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GK cab pairing question from noob

Discussion in 'Amps and Cabs [BG]' started by Darkhorse1962, Feb 4, 2017.


  1. I am looking to get a small cab (GK CX115 perhaps) that can pull double duty as a practice cab and a second stage cab for more output when needed.

    My current set up is a Mark Bass LM Tube 800 head
    GK cx410 800 watts 8 ohms.

    I play both active and passive basses into it if that matters.

    I know NOTHING about ohms, impedence or anything like that. Will the CX115 achieve my intended purposes?
     
  2. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    Any reason why you wouldn't want to get a matching CX410? From a sonic and power handling aspect it would likely be optimal, though it might not be as light and cheap as the 115 (I get that aspect as well if that's primarily what's driving your decision). I figured I'd ask though.
     
    Sartori, Old Garage-Bander and Joedog like this.
  3. Adding a second cab will get you louder.
    Many here will offer opinions against using a 4x10 with a 1x15 because it might not sound good.
    Others will argue that it's OK.
    I don't have enough popcorn for that conversation but I can talk a bit about Ohms and Impedance.

    Ohms is the unit of measure for both Impedance and Resistance.
    "This cab has an impedance of 8 Ohms."
    "You need a 100 Ohm resistor in that circuit."
    Resistance is the opposition to D.C. (Direct Current) flow.
    Impedance is the opposition to A.C. (Alternating Current) flow.
    A common source of D.C. is that which comes from a battery.
    In audio, music, and the world of amplifiers and speakers, we are using A.C.

    As this applies to your question, let's start by assuming both of the speaker cabs in question have an impedance of 8 Ohms each. Because of the way impedances combine (another subject if you're so inclined) the total combined impedance of the two cabs will be 4 Ohms. This is sometimes referred to as the "load."
    "My new amp is capable of handling a 4 Ohm load."
    Note: You never want to connect speakers that have a total impedance that is lower than you amp is rated to handle.

    So we have a cab with one speaker that is 8 Ohms all by itself. And we have another cab that has 4 speakers, yet it also is 8 Ohms. How the heck does that work?

    Speakers (not cabs) come in different impedances, usually 4, 8, 16, or even 32 Ohms each.
    Going back to the way impedances combine, it is possible for instance to use four 32 Ohm speakers in one cab and wire them so the cab's total will be 8 Ohms.

    Because of the laws of electricity (Ohm's law, as it turns out) if you hook two 8 Ohm cabs to an amp, half of the power will go to one cab and half to the other. Sounds like a good plan right?

    It would be if both cabs had the same number of speakers, because the power gets divided evenly between all speakers and they all are doing the same amount of work. However, we need to look at what happens inside that cab with four speakers.

    Let's assume that your amplifier can put out 200 watts with both cabs connected. Remember we said that the power gets divided equally between cabs. So we have 100 watts going to the 1x15 cab and 100 watts going to the 4x cab.
    Well, that 100 watts is getting further divided inside the 4x cab. And in this case since all the speakers in that cab are the same impedance, the power going to that cab gets divided equally among the four speakers. This means each speaker is only getting 25 watts, when the other cab's speaker is getting 100 watts. What can happen is that the 15" speaker can end up working four times as hard as any of the other speakers. This may not allow you to get all that you can out of the 4x cab if you are maxing out the 1x15. So it could be considered a waste of resources.

    For this reason, and for sonic reasons that others will likely discuss, mixing cabs can have less than desirable results. There are cases where doing it works well, but it is pretty much trial and error. If you're betting the farm on getting the best sound and keeping all of your speakers doing similar amounts of work, then matching cabs is the odds-on favorite.
     
    Last edited: Feb 4, 2017
  4. I need a practice amp to haul around. Another 410 would be way too big for a basement rehearsal room.
     
    kap'n kro likes this.
  5. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    In that case, I'd recommend the CX210. Almost same weight, same cost, with like drivers and better power handling.

    The CX115 would work, but the 210 would be a slight improvement in almost every way.
     
    RickyT, Max Blasto, eriky4003 and 2 others like this.
  6. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    If you skimmed that very thorough, detailed, and factual response, this should be your main takeaway if you go the 115 or 210 route.

    Each of your cabs will get half the power, so your 115 or 210 will start breathing heavy before your 410 even starts to break a sweat.

    Keep the smaller cab on top so you can hear if it starts farting out, and keep volume in check to prevent that and you should be good to go! :thumbsup:
     
    Old Garage-Bander and Joedog like this.
  7. If you add a 2x10 to a 4x10 make sure that the 2x10 has twice the impedance of your 4x10. This way your power distribution is optimal with all the drivers in either cabinet getting the same amount of power.
     
