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Ported vs Enclosed Cabinet Subwoofers

Discussion in 'Subwoofers' started by u32t5645, Jun 15, 2005.

  1. u32t5645

    u32t5645
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    What is the significant differences, if any, in subwoofer technology concerning ported or enclosed/sealed cabinets? Advantages/disadvantages?

    I understand sub placement is important, but does either technology have any advantage on sub placement? I.e., does either technology have placement considerations the other doesn’t?

    Thanks!
     
  2. Ian J

    Ian J
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    Colin Miller explains it better than any of us could here :)
     
  3. eviljohn2

    eviljohn2
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    There's another excellent article here which covers all of the basic elements of subwoofer design and placement in fairly simple terms with helpful diagrams.

    Crucially, neither design is inherently better than the other - they just have different compromises and subsequently different characteristics. :)
     
  4. u32t5645

    u32t5645
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    Thanks for the links, guys!!! :smashin:

    Admin/mod - thanks for moving my query to the appropriate forum. Wondered where it went.
    :)
     
  5. Welwynnick

    Welwynnick
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    Fantastic article; should be compulsory reading for anyone who wants to know about speakers.
    Finally kills the myth that heavy drive units cannot respond to dynamic signals.
    Nick

     
  6. Nic Rhodes

    Nic Rhodes
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    Good advice so far, they are different and have different compromises. Beware those that say enclosed cabinets are the only way to go, this shows their ignorance, when done correctly both ways have much to offer.
     
  7. Cliff

    Cliff
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    A consideration that hasn't been mentioned is that it is much easier to hit the stops with a ported design. The cone can travel much more freely.

    From personal experience, I have an early REL Strata which was fine with "normal bass". In fact it was designed for high quality reproduction with a low extension rather than for dynamic LFE tracks.

    I just make sure the levels are not too high otherwise there are nasty hitting sounds!

    Later models of the Strata were enclosed designs.
     
  8. micb3rd

    micb3rd
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    A generalisation that not really rings true on most correct designs.

    Proper vented designs actually have greater mechanical power handling at lower frequnecys then sealed designes due to the reduction of excursion above fb (vent tuning point).

    In general a vented design will be more efficent (more output with less power) and have a deeper frequency response if tuned correctly.

    Group delay around tuning can be large in vented but group delay becomes a inconsignificant issue below 33hz so tuning low hides this problem in a area we can't detect.
     
  9. Ian J

    Ian J
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    I agree with Micb3rd that whilst your REL Strata may have "bottomed out" neither my SVS cylinder nor my budget SVS PB-10 have ever done that, even on the well known demo pieces and all SVS designs are ported.
     
  10. Crustyloafer

    Crustyloafer
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    Me too, I never have my REL Stentor 3 remotely close to bottoming out and it's a ported design of sorts, although cleverly the port is only used at certain frequencies and below due to REL's Acoustic Resistive Matrix loading.
     
  11. Nic Rhodes

    Nic Rhodes
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    I think this shows that it is all down to how you engineer the subs. My all time top 'want' in subs is ported (Big Genelec) but I use sealed Servo15 and rate that highly. SVS are great and are ported and Velodynes are great and are sealed. Look to each to their merits, rather than generalising in 'types'.
     
  12. u32t5645

    u32t5645
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    I think you are right, engineering is the key. Rel, SVS, Velodyne, they all sounded good, preferred Velodyne, but didn’t hear them next to each other.
     
  13. dAVefaulkner

    dAVefaulkner
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    I've heard it mentioned that you could seal a ported unit to improve the frequency response - or at least get a more favourable response for a particular application but maybe you should be using a BFD instead to achieve this. Of course, you're making the unit do something that it wasn't designed to do but we all like to experiment. Is this a common thing to try or is it highly frowned upon?
     
  14. sonic65

    sonic65
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    I think you would find the results disappointing or at the best not a great deal of apparent difference. Sealed units require higher amplification and the cabinet is normally lined with acoustic wadding. Box resonance is another issue. You could end up with one-note bass.
     
  15. dAVefaulkner

    dAVefaulkner
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    I did a bit of digging and found this interesting post from Ilkka R. Maybe this characteristic is unique to the PB10? Although noah katz's comment in this thread makes sense:"Just plugging the port would give a very overdamped response with rolled off bass, because of too low driver Qts and too big a box." - i.e. you're making the unit do something that it wasn't designed to do. However, some speakers are supplied with bungs to block the ports, presumably to help tune the in-room response. Perhaps I'll ask SVS what they think...
     
  16. micb3rd

    micb3rd
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    It totally depends on the driver and the enclosure used.

    Some drivers respond well to small/large sealed enclosures other don't

    Depending on the driver and the size of the enclosure will effect our system response, High Q (Qtc 0.85+) will give more boomy responses with a sacrifice of low end, others will give resonable Mid Q (Qtc 0.707) a which can good balance and some Low Q (0.5-6) optomised for lowest end bass.

    Of course it does not hert (as long as you are carefull) to try and block vent ports you just can't assume it will work the same way for every subwoofer.
     

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