DIY SVS Sonosub Complete

Discussion in 'Home Theater Projects' started by Troy R, Mar 10, 2004.

  1. Troy R

    Troy R Stunt Coordinator

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    I finally finished my DIY SVS sub. I bought the driver back in November and never had any extra cash or time to do anything with it until recently.

    The sub sounds pretty good. I haven't had much time with her, but she is a step up from the predecessor (Polk PSW450).

    The two problems I am having is that it doesn't seem to be playing as low as it should. Or maybe I just can't hear past 22hz or so, but it seems to be hitting brick wall after that, although I haven't really tested it fully to see, this was just from a few quick test tones at low volumes. My design was supposed to be -3 dB's around 20 hz or so... Oh well, it still sounds pretty good.

    The second "problem" is that I can localize the bass. I think it's mainly due to the pressure wave that it's creating in my little apartment. I can "sense" where the wave is coming from so that is kind of distracting. One things for sure, I'm definitely pissing off the neighbors!

    More construction and misc. pictures

    You can see the "mini" PSW450 sitting next to the sonosub which is around 36" tall:
    [​IMG]
     
  2. DanielKellmii

    DanielKellmii Supporting Actor

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    Looks great. About how much did you spend?
     
  3. Troy R

    Troy R Stunt Coordinator

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    Thanks!

    Around $250. The only major expenses were the driver ($50) and the amp ($90). Luckily I got the amp from scratch and dent at Parts Express. The thing looked brand new to me!
     
  4. ColinM

    ColinM Cinematographer

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    The PE amp, if item 300-796, has a boost at 30hz and a subsonic filter in the low 20's. If 300-794 the SS filter is at around 19hz. May have an effect on the f3.

    I built mine based on 90l, 9" x 3" flared port. I could freely EQ boost on the 20hz slider, never bottomed. I modified the SS filter as well, down to 17hz. Great sound!
     
  5. Troy R

    Troy R Stunt Coordinator

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    I do have the 300-794 amp. Thanks for the info! the sub does sound great. I heard some things I've never heard before on a few CD's yesterday.

    The sonotube vibrates a bit so I'm wondering if that is why I can localize it so easily, or if it is just the pressure wave. I'm not sure. I'll have to move it to another spot and see what the results are.

    Is there anything I can do to the sonotube so that it doesn't vibrate as much?
     
  6. Patrick Sun

    Patrick Sun Moderator
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    How high is the sub crossed over with the main speakers? The higher you go in frequency, the more localized it'll be.
     
  7. Troy R

    Troy R Stunt Coordinator

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    I've got the crossover at 40hz trying to bring it up underneath my speakers which go down to the low 40's. I have my speakers running full range.
     
  8. Aaron Gilbert

    Aaron Gilbert Second Unit

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    Looks good! 40Hz crossover? Do you know the slope? If it's the standard 4th order 24db/octave, you should _not_ be able to localize the subwoofer at all. I have my subwoofer running an 80Hz 24db/octave crossover, and it is not localizable. Vibrations in the subwoofer cabinet could very easily make it stand out, as they will often be at a much higher frequency than your crossover. Which parts are vibrating? The tube itself should have very little vibration. Looking at your construction photos, it certainly looks stout enough and I wouldn't think you need to add anything.

    Aaron Gilbert
     
  9. Troy R

    Troy R Stunt Coordinator

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    Thanks!

    I believe the slope on the PE amps are 12 dB/octave.

    Since I haven't really played with it a lot it's hard to say what the problem with localization is. It's probably just the pressure wave or location. I'll have to keep investigating and see what I can come up with!
     
  10. ColinM

    ColinM Cinematographer

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    http://www.partsexpress.com/pdf/300-794.pdf

    The slopes look as if it will still pass enough of a signal at higher frequencies to be heard. Knob at 40hz, it's -3 at 70.

    I sit right next to my sub (endtable), crossover in the middle (80ish?) and my AVR's 100hz filter at 12db on top of that should yield a 24/36db slope, and it's not really easy to locate...
     
  11. Troy R

    Troy R Stunt Coordinator

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    Thanks again for the info Colin.

    I hope to some day in the future get a nicer crossover and an EQ of some sort. but the wife and our new house is going to put a lock on the stereo spending for a while! At least with the new house I'll have my own stereo room to set the sub right in the middle of my speakers if I have to.
     

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