Avatar B112 on top (12" Eminence Kappa 12 and a horn, cheaper than I could build it). My rig is pretty flat from 30hz to 10k, and makes about 115-118db or so (enough for my needs so far).

    I didn't notice whether you play a 4 or 5 string (I play 5). For a 4 string the Eminence Omega Pro 15 is a pretty nice driver for the money in a reasonable sized box.
     
  3. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    You might do a search for some threads in which Bgavin discusses using an Eminence B-102 10" for highs and an 18" Eminence (forget which model) for lows. Apparently they balance nicely and the B-102 has a whizzer cone and is good to about 7khz without a tweeter.
     
  4. Hey ESP, thanks for both of the replies. I appreciate you taking the time to explain some of your ideas. Yeah, I've been playing since about '75 when I transitioned from guitar to bass. It's been about 5 years since I last owned a bass, and I'm finally starting to get things back.
    I'll do some more checking around to see what kind of ideas I can come up with.

    Thanks..

    Mag...
     
  5. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Magento, you'll find that designing the cab takes a lot longer than physically building it. It sounds to me like you've got too many possible combinations floating around in your head and you need to narrow it down. Keep thinking it through until you know what speaker configutation you want, how loud it has to go, how low it has to go, how many watts it has to take, etc etc.......

    I've spent the best part of 12 months researching my latest project (5 bookshelf speakers to make up a 5.1 surround sound system). In that time built the prototype of the sub, and I knocked together only one of the satelite speakers just last weekend. The rest of the time has been spent running different speakers and combinations through speaker modeling programs and weighing up cab size Vs frequency response Vs loudness Vs price. Unfortunately for me I've designed several combinations that work on paper and had to decide which to actually build. I thought I'd start with the cheapest one. Unfortunately that is the overriding factor for me - but it may not be for you...............
     
  6. The Eminence Magnum 18LF in QB3 is a nice match for the Eminence B102 for 4-string. I own both, and bi-amp.

    The Magnum will put out a huge amount more noise than a single B102, so if max loudness is your desired result, a pair of B102 is required to keep up with a single Magnum 18LF. This gives you a 2x10 for highs, and a 1x18 for the lows.

    The 2x10 B102 pair in SBB4 can be used standalone for small gigs, full range. It won't have a lot of bottom, but will sound like your typical JBL E140. Used full range, the B102 is good for 75 watts and 110 SPL (each). Bi-amped from 150 Hz and higher, it is good for 200 watts and 115 SPL (each). A pair at 400 watts is 118 SPL.

    The QB3 alignment for the Magnum is 3.8 cubic feet tuned at 39 Hz. F3 is about 46 Hz... perfect for a 4-string. It will accept a full 650 watts input power before it starts exceeding Xmax. SPL is about 120 at 43 Hz.

    Using a stereo power amp such as the PLX 3002, you can expect 450 watts per channel into 8 ohms. This means the Magnum will produce 121 SPL before the amp runs out of power. The alternative is using two power amps, one bridged for the Magnum. If you intend to do this, add more B102 10" drivers.

    At 450 watts per side, this is ghastly loud.
     
  7. rumblinbass

    rumblinbass

    Aug 22, 2003
    Wimberley, TX
    Petebass, bgavin,

    I've been considering building a cab for a long time, right now I'm considering a 6x10 configuration. I have read through a few books aready - "Loudspeakers for Musicians" by Vivian Capel, "Great Sound Stereo Speaker Manual"and Designing, Building, and Testing Your Own Speaker System" by David B. Weems.

    Right now I also work with somebody that has also built all of his own cabinets for all of his PA's - he has a side business that he has had for years setting up PA's for concerts. He has been building his own cabs for years and has a wealth of information.

    Anyways, I have done several searches and read many of your posts. I would like to ask you for your opinion or recommendation on a couple things: are there any other books that you would recommend (?), what type of building materials do you prefer (...and where do get them?), what speaker would you recommend for a 6x10 cab?

    I have already done some research and have an idea of what I would like to do and the materials I want to use, I am just wanting other opinions from experienced cab builders.
     
  8. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    After messing with homebuilt cabs a bit I concluded it's something I could jack with forever and probably not be a lot further down the road. I'm no techno buff so I just kept it simple with 15's. I built a test cab that held 6 15's (dubbed ShpeakenShtein, Frank for short), real monster, so I could do comparsions. Quickly learned that if I couldn't play speakers side by side, no way to really make any kind of determination.

    Picked up Altecs, JBLs (including a pair of K-145s, but they were smoked so they got shipped back), Celestion, among others. The speaker I liked most was an Altec 421-8LF. Ironically, it sounded very much like an Aguilar GS 112 cab I have, only the Altec was noticeably clearer. But I definitely did like some combinations better than others and that did pretty much carry over using different basses. But many, if not most, sounded brite enough to me, especially the JBLs. The Aggie goes to 16 kHz so if that comparison is of use then they seemed good to go. But I had bought the Aggie to begin with to cover for the expectant lack in upper mids and highs.

