Sealed subs vs ported subs

Discussion in 'Archived Threads 2001-2004' started by Jeff.bart, Sep 9, 2002.

  1. Jeff.bart

    Jeff.bart Stunt Coordinator

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    Sealed woofers used to be considered better for music, but is that still the case? When I read about subs, some reviewers make it seem like I am making a sacrifice by choosing one over the other. Since I listen mostly to classical and jazz, I am considering a sealed sub, but I have to believe that technology has progressed to the point that good ported subs can handle both music and HT equally well. I don't need supercharged HT sub output, just very good output?

    Thoughts? Any particular sub brands that would better suit my needs?
     
  2. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Room also has a tremendous effect on bass. Even with the right sub you could still get boomy sound.

    Personally I don't think sealed is necessarily better than ported for audiophile bass, it really depends on other things as well.

    What's the price range?
     
  3. Jeff.bart

    Jeff.bart Stunt Coordinator

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    Preferably no more than $600, but maybe $700 depending on what I get for the rest of the system.
     
  4. Ben_wood

    Ben_wood Stunt Coordinator

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    Jeff, you should check out the Hsu VTF-2 or VTF-3. They are dual ported subs that can be optimized for either music or HT by merely plugging one of the ports and flipping a switch on the back!
     
  5. Lew Crippen

    Lew Crippen Executive Producer

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    Also check out the Adire Rava (sealed—$400) and the Dharman (ported—$600).
     
  6. Michael R Price

    Michael R Price Screenwriter

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    Jeff, can you tell us what kind of SPL you listen at (90,95,100db?), how much depth you'd like (15,20,30Hz?) and what size room you have? This will help us recommend something to you to best suit your needs and budget.
     
  7. Kyle Richardson

    Kyle Richardson Screenwriter

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    Most ported subs get a bad reputation because manufacturers stuff too large of a sub driver into too small of an enclosure. They do this for two reasons 1. The smaller, the better for sales (SAF) 2. This creates a bump in the midbass region which the inexperienced listener will attribute to "louder" in the showroom and will "appear" to be the better subwoofer.
    The second reason why it sounds louder is because of this midbass bump but it sacrifices tightness, accuracy and the ability to extend to the lowest octave with authority.

    With that being said, if you design the right enclosure and tune it correctly then you can have a ported sub that is very musical and will still have the ability to get loud for home theater. In fact, you can even tune a ported design so it mimics a sealed box frequency response almost exactly.
     
  8. Brian Bunge

    Brian Bunge Producer

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    Kyle,

    Also, something I know you already know but others here might not is that actually the biggest drawback to the small enclosure is that it becomes physically impossible to tune the sub below 30-40Hz. Which of course the diehards around here would hardly consider such an animal a subwoofer.

    Brian
     
  9. Jeff.bart

    Jeff.bart Stunt Coordinator

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    Michael, you had to ask. Truth is, I still haven't bought an SPL to check the speakers I have -- 10-year old Cambridge Soundworks Ensemble2 (the one with two minis and two bass modules); the CS Center 2; dipole surrounds, and Powered Sub 2.

    Funny, but I almost went to Radioshack to get an SPL today. I plan to buy one this week. I'll get the Avia soon too. I was just waiting till I bought my first DVD player. In any event, it certainly would help if I knew how well I have my current speakers set up.


    Once I get my new receiver in a month or two -- probably the Yamaha rx-v1300 -- and upgrade my speaker wire, I'll test the speakers again. Perhaps they'll sound a lot better with a new A/V, wires and some fine-tuning. My hope is to wait until after Xmas shopping season to buy my next speakers, no later than February.

    The DIY approach is intriguing since that's pretty much what I've done with PCs. Then again, I am tired of spending time on electronics. Part of me just wants to spend the damn money for new, finished speakers. But the other part of me knows, based on my experience with PCs, that I will get a lot more quality and pay a lower price, while getting sound more suitable to my taste, by going the DIY route. That means (sigh) more extensive research on the process of doing that.

    Now my HT room is quite irregular, 22 feet long from right to left. Probably 250-300 suare feet. that's the simple answer.

    the more complicated answer is this. Looked at from right to left. the first 3 feet of the length is 8 feet wide. The next two feet are 9 feet wide. The next 10 feet of length is 12 feet wide. (That's where the TV and stereo rack are, plus speakers and sub). Then the wall juts 3 feet in at the front, so the width of the room narrows from 12 feet to 7 feet for the next four feet of length (again moving right to left). The final 4 feet of length at the left end is 4 feet wide. At that point, you reach a pair of screened wooden door thru which some sound leaks.

    My biggest problem is limited placement the sub has to go in a right-angled corner for aesthetics and space reasons, so there is some boominess. That is enhanced by the nearly base left Cambridge Soundworks base module. The sats have more options.