    Winoman and Old Garage-Bander like this.
  8. My only complaint about mixing a 4x10 and a 1x15 has nothing to do with sound. Everything to do with a 1x15 being outclassed by the 4x10 in every way leading to damage for the 1x15.
     
  9. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    Sure, given that in your 8ohm 410, each of the speakers is running at 32ohm, a 16 ohm 210 (with both speakers also at 32ohm) would fix up that power distribution problem right up.

    Primary issue is actually finding a 16 ohm 210 though, as they're really not very common. Feel free to try and search one out that's also light and cheap, but if not I stand by my CX210 recommendation and being careful.

    The second potential issue, is your desire to run the smaller, lighter cab solo for rehearsals. I'm not sure what kind of output your amp would put out at 16 ohm, but it might not be enough through a single 210 depending on volume.
     
    Gearhead17 likes this.
  10. matante

    matante

    Nov 3, 2003
    Los Angeles
    A 4x10 with your amp is loud enough to play anywhere, even stadiums. If you can't hear yourself with that rig you're playing stupid loud and causing permanent damage to your hearing.

    It sounds like you just need to buy a smaller cab for practice use, a 1x12 or a 1x15. You don't need to think about adding it to your current rig for gigs though, unless it's just for looks.
     
    Winoman and srayb like this.
  11. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    Another good point depending on sonic needs. I know that for me personally, 500w via the LM Tube 800 @ 8ohm into a 410 would probably be more than enough for any situation I'd ever find myself in. I know that others need 2x810 to get the volume their looking for, so YMMV and all that, but something to consider.
     
  12. A half way decent solder slinger might be able to rewire a 4 Ohm 2x10 to be a 16 Ohm 2x10.
    A full way decent solder slinger might be able to wire up a 4/16 switch.
    Using a 16 Ohm cab just for practice would be OK with a solid state amp.

    -edit- I removed my 1st quote. It was not intended to go out over the air.
    I proved myself wrong before I finished the thought. It just didn't get deleted properly.
    Glad I didn't say something I would be sorry for, again.
     
    Last edited: Feb 4, 2017
    Winoman likes this.
  13. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    It has nothing to do with solid state or the load the amp sees, at least not from a danger perspective.

    That Little Mark Tube does 800w 4 ohm, 500w 8ohm, and.... 250w maybe at 16ohm?

    I don't know about you, but 250w and a single 210 couldn't keep up with any of my drummers.
     
    Mystic Michael likes this.
  14. A cabinet that has an impedance of 16Ω will not be significantly quieter than the same cabinet at 8Ω or even 4Ω.
     
  15. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    My thought was more with the amp output. Let me know if I have that wrong - no official specs listed for the LM Tube 800 at 16ohm that I could find, so I just guesstimated.

    EDIT: OK I guess I take it back and see what you mean. I suppose I'd be surprised if a run-of-the-mill 210 could keep up with any of my drummers regardless of wattage.
     
    Last edited: Feb 4, 2017
  16. Watts are a really poor guide as to how loud an amplifier is. To get twice as loud you’d need a ten times increase in applied power. Dropping from a maximum of 500W to a maximum of 250W is not that meaningful. Most players seldom reach the full power capabilities of their amplifiers. The OP wants the smaller cabinet to function in a rehearsal situation. I can only hope he doesn’t use the amp at it’s maximum. His hearing is valuable.
     
    Last edited: Feb 4, 2017
  17. Maybe best just to grab a small/mid size combo to keep at home.
    Practice at home isn't really about duplicating tone at a gig, or even rehearsal.
     
  18. I was refering to using the 2x10 with the 4x10.
    Sorry if I didn't make that clear.
     
  19. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    Sorry about that, my brain was fully on the single cab track at that point!
     
    Old Garage-Bander likes this.
  20. Jules Meuffels

    Jules Meuffels Commercial User

    Apr 14, 2016
    The Netherlands
    Custom Shop Bass Cabinets
    You're best off buying another 8Ω cab, doesn't really matter if it's 2x10, 2x12, 1x12, 1x15 or 4x10"! To see what works best as a single cab, and also pared with your 4x10, you try them! Since your looking for smaller and lighter, best guess is a 2x10. If you still want a 1x15 make sure it has a tweeter for use as a single. (unless you prefer dark, deep and slow sound) If you're new cab is also high in watts like the GK, you'll have a killer stack. :thumbsup:

    And to answer your question; the GK CX115 will do great pared with the 4x10, but will only do good as a single if you play at moderate volumes because the 300w speaker will fart out fairly quickly if coupled to your amp.
     
    Last edited: Feb 4, 2017

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