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Mixed Driver Size Myopia!

Discussion in 'Amps and Cabs [BG]' started by Wolffgang, Oct 17, 2013.

  1. So, you only have to lurk around TB for a few minutes to hear a lot of well-reasoned arguing for why mixing driver sizes is bad; I'm not here to dispute that. I saw a thread recently asking why this doesn't apply to fEarfuls and the like, and the answer was that the their crossovers fix it; makes sense.

    So, my question is, why doesn't the 'typical' 4x10 + 1x15 setup have a crossover in the 15? Crossovers are cheap are hell. In fact, why isn't the 15 an LF even, maybe? I have (and love!) a fEarful stack, so I don't need to be converted here, but why is this a new way of doing things? Like, if the luminaries Talkbass can figure this out, why not major manufacturers?

    Please, explain why my question is asinine below! :D
  2. TB represents a very small percentage of bass players. My best guess is less than 10%. Most bassists simply don't get into gear like someone on TB and don't go beyond what their local store(s) sell. If there is no demand for more "scientific" cabs why would major manufacturers make them? And by demand I mean thousands of units. Also they would be more expensive to build, require more R&D and reduce profit margins. Plus your typical salesman is not going to understand how or why they work so I would imagine they would be a tough sell.
  3. Look at what is achieved by one little 6.5" mid driver in the fearful, then decide if you want to lump a 4x10 to do the same.
  4. I'm certainly not saying it would be a better solution, just that on the production scale of major manufacturers, a crossover seems like a cheap addition to gain an edge over the competition not doing so. Or are we all drinking the koolade, so to speak?
  5. Firstly you got it ass backwards, the 15 is better at highs and the 4x10 better at lows.

    Secondly you're not listening.

    Further: There is no point to selling such a crossover when the customers would need to realise how they had bought pups. The crossover isn't so cheap either, and would have to be designed for each pair of cabs, and they would have to direct the 4x10 to be used on lows, thereby exposing their marketspeak, never gonna happen!
  6. Oobly


    Jun 19, 2008
    Because they're both full-range cabs which haven't been designed to be used together, but as standalone cabs. A user can do this for themselves by using a stereo amp with a built-in crossover and adjust both the relative volume levels and crossover point, but then at least one cab won't be used for the whole range of frequencies that it has been designed for.

    Some manufacturers have started making better multi-driver cabs with crossovers (like Barefaced, Acme, etc), but it takes a lot of R&D and costs more, as bassboysam said and informed bass players who actually know why it could be bad to mix driver sizes are few and far between, also like bassboysam said.

    Most bass players are happy with standard cabs and don't know there's anything better out there.

    Demand drives supply. We need more informed bass players who vote with their wallets.
  7. Oobly


    Jun 19, 2008
    But the 15 will have poor dispersion on highs. Anything above 1kHz will be very directional. Then again a 410 has its own dispersion issues....
  8. Yes, better is less poor.
  9. Mr. Foxen

    Mr. Foxen Commercial User

    Jul 24, 2009
    Bristol, UK
    Amp tinkerer at Ampstack
    4x10 has worse dispersion issues than the 15, since the tens are next to each other.
  10. To summarize the above posts and hopefully clarify, there is no benefit to crossing-over similar full range cabinets. Driver size alone means nothing. All you would be doing there is forcing one cab to handle ALL the low end, and remove frequencies the other cab could easily reproduce, hence resulting in a very inefficient system.

    Think about this more in a 'PA' sense... the different drivers/boxes in a large front of house system use optimally tuned cabinets and driver sizes to maximize both the efficiency of the system (i.e., larger drivers can, in most cases, more efficiently produce low end... i.e., you need less of them to obtain high SPL than smaller drivers), and (this is key) to maximize dispersion (the frequencies from the upper midrange on up tend to beam a bit when reproduced by larger cones (i.e., they come out very directionally from a larger driver). The confusion arises with a 15" driver in a bass cab. The typical 15" driver is much more similar in frequency response to the typical 10" driver designed for bass guitar backline than a true sub-woofer spec'd 15" driver with massive low end capability. Again, driver size alone makes little difference.

    So, it makes quite a bit of sense to get a large, relatively efficient driver for the low end, and then the smallest driver you can get for the top end of the tone of a bass cab, hence the 12/6 or 15/6 type designs (or in Andy Lewis's Acme cabs... 10" drivers specially voiced for low end and 5" mid drivers). Of course, if you put small drivers next to one another in a horizontal configuration, they act more like large cones, again beaming the high frequencies.

