Mixing driver sizes

Discussion in 'Amps and Cabs [BG]' started by Mr Gaston, Dec 18, 2014.

  1. Mr Gaston

    Mr Gaston

    Nov 16, 2014
    Abilene Tx
    Oh boy am I going to get it now!

    Yes, I have done searches. In those searches I have learned that some people's view is, "You have to be stupid to mix driver sizes. It's anti-scientific. How can you possibly be that dumb?" Also, science people call speakers "drivers". On the other hand, some say "But dude, I don't care how sciency it is, my 210 and 15 sounds so cool together." The manufactures seem ok with mixing drivers.

    What my searches have not turned up is the actual science that mixing drivers desecrates. I have seen vague references to dropouts and beaming but nothing about how this actually takes place.

    In my simple little mind I don't see any problem with two cones of different sizes moving in unison and in phase. I don't see how one would interfere with the other at all.

    I'm not saying that the anti driver mixing people don't know what they are talking about. I'm just saying that I don't understand how that would happen and haven't seen it explained. I am actually very confident that there are a number of guys here that can explain it.

    Show me the science.
  2. Mr. Foxen

    Mr. Foxen Commercial User

    Jul 24, 2009
    Bristol, UK
    Amp tinkerer at Ampstack
    Mixing drivers makes them not move in unison and phase. That's why they are different, rather than the same. Plus speakers don't even move in unison with themselves, its bigger ones tend to beam more, but not consistently with regards to size because some are more flexible than others.
  3. Pay attention to the posts in that thread from Bill Fitzmaurice.

    You would also do well to search out other posts and papers by him on this and other sites.
    Mystic Michael likes this.
  4. shoot-r


    May 26, 2007

    Yes, Yes, and YES!!!!!!!

    Read "ANYTHING" Bill F. took the time to post here at T.B. and then take it to the bank.
    He absolutely knew what he was talking about.
  5. nostatic

    nostatic Supporting Member

    Jun 18, 2004
    central coast
    Endorsing Artist: FEA Labs
    Or read anything by Duke LeJeune posted here as well.
  6. will33


    May 22, 2006
    Ever see PA cabs that are "physically aligned", where the mid is set back into the cab farther than the woofer, then the tweeter may be set back a little or forward a bit?

    That aligns the voice coils rather than the fronts.

    That had some to do with alignment.......then you throw a passive crossover into the mix and it's out the window again. :)

    A lot of those types were bi/triamped.

    Point is when you have different drivers with their differing responses playing the same signal it will cause interference that can be constructive and destructive, often both at different frequencies.

    I mostly heard that as differing tone (response) in different spots in the listening area.

    Then again, I used to run "mixed rigs" all the time, including the 115+410 stack. The sky didn't fall. I didn't sound like total crap. But I did have more problems getting a consistent tone throughout the listening area. Adjust it to fix something in one area and it would make it worse in another area. Went to matching speakers and some of those problems lessened. Made it easier to get a good sound over more of the audience.

    This mostly applied to smaller gigs where you drive the whole room, or a good portion if it with your rig.

    When you're piped through a big PA that does the heavy lifting it doesn't matter much.

    The PA also has matched speakers playing each portion of the bandwidth. :)

    Somebody likes the sound of mixed up rigs, hey that alright. Unless they have each type of speaker mic'd up and balanced just like the rig is, that sound still isn't making it out front though.

    There's lots of variables of how things sound at a gig. The vast majority of the audience is not equidistant from all the speakers, so there will always be phase/time arrival stuff going on. The matched bass rig just removes one variable. Makes it easier to get consistent sound.
    Last edited: Dec 18, 2014
  7. Ben Noblit

    Ben Noblit

    Dec 28, 2009
    My experience as well. I used to be a flat-earther, (if Flea does it he must be right!) but on a lark I decided to try out the concepts the sciency folk were talking about. Whaddaya know, it actually helped a lot.
    lomo, Jim Carr, will33 and 1 other person like this.
  8. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Syracuse NY
    Endorsing artist: Dingwall Guitars
    And there's nothing wrong with doing what you want. Its your rig, your bass, your tone. Using matching drivers and paying attention to their alignment can allow you to have a better chance of things working together in the most effective way. It takes some of the unknowns out of the equation. Also, if you're a player who has to be concerned with bass tone in the 'room' keeping it coherent and even in the front of house from the most positions, then it also pays to work with the science. Plenty of guys don't have this worry because they'll never be playing in front of people, or if they do they're playing gigs with full PA support, etc. For me, I'd say that 50% or more of the gigs I do these days (probably closer to 75%+) are with my amp providing all the bass in the FOH. So I pay attention.
  9. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Before assuming that the plase reaponse plots in the referenced thread look so darn horrible (as some of the arguments suggest the sawtooth look might be), it would be helpful to understand that the vertical scale is limited to plus/minus180 degrees, and that when the response goes beyond +/-180 degrees it drops to the opposite side of the graph, so varying around either + or - 180 degrees by even a few degrees would cause a sawtooth when using the scale that's presented in the graph WHICH IS NOT WHAT IS HAPPENING IN THE REAL WORLD MEASUREMENT... it is a measurement artifact!!! Folks, know your data before basing your argument on incorrect understanding.


    With reasonable designs that support similar phase response, the difference in the phase response may in fact be less than the phase response of seemingly identical drivers. In manufacturing, no tow drivers have an identical phase response either, it's just a real world variable that in practice makes less difference than some folks so enthusiasticly suggest.