    The biggest problem is the placement of the L-R surrounds. The L surround is fixed to a wall, two feet from the back. but the R surround is at a corner where the width changes from 8 to 9 feet. So the dipolar has only 7 inches from the back wall. I'd have to hang it from the ceiling to get it two feet off the back wall. Otherwise it would have to go on the far right corner, thereby separating the rear surrounds by 18 feet.

    If that's too much, I understand. At least I did myself the favor of truly measuring it all out. I gave up the first time I tried last week.
     
  10. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    I also can't wait until December, to celebrate a very merry Xmax holidays.
    If you have a 22 foot width, that axial room mode will likely produce a null between the side walls at 26hz. You'll likely get a spike at 51hz and another null at 77hz.
    This is if your subwoofer is against a side wall and the listening position is between the side walls. My little program can't calculate the other room modes but it will soon enough. [​IMG]
    If you have microsoft Excel you can download the worksheet I made that can help you out. Click Here.
    As for a DIY subwoofer, there isn't any research needed if you follow the instructions for a recommended enclosure + driver. I like the Adire Tempest in vented adire alignment enclosure. Basically you just build the box per instruction, screw in the amp/driver and you're good to go.
    A 120 watt amp ($80) will be 3 decibels less than a 250 watt amp ($120) at Partsexpress.com. Add that to $20 for MDF and $150 for a tempest and there's your subwoofer.
     
  11. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    If you know the sensitivity of the subwoofer, distance from listening position to subwoofer, and amplifier power you can predict the levels of bass (not counting room interaction/bass modes).

    For a 250 watt Tempest in your room at about 10 feet away will produce:

    113db @ 1 meter
    103db @ listening position with peaks of 110db

    That's pretty close to THX recommended levels, while adding a second tempest should get there.
     
  12. ColinM

    ColinM Cinematographer

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    Chris - Thank you for the XL...
     
  13. Jeff.bart

    Jeff.bart Stunt Coordinator

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    Thanks for the excel file, Chris. I'll do that this weekend.

    On the DIY stuff, I don't want to deal with putting a finish and gloss on or buy my stuff from different suppliers. One supplier for driver, amp, enclosure. How long does it take to put a speaker or sub together? I'd have to get some tools at Home depot, but that's easy enough. Yet would I really save any money compared, to say, buying a $500 range SVS or Hsu?
     
  14. Dan Hine

    Dan Hine Screenwriter

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    Jeff,
    I would say that if you don't have the tools already and only see yourself using them one time to build a sub then DIY probably isn't for you. If you think it might turn into a fun hobby or if you might tackle other projects then the tools would be a great investment.
    You could also go to Acoustic Visions and order a flat kit. They would still not be "finished" but you can hold off on doing that until you are certain how you want to finish them. Speakers offer plenty off enjoyment in unfinished form. Just ask Patrick Sun! [​IMG]
     
  15. Richard Greene

    Richard Greene Stunt Coordinator

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  16. Michael R Price

    Michael R Price Screenwriter

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    Jeff, since it appears as if you are looking at the DIY route... (don't give up because you don't have tools... do you have any friends with tools?)

    Find out what the absolute largest possible size you can stand is. In general, the larger you build your sub the more performance you will get for your money. Can you live with a 24" wide, 6 foot tall sonotube? Or does your space limit you to an 18" cube?

    Regarding your decision of sealed vs. ported, I think you will have to decide for yourself since we all have different opinions. However, you should keep in mind that the ported subs we are talking about are probably not what you are used to. They sound is not boomy, or poorly defined. This isn't saying that sealed subs are pointless; rather, for many HT and music uses the benefits of depth and clean output can outweigh the cost in sound quality.
     
  17. Jeff.bart

    Jeff.bart Stunt Coordinator

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    Tks, Richard. Yes, Michael, I am seriously considering DIY. I am pretty sure my father, a former engineer, has most of the tools I would need. He just happens to be a 400 miles away, but nothing that poses a big obstacle. Still, Dan's question is the operative one. I don't do anything half assed, so if I am gonna go the DIY route, it's gonna be for the long run. I just don't know if I want to commit. I'm gonna look into it some more ...
     
  18. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Some topics I've come across on the forums you can look up:
    Line array/flown cluster (I know you probably won't use this)
    Passive Radiator
    Dipolar
    DIY bass trap/helmholtz resonator
    Infinite Baffle
    Transmission line
    Bass Horn
    Servo drive
    Bandpass
    Ported
    Sealed
    Free air resonator (the cheapest way to go) [​IMG]
     
  19. Manuel Delaflor

    Manuel Delaflor Supporting Actor

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    Jack,

     

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