Making a Tempest SBB4 Sound "tighter" ...

Discussion in 'Home Theater Projects' started by Joe Mihok, Sep 20, 2004.

  1. Joe Mihok

    Joe Mihok Second Unit

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    So I have a Tempest SBB4 ref design I built early this year. I've been very happy with it for HT but just recently I've been listening to alot of music and I find that it sounds a tad bit slow and bloated. I've tried moving the sub to different locations in the room but it only gets worse. I was thinking about changing the port tube length to tune it lower. Will this in turn make it sound "tighter" ? Is there any drawbacks to tuning this enclosure lower, say from 18hz to about 13hz ? I'm fairly inexperienced so I apologize if I sound like an idiot [​IMG].

    The SBB4 enclosure is 194L with 64 ounces of PolyFil. Right now I'm using homemade ports made of 3" PVC with flares (using two ports). In LSPCad I'm tuned to roughly 18hz.
     
  2. GrahamT

    GrahamT Supporting Actor

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    Dont mess with the tuning frequency, Adire knew what they were doing when they designed it. Have you plotted the frequency response? I found that I had a huge hump at 40 Hz which comtributed to the bloated sound. ALso, since your sub produces very low frequencies, they tend to hang around longer making it seem slow. maybe excess room gain down low is contributing as well.
     
  3. ThomasW

    ThomasW Cinematographer

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    Have you measured in 'in-room' frequency response?

    If not you're shooting in the dark.........
     
  4. minhG

    minhG Stunt Coordinator

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    Joe,

    I strongly suggest you measure, i thought my shiva sounded 'off' and i kept diddling with the levels etc. When I finally got a meter, i reset all the levels and to my surprise a frequency sweep from 20hz-60hz came up pretty flat, some small 3-5 db bumps but nothing major. i realized it sounded 'off' to me because i was use to very boomy bass.


    where are you getting your reference point for 'tight' bass?
    even if it measures flat, at least you'll know that you want a bump at certain frequencies to sound better for you. and for that you can use some equalization.
     
  5. Joe Mihok

    Joe Mihok Second Unit

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    Thanks for the responses. I guess I'll have to break down and get a SPL meter from RatShak. I already have the corrected Excel spreadsheet. I'll post my results later on in the week. I've actually just ordered a pair of 3FP's from creativesound.ca. I'm gonna replace my homemade vents just to make sure everything is identical to Adire's plans, plus it'll look better. I couldn't afford the 3FP's at first due to budget restrains. If I've learned anything from DIY projects, it's to not be so damn cheap cause you'll end up doing things twice. Do it right the first time around and wait if you have to. Oh well, live and learn right ?
     
  6. Rory Buszka

    Rory Buszka Supporting Actor

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    I think you might have the wrong alignment for you. The Adire Alignment might be much more to your liking. As I remember, I think SBB stands for Super Boom Box or something like that. Or, you might try a sealed alignment with your Tempest. The Tempest isn't the problem. It's a very nice driver.
     
  7. Joe Mihok

    Joe Mihok Second Unit

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    The SBB4 is supposed to have more mid-bass punch than the AA. This is exactly what I want. So far it's been unreal when it comes to HT.

    I did some research yesterday and I figured out that I was using LSPCad incorrectly. Instead of using two 5" PVC pipes with flares to get 18.8hz, I was using two 12.5 inch PVP pipes (Damn I can't believe I did that). I obviously didn't get enough sleep and didn't realize that it was supposed to be 12.5 cm, not inches. I have no idea what the resulting tuning frequency would be but it's way off from Adire's plans. Like I mentioned above, I ordered two Precision Sound 3FP's and I'm going to cut them at 5" like Adire recommends. I'll post my results when the 3FP's come in.
     
  8. Joe Mihok

    Joe Mihok Second Unit

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    Okay, today I paint my sub with one more coat and add the Precision Sound 3FP's. For the past 4 months, the sub has been just plain old mdf. Yesterday I cut apart my dads solder job on the tempest/binding posts because it looked really messy and 2 connections were very loose. I will be resoldering today but I had a question. I remember having a real hard time soldering monster cable (10 AWG) from my tempest driver to the bi-wire binding post .... that's why my father ended up doing it (but did't do a really good job it turns out). Anyways, it would sure be easier if I could use a higher # gauge wire. Would it be bad to use something like 18 AWG ? Would I lose any quality in sound ? The wire would only be 1.5 ft.. Thanks
     
  9. GrahamT

    GrahamT Supporting Actor

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    Use 14 gauge, get some spade terminals from rat shack and clamp them on. If that isn't enough, solder the spades.
     
  10. Joe Mihok

    Joe Mihok Second Unit

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    Excellent. That should be way easier. I'll try that tonight. TY [​IMG]
     

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