Sealed vs. Ported subwoofers... wow, there is a difference...

Discussion in 'Home Theater Projects' started by Javier_Huerta, Jun 7, 2004.

  1. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Hi all,

    I just finished my 4th & 5th subwoofers... thanks to all for your help! I guess I've come a long way since I got here. This forum is absolutely invaluable.

    Anyway... I wanted a couple of subs for my B&W DM602S3 speakers. They have nice bass, but are seriously lacking in the 50 hz and under area.

    I built a pair of sealed 130L subs, based on the Cerwin-Vega HED-12 driver (the only one I've been able to find around here at a decent price). I have previously used this driver on a 118L design, tuned to 20 Hz, and was surprised at the results (better than I couldhave ever expected).

    So, I thought about going sealed this time, just to see how much sound quality I could gain by doing so.

    Well, I learned a lot from the lesson. While the ported subs (I'm using them at my HT) go down very deep, and have lots of SPLs, the sealed subs are almost undetectable... that is, until I turn them off. Then, the B&W's sound positively anemic. It's amazing how needed a good pair of subs are for music listening.

    My best experience came with the "Kind of Blue" SACD, playing through my system (a modded BottleHead tube preamp and a Rotel RB1070 amp, plus the ubiquitous 300-794). The bass lines are perfectly defined now - no longer a soft, faint image of a bass, but a real, clear and fast sonic image. The lowest of the low bass is not as audible here, but to be honest, I can't think of any CD that really needs 20 Hz bass (except for pipe organs and Marcus Miller, that is).

    I wonder - how much could I gain by using a better subwoofer driver next time? Hmmm.... tempting!

    Even more tempting, though, is to build an IB now.
     
  2. Mike Keith

    Mike Keith Second Unit

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    Some drivers work much better in a sealed enclosure then a ported one, some are the opposite, some work well in both alignments. All things being equal there is not that much difference in overall sound quality between the 2, but the ported will nearly always have more output and go lower. I have 2 subs using the Adire Maelstrom drivers, they work well in both sealed or ported designs. The cabinets I constructed have a closable port valve so that I can (in about 2 or 3 seconds) close the port. I can hear a difference but it's not a lot, it does integrate with music better then the ported, but if I closed my eyes I bet it would be difficult to tell which was witch.

    How about some pictures of your project?
     
  3. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Thanks Mike,

    I'll post some pics later today (I just took them). The subs are pretty similar to the B&W's - short, but wide and deep. They actually look nice together.

    What surprises me the most about the subs is, I compared them to my AA Tempest enclosure, and I found out that even though my sealed boxes are definitely more rolled off in the lower end, I like their sound a bit more. It *may* be due to the room gain, but I feel the sealed box is quite a bit tighter sounding.

    Another thing I found out is that they are less efficient than the ported design. I was expecting that, though, and since I rarely listen to music as loud as I usually listen to HT, it's not a big deal.

    Best of all is, if I ever get my hands on a Titanic 12" MKIII, it will be a direct bolt-on on my current enclosure. I can't help but think the driver is the weakest point in my design... the enclosure itself is made from dual 3/4" MDF sheets, and the bracing is copied from the Adire Alignment plans, so it's pretty solid and heavy.
     
  4. Geoff L

    Geoff L Screenwriter

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    The HED drivers are not that bad. Don't expect a night a day difference if you get you hands on the T-III your looking to possibly get.

    SPL and thermal power handeling may be a different story depending on whats driving them. But if both subs, the HED and the T-III are in their proper sealed required volume, I doubt you'll justify the difference in driver costs, (unless your looking for more clean spl in your sealed design).

    The HED drivers are a good deal if you can get them at a sale price or maybe wholesaled like me.
    $40.00 shipped for either the SVC or DVC ~{NEW "HEDD-12"}~..Their also better looking than last years HED drivers.

    The newest ~{HEDD's}~ are out now and even a better driver. For the poor man, or one that lives where it is diffucult to get higher end DIY sub drivers, the CV HED's are no slouch and worth giving a spin for DIY......

    Very good price to performance ratio, and I dislike CV products terriably.

    Cheers
    Geoff
     
  5. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Hello Geoff,

    I didn't know that much about HED drivers. I was very surprised at the low end levels I could achieve with my ported design, so I decided to try my luck with a sealed one.

    So far, I'm delighted with them. I did get them close to the price you mention ($55), and, as you say, it was impossible for me to get my hands on other drivers. So far, I haven't had any problems with either design. I didn't follow the sealed box suggestions, though - I aimed for a Q of around 0.57, so the box was quite big.

