PR Options For 10"’s


  • Member
    TeeCee on #75

    I have some 10″ subs that have been freed up recently and I was thinking about doing some experiments with PRs. Do you offer any PRs smaller than 15″? If not, would a 15″ PR be a decent option or a waste? I’m looking at a box around 1.4 cu.ft. tuned around 25 – 30Hz.


    Member
    Admin on #1455

    I do have 12″ PR’s. You need to make sure the woofers are decent to use with PR’s though. Do you have parameters or model numbers?

    John


    Member
    TeeCee on #1456

    The speakers I have “left over” are Infinity Kappa DVC;s. My biggest issue with them at the moment is that they are 4Ohm coils so I would have to run them at 8Ohms and the price increase for an amp to push them is more than the cost of a 4Ohm speaker like the Infinity Kappa Perfect 10.1, which I’m also considering.

    The 100.3DVC doesn’t seem to be listed on Infinity’s web site any more but the parameters are in BassBox Pro. If you can’t get them, I can pull them out later and post them here.

    The 10.1 is stil listed:
    http://manuals.harman.com/INF/CAR/Boxes%20and%20Parameters/KAPPA%20PERFECT%2010-1%20Enclosure%20Sheet.pdf


    Member
    TeeCee on #1457

    Can you post the parameters for the 12″ PR’s? I’d like to plug them in to BassBox Pro.

    @stryke wrote:

    I do have 12″ PR’s. You need to make sure the woofers are decent to use with PR’s though. Do you have parameters or model numbers?

    John


    Member
    Admin on #1458

    Here are parameters for the 12″ PR’s:
    Fs: 7.3 Hz
    Qms: 37.8
    Vas: 279 L
    Mms: 670 g
    Sd: 530 sq cm

    There is also a 970gram model but you would be tuning about 22hz with a pair of them. Looks like a pair of the 670’s will tune you right around 27hz.

    The driver you have has fairly low motor strenght but could be ok.

    John


    Member
    TeeCee on #1459

    Can you define motor strength or point to where it might be defined?

    I will gladly admit that I look at just a few parameters to see if I’m interested in a sub and then throw it into software to get an idea of it’s response in a particular application.


    Member
    TeeCee on #1460

    bump.


    Member
    dB on #1461

    Electromotive force can be found by squaring Bl and dividing my Re. The resulting number is one you can use to easilly compare from driver to drive, very much like horswpower for a car. 100 is 2x as strong as 50.

    Driver 1
    BL = 14
    Re = 7.8

    Driver 2
    BL = 9
    Re = 1.9

    Which one is stronger? Driver two by almost a factor of 2. Many MFR’s will give a BL rating for coils wired in series, but show the DCR as paralell to try to make you ‘think’ it has a stronger motor.

    Marketing types. (Can’t stand em)


    Member
    TeeCee on #1462

    Cool. Is the BL based on the magnet?


    Member
    dB on #1463

    Very loosely – yes.

    B is the measure of flux density across the magnetic gap (strength of the magnetic field) and L is the length or quantity of wire in the coil submersed in that magnetic field.

    X size magnet, and Y size coil do not always add up to x+y however.

    Magnetic material grade, and level of magnetization, as well as magnetic conductivity of the steel used in the return circuit, the shape of that steel and whether it’s saturated or not, all affect B.


    Member
    TeeCee on #1464

    Check.

    If it’s not too much, can you state how the various BL units relate so I can compare apples to apples?


    Member
    TeeCee on #1465

    Oh – is this purely a calculation or is it actually measured (at least on a prototype or production reference)?


    Member
    R. Buszka on #1466

    BL is a measured parameter and only vaires negligibly from motor to motor. Ideally it shouldn’t vary at all, and the margin of variation would be extremely, extremely small, unless the magnets weren’t the right kind or strength, etc.


    Member
    TeeCee on #1467

    Thanks.


    Member
    dB on #1468

    Typical consumer grade ceramic ferrite varies from a low of around 5% to a high of a little over 10%. This is the largest cause of unit to unit variations in driver parameters in production.

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