Does a speaker's bi-amp connection ability change it's power handling capacity?

Discussion in 'Beginners, General Questions' started by Keith^S, Sep 29, 2005.

  1. Keith^S

    Keith^S Extra

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    I wasn't reall sure how to word the title, so please excuse it if I butchered it.

    I'm considering buying a pair of Polk Audio lsi9 speakers, and Polk's recommended amplifier power is 20-200 watts for each (speaker, set of terminals?). From reading the lsi9 manual I downloaded from Polk's website, I see that these have two sets of terminals on each speaker for bi-amp setups.

    So, does this mean that each speaker is rated to accept 100 watts into each set of terminals, effectively giving the speaker a total of 200 watts?

    Or, does the 200 watt rating mean that each set of terminals can accept 200 watts (effectively giving 400w total to each speaker)?

    Thanks for any help
     
  2. John S

    John S Producer

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    Once you bi-amp'd, I would not not even think about the power rating, except for the low end driver which I would effectively put at the full rating for the speaker.


    Notthat I have a good answer to your questions, but power where upper mid and highs are concerned really isn't a factor at all.
     
  3. John Garcia

    John Garcia Executive Producer

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    The max rating of 200w means something in the x-over is rated to 200w and will most likely fry if you exceed that by much, regardless of which terminal.

    Essentially what you are doing when you biamp is allowing each driver to draw as much current as it needs without having to share with the other driver(s). It also is going to depend on the actual needs of each driver; the tweeter is not likely to require as much current as the midbass drivers, so feeding it with 2X what it needs doesn't really buy you anything.
     
  4. MikeUp

    MikeUp Agent

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    John Garcia...California...

    Is this the Hermano man himself?! Not to embarrass you in front of the whole forum or anything...
     
  5. Keith^S

    Keith^S Extra

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    Thanks for the replies everyone. It was a big help!
     
  6. Ted Lee

    Ted Lee Lead Actor

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  7. Allan Jayne

    Allan Jayne Cinematographer

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    I would say the 200 watt rating is for the entire speaker system, all sections and all sets of terminals combined.

    The 200 watt rating of your speaker system assumes most of the delivered power output will be low frequency and in the case of a bi-amping setup, entering the system via the woofer terminals. I am (wildly) guessing that the woofer will take about 180 watts, the mid range speaker about 18 watts, and the tweeter about 2 watts.

    If a speaker accepts X watts and you do bi-amping, forcing one half of X watts into the mid-range and tweeter section by turning the treble control way up, you will definitely get a blow out.

    The wattage rating of a speaker system assumes the reproduction of sound likely to be found in nature or at a concert of acoustic instruments. Most of the acoustic energy is in the lower frequencies. Your bi-amp system volume controls must be coupled so that the various amplifier sections deliver power output comparable to the reproduction of sound likely to be found in nature. Clipping of the input signal, or certain rock music with electronic effects, will result in an overabundance of higher frequencies and then all bets are off regarding the speakers' acceptance of 200 watts.

    Excessive power can result in excessive excursion followed by physical damage to voice coils and tearing of cones as well as burning out of crossovers and voice coils.

    A completely separate topic. Within the above limitations, 200 watts could stand for a momentary burst of sound as opposed to continuous sound. I don't know the answer to that one for the particular make and model of speakers.

    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  8. ChrisWiggles

    ChrisWiggles Producer

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    It also depends on how you are bi-amping. If you are active biamping and HF and LF are separated, the power needed for the HF is a lot less. If you are passive bi-amping, the HF amp will still be driving a full range signal rather than a crossed over signal and can be driven into clipping by the unused LF components of the signal which can damage the tweeter.

    If you're not looking into bi-amping, just always remember that more watts in an amp is always preferred. It is best to exceed the speaker's wattage rating with your amp capability.
     
  9. Allan Jayne

    Allan Jayne Cinematographer

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    Driving a bi-amping setup with a higher power LF amp and a lower power HF amp from the same full frequency range input resulting in overloading the HF amp is an improper setup from the git go.

    The results of clipping of LF peaks are HF that go right through to the midrange speaker and tweeter and are audible as a fuzzy distortion.

    The HF amp must have enough of a power rating that clipping does not occur after any incoming LF is attenuated as best as is possible using built in tone controls. The amplified LF, when undistorted, will be (again) attenuated significantly by the HF speakers' crossover. Some amps when used as HF amps for bi-amping may require a full range crossover at the output and a dummy load across the woofer crossover output.
     

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