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Thread: quest for sub equalization...

  1. #21
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    Ok, indulge me with these experiments please Curtis...
    (when you get time of course).

    Max Extension Mode.
    Turn your sub's volume up to 70dB using your pre/pro and an SPL meter.

    What SPL's do you get for...
    10, 15, and 20Hz?

    If you have "The Incredibles", test this please.
    (max extension, sub matched with mains)
    Time 0:37:45 to 0:38:30
    With an average SPL of 75-80dB and peaks in the 100-105dB range (using the RS meter in "fast" mode) what type of output do you get? Is the bass distorted, or does the sub bottom out at all? This is my weekend volume level which is about as loud as my favorite theater. The SVS bottomed in 12Hz mode at these SPLs.

    SPL level is definetly an important number, just as frequency range, and a flat response are. If you can't go over 90dB without compression or the sub starts to distort at 25Hz, the accuracy of the sub is going to be poop unless you listen at 60dB and don't care about extension.. Now that I've experienced the difference a BFD can make, I think the biggest problem with speakers/subs not being "accurate" are huge swings in the FR. I'm not looking for 115-120dB reference peaks, just 100-105dB hits.

    I'm definetly curious about what results you get!
    Last edited by Nicholas Mosher; 04-10-2005 at 09:03 PM.

  2. #22
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    Quote Originally Posted by Nicholas Mosher
    Turn your sub's volume up to 70dB using your pre/pro and an SPL meter.


    SPL level is definetly an important number, just as frequency range, and a flat response are.
    What frequency at 70dB?

    That is fair, but I disagree a bit...do you care how loud your speakers can play? Is it as important as FR and a flat curve? Those three numbers do not tell you how the sub will sound. Just like I can give you two speakers with the same specs and FR measurements, they will sound different.

    For music, I don't think SPL is as important, for HT, it depends on your individual listening levels. Those 106dB peaks I just experience, I can't imagine someone listening to that movie louder than that and thinking it was safe.
    -curtis

  3. #23
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    OK...I just watched that time sequence on the Incredibles. First, that is around 10dBs louder than I would play it......wow, what an experience!

    Anyways, during that sequence, with the meter set to fast and the 100dB scale, it pegged 106 two or three times. No adverse affects and no bottoming at all.

    I will try the indvidual frequencies tomorrow.

    That canyon I had at about 40hz....one of the Hsu guys told me that the best way to get rid of it is with a second sub and or room treatments. Other than that, he says the in-room response is not bad and that I might not benefit from a BFD much. And that dip around 95hz is a Radio Shack SPL meter issue....so how did I get rid of it I wonder?

    More measuring this week to make sure I am doing it right. It has become more important to me now to make sure the measurements truly explain my room. It is a great learning experience in process.
    -curtis

  4. #24
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    I disagree that the 95Hz dip is a problem with your meter. It doesn't show on your third location sweep, and it isn't a general problem with the meters since mine didn't demonstrate that even when compared to my other measurement setup.

  5. #25
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    Yeah, 105dB peaks are my upper-limit. I usually peak between 100dB and 105dB on weekends.

    Glad to hear you didn't bottom out or get any port chuffing in "Max Extension" with only one port free. I'm curious now what you get for SPLs with the Infrasonics. Just calibrate to 70dB with pink noise, then run some infrasonic tones from 10Hz to 20Hz.

    What I meant by SPL importance is that if the sub can't fill-out your room with clean bass at SPLs you want, then no matter how accurate it is it will always be lacking. There is an interesting thread at AVS regarding transient response/accuracy in the sub section. Hopefully it flourishes into good reading, as I'm interested in learning more about this topic (TR).

  6. #26
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    With the test tones I have, they do have a pink noise level setting track.

    70db is what they recommend. All freq's are referenced from that setting.

    Gotta find enough free time, when wife and kids are not home, to take readings using this new disc. Still have to insert the BFD into the chain so the wife does not notice it (Hmmm....maybe Curtis is on to something being wifeless!!)

    I gotta say, though, even un-EQ'd, "I, Robot" sounds pretty darn good!
    Ed

    * Sierra-2EX's W/V2 crossover upgrade
    * (2) Rythmik F12's
    * Parasound Halo P6
    * Audio by Van Alstine DVA-M225 Monoblock Amps
    * MiniDSP 2x4HD For Sub calibration
    *World's Best Cables Canare 4S11 speaker cables

  7. #27
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    Nicholas,
    Did you hear chuffing with the PB10 with stuff below 25hz? I agree with your re-wording of SPL importance.

    Thanks for the heads-up on the transient response thread....that will be interesting. I do know that there is a measurement/test for drivers that tests impulse response...testing how quickly a driver responds to a signal.

    This transient response I think is directly related to how articulate a sub is, which is one of the big differences I have heard when comparing subs.

    For the FWIW file - the gain on the VTF-3 is at about 25%, a quarter turn, and the sub level on my pre-pro is at -1.
    -curtis

  8. #28
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    I would love to see cumulative spectral decay for the various popular subs as Dave F. lists for his speakers.

    In fact, I'd love to hear Dave F. give his opinion on spectral decay/transient response and speaker accuracy when it comes to subwoofers. In fact, in fact (double), I'd like to see AA release it's own subwoofer.

  9. #29
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    [/QUOTE[ In fact, in fact (double), I'd like to see AA release it's own subwoofer. [/QUOTE]

    How about a matching powered sub/pedastal stand for the 170's?!!
    Ed

    * Sierra-2EX's W/V2 crossover upgrade
    * (2) Rythmik F12's
    * Parasound Halo P6
    * Audio by Van Alstine DVA-M225 Monoblock Amps
    * MiniDSP 2x4HD For Sub calibration
    *World's Best Cables Canare 4S11 speaker cables

  10. #30
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    Quote Originally Posted by Nicholas Mosher
    I would love to see cumulative spectral decay for the various popular subs as Dave F. lists for his speakers.

    In fact, I'd love to hear Dave F. give his opinion on spectral decay/transient response and speaker accuracy when it comes to subwoofers. In fact, in fact (double), I'd like to see AA release it's own subwoofer.
    I would too!

    When I first got my Ascends, I asked about Ascend making their own subwoofer. The answer was something like "With as good as the Hsus are, and since we are able to sell them, there is no need to."
    -curtis

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