    Of course, there are always trade-offs. A 410 with a good tweeter can sound marvelous, and a 15/6 with a simple crossover can sound sterile and lifeless. No 'one best way' with bass backline cabs, which are often designed to be part of the tonal signal chain versus pure 'reproduction of tone'. Any speaker design is a compromise and trade-off of many, many specs and performance/tonal goals.
  11. If someone wanted to improve the lot of a majority of bassists they would design a high power mid-high box with a massive passive crossover that could be tweaked to crossover at a coherent frequency with whatever 4x10, 8x10, 2x15, getting sent the lows.
  12. All very well explained, thank you. I'm not sure how I somehow selectively forgot that those cab configurations are aiming to reproduce the same frequencies after just saying that I read other threads about it.

    So assuming that the designers of cabs knew/know this, why market stacks with mixed driver sizes? A case of industry imitating artists ie people just kind of started doing it and the companies just kind of went with it rather than trying to explain why they were wrong? I know this point is only really speculation, but since I have geniuses doing the speculating...
  13. Sales trump science.
  14. MCS4


    Sep 26, 2012
    Fort Lauderdale, FL
    Yeah, the number is probably well under 1%. You can sit around a Guitar Center all day polling folks who stroll through the bass section and I'll bet you won't find more than a couple who have even heard the argument that mixing cabs is bad -- much less who believe it is true. So the pool of players whose purchasing decisions might be affected by these things is minimal, at least in comparison to the consumer bass of the mass-manufacturers.

    It also doesn't help that, for all of the convincing-sounding science behind the concept, there are tons of bassists out there (including myself), who have used both mixed-cab and identical-cab setups in live settings for years and years without noticing any issues with mixed cabs.
  15. 1958Bassman


    Oct 20, 2007
    Inductors for passive crossovers aren't always cheap. Add being large enough to handle a ton of power without saturating and the cost increases exponentially. If you mean that active crossovers are cheap, the fact that only one type of speaker isn't used by all amp owners makes flexibility necessary, so variable crossover points and maybe variable slope/Q adds to the cost.

    You're really asking manufacturers to be customizers and that's not the focus of their business.
  16. +1 Just like with most things in life, this definitely isn't a pure black and white 'good versus bad' thing. Various stacks used by many players successfully for years can obviously sound fantastic, and in the case of the classic 15/410 stack, if you aren't pushing the 15" driver beyond its capabilities, for the most part, it will sound fine (or even more than fine!).

    There unfortunately is quite an 'overstatement' of the impact of a couple very limited spec's (like upper midrange dispersion) by many of the more technically oriented posters on TB. A bass backline system has hundreds of non-linear feature interactions that can result in surprisingly good overall performance based on evaluating them on just a couple of spec's on paper, and on the other end of the spectrum, surprisingly dog-like tone when a system is built to maximize specific, limited performance spec's.

    However, I've learned a lot on this site, and it is good IMO for those of us who are interested in gear to have a basic understanding of the trade-offs we are making when configuring a rig.

    For example, I primarily gig a two way 212 cab with tweeter. I've gigged and owned most of the mid driver loaded cabs on the market (I really do like trying different gear!). I found the trade-offs I'm making with my relatively vertical oriented 212 with relatively low crossed tweeter to be 'better' than the trade-offs I was making with the 12/6 and 15/6 and 10/5 cabs I've played. All sounded good in their own way, and all had costs and benefits associated with their designs.
  17. 1958Bassman


    Oct 20, 2007
    High power applications don't use passive crossovers because A) they blow up at precisely the wrong time, B) they introduce phase shift that doesn't occur with active crossovers, C) they're expensive when designed for high power and D) the insertion loss makes even more amplifier power necessary, which costs more. Also, active crossovers can be designed to have a steeper/switchable slope (symmetric/asymmetric), have constant/variable Q, maintain unity gain and separate crossover points for HP and LP.
  18. Yeah, costly and power hungry but with enough switching options you could always sound good.
  19. coreyfyfe

    coreyfyfe Supporting Member

    Nov 19, 2007
    boston, ma
    They can and have. They just don't sell as well as legacy products. Ampeg had a few 15/10 15/10/tweet cabs, SWR has the triad. They move more 4x10s, 1x15s, etc than the well designed (from a reproduction standpoint) cabs.
  20. Were those cabs crossed over?

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