    (on a well designed product) what is really important, is to show a SUMMED phase plot exclusive of the scale discontinuity and the results of the graph will be shockingly similar to each cabinet by itself rather than the wildly inaccurate plots shown where the ARTIFACTS are doubled... they are NOT the real representations. And before folks say I am not understanding the science, I am all about science, I am all about the math, i am all about the real engineering. I am also all about understanding what the presented data means, and is it accurate or misleading.
    fdeck, Miskatonic, SandCBass and 6 others like this.
  10. My own mixed stack sounds better when biamped ( electronically crossed over with separate power amps ). I must be able to detect the raggedy sum of two sawtooths that are out of alignment at some points.

    I don't do it much because it's a very big haul for only one cab worth of bass.
  11. johnpbass


    Feb 18, 2008
    Glen Mills, PA
    I get it that some maufacturers have product lines that have a similar tonal profile. However, my thinking is that there must be some tonal difference in the cab line between say a 210 and a 115, otherwise why bother making the different cabinets? Make one or the other. That to me (and I'm not a scientist by any stretch) says you need, at the very least, separate EQs for each cab. Admittedly, I'm no expert on the subject, so I'll just be quiet now!:D
  12. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    There CAN be different tonal goals for different cabinets, but there doesn't have to be (but at that point there's not all that much point in different cabinets is there?)

    There are also same sized drivers that sound very different (as an example, the JBL 2225 versus the 2220A, or the D-140/D130)
  13. Jim Carr

    Jim Carr Dr. Jim

    Jan 21, 2006
    Denton, TX or Kailua, HI
    fEARful Kool-Aid dispensing liberal academic card-carrying union member Musicians Local 72-147
    It may be because the cabinets DO sound different, but more importantly, isn't it that many bassists believe a 15 goes low, a 10 is quick, and a 12 is just right? Having the right diversity in ones product line increases sales and profits. :D

    Manufacturers push that line by supplying mixed rigs to endorsers. The whole mixed-cab thing started with the bi-amp craze over 30 years ago.
    johnpbass likes this.
  14. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Syracuse NY
    Endorsing artist: Dingwall Guitars
    I think that probably the real tonal result is more likely to be some wonky sound due to different cabs with their own tonal profiles and how those may emphasize or de-emphasize specific tonal ranges or frequencies when 'laid over' or along with another cab. Its more likely to be a crap shoot when it comes to the end product. Some cabinets may compliment or produce perceived negatives when combined. I feel like if you're carrying a room any issues are 'magnified' by having to fill that much space.
    Jim Carr likes this.
  15. Rick James

    Rick James Inactive

    Feb 24, 2007
    New Jersey
  16. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    I don't think this is accurate in most of the cases where the cabinets were designed (with engineering, not with seat of the pants "wink & a nod dead rekoning" with this factor in mind. With the appropriate choice of drivers (which may NOT be drivers that would be a good choice if they had to reproduce acoustically over the entire range), combining drivers can allow a skilled designer some additional options to get performance that is not reasonably possible otherwise.

    For example, there are some 15" drivers that have very nice, round low end profiles but just do not have the response above say 500Hz to be useful without help. Now, say there's an overdrive component, which that 15 would really mask the harmonics but would not sound right using sat a typical 6" or even an 8" driver, perhaps a 10" or two run full range would acoustically match up well not just under clean conditions but really shine under moderately overdriven conditions.

    It's not a simple yes, good and no, bad scenario, there is a lot more going on between the lines (of a well engineered product) than many of the "science only" guys are willing to admit (either because they don't understand, or they have an agenda of their own). Automatically dismissing any design by putting blinders on is not very constructive, nor open minded. If it's not something that you like, that's not a problem, but telling other people not to like it based upon mis-understood, or mis-applied science isn't right either.
  17. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Syracuse NY
    Endorsing artist: Dingwall Guitars

    The problem is that you're assuming that a buyer is purchasing cabinets within the same product lines or even the same company. And so many times what I witness is your average player who's coupled an Ampeg with a Hartke, or a GK, or whatever they could find at a good price or whatever was in the local shop at the time.

    You also might want to note that I've regularly and repeatedly said that people should play what they like, and that different sonic situations call for different solutions and/or choices.
  18. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    And I am going to point out a factual error that Bill constantly talks about, "that a 410 and 115 have essentially the same frequency response" as either uninformed, misunderstood, or based on some agenda that i am not aware of.

    SOME 115's MAY have "essentially the same frequency response as a 410", but this statement also allows that they may not, which matches better what I have seen with my measurements of popular speaker cabinets (both mine and others). There are a lot of things that are possible with a 410 that are not possible with a 115, especially considering overdriven tones, and specific voicing options that can be done with a 10" driver that is intended to be more midrange centric. If all 410 cabinets sounded "the same" and all 115 cabinets sounded the same (which of course they don't), then there might be more truth in his statement, but they don't (or don't have to).

    Closed mindedness would not have allowed for many of the most important improvements in the bass guitar world to come to market. Think about all the really great products that fly in the face of closed minded tradition, starting with the electric bass (dyed in the wool double bass players of olden days I'm sure lamented that new fangled electric bass as being capable of nothing but crap), solid state amplifiers, switchmode power supplies, class D, composite materials in basses, etc. There's a lot of great technology that has gotten the big thimbs down from closeed minded folks over the years yet have become popular standards. I'm just asking that folks not be automatically closed minded about anything... unless you really understand the details of what's possible, not just the urban myth itself.
    dukeorock, Foz and slade like this.
  19. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Right, but how come the detractors seem to imply ALWAYS in their arguments? There is no ALWAYS when it comes to personal tastes, and other people's preferences aren't necessarily wrong, or bad, or stupid, or whatever negative word used to describe their preference.
    slade likes this.