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SVS Port Blockers

Discussion in 'Subwoofers' started by stevefish69, Oct 15, 2005.

  1. stevefish69

    stevefish69
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    Has anyone had a play with the Port Blockers on their SVS Sub, or do you leave them factory set?

    Now that i've got a nice response using the BFD, i can't help thinking that maybe tuning my 20-39PC+ to 16Hz may give even more room shaking low stuff :rolleyes:

    I realise that there will be some loss of headroom, but because i never listen anywhere near reference, this should not be an issue. Might have a run to the loft now and report my findings.

    Steve
     
  2. AngelEyes

    AngelEyes
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    Hey Steve,

    I have been playing with the port bungs on my PB12 Ultra today and I will be posting shortly with some SPL sweep results so it may give you some idea about what the difference might be.

    From what I can see with my setup the gain in lower frequency output means a lot more PEQ clipping of the rest of the range to get anything like a smooth curve... anyway take a look and you will see what I mean...

    :)
     
  3. Ian J

    Ian J
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    If you read Ilkka's exhaustive test of the 20-39 PC Plus here you will see that he got the best results from the sub when one port was blocked and the sub tuned to 16Hz.

    One of these days I will get around to doing mine when I can find the bung
     
  4. recruit

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    Isn't it time you changed subs Ian, something like a box/tube Ultra :D
     
  5. Nimby

    Nimby
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    Don't tease! You know very well he can't have an Ultra now.... not even if he could afford it. :blush:

    Perhaps he could pull some strings with the Big Guys at SVS. (for services rendered) :cool:

    But he still wouldn't be able to brag about it until AV Sales started selling the damn things. :devil:

    So it's a note up the chimney to Santa. :rolleyes:

    Or a grey import with built-in fire guard and complimentary SVS toasting fork. :oops:

    Nimby :D
     
  6. Ian J

    Ian J
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    oooh you can all be so hurtful :D
     
  7. chrisgeary

    chrisgeary
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    i used to tune my 20-39pc+ to 12hz and run the filter at 16hz (otherwise i would get a increasing peak from 20hz down to 12hz). my room was 6m x 3m and at -10db listening level, there was still 3-4db headroom on darla and other bass heavy scenes. i will tune my box svs to 12hz too. whilst 16hz and indeed 20hz is arguably suitable enough for most material, i hate missing out on deep bass.. and for some movies, notably master and commander, finding nemo etc, response to 12hz is a requirement IMHO.
     
  8. recruit

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    :D

    And you must be due for an upgrade too hey Nimby ?

    :devil:
     
  9. Nimby

    Nimby
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    Hmm. I'm strongly attracted to a 4 x 15" true IB. But I'm still trying to find suitable IB drivers on this side of the pond. The freight charges for such a heavy package from the US make the project look decidedly iffy as it doubles the price when VAT is also included. None of the 15" car-fi drivers I've looked at locally are much good for an IB. Fs and Xmax are just not suitable for IB use.

    Nimby
     
  10. stevefish69

    stevefish69
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    OK

    Thanks for the responce people.

    I now have 1 port blocked, and have re-set up the BFD to give a good'ish response. There is a bit of a peak up from 20Hz down but that doesn't concern me as it'll just add to the bone shaking effect when needed.

    I do not use the correction figures anymore because my meter is an industrial one that we use at work, and has been calibrated down to 30Hz and appears to remain linear below this.

    I have alos adjusted the phase, which has sorted out the dip at 80Hz, but i still have a large drop off at 100Hz which i presume is the room sucking out this frequency.

    Hellboy was on last night, so might give this a spin tonight.

    Steve
     

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