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Ported or closed?

Discussion in 'Subwoofers' started by PJTX100, Jan 10, 2005.

  1. PJTX100

    PJTX100
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    Hi, have my eye on a couple of subs, some seem ported, others seem to be enclosed. Would have thought that simplistically the ported models would "move more air"? Can someone explain the difference thanks...PJ
     
  2. MSYam

    MSYam
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    Basically, ported subs allow the air to move more freely, thus allowing the sub to breathe easier, allowing the sub to hit very low frequencies.

    Closed subs can tend to sound tighter and punchier (but can also go low very too). You will probably find that most subs are not ported, which in my opinion is ideal for watching films. A strong powerful sub does not necessarily need to be ported - keeping it closed ensures a crisp tight sound.
     
  3. whats_this

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    Heya PJ, the sub will add so much to your movie experience, which ones you got you eye on in particular? In regards to ported and closed they are just a different way of making the cabinet and there is no real advantage of one over the other. As long as the workmanship is good both can produce an excellent sound.

    Someone emailed tom at svs a while ago and that was his opinion anyway. couldnt find the thread but i'm pretty sure that was the conclusion as far as i remember.
     
  4. PJTX100

    PJTX100
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    Hi there Whats_this
    Well, I'm looking at either the Vita 100, the BK XLS200, or just to be completely different the Yamaha SW315 (which is ported). I know the Yammy is not top of people's list around here, they claim figs which are a bit iffy to say the least, but the one's I've heard I've liked and I fancy something a bit different! It also looks good too!
    ...PJ
     
  5. Big Bert

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    Hi PJ,

    I have just replaced my Yamaha YST-SW320 with a BK XLS200, believe me there is noooooo comparison. Yes the Yamaha looked different but we're talking about sound here. You could hide the BK in a corner it is so small, but once you see how beatifully made they are, you'll want everyone to see it.

    Gordon
     
  6. PJTX100

    PJTX100
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    Hmm. OK, go on, I'm ready to be convinced! Tell me how much better it sounds - more slam, more power, more refinement, more... everything?!
    ...PJ :thumbsup:

    PS are both the Yammy & BK supposed to be spiked?

    PPS would forward or downward be best??
     
  7. Big Bert

    Big Bert
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    PJ,

    The 200W amp in th XLS200 is way more powerful than the "250W" amp in the Yam. The XLS200 gives a far more "defined" sound and certainly has plenty slam. It's tuneful as well if your looking at using it for music.

    The Yam did not come with spikes (I've got a laminate floor anyway and her who should be obeyed would not approve of spikes) but had small rubber stick-on disks. it has it's own peculiarly shaped base anyway. The XLS200 does come with spikes but it has nylon screws in threaded into it's feet, I've left them in place and it works fine.

    I went for downward firing (keeps her happy because it just looks like a very nice box) but I believe it does not make any difference.

    Hopefully that helps you, I just have to add that I started using the XLS200 just before Xmas, tweeked it for ages. Now I just cannot get enough, I'm re-listening to CDs and re-watching films - IT'S GREAT :thumbsup:
     
  8. MSYam

    MSYam
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    Big Bert, I am also about to go for the XLS200 in the silver finish I think. Which finish is yours in?

    Is there any chance of putting any pics on for me to see what the finish is like?
     
  9. KHCC

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    Mornin'

    Going back to the original question, a couple of big differences is that with a closed/sealed enclosure, the sub relies on the trapped air for suspension thus not using it's own suspension so much. With a ported enclosure, yes the driver can breath, but the main reason for the port is for tuning the enclosure there for enabling a deeper sound. This is because it is possible to tune the enclosure down to a specific frequency i.e 18Hz. But designers have to be weary of byproducts like frequency peaks where the driver is more efficient due to the tuning and also any frequencies played lower than the tuned frequency, the sub has to work very hard which is where you get to maximum excursion and the sub starts flapping as the amp can't control the cone properly and may even start clipping. Problems are that if the sub is driven this hard alot it will shorten the life of the driver as the suspension gives up early and aswell as that if the amp is not stout enough it will go into clipping then the voice coil will heat up and will be damaged.

    It is also noted that drivers of a ported enclosure will play the tuned frequency very well and be very efficient at the frequency and will hardly move. As said before the byproducts of tuning lower get worse which is why there is a trade off, otherwise designers would be tuning down to 5Hz or lower and get thunderous low end but in doing so you will get what is known as a one note box where it is very efficient in one area of the bass region and you just get boom.

    In terms of sealed enclosures, designers can make the enclosure tiny and use the air pressure to help control the driver, but to move a driver in half the air space you need twice the power, which means they can use big monoblocks i.e. 1000 watts for a 10" long throw high excursion driver and get the thunderous lows that way. The byproduct is punchy accurate bass due to the tiny amount of air it has to compress. but the downside is a subwoofer that is less afficient than a ported sub.

    hope this explains something, not least that I can waffle :D

    Regards
     
  10. PJTX100

    PJTX100
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    This ain't waffle, it's fascinating stuff. :thumbsup:
    I'm sorta convinced now that only the XLS200 will do, I'll probably go for forward facing 'cause it's in a dedicated room off-limits to kids & wife, the only problem is I can't decide on the colour. :blush:

    Decisions, decisions... ;)

    ...PJ
     

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