Subwoofer specs - what to look for?

Discussion in 'Beginners, General Questions' started by Jill_S, Nov 7, 2003.

  1. Jill_S

    Jill_S Auditioning

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    For subwoofer specs I see things like woofer size, watts, frequency response and crossover frequency. Can you explain to me how these impact how powerful a subwoofer feels? Is watts the biggest factor in power? I know it depends a lot on manufacturer, design and the room it's put in, but I'd just like a general idea.

    Also, how does the wattage of the subwoofer relate to the wattage of your receiver? Can you have a 200 watt sub and a 100 watt output per channel on your receiver?

    Thanks.
     
  2. John Garcia

    John Garcia Executive Producer

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    Sub wattage has nothing to do with the receiver, they are completely separate and independently controlled. Calibration will get the levels to match, regardless of power output of the main speakers and the sub.

    How powerful it feels is entirely related to it's power rating and frequency response. Wattage alone is not the key, but how well the sub uses that power across it's range.

    If you are looking for tactile feel, you will want to look for something that is solid to a minimum of 25Hz, though 20Hz is the goal, since that is the bottom of the average person's hearing (though lower frequencies still have an effect).
     
  3. ChrisWiggles

    ChrisWiggles Producer

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    You want to know a few things, but basically SPL levels it can hit, along with how low it goes. You also want to try to get flat response.

    BTW, what kind of budget are you looking at? The folks here can recommend all sorts of subs depending on your budget/constraints.

    Keep in mind also, that while lots of watts can sound impressive, it is not always better, a sub designed to be very small will need a lot of power to create sound more through brute force, whereas something like an SVS is very large, and the large volume allows it to be very efficient, and hit very loud volumes with relatively little power, yet also extend very deep, while this would need to be sort of "forced" out of a smaller sub by equlization, or servos, or the like.
     
  4. Drew_W

    Drew_W Screenwriter

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    I'll add in here that subs usually come with their own amplifiers built in, so they present no load on the receiver. You simply connect it via the mono rca out on the back of the receiver (sub preout, or just sub out).

    And as always with speaker purchases, buy with a dealer who will let you return speakers in the event that they don't sound up to snuff in your room. I went through 3 subs until I was happy in my setup.
     
  5. Wayne A. Pflughaupt

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    Jill,

    I’ll attempt to explain some of this and hopefully keep it simple – not that I don’t think you can handle an in-depth technical explanation, but because that would be too time consuming considering the scope of your question.

    Hitting the high points:
    Frequency response – Most subs operate in the frequency range between 100Hz (highest frequency) and 20Hz (lowest). For home theater purposes, you want the sub to get down as close to 20Hz as possible. The frequencies that low are felt more than heard, and that gives a really visceral effect with action flicks.

    Crossover frequency – Put simply, this is the place where the sub stops working and the other speakers start. For instance, the sub frequency range I mentioned above, 20-100Hz: 100Hz is as high as the sub goes; everything above 100Hz is handled by the other speakers. This “division” is accomplished by an electronic crossover; it effectively separates the high frequencies (which go to the main speakers) from the low frequencies (which go to the sub.)

    Things like wattage and woofer size get pretty involved – lots of “ifs” and “on the other hand’s.” Thus it’s probably best to go with some sub design info and room size-to-sub size guidelines.

    There are several common designs for subs, but most of the best home theater subs are either a sealed or ported design. Generally speaking, a sealed sub will do better at hitting the lowest frequencies, while a ported sub will play louder. Of course, there are exceptions, but that is the rule-of-thumb.

    Regarding room size vs. sub size: In my opinion, and I know many others here share the same view, don’t waste your time or money with a sub smaller than 12”. Now, there are some instances, like if your room is tiny (I’m talking a kid’s bedroom here), that you can get away with a 10” sub. But for an open living room area, go with at least a 12” if you want to get anywhere close to that 20Hz figure with the kind of volume you need for action flicks.

