Sealed Stryke SB-12 Sub and Room Gain..

Discussion in 'Archived Threads 2001-2004' started by Peter Johnson, Jan 28, 2001.

  1. Peter Johnson

    Peter Johnson Stunt Coordinator

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    I have asked a few questions before, but have recently been working a lot a a DIY sub was forgotten about for a while.
    I have never built a DIY sub, so you guys are the people to ask..
    I wish to build a music only sub to match up with a very decent 2channel music setup. Consists of nOrh marble 7.0's, Cyrus 3 amp and a NAD 540 cdp (weak link.).
    I am after very fast bass to match in with the very quick bass offered by the nOrh's. I dont want slow, boomy bass.
    I think a Sealed sub is the safest route to take, as it has the least questions about performance, and is easy to construct. I have modeled the SB-12 sealed sub and have come up with an F3 at around 30Hz, no matter what the volume increases about about 80L. The qtc lowers in WinISD as the volume increases. I dont really want a 200L box in my room...Can anyone more experienced than myself estimate what would be a good volume to suit my needs?
    I get the same response with the SB10, in a smaller enclosure, but it is very inefficient, hence will need more power, and will therefore be more expensive to drive...
    The rolloff seems quite flat, and I am wondering about how much the extension will actually change. My room is about 5.8m deep, 3.8m wide and 4m high. It is plastered brick walls, carpeted floor, bed, and glass windows, with curtains.
    Can anyone give me an estimate as to what will actually occur in my room. I would like to get below 25Hz, is this possible???
    I am on a very limited budget ($US400,tops), and live in Australia. Shipping on these things aint going to be cheap. I have an Adire Dealer in Australia, who sell drivers for about 2.5x the $US price in $AU, so they are a little more expensive for me...
    Any other driver which give a better response without creating slow bass?
    Thanks for your help.
     
  2. Greg Monfort

    Greg Monfort Supporting Actor

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    Since there's no such thing as 'fast' bass, I assume in your case after perusing the n0rh site that you mean the emphasis of harmonics Vs the fundamentals, i.e. rising response.
    For a sub to blend properly requires that it have a ~matching rising response, so a sealed Qtc =
     
  3. Jones_Rush

    Jones_Rush Stunt Coordinator

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    PJ,
    Here is an E-mail from a friend of mine (which is an experienced DIY sub builder):
    The very nature of deep bass sound is resonant and long lasting --ask any musician who plays a bass-- they'll
    laugh at the term "slow" when applied to bass tones.
    They want "slow" resonant bass tones that rumble
    throughout a room and sustain for a long time.
    They'd be very disappointed if their instruments
    produced "fast" bass.
    Listening rooms are "slow" -- bass resonances can resonate ("ring") for 200 milliseconds or more before they've declined by 30dB from the original signal. Given the behavior of listening rooms, the quest for the best possible transient response from a subwoofer (sealed enclosure with Qtc of 0.5) seems like a moot
    point. Home listening rooms are so "slow" that the transient response (actually "group delay") differences among ported and sealed sub enclosures are difficult to hear. (Ported subs do provide a lot more output at 20Hz. compared with sealed enclosure subs -- that's audible and very useful in large rooms.).
     
  4. Jack Gilvey

    Jack Gilvey Producer

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    I agree about the concept of slow vs. fast bass. Deep bass does "bloom", but "perfectly" reproduced (or even produced)deep bass still sounds wrong to many audiophiles. In fact, I'm sure many wonder why that passing train they experience on their morning wait at the station sounds so "boomy".
    If we accept this:
     
  5. Jones_Rush

    Jones_Rush Stunt Coordinator

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    If you accept this:
    "I agree about the concept of slow vs. fast bass. Deep bass does "bloom", but "perfectly" reproduced (or even produced)deep bass still sounds wrong to many audiophiles. In fact, I'm sure many wonder why that passing train they experience on their morning wait at the station sounds so "boomy"."
    Then you should NOT have said this:
    "...it would seem even more important to strive for excellent transient response, given that the room will invariably make it even worse, and is anything but "moot"."
    If DEEP bass is SLOW by nature, and suppose to "bloom"
    and sound wrong to many people, then it's not the
    transient response (group delay) we need to change,
    It's our own EARS/MIND which actually need to
    accustom to the authentic sound of nature, instead to
    try make nature sound like we want it to sound...
     
  6. Jack Gilvey

    Jack Gilvey Producer

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