explain to me about multiple subwoofers

Discussion in 'Archived Threads 2001-2004' started by felix_suwarno, Jan 16, 2002.

  1. felix_suwarno

    felix_suwarno Screenwriter

    Joined:
    Dec 2, 2001
    Messages:
    1,523
    Likes Received:
    0
    Trophy Points:
    0
    explain me :

    what is the advantage?

    how many is enough?

    room size versus number of subwoofers?

    placement?

    the no-no list / what not to do? ( i heard about cancelling phenomena from 2 different sizes sub placed on different locations )

    thanks in advance
     
  2. Cees Alons

    Cees Alons Moderator
    Moderator

    Joined:
    Jul 31, 1997
    Messages:
    19,412
    Likes Received:
    312
    Trophy Points:
    9,110
    Real Name:
    Cees Alons
    You can have more than one sub just to get more power (louder sound), but in most rooms and with most subwoofers, that's certainly not necessary. If you want to do it: what's not done (very stupid) is to have them out of fase. This means they are effectively canseling each other.

    What is useful, is having more than two subs for another reason: one sub for the subwoofer (effects-) channel, and one or more to make some other channels (often the L & R or the Center) "full range". Some people prefer the L and R main channels to be full range, because they consider the soundstage better suited for audio listening that way.

    If you do not have that, you generally choose to set your fronts to "small" (as compared to "large") on your DTS- or DD-processor and the processor will then send the lowest frequencies of those channels to the LFE-channel (hence your sub, if you have one).

    This isn't bad, because it's impossible (or almost impossible) to locate te spatial source of a bass sound in a room < 10' x 10', or so.

    Again: not to be hooked up or switched in the wrong phase!

    Cees
     
  3. steve nn

    steve nn Cinematographer

    Joined:
    Jan 12, 2002
    Messages:
    2,418
    Likes Received:
    0
    Trophy Points:
    0
    Two subs work great for me.Front speakers set to small.Gives me a much rounder sound and adds more sonic feel and has more base than I can handle on 6 channel DVD.Where to place them is a matter I think only you can decide what sounds best.It will give you much more leeway. steve nn
     
  4. felix_suwarno

    felix_suwarno Screenwriter

    Joined:
    Dec 2, 2001
    Messages:
    1,523
    Likes Received:
    0
    Trophy Points:
    0
    thanks for response.

    but what made them out of phase?
     
  5. BruceD

    BruceD Screenwriter

    Joined:
    Apr 12, 1999
    Messages:
    1,220
    Likes Received:
    0
    Trophy Points:
    0
    This is a very difficult question to answer with any kind of quick answer, I will attempt to give a little background.
    If you are looking for a balanced bass response, the answer below is not likely to give you that result.
    quote:
    -----------------------------------------------------------
    Gives me a much rounder sound and adds more sonic feel and has more base than I can handle on 6 channel DVD.Where to place them is a matter I think only you can decide what sounds best.It will give you much more leeway. steve nn
    -----------------------------------------------------------
    In the above example you will probably get more bass, but not necessarily well balanced bass throughout the 20Hz-200Hz range. Your preferences in HT are what matters so listen to whatever pleases you for sure.
    The phase switch (most subs have one) tries to match the in/out movement of the speaker cone of the sub with that of the main speakers or another sub. Distance from one speaker or sub to another may change phase. Example: putting a sub in the rear of the listening room may require the phase switch to be adjusted. The position of the phase switch that gives the most bass is the correct setting.
    How to get balanced bass in your HT room
    Controlling specific bass frequency peaks and valleys (every HT room has them) is critical to getting smooth and deep bass response. The peaks and valleys can be controlled, but typically not by adding more subs.
    Measuring the actual bass frequency response of a sub in multiple positions to find the best position (with the smallest variation of SPL output from 20Hz-200Hz), will help optimize the bass response for that room and sub combination. Two subs adds some complexity to this task.
    After that, we usually add a Parametric Equalizer just in front of the sub to reduce any specific frequency peaks we couldn't get rid of by just sub positioning.
    This measurement for best position can be done quite simply with a RS SPL meter, a test CD like the Stryke disk and writing the SPL response of each frequency produced by the sub on paper or an Excel spreadsheet and then graphing. Use a logarithmic "X" axis on the Excel graph.
    All SPL meter readings should be taken at your listening position.
     
  6. felix_suwarno

    felix_suwarno Screenwriter

    Joined:
    Dec 2, 2001
    Messages:
    1,523
    Likes Received:
    0
    Trophy Points:
    0
    is it worth the trouble to have multiple sub? personally when i have more money i prefer to just buy the hyped svs ultra with the samson amp. one should be enough for a 5 times 4 meter room. or not enough?

    i am confused.
     
  7. BruceD

    BruceD Screenwriter

    Joined:
    Apr 12, 1999
    Messages:
    1,220
    Likes Received:
    0
    Trophy Points:
    0
    With your room size it sounds like one sub would be best.
     
  8. felix_suwarno

    felix_suwarno Screenwriter

    Joined:
    Dec 2, 2001
    Messages:
    1,523
    Likes Received:
    0
    Trophy Points:
    0
    ok, i am done with this question, thank you very much
     

Share This Page