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Series wireing and db loss

Discussion in 'Amps and Cabs [BG]' started by ThunderStik, Nov 8, 2002.


  1. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    If you have 2 - 8 ohm 100 watt drivers and wire them in parallel you get a 4 ohm 200 watt system.
    If you wire those same drivers in series you get a 16ohm 100 system.

    Outside of the system impedance those same drivers lost 100 watts in power handling which is a 3db loss. Where does the loss in or gain (depending on how you wire the system) in power handling come from?

    If you use 4 of those same drivers and and wire series/parallel you get an 8 ohm system but what is the power handling of this system? I saw a diagram that shows wiring and power handling but I cant find it. TIA
     
  2. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    AFAIK you *don't* lose power handling. Should be the same for series and parallel.
     
  3. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    Please elaborate. Why can the 2 drivers in parallel handle 200watts and in series only handle half of that?
     
  4. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    I'm saying I believe your assumption is wrong. Parallel or series, power handling is still 200 W AFAIK.
     
  5. jpwinters

    jpwinters Guest

    Aug 22, 2002
    Norfolk, Va
    Both configurations will handle 200 watts, Just 0ne will do it at a higher impedence.
     
  6. You got it a slight bit backwards. Speakers will take the power they say they'll take no matter how they are wired or what the impedence is. What changes is the amp. Amplifiers put out different power (watts) at different ohm ratings. If you read most solid state power amps or bass amps it will tell you the power for 8,4,2 ohms but on some tube amps it has a ohm rating switch for 4 or 2 much like an Ampeg, 300 watts at 4 ohms or switch for 300 at 2 ohms.

    All I can say is be very careful with this stuff. If you don't know find a good house soundman with a good attitude and ask him a very direct question on how this stuff works. But as far as I know what I wrote is how it works, if I am wrong please email me the correct way.

    Peace
    J.
     
  7. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    I was always under the impression that a series connection halved the power handling capability.

    What would the power handling be on a series/parallel system with 4 of the above drivers be.

    EDIT added remarks.

    I know about the amps impedance and output but I have seen digrams that show a halving in power handling when wireing was done in series, thats why I asked the question " where does the loss come from".
     
  8. Nope, power handling remains the same. Four 100 watt drivers would handle 400 watts regardless of how you wired them.
     
  9. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    I have seen diagrams that show a halving in power handling when wireing was done in series, thats why I asked the question " where does the loss come from".
     
  10. Alright this is how I would do it. Here are two ways:

    #1: If you are using four cabs with one speaker in each and each speaker is 8 ohms and your amp can do a *2 ohm load* if it can't don't try this. If your amp has two speaker outs take one and go to cab A and then parallel that to cab B and then go amp to cab C and and parallel that to cab D. If you only have one out you can try going amp to cab A,B,C,D. These two methods will give you a 2 ohm rating and may sound a little dirty because of the gain in THD (total harmonic distortion).

    #2: If you have one cab with four 8 ohm speakers go this route. Parallel A to B and then C to D. Now take you positive wire from you connector and go to A then take your negative wire to C then take a single wire and hook the negative of B to the postive of D. This will give you an 8 ohm load and the better sound.

    Now you should really check the output rating of the amp here. You should go by the PROGRAM output rating not the peak or continuos. If your PROGRAM rating is 200 watts at 4 ohms you should only use one or two of the speakers just for the sake of strain on the amp. I don't think it will hurt amp if you put a bunch of speakers on it as long as the impedence is correct. To me it just sounds better if it is only pushing what it was made for.

    Well that my two cents
    J.
     
  11. ihixulu

    ihixulu Supporting Member

    Mar 31, 2000
    getting warmer
    There is no loss. Either you read the diagram wrong or the diagram was wrong in the first place.
     
  12. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    But see, everybody's trying to tell you: there *is* no loss! Either the diagrams you mention are wrong or you may have misunderstood them.

    As was stated above, what changes with varying speaker cab resistance is the power your amp can push into them. Theoretically, an amp (thinking about a typical solid state bass amp as an example) that can push 400 W into a 4 ohm load can only push around 200 W into an 8 ohm cab. (In practice the mathematical ratio is not so neat, but this is in the ballpark.) But this has nothing to do with how much power your cab can handle--that stays the same.

    And think about it: if your assumption were correct, that would mean that power handling would drop even further as you added even more speakers. Eventually, you would get to the conclusion that if you hook up *several dozen* 100 W speakers, the total power handling capacity of the system is 1 W or less. Does that seem plausible?
     
  13. absolutely correct:

    As was stated above, what changes with varying speaker cab resistance is the power your amp can push into them. Theoretically, an amp (thinking about a typical solid state bass amp as an example) that can push 400 W into a 4 ohm load can only push around 200 W into an 8 ohm cab. (In practice the mathematical ratio is not so neat, but this is in the ballpark.) But this has nothing to do with how much power your cab can handle--that stays the same.


    ***********************************

    the (solid state) amp's output transistors can put out MORE current (thus wattage) when the output load is a LOWER resistance. Of course, there is a limit to how low you can go, lowest possible resistance (dead short) will cause the power transistors to destroy themselves....
     
  14. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    Im not trying to hook up a cab or anything. I saw a diagram a while back and along with the wireing it was showing the power hadling capacity for a theoretical set of drivers and it had the power handling cut in half on the series wireing.

    I have no problem with there being "no loss" as this is what I beleived before I saw that diagram, but after that I could not figure out there would be a loss in power handling so I decided to ask the question here. So the diagram had to be wrong.

    I wish I could find that damn diagram. Really , I just could not see how there would be a loss, now I know why I could not figure it out .....because it was WRONG WRONG WRONG.
     
  15. Phat Ham

    Phat Ham

    Feb 13, 2000
    DC
    I've never been able to find a definition for program power handling. Has anyone else? IMO it's just one of those things amp manufacturers made up to make it seem like their amps are more powerful. I'd still go with the RMS (aka continuous)rating.
     
  16. 1) There is no loss. I think that's been established:D
    2) The only power rating that really means anything is the Continuous Average power, often misnamed RMS power.
     
  17. Phat Ham

    Phat Ham

    Feb 13, 2000
    DC
    what's the difference?
     
  18. RMS is a term that can be applied to AC voltages and currents. It's true that power is current multiply by voltage but the RMS formula doesn't translate to power, because of the complex phase issues in power. Continuous average power is what the speaker/amp manufacturers quote as RMS. It's wrong but I think they do it because it's a term most people are familiar with.
     
  19. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.