Bi-Amping question

Discussion in 'AV Receivers' started by Christian B, Oct 16, 2003.

  1. Christian B

    Christian B Agent

    Oct 12, 2003
    Likes Received:
    Trophy Points:
    Looking to get an Outlaw 7100 which does 7x100 at 8 ohms or 7x165 at 4 ohms. My fronts are LSi15s, and if I bi-amp them they will receive 100x2 since they have 2 8 ohm loads. That means the tweeter and both 5.25"s will share 100 watts of power while the 8" woofer will get the remaining 100 watts. NOW my LSi9s will receive 165 watts due to having a 4 ohm impedance. The LSi9s tweeter and dual 5.25"s will share the 165 watts of power. SO the LSi9s mids/uppers will get 65 more watts than the LSi15s mids/uppers. Make sense? Trying to figure out a way to give my LSi15s upper section more power but the only way would be to get a separate amp that will drive 8 ohm loads better. This makes me angry LoL!

    Do you guys have any suggestions? I was also considering the Marantz MM9000 which is 140x5 at 8 ohms and probably somewhere near 200x5 at 4 ohms, although I've heard mixed feelings about that amp. ANY and ALL input is GREATLY appreciated!
  2. Wayne A. Pflughaupt


    Aug 5, 1999
    Likes Received:
    Trophy Points:
    Katy, TX
    Real Name:

    I expect that no one has responded because they have no idea what “LSi15” and “LSi9” is. There are literally thousands of home theater products on the market, tens of thousands of you include older discontinued products. The folks here are fairly knowledgeable, but it’s unrealistic to expect that they can identify every product ever made merely by model number.

    That said, a Google search on LSi15 got me what I needed - fortunately.

    If I understand the question, you’re concerned that the dual 5.25“/tweeter array on the LSi15, with 100 watts, will be under-powered compared to the identical 5.25”/tweeter array on the LSi9 at 165 watts.

    I don’t see this situation as anything to worry about; these things often look worse on paper than they are in real-life application.

    Still - if you look at the specs for both speakers on Polk’s web site, you can see that the mid/tweeter array in the LSi15 is high-passed 6db/octave at 150Hz. Meanwhile the LSi9 operates full-range, with response to 38Hz (an optimistic number, I’m sure, but that that’s outside this discussion).

    Since the LSi9 operates full-range, it will require more power than the same array on the LSi15. Even if you have the 9 set as a “small” speaker, it will still be operating nearly a full octave lower than the 15.

    Anyway you cut it, the 9 needs more power than the mid/high array of the 15.

    Wayne A. Pflughaupt

Share This Page