    In all, I felt hard pressed to produce any better than people that do it for a living. Not really any cheaper when you consider the time involved, although more entertaining.

    Speaker manufacture in general I think has improved a lot over the years. I definitely vote for the lighter rigs, with 50 lbs pushing limits.

    But it's really cool to sink your teeth into something, no matter how it turns out. The Journey is the Destination. Enjoy!
     
  9. I kinda like the Phil Jones theory - many small speakers in a box. I found a 5.25" speaker that will go down to 50 hz in an 11 liter box. So I could put 8 of them a box and it would have 97 dB @ 1 m, handle 480 W and they cost $14 each. I used WinISD and came up with a box around 90 liters or 3 cubic feet. That's smaller than most 1x15 cabs. The other good thing is you don't need a tweeter as the freq. response goes up to about 9 khz.
     
  10. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    Yeh, some the cabs I've seen with 6 or 8 small speakers ranging from like 3" up to maybe 10", then mic'd. Whatever works.
     
  11. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    It's good to see you've done a lot of reading. You seem to have done more reading than I have. However I'd like to point out that I have no where near as much experience as some of the other guys in here, Bruce especially, and consider myself to be very much in the learning phase. Cab design is one of those things where the more you learn, the more you realise you don't know. I actually had that book by Weems in my hand the other day and I nearly bought it. Maybe I should have :)

    The best book to read on this is definitely "The Loudspeaker Design Cookbook" by Vance Dickason. I read it as a complete novice and found it difficult to understand at first. But once you've got a basic idea (as you probably have) it starts to make sense a lot of sense.

    As for materials, Bruce says MDF and he's right. That's what I used on my small Hi-Fi speakers but for bass-rig-sized enclosures, I find it is way too heavy. I like to factor the final weight into the enclosure design because I feel the advantages outweigh the acoustic trade-offs. So I use Plywood for bigger enclosures. Timber thickness depends on the cab.

    As for good speakers for a 6x10, we'll need some more info. How big of an enclosure can you manage? What are you after in terms of volume and frequency response? 4 string or more? Have you got any particular drivers in mind?
     
  12. Some very interesting discussion happening in this thread.
    Since I first posted this topic, I've been trying to gather as much information about speakers and cab building/wiring as possible.
    But the hardest part is still choosing the right speaker at the right price. Sure I want to be able to custom build exactly what I want, but after looking at the prices of some drivers alone, it's easy to see that one could end up spending more than a prebuilt cabinet.
    It's especially hard when you don't have access to the speakers to actually hear them, and end up going with its specs instead. That's when experienced people such as you come in. Many of you have tried different 15" drivers and know their good and bad points, versus their prices.

    Is there an online speaker shop that carries a good variety of bass drivers? I could surely use some links if anyone has some.

    Could someone please recommend certain brands and models of speakers to help me with a starting spot? That would be great if possible.
    Also, I'm looking for a place that sells cabinet handles, corner protectors, casters, etc.. Perhaps someone could steer me to a good place to look.

    Thanks again for the help...

    Mag...
     
  13. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Some good calls in this post.

    Picking the driver IS the hardest part. But if the speakers seem expensive compared to commercial offerings, there's a reason. Small builders don't have the economies of scale that the big boys do. As an example, we're buying plywood one sheet at a time, so what bargaining power have we got compared to someone buying it by the truckload? The same applies to the purchase of the speakers. The advantage swings back in our favour when you consider we're not signing our souls away to one speaker manufacturer. It keeps our options open.

    Think of it this way. Which costs more buy - a personalised custom hand-built bass, or a mass produced bass? For some reason people expect this to reverse when we substitute the word bass for Speaker cab. It is possible to build semi-decent cabs on the cheap (I've done it). It just depends on what comprimises you're prepared to accept. The same applies when selecting a commercially available cab............

    You raise a very good point. No amount of cab designing can substitute for hearing the speaker. Why? Because the cab design is aimed at getting the speaker to behave a certain way, but it does not account for the speakers colouration of the sound. ALL speakers colour the sound, yes even studio monitors. Anything you have read to the contrary is a marketing myth.

    As for an on-line shop, start with http://www.partsexpress.com. They seem to sell speakers and hardware. You may also want to check out Selenium, Beyma, and JBL - they make good stuff. If you're looking for cheap-but-decent, try P.Audio. For some reason I have trouble recommending Eminence. I have only ever had one Eminence loaded speaker (a Feder BXR 15) and it was awful. Their stuff is a bit "hit & miss" in that some speakers spec up well enough, other are dreadful - sometimes within the same product group.

