Meaning of "Free Space"

Discussion in 'Speakers & Subwoofers' started by MikeDuke, Sep 20, 2004.

  1. MikeDuke

    MikeDuke Stunt Coordinator

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    Can some one tell me what this means?

    This driver is used in 100litre cabinet using two large profiled reflex ports; naturally, this system descends to 32Hz at –3dB in free space! With a little help from the amplifier’s optimized response, this limit is pushed even lower.

    Thanks
     
  2. Craig Chase

    Craig Chase Gear Guru
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    Free Space would be without the benefit of a room boundary adding to the output of the subwoofer (I am guessing this IS about a subwoofer based on your post) ... 1/2 space would be one boundary (ie - floor), 1/4 space would be two boundaries (floor/wall) and 1/8 space would be corner located on the floor.
     
  3. MikeDuke

    MikeDuke Stunt Coordinator

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    Yes it is about a subwoofer. Sorry for not saying that first.
    Thanks for you reply. Do you think that is good, bad, or average.
     
  4. Craig Chase

    Craig Chase Gear Guru
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    That is a pretty decent response... Though it would take a lot more information to say anything definitive... With enough amp power and driver excursion ability, it COULD be a very powerful set up.
     
  5. MikeDuke

    MikeDuke Stunt Coordinator

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    Well this is from the JM Labs SW900. It has a 13.18 in driver a class A/B 400 watt amp. Not sure about excursion though. The driver may have an Xmax of about 9mm. That was from the previous driver so this one should have at least that. I know that the Bl is 16.6. The sub has 2 ports. The ports are 2.75 inches in diameter and are 8.26 inches in length. The cabinet is 100 liters.
     
  6. Craig Chase

    Craig Chase Gear Guru
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    It looks like a pretty good subwoofer... With SVS having the PB2-Ultra for $1799, there is some SERIOUS competition... Is there something compelling about the 900 that you like ?
     
  7. MikeDuke

    MikeDuke Stunt Coordinator

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    One more stat. It is also a 3rd ordered design that is boundary loaded.


    What do I like?
    Well, It just hits so hard for home theater. In my opinion it can put out some serious SPL. Plus it is very musical and tight. I can not find much if any distortion in its sound. Plus, I can not lie, I like the fact that they make everything on this sub. The amp, enclosure, cross over, driver are all designed and assembled by JM labs. Every one who has heard it has been very impressed. Even someone who has a sunfire true swoofer was impressed. Let me put it this way. In my view. This gives me the sound quality of a Wilson Audio Watch dog while giving up only over all SPL. But my room is so small that it does not matter. I never heard an SVS so I can not judge it.
     
  8. Craig Chase

    Craig Chase Gear Guru
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    Mike- It sounds like you LOVE this subwoofer... JM labs is known for being a fantastic company.

    Sounds like an easy decision to me... Buy It... [​IMG]
     
  9. MikeDuke

    MikeDuke Stunt Coordinator

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    I do have it. [​IMG]

    I just want to try and get the word out to other people that this should be an option to look into.
     
  10. Craig Chase

    Craig Chase Gear Guru
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    Well then... How much is it ?
     
  11. MikeDuke

    MikeDuke Stunt Coordinator

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    The retail price is $1750.
     
  12. Craig Chase

    Craig Chase Gear Guru
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    A review By Edward J M is in order... JMlabs 900 Vs. SVS PB2-Ultra... $1750 Vs. $1799.... !

    $1750 seems pretty good for that sub. Glad you like it !
     
  13. MikeDuke

    MikeDuke Stunt Coordinator

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    I am sure that it would be a great review and comparison. I have read Edward J M's reviews and I am impressed. He seems to be very fair and thorough. It would be interesting to see how the SW900 with one driver compares to a sub with 2 drivers.
     
  14. Craig Chase

    Craig Chase Gear Guru
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    Ed does the best subwoofer reviews I have ever read... and he has also established a set methodology that is easy to follow.

    And his measurements are VERY thorough... I don't know of a magazine that does as well.
     
  15. MikeDuke

    MikeDuke Stunt Coordinator

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    I agree. Again I would love for that to happen. Just to see what his measurements show. Can he be convinced?
     
  16. Craig Chase

    Craig Chase Gear Guru
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    Perhaps if you were to bring yours to him... Or get a dealer for JMlabs to send a review sample out.

    Of course, they MIGHT have to put up with being back ordered for a while after Ed was done, we would not want THAT to happen... [​IMG]

    Ed - Nice of me to volunteer you... eh ?
     
  17. MikeDuke

    MikeDuke Stunt Coordinator

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    I just called and I found out that I will not be able to get a SW900 out to ED. My dealer is closing, and it is kind of a pain for me to break it down and ship it. Maybe ED can goto a local JM Labs dealer and try to get one for a weekend to test. Other wise, unfortunately I do not see it going any where. Too bad
     

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