    Some basic guidelines: A decent 12” sub should be good for a listening area 3000 cubic ft. or less (you have to figure all areas open to the listening room when calculating room volume). Between 3000-4000 cubic ft., go with a 15” sub. Larger than that, you will need an 18-incher, or perhaps two of the smaller ones.

    As John mentioned, don’t worry too much about sub wattage vs. receiver wattage. The manufacturer of the sub will make sure it has enough power to deliver maximum performance.

    You might want to check our FAQ and Primer for more detailed information.

    Hope this helps.

    Regards,
    Wayne A. Pflughaupt
     
  6. Jill_S

    Jill_S Auditioning

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    Thanks to all for your time and patience in explaining things to a novice. Your explanations helped a lot.

    Unfortunately, it makes me realize how inadequate my living room is for home theater. Sigh. It's 30 x 35 x 14 with an open stairway to the basement and a 10-foot wide doorway opening into the kitchen. It's got hardwood floors, wood ceiling, and one wall that's mostly windows. Yup -- definitely not ideal.

    I have the JBL NSP1II speaker package (4 bookshelf N24IIs, plus one center N-CenterII). I haven't bought a receiver yet, but I'm looking at the Denon 1603, Onkyo TX-SR501 or Pioneer VSX-D812K.

    I don't need great sound -- just wanted my DVDs and CDs to have a little more life. My budget is tight and I was going to spend like $300, but now I guess I might as well buy the 10" Dayton sub for $125 since another $175 isn't going to get me the power I would really need. Am I right?


    Thanks,
    Jill
     
  7. John Garcia

    John Garcia Executive Producer

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    That is a pretty large room. For $375, you might want to look at the new JBL. It may be able to do what you need. I am not a fan of JBL subs, but it is getting good reviews from people who know what they are talking about. If you haven't seen it, Pablo put together a good list of less expensive subs, take a look at this thread:

    http://www.hometheaterforum.com/htfo...hreadid=167554
     
  8. chun howe

    chun howe Stunt Coordinator

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    room acoustics is very important to get the most out off your subwoofer.

    i am going to build a stage for my sofa just like my friends HT.

    he has HSU and the 10" sub rocks the whole theater room due to the 1 foot stage.

    i have SVS 25-31 PCI. 12" sub.

    with your room size you are better off save now and get later. you will probably need at least 2 subwoofer.
     
  9. John Garcia

    John Garcia Executive Producer

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    Since it's a basement, you can probably get away with one good sub, probably even a 25-31PCi (which means saving a bit more). Stick it in a corner, and the concrete will help reinforce the sound. A friend of mine has a room just about that size with a concrete floor, and I was surprised to find that the 25-31, when placed correctly and calibrated, was able to move impressive amounts of air in such a large room. The SVS was about 9ft away from me, and it still made my pant leg flap. [​IMG].
     
  10. Jill_S

    Jill_S Auditioning

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    Thanks for the suggestions. I will check out the recommended models. (By the way, my room is on the first floor with a wood floor and there is a basement below it.)

    One other question about sub placement. I was thinking about putting it in the corner to the left of the TV (if it sounds good there). I'm going to be installing bookcases along the walls to either side. Can I sort of encase the subwoofer by building the bookcases to either side and above the sub? Or should I keep the bookcases away and give it more space? How do the sound waves travel?

    Thanks. Your input is SO appreciated! [​IMG]

    Jill
     
  11. RonJon

    RonJon Auditioning

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    Jill,

    Another option that would really cover the bases(no pun intended)for you would be 2 Velodyne VX10 subs. You can check them out at: 6th Avenue Electronics. They are reputable and have .06 shipping per item.
    They would come in under $300 for both delivered.
    Split them out from your receiver with a Y adapater from Radio Shack and some cables and you would have a great sounding bass set up.
     
  12. Jill_S

    Jill_S Auditioning

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    The Velodyne's look like they may be a good solution, though I just noticed the Dayton sub is now on sale for $99. Two of those seem pretty tempting too...

    Any answers to the question of putting bookcases on either side of sub?

    Thanks,
    Jill
     

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