Dual Subs?

Discussion in 'Speakers' started by JasonWUC, Jul 12, 2003.

  1. JasonWUC

    JasonWUC Agent

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    Hello All,
    I have a chance to get replace my existing DefTech PF-15s with some M&K subwoofers (MK-5000 & V-125.)Is is better to have:

    -Stereo subwoofers attached to the LFE channel?

    or

    -One subwoofer on the LFE channel and two smaller subs in-line with the surround and surround-back channels; so I can set those speakers to 'large' setting?



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  2. Terry Montlick

    Terry Montlick Stunt Coordinator

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    If you put both subs on the LFE channel, you can in general get flatter subwoofer response over a wider listening area. That's assuming you place the subwoofers optimally, which is easier said than done.[​IMG]
     
  3. JasonWUC

    JasonWUC Agent

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    If I use one sub in the LFE channel, one sub matrixed with my surrounds (via speaker level inputs), and one sub matrixed with my surround backs, won't that create the same node/anti-node cancellation effect? Or would the two matrixed subs be too hard to integrate into the room considering they would be reproducing a different bass signal than the LFE?

    Is it much better to go with the stereo subs from the LFE and set my surrounds to 'Small' on the processor?
    Is there enough bass signal in the surround/surround back channels to warrant matrixed subs and setting them to 'Large' via the processor?
     
  4. Richard_M

    Richard_M Second Unit

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    Hello Jason,

    You should do some searching on this forum regarding sub placement, Terry has given good advice.

    By all means you can play to your hearts content with all sorts of options, but I bet you end up doing what Terry has suggested.

    I found over the years that there are a lot of variations one can play with, but in the end the object of the whole exercise is enjoyment, and once you have properly calibrated your whole system you can then reap the rewards.

    Richard
     
  5. JasonWUC

    JasonWUC Agent

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    I'm sorry, my intent was not to disregard Terry's advice, I truly appreciate it. I've read a lot about dual-LFE subwoofers, but not a lot (in magazines)about the benefits of setting surround/surround back speakers to 'large.' I wanted to see if anyone on the forum has compared the two styles and had a strong opinion on one or the other.

    Thanks for your input.
     
  6. Wayne A. Pflughaupt

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    Jason,

    You might take a look at the info at this post for some good information.

    You can’t get “stereo” subs from the LFE feed because it is mono. All you’ll have it two subs delivering the same signal. However, there is nothing wrong with that.

    There is a good reason why you don't see articles in the magazines extolling the “benefits” of using a rear sub. It’s because there isn’t any. Usually there are only one or two "prime" locations in a room for the subs, and the chances that one of them is exactly where you need to place a rear sub (i.e., centered between the rear speakers, etc.) is pretty slim.

    Basically you want your two subs positioned where they perform the best – i.e., the smoothest response, lowest extension and highest SPL level. In most rooms, parametric-equalized corner placement - a corner with uninterrupted walls in both directions - delivers all three of these parameters.

    Without equalization, corner placement will deliver the lowest extension and highest SPL level, but often less-than-optimal response. Smoother response can often be achieved with careful out-of-corner placement, but at the expense of maximum output and extension.

    I'm only speaking in generalities here. As is noted in the post linked above, every room is different and there is no "magic formula" that works in every single situation. Optimizing subs in most rooms, with or without equalizing, is not a “quick and easy” proposition. It is time consuming and requires much measuring, testing and listening.

    Regards,
    Wayne A. Pflughaupt
     

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