Sub placement "Q"

Discussion in 'Archived Threads 2001-2004' started by Carson E, Dec 20, 2002.

  1. Carson E

    Carson E Agent

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    Is placing a sub next to and in line with a front R or L speaker OK? Yes, I'm somewhat new to 5.1 setups.
    Also sub is 15" wide and front spks are 19'' from side walls of a 15ft. wide room. So would placing the sub between the speaker and the wall be theoretically better or on the inside of the speaker between spk. and TV, 3.5ft.

    I use B&W 604S3 as mains and rears and music is 90% of listening. Most music does not need the sub but there are several CDs that do so the best music experience is what I'm looking for.
    Also due to a disability I can't be moving the sub a lot to experiment. Really appreciate any advise on inside or outside and distance from mains.
    Carson.
     
  2. Kevin C Brown

    Kevin C Brown Producer

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    The best rule of thumb I've comes across for sub placements is:
    1) In a corner for the highest output.
    2) 1/3 or 2/5 along the longest wall for flatest freq response.
    [​IMG]
     
  3. Bob McElfresh

    Bob McElfresh Producer

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    Since you are not mobile, I suggest you get:
    - A six pack of premium beer
    - A friend or nearby neighbor
    - A long CATV coax cable and 2 "F-to-RCA-Male" adapters from Radio Shack. Use this to make a 25 ft subwoofer cable for about $12.
    Prep:
    Chill the beer. Make the long subwoofer cable. Que up some bass-heavy CD. Disconnect all other speakers.
    Invite the friend over and have him put the subwoofer in place of your primary listening position. Use the long CATV coax as the subwoofer cable. Start playing the CD, perhaps even putting the bass-heavy music in a A->B repeat loop.
    Have the friend crawl along the floor near the un-active speakers where you MIGHT place the sub. When he/she finds a spot where the bass sounds smooth, not-boomy, put a beer in this location. Start at one side of the room and continue across the front wall. You should then have 2 or 3 smooth positions picked out at the end.
    Have the friend re-locate the sub to the spot that seems best to you. Re-connect the speakers, open the beer and sit back and listen. Try one or two of the other spots, opening the beer that marked each location as you do.
    Eventually you will find the ideal spot for your sub, or be so drunk you wont care. [​IMG] (The ideal placement will probably be in a corner or 1/3 or 2/5 along the front wall as Kevin suggested.)
    Remember that music and movies are almost always better when shared.
    Hope this helps.
     
  4. Carson E

    Carson E Agent

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    OK. 2/5Th's up the long wall would be 11 feet from the front wall and 5 feet from my listening position and somewhat in front of the front main. Strange but I don't dispute the point as I'm learning.
    I like the reverse listen advise. That sounds like a winner. Hope Diet Coke will work as well. Probably not. [​IMG]
    I had recently read about getting the sub out of the corner and placing in line with mains to create a better musical sound. So that's why I asked about the original setup as I'm a little bass heavy without any room treatments yet.
    I appreciate the advise and will follow through with it.
    Thanks guys.
    Carson.
     
  5. Kevin C Brown

    Kevin C Brown Producer

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    Carson- And, if you do put it in a corner, then you could go for an eq for taming some of the peaks that result, but that's another subject entirely... [​IMG]
     
  6. Steve_Ma

    Steve_Ma Second Unit

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    The answer to your question is largely dependant upon the room. FWIW, my sub ended up right next to my front left main.
    Like you, music was my main priority and I was obsessed with getting the most accurate response (and best sub integration) my room and equipment would allow for both music and movies. Here's what I did:
    First, I got a test disk. I then played test tones with the sub at different spots in my room and took measurements with an SPL meter to see which gave me the "flattest" overall response. Sonnie's excel worksheet/graph was a big help and can be found here. Sonnie, if you read this, You Rock for taking the time to put that together!
    This method and software can also be used to test different crossovers and connection types as well (line level vs speaker for instance). I left the sub in the spot that gave me the flattest response. I then decided that since I now had the “best spot” I wanted to take the same measurements using different crossover points and connection methods. After all was said and done, I ended up using the dedicated LFE out on my AVR to connect the sub (and the fixed 100hz crossover) as it measurably gave me the flattest response.
    This taught me a lot about my equipment, room, and crossovers. The process can easily take a couple of hours. It helps if you have a laptop with MS Excel loaded. In your situation, Bob is clearly on the right track with the chilled 6pk, a good friend, and an extended cable. It’s slightly labor intensive, but for me it was worth the time it took. I now have more confidence that I am hearing what I am supposed to be hearing... given the limitations of my room and equipment have, anyway.
    Best of luck
    --Steve
     

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