Vented or sealed sub?

Discussion in 'Archived Threads 2001-2004' started by Jake T, Sep 20, 2001.

  1. Jake T

    Jake T Stunt Coordinator

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    Can anyone tell me why I should choose one over the other?
    Thanks
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    Jake T
    --"The Things You Do In Life Echo An Eternity"
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  2. Mike V

    Mike V Stunt Coordinator

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    Very generally,
    Sealed subs tend to perform better for music than vented subs, and vice versa.
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  3. Jake T

    Jake T Stunt Coordinator

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    thanks Mike
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    Jake T
    --"The Things You Do In Life Echo An Eternity"
    ----Russel Crowe, Gladiator
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  4. Robert A

    Robert A Stunt Coordinator

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    Jake,
    A sealed sub has a slight dB peak at is tuned frequency and then it has a very steep fall off. A correctly tuned vented enclosure has a more flat response with a much deeper fall off. If you want to hit those really low notes or if you like natural sounding music. you'll want a vent. If you like to listen to popular music and you like the nice thumpin' go with a sealed enclosure.
     
  5. Samuel Des

    Samuel Des Supporting Actor

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  6. Jack Gilvey

    Jack Gilvey Producer

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  7. Samuel Des

    Samuel Des Supporting Actor

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    Robert:
    quote: A sealed sub has a slight dB peak at is tuned frequency and then it has a very steep fall off. A correctly tuned vented enclosure has a more flat response with a much deeper fall off.[/quote]
    Jack:
    quote: This only describes high Qtc boxes, over .707 or so. A properly designed sealed woofer actually has no bump in the response, and a much more gradual rolloff below resonance than a vented sub, typically 12db/oct. vs. 24db/oct. for a reflex. This more gradual rolloff results in better transient stability, and, in general, a "tighter" sound. A vented sub can be designed to have a lower F3, though, and can generally go deeper.[/quote]
    When Jack says, "high Qtc," does this refer to the physical character of the sub box, or to the driver, or some combination of both?
    Does "reflex" refer to the elasticity of the driver?
    Does "F3" refer to a musical note or "frequency", like "frequency 3" or something like that?
    Robert:
    quote: If you want to hit those really low notes or if you like natural sounding music. you'll want a vent. If you like to listen to popular music and you like the nice thumpin' go with a sealed enclosure.[/quote]
    This sounds reasonable to me as a layperson. But given the enthusiastic response to the Adire subs, I wonder if this is true. I have no frame of reference to judge the statement's merits.
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    Best, Sam
    Edit
    1. Removed anonymous labeling
    2. When I refer to the Adire, I meant to say the closed models. I regret it it was unclear from the context.
    [Edited last by Samuel Des on September 21, 2001 at 04:02 PM]
     
  8. John Garcia

    John Garcia Executive Producer

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    Sealed subs typically try to kill off or minimize the back wave of the sub to reduce distortion, while vented subs USE the back wave to produce additional bass via the port. Most vents/ports tend to produce "noise" as the air passes through them and will color the sound slightly. As was mentioned, the vent/port can be tuned to a specific frequency, typically in the ~40Hz - 50Hz range. At higher volumes, port noise and distortion can be problems for vented subs. Sealed subs remain "tight" because the air inside keeps the sub's motion in check, for the most part.
    Along those lines also, sealed subs require more power to perform, as a tuned port sub is a bit more sensitve and will produce more sound from less power. This is one reason why vented subs are more common.
     
  9. Dustin B

    Dustin B Producer

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    40-50hz tune for a vented sub? Are there any decent home theater subs tuned higher than 30hz?
    I could understand a 40-50hz tune being common in car audio, but not with a sub built for home use. And if you want quality bass in a car with a vented enclosure don't you have to tune below 30hz there as well.
    If you tune really low (20hz down to as low as 12hz depending on the driver), then a vented sub can come very very close to sounding as good as a sealed sub.
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    Dustin
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    My Adire Tempest Sonosub
     
  10. John Garcia

    John Garcia Executive Producer

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    "DECENT" is the key word. Most of the average (ugh)Circuit City/Best Buy subs I've seen are not tuned that low. Not sure if this is the intention, or just the nature of the design, but it seems pretty common, and most roll off completely before 20Hz, some as high as 30Hz. SVS and others of higher quality tune much lower.
    I'm not saying that vented subs cannot sound good by any means.
    Yes, 40Hz is very common in car audio subs.
     
  11. Jack Gilvey

    Jack Gilvey Producer

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  12. Jack Gilvey

    Jack Gilvey Producer

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    quote: If you tune really low (20hz down to as low as 12hz depending on the driver), then a vented sub can come very very close to sounding as good as a sealed sub[/quote]
    This is becoming more true all the time, although there will always be group delay and transient response differences. Many modern drivers like Tempest have such a low Fs that it's feasible to tune to 20Hz and below. In that case, the vent only comes into play in the very low frequencies, and the upper passband, the more critical "musical" frequencies" are handled by the driver itself. The term "boom box" for vented subs was coined, I'm sure, after hearing a misaligned sub tuned very high.
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    [Edited last by Jack Gilvey on September 21, 2001 at 11:12 AM]
     
  13. Samuel Des

    Samuel Des Supporting Actor

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    Delete.
    [Edited last by Samuel Des on September 21, 2001 at 07:44 PM]
     

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