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Matching Cabs to Heads

Discussion in 'Amps and Cabs [BG]' started by Char-Lee, Sep 3, 2004.


  1. Char-Lee

    Char-Lee

    Aug 29, 2002
    Spokane, WA
    I've been reading alot of different recommendations from different amp companies (Ampeg, Epifani) as to how to match cabs to heads. Some say you need to have a head that pushes more power then the cabinets pull i.e a 300watt head with a 100watt cab. But I've also seen the classic Ampeg 810 with the SVTCL and that setup is the opposite cab is 800watts head is 300watts. I run a Mesa Big Block 750 with a mesa 2x10 (600 watts @ 8Ohms) and an Ernie Ball 2x12 (600 watts @ 8Ohms) So thats 1200 watt handling at 4ohms correct. And my head should be pushing out 575 watts @4ohms. I've EQ'd the amp compressed my bass and I'm just cliping the crap out of the speakers. I never had that problem with my Ampeg 810 and it only handled 800watts at 4ohms. I'm just frustrated can an body help or give me any recommendations.

    Thanks
     
  2. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    There is no way that the MM 2x12 is going to handle 600 watts if you are running it full range. More like 300 to 350 ... and the rating on the 2x10 ? again not, if you are running it full range. If it were the top half of a bi amp rig, taking the 125 hz and up range, maybe.

    From experience, you will learn to through the factory ratings out and trust only your ears...

    The 2x12 can get pretty loud with 300 watt's as long as you don't over-emphasize the sub-60 hz range. The cab itself will go pretty deep, but you get lot more volume out of it if you go easy on that end of the EQ. It is not the cab for dub ... the 8x10 is though ...

    With my basses, I'm running 40 at +2, 80 at +2, 800 +2 1800 to 3500 -2, 5k -2. Get's a nice thick sound with no fret clack. I'm doing mostly 'rootsy' stuff with an Active J, Active PJ, Passive J fetless and a Passive but hot G&L SB2. A mix of rounds and flats.
     
  3. xyllion

    xyllion Commercial User

    Jan 14, 2003
    San Jose, CA, USA
    Owner, Looperlative Audio Products
    Yep, the ratings really don't tell you much. Nothing beats your ears for deciding what you like.
     
  4. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    The Republic of Texas
    Make sure that nothing in your signal up to the cabs is clipping (try adjusting various levels along the way to try to maximize output without clipping anything.

    If you are just overdriving your cabs with a clean signal, maybe you need to upgrade one or more cabs...

    Good luck.
     
  5. scottbass

    scottbass Bass lines like a big, funky giant

    Jul 13, 2004
    Southern MN
    Some say you need to have a head that pushes more power then the cabinets pull i.e a 300watt head with a 100watt cab.

    There is a complete and serious lack of understanding here!

    Cabinets don't "pull" power, they WITHSTAND it. If you "push" 300 watts from an amp (head) into a cabinet that will only witstand 100 watts, it's bye-bye cabinet!

    Your amp (head) may be rated something like 300 watts at 4 ohms, 150 watts at 8 ohms, and (if it's tough) 600 watts at 2 ohms. Your cabinet has only one impedance, and it's probably either 4 ohms or 8 ohms. If your amp (head) puts out more power at that particular impedance than your cabinet will withstand, you will fry the cabinet if you turn the amp up loud.

    Some people are careful about the volume level and get away with using cabinets that are rated for less power than the amp (head). Then again, some people drive drunk and never get caught.

    Risky behavior is risky behavior. Use a cabinet (or pair of cabinets) that will handle what your amp puts out. Or get a smaller amp. Or be prepared to fry your cabinet during the middle of a gig.
     
  6. Char-Lee

    Char-Lee

    Aug 29, 2002
    Spokane, WA
    Thats what I've always thought, you need a cab that can handle the power the head is putting out at the same ohms. But if you check out Epifani's website they have an information section and thats were it confused me.
    http://www.epifani.com/faqs.htm#2

    So I think I'm on the right page, the cabs I have right now just are not handling the 575watts I'm putting out at 4ohms. I don't have these cabs bi-amped I'm running just full range mono. Damn I wish I hadn't sold my 8x10. Anyway I wonder why Epifani would recommend that sort of set up?

    So what cabs do you guys think would do well with a Big Block 750 (750watts @ 2ohms) active Modulus Flea bass and I'm sure this has an effect on it, we tune down to C# and B so my four string is actually strung with a 5st set minus the G.

    I appreciate all the help
     
  7. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    The Republic of Texas
    Try drivnig each of your two cabs one at a time and push it until you start hearing the distortion you're talking about above. If one starts crapping out at a relatively low volume level then that cab is your weak link in your system (I would guess it's the MM 2x12). Either get rid of that cab and try something else or sell both and start from scratch (cab-wise).

    If the Mesa 2x10 is one of the better ones made, the cheapest solution would probably be to buy an older Mesa 1x15 Diesel cab to mate with the Mesa 2x10 you already have. You can keep or sell the MM 2x12.

    Starting from scratch, recommendations would be based on how much money you have to spend.

    Schroeder, Accugroove, Bergantino, Epifani (NYC -- I don't like the UL series), Aguilar GS112 sound good combined with the GS210, and Eden XST cabs are pretty good.

    Good luck.