tweaking my sub is confusing

Discussion in 'Archived Threads 2001-2004' started by Jacob_R, Sep 24, 2002.

  1. Jacob_R

    Jacob_R Extra

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    I'm pretty happy with the way my setup sounds, but sometimes my sub sounds a little too aggressive. I know I can adjust the level and the cut off frequency, but I'm not sure how I should go about doing this. Is there some formula most people use? Is there a cut off frequency I should leave it on that matches a setting on my receiver? I don't want to abuse my sub, but when I turn it down a little it sounds like it should be a little louder, so when I turn it up a little, it sounds a little distorted. Any help would be appreciated.
     
  2. John Garcia

    John Garcia Executive Producer

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    Do a search on "calibration" and/or "SPL meter", and also see:
    http://www.hometheaterforum.com/htfo...threadid=55635
    Using test tones, either internal to the receiver, or from a test disc, and an SPL (Sound Pressure Level) meter is the appropriate way to set all of the levels for your speakers.
     
  3. Mark R O

    Mark R O Stunt Coordinator

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    Jacob,
    You'll need to choose between the x-over on the receiver or the sub. If both are active or adjusted to similar settings, they will conflict rather than compliment one another. Anything from boominess, loss of dynamics and detail, to "breathing" may result. I would choose the x-over that has the widest adjustment range (at least to start). Many receivers have a fixed cut-off freq. of 80 to 100 hz. IMHO, 80+hz is too high for the majority of systems. Even smaller speakers with modest subwoofers tend to blend better and give a smoother sound with x-over settings of 65 and below. The difficulty you are having is often caused from crossing the sub way too high, and then lowering the level to take away some of the "agressiveness" and bloat. Problem is, this takes a toll on dynamics and creates a gap between sub and mains. When you turn it up to compensate, strong bass and transients overload the woofer, causing the scary sounds you are getting. Try running around 65hz, and you'll find that you can set the level higher, bass will be faster and cleaner, plus the mains will appear to clean up as well. Also, if it is practical, move the sub around. Even a foot or so can make dramatic differences. If it sits on carpeting, raise of the floor with spikes, blocks, whatever. Hope this works out for you. Good luck!
     
  4. Jacob_R

    Jacob_R Extra

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    thank you!
     
  5. Bob McElfresh

    Bob McElfresh Producer

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    Mark gave a great post. Let me focus a bit more on what he said.

    Unlike a direct speaker, you actually hear a large ammount of subwoofer sounds reflected from your walls. And these sounds are like a rock dropped into a square/rectangular pan - the reflections sometimes add, sometimes subtract so that litterally the sound is much louder if you move your head a foot or so.

    Usually, you want the lowest possible frequency reflected for the umph for movies. This means putting the sub in a corner with the longest un-broken walls to either side.

    Some people do this: they disconnect all their regular speakers. They put the sub in the room where they usually sit and fire up a bass-heavy track (music or movie). Then they crawl around the corners and listen to the sound. Some spots will sound boomy/muddled. Other spots will sound nice and tight. The nice spots are marked with some masking tape.

    Then they locate the sub in one of the marked spots, re-connect the speakers and listen. Sometimes they move the sub to one of the other spots and listen again. Eventually you find a good spot and NOW you use a SPL meter to make the sub output match your other speakers.

    Note: you can make a long subwoofer cable by going to Radio Shack and buying a long CATV cable with the "F" connectors already attached. You then buy 2 "F-to-RCA Male" adaptors and presto: a 25 foot sub cable for about $12.

    Hope this helps.
     
  6. JoeyS

    JoeyS Auditioning

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    everybody's theory seems to conflict.

    if you set all the speakers to "small" like everybody says than the woofer has to be crossed to the max to cover all ranges and the receiver will decide at what level to cross. then when i cross my sub to the max it is no longer NONdirectional and distorted i can tell exactly where it comes from. if i lower the sub frequency like suggested above than my fronts have to be set to LARGE or i will have a gap in frequecy,

    i have a 15" downward firing sub

    please help
     
  7. Oren

    Oren Stunt Coordinator

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    Joey, I can sympathize. You do have to coordinate the receiver's crossover and your sub/sat crossover or you can have a gap.

    I can't customize my receiver's crossover and, worse, I don't know what it is (Sony STR-DA333ES). I suspect it's at 120Hz. So, like you say, my solution was to just set the speakers to cover the full range by turning up the sub's crossover to the max (120Hz) (the sats can go down to 100Hz and are set to small) and then let the receiver dictate the crossover. I tried setting the speakers as large, but then the sub frequencies didn't go anywhere and it sounded horrible.

    I haven't noticed any directionality in the lower frequencies, and I'd rather know that the full range is being covered.
     
  8. Vince Maskeeper

    Vince Maskeeper Producer

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    Joey,
    There is no need to spam the board with 4 copies of the same question. Post your question once, and people will help you.
    Please direct any answers to the first thread Joey started on this subject:
    http://www.hometheaterforum.com/htfo...threadid=98830
    Thanks
    Vince
     

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