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Mismatching cab impedances...

Discussion in 'Amps and Cabs [BG]' started by GeorgiaHonk, May 13, 2004.

  1. Sorry if I'm beating this cabinet thing into the ground, but... :confused:

    During my course of the Great Cab Search 2004, I've sifted through the myriad of wonderful advice I've received here at TB and have basically decided to get an Eden 215XL. I have always been fond of the Eden tone. I think this cab will be a good way to get my favorite old school tones, and it's 4-ohm impedance will allow me to push 300 watts into it. But if I need more mids, I want to be able to add a 1X12 cab in the near future.

    Since most 1X12 cabs seem to be 8-ohms, I was wondering if there would be any danger to either of these cabs by running them together at a 2.67-ohm load? My amp will push 450 watts with a 2-ohm load. I know that one of the cabs would "see" more wattage, but which one? I assume that unless I run the volume wide open, there shouldn't be any damage, but I want to make sure first.

    I'm beginning to think that having two cabs at different impedance ratings might be a nice way to have a modular bass rig: using the 1X12 at 170 watts for downsized and/or acoustic gigs, but still able to bring the beef with the 2X15 alone (300 watts) or together with a 1X12 (450 watts).

    Do you folks think an Aguilar GS112 would be a good sonic match for the Eden? I don't have a local Aggie dealer, but I do have a Berg dealer just down the street. ;)
  2. too bad you dont have a Mesa 400+ head, it has two 2-ohm outputs, two 4-ohm outputs, and two 8-ohm outputs, so you can pretty much plug any cabs you want into it. If you want to plug two 4-ohm cabs in, just plug em both into the 2-ohm outputs, and so on, and so forth
  3. Happy MurphDay

    Happy MurphDay

    Mar 9, 2004
    Hear me out, if i were you, i would get a eden 210xlt, it can take as much power as the 2x15 and would pair up perfectly, you already have the majority of the low end covered, and if you want to add more, go for the 210, it has great punch, and would look wicked awsome on top.
    if you want the specs goto:
    you can usually see them on E(vil)bay for about high 300s to low 400s
    it would still give you the great eden tone pus you can get them in both 4 and 8ohm which would solve that delema
    plus that little box is really good for small gigs, and if you need more sound bring his bigger brother ;)
    i have yet to play the aggie you speak of, but it gets great reviews around here, sonicly, the aggie will help anything, but id loo into the 210, jmho
    good luck with the GCS 04'
  4. Happy MurphDay

    Happy MurphDay

    Mar 9, 2004
  5. Each pair is routed to individual taps on the output transformer. If you like your amp working, you better not try mixing and matching.
  6. If you Mismatch Impedance - you also get mismatched volume matching. The amp will not care as long as the combined impedance is above the amp's minimum, but the higher Impedance speaker [system] will receive proportionately less of the amp's power.

    For Example: a 4 ohm and an 8 ohm cab, paralleled together, would be fine with a 2 ohm minimum amp (but risky on a 4 ohm minimum amp), and the 4 ohm cabinet will receive 2/3rds of the power and the 8 ohm cabinet will receive 1/3rd. (I think that was stated correctly ....).

    This is a little unconventional (after all, it's an old guitar player trick), but it can be very useful in tuning in your sound, or helpful adding lower rated drivers / cabinets with larger units.

    The point is .. don't be afraid to experiment. The one thing I can say absolutely is not "Your Mileage MAY Vary", but "Your Mileage WILL Vary".
  7. Excellent advice, and just what I was looking for. NOW...let's say I want to "create" a cabinet. I start with a 2X15 cab, but I wish that it also had a 12" driver in addition to its 2 15s. Assuming the initial 2X15 cab is rated at 4-ohms that would mean each driver is an 8-ohm speaker, correct? Now let's say that I add an 8-ohm 1X12 cab to the rig --- now I would have three 8-ohm speakers, each receiving 1/3 of the amps power, correct? OF course, this is over simplified and ignores cabinet dynamics, etc., so I may be way off base here, but my original intent was to add a 12" driver to the 2X15 in order to provide equivalent power to all three drivers. In order to do this, wouldn't the 12" single driver have to be the same impedance as each speaker in the double-loaded cabinet?

    Thanks in advance...
  8. If you want each driver to receive the same power, that is correct, make them all 8 ohm.

    In reality, it is way more complex, as the sensitivity of the two driver types will also play into the equations, and the final sound will also depend on the frequency dirrerent response and other black-magic elements.

    To me, there are three choices:

    Hire someone that really knows what they are doing ...
    Offset limited knowledge and experience (which I too have) with lots of elbow grease and build a bunch of prototypes ...
    Try every cabinet and cabinet combination known to man (which is what most folks end up doing)

    To further screw it up - every room you play, every different instrument, every group you play with, every quirk of every personality - will effect things. What you like today, will be different tomorrow - perhaps different as-in love, perhaps different as-in hate.
  9. I run a 2x12 four ohm cab and a 1X15 eight ohm cab for the specific reason that each speaker is 8 ohms in parallel. Now granted that is oversimplifying things but the perceived output of each speaker "IS" matched to my ears and I really like the results.
  10. didj


    Sep 9, 2003
    Los Angeles
    Same here, I run a 2x10 4 ohm cab with a 1x15 8 ohm cab. Electrically, its 3 - 8 ohm speakers in parallel. I like the way they sound together. It sounds balanced volume wise, and the 1x15 seems to fill up the bottom, which makes the tone more balanced.
  11. notabob


    Sep 20, 2003
    cincinnati ohio
    im running (as of today) a 4ohm 210 and an 8ohm (i think, it may be 4 though) 18" in parallel. i cant figure out how to use the crossover on my tmax yet, but once ive got it, everyone is going to die...hahaha. thanks for this information, it has been quite...informative.