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Bass management -- active x-over or equalization?

Discussion in 'Archived Threads 2001-2004' started by Ken Woodrow, Oct 22, 2001.

  1. Ken Woodrow

    Ken Woodrow Stunt Coordinator

    Feb 12, 2001
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    I'm looking to get the best subwoofer performance possible out of my 10x17 HT for music and movies. My principal constraints for subwoofer choices are LOCATION (only one or two places to put a sub, both in the back corners of the room) and INTEGRATION (I need the subwoofer to integrate seamlessly for both movies and music, with the emphasis on music).
    I'm 98% sure that I will be going with a SVS sub. But several questions remain, given the limited flexibility of most pre/pros to handle bass management:
    1. What has the most versatility in terms of integrating the sub with the main speakers -- an active multi-channel crossover unit, like the Outlaw ICBM, or an equalizer, like the Symmetrix or ART sold by SVS? I realize that the equalizer works only on the bass channel and that the ICBM lets me set different x-over points for different speakers, but all five of my speakers are identical and are basically flat to 70 Hz. So far, I don't have DVD-Audio or SACD, but may in a future upgrade.
    2. What advantages does outboard amplification have over a powered (PC series) sub? More headroom?
    3. What is better for music, a CS Ultra or CS sub? Particularly in terms of speed, accuracy, integration, etc.
    Thanks so much.
    - Ken
  2. Wayne A. Pflughaupt


    Aug 5, 1999
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    Corpus Christi, TX
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    First, welcome to the Forum!
    I can help you with most of these questions. A few will require input from other Forum members.
    One of your rear corners will work fine for your sub. Choose the one with the “most wall” in both directions. In other words, if one corner has a doorway nearby, you would not want to use that one.
    An equalizer or crossover is not an ”either/or” decision. One has nothing to do with the other. You need both. The crossover determines the sonic division between the mains and sub. The equalizer is to smooth out the sub’s room response, for maximum performance. Since you haven’t made a purchase yet, I recommend getting a parametric equalizer instead of one of the 1/3 octave graphic models that SVS recommends. A parametric equalizer is capable of much better precision than a 1/3 octave EQ.
    Since your speakers start to roll out below 70Hz, I’m guessing they are not large floor-standing models? In this case, you want a crossover point high enough to make sure they are not overdriven, probably 100-120Hz. I don’t know what your equipment is like, but you will have to have a receiver with pre-out and main-in jacks on all channels to utilize the ICBM, or outboard amplification on all channels lacking in and out jacks.
    Others may express a different opinion, but in my case it was no problem integrating a sub for music and movies, at least with the crossover I used (24dB/octave slopes, 90Hz). I EQ’d to get the best (read smoothest) response and performance for music. This might not be optimal for movies, but I feel that accuracy and extension is ultimately more important and satisfying than merely adjusting a sub for “maximum boom.” “Maximum boom” typically means a severe hump in response at a certain frequency (typically a low one, for the most visceral effect) which will mean poor performance for music. In my experience the only difference between movies and music for a properly equalized sub is volume level. I find that the setting that works best for movies is usually a little “heavy” for music. So, you will want to turn the sub up for movies and down for music.
    As far as which is better, powered or non–powered subs, the former has the benefit of precise engineering by the manufacturer, that is, carefully matching the amplifier to the driver’s capabilities. With an non-powered sub, you have to figure that out yourself. However, in the case of SVS, they have already done that for you by recommending certain amps to go with their subs.
    Since I don’t have an SVS, I’ll have to let someone else recommend a choice for you.
    Wayne A. Pflughaupt
    My Equipment List

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