Calibrating my subwoofer?

Discussion in 'Beginners, General Questions' started by Phil_Lunar, Apr 27, 2003.

  1. Phil_Lunar

    Phil_Lunar Stunt Coordinator

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    might be more appropriate to this section :


    First, I must tell you that I've read a lot of past thred on this matter, but I still don't get it....

    I got a Kenwwod VR-410 receiver, 5 speakers kit(small) from Kenwood and for sub I was previously using a passive low end 8" Kenwood sub but now made myself a nice Shiva Sonotub and I've been running it for 1 month.Both my sub have been powered by my old 100WX2 Pionner Stereo amp(so I am runnig it like a poweer sub via the pre-out LFE

    Now I got Avia Guide disk and a SPL analog meter from RadioShack

    I got no problem to calibrate the 5 channels, but I got to the sub, it is a whole different story : I've read on most post here that to properly calibrate your sub level, on Avia on the chapter 7 subwoofer set up(the test when it alternate between a High noise and a low noise) I should read on my SPL(set to C and slow) the same DB for both sound noise right?

    well there must be something wrong on my set up because if I crank it that much, it is way to much bass(very strong boomy distorted, ear bleeding bass!!)

    Now don't get me wrong, I love strong bass, but tight bass, and I found that with DB hit on my SPL 10 DB lower than the higer pink noise seem to be quite a good level. And I still have very good Wall shaking bass!

    now I know that you have to set your system the way each of us like it, but I am the kind of guys that love to follow rules when calibrating, and this one dosen't match.

    at first , I tought that it was becaue of my poor first 8" sub and that he wasen't able to deliver a high level, but now with my DIY Shiva, I still got the same king of setting needed(of course It sound way much better and deeper!)

    anyone else experiencing the same king of trouble(if I can say so)?
     
  2. Lee Carbray

    Lee Carbray Second Unit

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    Phil, do you have the cinema eq on? That will mess up your base response. I have the VR-509 and with the EQ on you cannot properly adjust the base.
     
  3. Phil_Lunar

    Phil_Lunar Stunt Coordinator

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  4. Bob McElfresh

    Bob McElfresh Producer

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    A couple of things:

    - Your sub could be in a bad position where waves from 4 walls intersect at your listening position to create unusual peaks of sound. Try some of the popular subwoofer-placement techniques first.

    - Get a bass test-tone CD or download the NCH Test Tone generator and burn your own test CD. Use the SPL meter to chart the room-response at each octive frequency from ...16-120 hz. This will tell you how 'flat' your room response is. Hint: search the "Speakers and Subwoofers" fourm for "House Curve" to find others who have done this and posted their results.

    - If all else fails, you may be a canidate for the $130 Behring Feedback Destroyer (BFD). This cool device is a programmable parametric equalizer. Using your room-response data from above, you can tell this thing to reduce the problem frequencies to bring the peaks down. Search the Speakers fourm for "BFD" for more info.

    Good Luck and let us know what you did/results even the things that did not work.
     
  5. Phil_Lunar

    Phil_Lunar Stunt Coordinator

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    Well well...

    let see I've trying several position for my sub but since I got quite a Akward room, this might be a problem.

    I got a 22X20 feet room(4 concrete wall), and out of this room , I've made a 12X15 smaller kind-of-room out of big tick curtain.

    Here is a map(if I can say so) of my room
    ________________
    |----------------|
    |-------________|
    |-------|-1-TV-2|
    |-------|--------|
    |-------|--------|
    |-------|-couch-|
    |______|___3___|

    the 3 numbers, referer to the 3 positions where I've tryed my sub so far. the position 3 is the best one and the one I am using now.

    I've used a test tone generator already, and I got a pretty flat response(I will try to put a table here sometime later if I can) but let say I am quite in a +-4 db(using Radio Shack SPL correction values) from 80Hz down to 18hz where I am starting to loose it.

    as for the BFD Well, like I said, it is not realy a big problem since with my actual setting(10DB lower) I got very good tight Bass response and I really enjoy listening to movie on my system.

    so maybe, it is just because of my room. I can live with that until I move to a Own house where I will have a real room for HT.

    thanks anyway!
     
  6. JohnnyG

    JohnnyG Screenwriter

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    Here's my similar story:

    I just moved out of my old house and I'm living with my in-laws until our new house is built. I have a pair of Infinity IL60 powered towers and they calibrated perfectly in the old ~20x20 foot room. The room they are in now is ~13x25 and they are at the front, across the narrower wall. After setting the whole system up, I popped in Avia, whipped out my Radio Shack SPL meter and hit the test tones. WAY TOO MUCH BASS at the 'proper' level! I thought that maybe the battery was dying in the SPL meter, so I replaced it but the results were the same.

    Until I can put some time into it, I just lowered the sub control by 5db, but it's really still too much. The Infinity's have the RABOS single-band parameter EQ in them (it's disabled right now) and I hope this is the solution to this problem, but it's been a real head-scratcher so far!
     
  7. Phil_Lunar

    Phil_Lunar Stunt Coordinator

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    well, at least I am not alone! [​IMG]

    not much of a problem, but like you said, a real head-scratcher !
     

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