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Speaker wiring; calculating total watts not ohms

Discussion in 'Amps and Cabs [BG]' started by LeftyLB70P, Apr 27, 2009.


  1. LeftyLB70P

    LeftyLB70P

    May 4, 2005
    Athens, Ga.
    Ok, I need some help because I am baffled on this. I understand the rules in calculating ohms when wiring speakers in cabinets but I just stumbled on something that has me confused.

    I have 2 cabinets that are loaded with the same speakers, 1 is a 4x10 and the other is a 2x10. Both contain speakers that are rated at 200watts & 8ohms. The 2x10 is wired parallel and has a 4ohm load and the 4x10 is wired parallel/series and has an 8ohm load. However (THIS IS THE PART THAT STUMPS ME) the 4x10 is rated as a 600 watt cabinet and the 2x10 as a 400 watt cabinet. So does the wiring scheme change the total wattage and what is the math (if 2 200 watt speakers in parallel = 400 watts then why do 2 'sets' of those in parallel not equal 800 watts -- you see my confusion)?

    Thanks to anyone who can explain this to me.
     
  2. Bassgrinder77

    Bassgrinder77 Banned

    Jan 23, 2009
    No. Each speaker in the cabs you described takes equal power (watts) within it's cab.
    According to their cab power ratings, your 2x10 has heavier duty drivers (200W each) than your 4x10 (150W each).
    Or, perhaps the differences in mechanical loading (volume, porting) causes the mfr. to be more conservative in rating the 4x10 than the 2x10. Not certain about this.


     
  3. Your theory & math are fine. Something else is off.

    With the numbers above, either the 4x10's max power is 800 Watts or it's drivers are 150 Watts each.

    Might be something off the beaten track giving the 200 Watt derating in the 4x10. Best I could guess on that would be 1/4" jack's current rating. Anyone?
     
  4. Wes Whitmore

    Wes Whitmore

    Mar 10, 2003
    Columbus, OH
    Maybe the crossover is the weak point here. Not many over 600 watt passive crossovers exist...and if they do, they are super expensive.
     
  5. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Either the drivers are not identical or someone flunked Second Grade math. :rollno:
     
  6. experimental bassist

    experimental bassist

    Mar 15, 2009
    +1

    Max wattage of a cab should take into account every electrical component in the system and be calculated based on, yes, the "weakest point" whatever that may happen to be. In this case, probably the crossover.
     
  7. bassmentguy

    bassmentguy

    May 15, 2005
    Some companies will actually underrate their cabs to keep their more adventurous customers from ruining a good product. It's good for a reputation if a product has never been known to fail.
     
  8. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    That has to be the quote of the year!
     

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