    You may want to download Bgavin's spreadsheet. There's over 1000 drivers on there and he's worked the math on them for you. If you know how to sort Excel spreadsheets, it's a great resource. (even though only a very small percentage of the drivers listed are available in Australia) :(
     
  14. I haven't had that much experience with Eminence either, but I consider their standard products kind of middle-of-the-road. However they custom make speakers for almost all the high end guys out there (Eden is the only one that makes their own). EA in particular has a reputation for excellent sounding cabinets - accurate and flat. So Eminence is capable of making some really good stuff.

    As far as cost goes, don't do this project to save money. In the long run, you can expect to pay at least what a similar manufactured cab would.
     
  15. patrickj

    patrickj

    Aug 13, 2001
    Baltimore, MD
    It's been my experience that this is only true if you put a dollar value on your time - which doesn't make sense if you're building for yourself. I've built a number of cabs, and each one has been significantly (anywhere from 1/2 to 2/3) cheaper for me to build (ordering speakers, going to the Depot for lumber, glue/finishing materials, etc etc) than anything I could buy. It's unreasonable IMO to set a price on your time when it's ultimately a leisure time activity you're engaging in.

    For an example, I am nearly finished with two 1x12 cabinets (these are my 'townhouse' / small gig cabinets - that 4x12 I recently finished is for large giggin out and about). A GS112, which I loosely copied, is roughly $400 new. The grand total for each of my 1x12 cabinets is about $170/each (and a full weekend + 3 evenings to assemble). Maybe I'm just lucky, but the reason I started building my own gear was because I could build something as good as store bought (not at first of course, the woodworking skill wasn't there yet even though the sound was) and save a ton of $.

    My advice is a bit simple, but it's worked quite well for me. Decide on what configuration you want (ie: 1x18 + 2x10), pick drivers for your project based on your budget, then design a cabinet around what you've got. I buy my speakers with little more than SPL/freq. range/intended use in mind, and once I've got them (ie: I'm commited to using them) then I start working on the actual box design. The complexity of bass speaker design IMO doesn't come so much from the difficulty of the design phase (it's hard to figure out, but once you understand things pretty well it's not so bad) but from the amount of options available and constant 2nd-guessing over so many options. If you can remove even one variable, it becomes that much an easier process.

    Whatever you build, brace well. Good bracing will make/break an otherwise excellent capable-sounding cab.

    :bassist: :bassist: :bassist:
     
  16. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Basstrader, I was talking about Eminence speakers that are available over the counter. I'm not saying they're bad speakers, I'm just saying that I am not keen on them at this stage.

    Patrickj, that's pretty much how I do it, but you forgot to mention the design part is something you repeat over and over until you come up with something worth building. Sometimes you end up with a cab size, or a -3dB point, or any aspect of the final design that makes you think "nope, this one won't work for me".

    It's very important to know what you like in a speaker. If you like it flat to 30Hz, great, design your speakers that way. If you like it punchy, design em punchy. But that's only part of it. I've spent too much time in the past focusing on frequency response and have now decided to learn more about excursion. Suddenly I'm finding out why some speakers cost more than others.

    I'd love to do a course of some sort on cab building. So far all I can find are Audio Engineering courses that have maybe 1 subject out of 20 on cab design with a program that looks fairly basic. I've also found a few courses with an Acoustics vibe, but they have a similar problem, though the subject matter seems more advanced. Any suggestions?
     
  17. Many of the over counter Eminence are fine drivers... just not the cheap ones.

    The Magnums, Omegas, and 10" Deltalite do just fine. Their budget drivers are... budget drivers.

    Don't ignore the Beyma. IMO, they are the JBLs of Spain.
     
  18. rumblinbass

    rumblinbass

    Aug 22, 2003
    Wimberley, TX
    Petebass,

    I should have thought before I posted. You, bgavin (and others ?) must be tired of the same comments and questions over and over again. I've read several threads where you respond to the same questions.

    Anyways, to the point - I'm just looking an opinion on an all-around good driver. I don't want a huge cab, I would like something comparable in size to the Ampeg or SWR 6x10. I don't want a power hungry driver since I'll be using 6 of them. Since I understand that there is give and take between power, freq. response and volume - I just want something that is a good compromise. Oh, and I play a 4-string.

    My other concern is lumber - what type of ply is good to use? 7, 9, 11, or 13 ply? I also don't want a really heavy cab either.

    I'm not looking revolutionize the cab building industry by building a super-light-weight or small cab, I'm just looking to build a good solid cab.
     
  19. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    I wan't brushing you off :)

    I was trying to narrow the options down a bit which we've now done.

    I'm at work at the moment but I'll have a look at a 6x10 design for you when I get a chance.
     
  20. rumblinbass

    rumblinbass

    Aug 22, 2003
    Wimberley, TX
    I didn't mean to say you were brushing me off I just meant that after reading my post and your response I realized that I should have been more specific. After reading previous threads I noticed that in order to get any help or advice I need to provide as much information as I can. Otherwise you and bgavin end up asking the same questions over and over again.