    Here are some pics of my set-up:

    [​IMG]

    In this image, the B&W speakers can be seen (on a set of DIY stands, too!). The subwoofers can be seen on the back. They are cubes, 58 cms. per side, with 12 cms. high legs, painted flat black. The woofer is downfiring, and I decided not to bolt the amp to their back (in case I didn't like them in the long run). The 300-794 amp can be seen on the foreground, feeding both subs. My CAT-5 speaker cable can also be seen (set up for bi-amping) to the Rotel RB-1070 amp, on the lower level of the rack. On the mid-level, the Bottlehead can be seen along with a Margules "Black Box". To top it all off, my Sony SACD player.



    [​IMG]

    These are the ported subs. I like them a lot more than my sealed boxes - they are slimmer and taller, plus the silver legs look quite nice with the TV set. So far, I still believe the sealed subs sound a lot better than the ported version - even after I tuned them at 20 Hz...

    I still have a pair of drivers left. Maybe I should try to do an isobaric enclosure now. [​IMG]
     
  6. Geoff L

    Geoff L Screenwriter

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    Javier

    The new HED driver model #s are:
    12"
    SVS-->HEDS-1200
    DVC-->HEDD-1202 dual 4-ohm

    The 8, 10, and 15" follow the same model number thing above.

    10"
    SVC-->HEDS-1000
    DVC-->HEDD-1002

    15"
    Etc.

    They have a much larger/deeper basket and it's chromed, along with a much larger magnet that looks to have a black boot on it.
    Cone is a Titanium Plated Co-Polymer and uses the V-flex long throw suspension. Large Nominex spider & No longer is their any coloring on the center dust cap, just a CV etched or stamped standard logo on the inverted dust cap.

    The cone color appears to be a med chrome graphit color, the pictures are not the best I'm looking at.

    Pulling this info from my latest cataloge and even they are OUT of all but a few 12's right now. They are the biggest buyer in the US for wholesaling out to dealers the CV driver line.
    I was told they have no idea when they will get some more as their new ship date has already passed, but do expect more of them shortly.

    I have NO spec on these aside from their supposed to be designed to work with/in smaller enclosers.
    I doubt the specs will change drasticaly just minorly here and their.

    They where ~{just released in mid May}~ some time. Can't even find a pic on the web anwhere, (they either show the old Hed driver, or no photo available), and the CV site has not been up-dated with the new HED drivers yet.

    Thought I'd give you a heads up, maybe you could exchange the 2-12' you have left and give the new HEDS a try once they get down your way. Ask your dealer/seller if he knows anything..

    They apear to be a better driver, but thats just from a visual stand point only. The pole has to be longer I would think (just a guess) with the whole driver being quite a bit deeper than last years HED drivers. Maybe a few more mm of clean xmax.
    Power handeling is stated as 250 continious for the 12" and 600 transit peek and built to be abused. Ok, what dose that mean...[​IMG]

    Anyway, glad you where able to find something to make some decent bass down that way on the cheap...!! [​IMG]

    Best of luck
    Geoff
     
  7. Mike Keith

    Mike Keith Second Unit

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    Nice loking subs, I especially like the cool silver legs on the ported ones. Nice work..
     
  8. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Thanks, Mike... I love the ported subs. I somehow thought the sealed ones would look nicer in their all-black finish, but I guess I was wrong [​IMG] My wife also prefers the ported ones, since she says slimmer always looks better. Next time, I'll try to build something without a huge footprint.

    Geoff, I didn't know about the new HED's. I checked out C-V's page, and couldn't find anything. I like the look of the old HED's, but it seems the new ones are nicer.

    There's one funny thing about the Cerwins, though. No matter how hard I try, I've never bottomed the drivers out, except if I drive them with pure sine waves at 20 Hz playing at really insane levels. They might be better than I originally thought! [​IMG]

    I took some better pics of the subs, too.

    [​IMG] [​IMG] [​IMG]
     
  9. Mike Keith

    Mike Keith Second Unit

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    You have very good finishing skills, both subs look great. The second set of pictures reveal a lot more detail, they look very professional.

    Good Luck.
     
  10. Wayne Ernst

    Wayne Ernst Cinematographer

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    Javier,

    Your subs look great. I like the legs on both the ported and non-ported versions.

    I just wish you had easier access to more drivers like we have here in the U.S. I'm sure you'd come up with some amazing subs, given your talent to make great cabinets. [​IMG]
     
  11. dave alan

    dave alan Second Unit

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    I agree, Javier...very, very nice work!

    Thanks for posting the pics, it's always great to see a job well done.
     

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