speaker set up questions?????

Discussion in 'Archived Threads 2001-2004' started by rodneyH, Oct 15, 2001.

  1. rodneyH

    rodneyH Supporting Actor

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    I am running b&w CDM7NT with a SVS 25-31. I have a new set up CD. I don't know the exact frequency (since I don't have the CDs "jacket" with all the info), but at a fairly low bass pass (I would guess under or around 50Hz), I am getting a "peak" of over 6-10dbs. I had the 2 ports working, the speakers are about 1 foot awat from each corner, slightly toed in. The room is 13 feet wide, 12 feet deep and 8-9 feet high. (fairly small room), and it is a box shape with NO opening (when I close the door). SVS NOT ON. The speakers are in an equal lateral triangle (about 9-10 feet apart, and 9-10 feet away from the listening position)
    I pulled the speakers away from the corner another foot (so now about 2 feet from either side) and decreased the "toe". and I used the foam plugs to seal the speaks. Still about 6 db peak (it got better, but not goog enough). The room have pluch carpet, 2 couches and 3 windows that are covered with wood velores. I really can't put the speakers much closer because they are nOT sheilded and will disrupt with the TV (but I could probably get them 1-2 feet closer, but that didn't seem to help). Should I just set them to "small" mode in my pre-amp so it will be crossed over at 80Hz, and ONLY use the SVS for bass?? (although this practice isn't ideal for DVD-A and SACD without bass management)
    one weird thing is that there is a sudden "dip" (below the baseline) right next to the "peak" in the bass that results in about a 8-10 db differnce???
    In contrast, I just moved from a place that the room was 3X the volume and these same speakers sounded like small bookshelfs no matter what I did. I can't believe what a differnce the volume makes.
    ANY IDEAS???????????????????
     
  2. Steve_Ma

    Steve_Ma Second Unit

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    Try switching the mains to small and sub to yes. Let your mains do what they do best (mid and high range) and let your subs take on all the low stuff.
    See what you think.
    --Steve
     
  3. Saurav

    Saurav Cinematographer

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    Go to www.audioasylum.com and read the FAQ section on speaker setup techniques - there are several that you can try, some will work better than others for a given situation. I'm pretty sure that keeping it equidistant from both walls is not helping your bass hump. I think I ended up using the WASP method, that seemed to give the best results in my room with my speakers.
     
  4. Bob McElfresh

    Bob McElfresh Producer

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    Rodney, I think the problem is your room. Box shapes are very bad for sound. The walls are close in size so you have 4 walls reflecting nearly the same low-frequency sounds.
    Lets run the numbers:
    12 ft wall will reflect: 47, 94, 188 hz
    13 ft wall will reflect: 44, 87, 174 hz
    (Using the formula: 565/Length-in-feet, and using 1x, 2x and 3x the fundemental frequency.)
    Notice how the 47 and 44 hz are within 10% of each other. My guess is this is where your peak is. You will also have a problem around 90hz and 181 hz.
    A lot of people have bought a product called the Behring Feedback Destroyer. This unit is a fancy equalizer where you can tell it what frequencies to reduce. Check the Advanced Topics fourm for "BFD" for more information.
    Good Luck.
     
  5. rodneyH

    rodneyH Supporting Actor

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    WOW, that is some amazing stuff, I will look into the other frequencies when I get my Avia disc and research the info on AA. Thanks for your help, that is why I come here
     

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