Is there any truth to the rumor that:

Discussion in 'Amps and Cabs [BG]' started by Bim1959, Apr 21, 2014.


  1. Bim1959

    Bim1959

    Apr 15, 2009
    Naples Florida
    Sales and electronic tech/piano tech: England Music Center - Clinton IA - now closed
    If you run 2 cabinets daisy-chained the first cabinet gets slammed more than the second. They both see the same power but the first cabinet takes more of the initial signal.

    I always thought that both cabinets see the same power - the amp "sees" a 4 ohm load for example and both cabinets share the signal equally.
     
    JR Bass 62 likes this.
  2. BrBss

    BrBss

    Jul 9, 2010
    Albuquerque NM
    Assuming the cabs have the same impedance, you are correct that they both receive the same power.
     
  3. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    You are right. The rumor is wrong.
     
  4. jeffmaxwell

    jeffmaxwell Commercial User

    Oct 8, 2007
    San Diego, CA
    owner, Silver Hammer Designs
    Both cabinets share the signal equally.
     
  5. B-string

    B-string Supporting Member

    The rumor sounds like something a guitarist at G.C. would say :D
     
  6. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    Whoever told you that one is pulling your middle leg.

    The speed of an electromagnetic wave propagating along a copper wire is somewhat less than the speed of light. I wouldn't worry about one cabinet getting slammed.
     
  7. lol, that's to funny.
     
  8. jumblemind

    jumblemind I also answer to Bryan Supporting Member

    Aug 27, 2011
    Knoxville
    Ha. Well maybe the rumor grew out of a misunderstanding of the fact that mixing drivers will divide the wattage unevenly among the speakers. Like daisy chaining a 1x15 and a 4x10...the wattage will be equal to each cab, but the wattage each speaker in the 4x10 sees will be a fraction of that seen by the one speaker in the 1x15.
     
  9. Mystic Michael

    Mystic Michael Hip No Ties

    Apr 1, 2004
    New York, NY
    I've never heard anything of the kind. There seems to be a never-ending wellspring of dopey ideas, continually bubbling up from the Nether Regions of Collective Stupidity. :rollno:

    MM
     
    BryanC likes this.
  10. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    I'm with B-String on speculating where that bunk came from. I've totally heard more than a lions share of that kind of stuff from salesfolk.
     
    B-string likes this.
  11. ReidK

    ReidK Jst sy n t lsy cmprsn.

    You make that sound like a bad thing...

    Reid
     
  12. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    I guess it depends on who is doing the pulling.
     
  13. Arjank

    Arjank

    Oct 9, 2007
    Above Amsterdam
    You mean series or parallel wiring? Cuz when you mean series-wiring the rumor is partially/sort of true.
     
  14. No it isn't.
     
  15. dincz

    dincz

    Sep 25, 2010
    Czech Republic
    With series wiring how do you know which speaker is "first"?

    That was a rhetorical question by the way :)
     
  16. Arjank

    Arjank

    Oct 9, 2007
    Above Amsterdam
    That's why I wrote it's partially/sort of true, it doesn't matter which one is first but it matters which drivers draws the most energy from the amp in a series wiring and that'll be the one with the lowest impedance. Since most drivers have manufacturing tolerances their impedance(around the Fs) and Fs varies. So, when you wire two woofers in series they will not draw exactly the same power form the amp, one driver will get less power from the amp which results in a less accurate sound. That's the reason I allways recommend parallel wiring, it doesn't have this problem. If you do wire in series make sure each woofer has it's own enclosure.
     
    Last edited: Apr 22, 2014
  17. Arjank

    Arjank

    Oct 9, 2007
    Above Amsterdam
    Give me a reason why series wiring is as good as parallel wiring.
     
  18. If your two drivers are not equal, it does not matter whether they are wired in parallel or in series. You will have an imbalance.

    If they are equal, then in series each driver will draw identical power. In parallel, they will draw identical power.
     
  19. eyeballkid

    eyeballkid

    Jul 19, 2009
    P bass pickups. ;-)
     
    Lindex and Geri O like this.
  20. Let's say we have a 4 ohm driver and an 8 ohm driver. Let's assume we have a 12 volt power supply capable of supplying as much current as we need.

    Let's first wire these in series. The total circuit impedance is now 12 ohms. The current flowing through the circuit is going to be 1 amp (Ohm's law, V=IR). Each driver is passing 1 amp of current, since it's a series circuit. You can calculate the voltage drop across each driver--again, using V=IR--and find the 4 ohm driver is getting a 4 volt voltage drop, and the 8 ohm is getting an 8 volt voltage drop. (Good, they add up to the total 12 volts) Now the power each driver is receiving: the formula for power is P=VI. So for the 4 ohm driver, P=4*1 or 4 watts. For the 8 ohm driver, P=8*1 or 8 watts. The 8 ohm is drawing twice the power.

    Now let's wire them in parallel. This time each driver has the same voltage drop but different current. The 4 ohm driver draws 3 amps (rearrange Ohms Law and get I=V/R, so I =12/4 or 3 Amps). For the 8 ohm driver, 12 divided by 8 yields 1.5 amps. The 4 ohm is drawing twice as much current. Now let's calculate power. P=VI. For the 4 ohm, 12 volts times 3 amps equals 36 watts. For the 8 ohm, 12 volts times 1.5 equals 18 watts. Now the 4 ohm is drawing twice the power.

    So it doesn't matter which way we wire two unequal drivers, either series or parallel. One driver always gets proportionately more power than the other. If one driver is twice the impedance, that proportion will still be 2:1 whether series or parallel. It's just one way the lower impedance gets twice the power, the other way the higher impedance gets twice the power.
     
  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
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