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Finaly A Start In The Right Direction...

Discussion in 'General Car Audio Discussions' started by MaddoxBay, May 20, 2004.

  1. MaddoxBay

    MaddoxBay Full Member

    Here is a little refresher...

    http://caraudiotalk.com/forum//index.php?s...l=dcr+impedance

    I should be picking up four of the Tangband's this weekend... Finnaly :lol:

    NOMINAL IMPEDANCE 4ohm
    DCR IMPEDANCE 3.2 ohm
    SENSITIVITY 1W/1m 84 dB
    FREQUENCY RESPONSE 28-1K Hz
    FREE AIR RESONANCE 28 Hz
    VOICE COIL DIAMETER 50 mm
    AIR GAP HEIGHT 8 mm
    RATED POWER INPUT 120 W
    MAXIMUM POWER INPUT 230 W
    FORCE FACTOR, BL 13.35 TM
    MAGNET WEIGHT (50oz) 1427 g
    MOVING MASS 95 g
    FERRO FLUID ENHANCED No
    SUSPENSION COMPL. 333 MN -1
    EFFEC.PISTON AREA 0.022 m2
    LEVC 3.1811mH
    Zo 113.9893ohm
    LEVC 3.1811mH
    Zo 113.9893ohm
    X-max 12 mm
    Vas 23 Litr.
    Qts 0.30
    Qms 10.53
    Qes 0.30



    I have a Lanzar Opti 1000.1D that I can run them on. I do want to go ported but this is in my daily driver (Pontiac Sunfire) so I still need a trunk.

    I would like to be able to get the four in there but i need some help moldeling up a box for these subs. I was thinking 2cuft tuned to 35hz as geolemon suggested. I need to know the port lenght and port area. Building the enclousher wont be a problem but I need all the assistance i can get with the design.

    Thanks,

    MaddoxBay

    P.S. Is DCR IMPEDANCE of 3.2 ohm what you would read on a DMM?
     
    MaddoxBay, May 20, 2004
    #1
  2. geolemon

    geolemon Full Member

    Sounds like fun! B)

    And yes, DCR is what you'd read on an ohmmeter... just the actual resistive component. It might not be exactly 3.2, but it'll be close.
     
    geolemon, May 21, 2004
    #2
  3. MaddoxBay

    MaddoxBay Full Member

    Thanks geolemon,

    They are reading 3.6 – 3.8 ohms.

    The build quality is a lot better that I ever imagined for the price of these subs. I am already impressed with them and I haven’t even played them yet. All the pictures that I have seen of the sub just doesnt do it justice.

    Four of these should do well for me. I am trying to figure a way to mount the box to the rear deck and fire them up through the deck and port them through the deck.



    thanks
     
    MaddoxBay, May 24, 2004
    #3
  4. geolemon

    geolemon Full Member

    If you do that, you might be best off completely sealing the trunk from your cabin...
    You'll gain 'cabin gain' (no pun intended), and also help eliminate any possibility of cancellations, due to reflected energy going into and back out of the trunk, cancelling against the direct-pathlength sound energy. Sound travels in every direction. ;)
     
    geolemon, May 24, 2004
    #4
  5. MaddoxBay

    MaddoxBay Full Member

    I don’t think that will be a problem sealing off the trunk. An extra increase in cabin gain was what I was shooting for.

    I would like to get the most out of the eights as I could and still sound good.

    I have already deadened the trunk some and will deaden the deck like crazy along with the doors.
     
    MaddoxBay, May 24, 2004
    #5
  6. MaddoxBay

    MaddoxBay Full Member

    What should the air velocity for 35 Hz be if porting straight into the cabin to keep from hearing noise?
     
    MaddoxBay, May 24, 2004
    #6
  7. geolemon

    geolemon Full Member

    The bigger the ports you can run, the better.
    The bigger the port opening area, the lower the risk of port noise.

    The actual number varies between software programs... but be a little conservative, if you can. ;)
     
    geolemon, May 24, 2004
    #7
  8. MaddoxBay

    MaddoxBay Full Member

    In order to get a decent port area I am getting a port length that is hard to work into my plan. I would like to use all four of the subs but if I can’t work this out I might have to cut back to 2 or 3 subs.

    Is it possible to stuff a port with a known amount of wool or poly fill to reduce the port length?

    Will this make the port act as if it were longer due to the increase in friction?
     
    MaddoxBay, May 25, 2004
    #8
  9. MaddoxBay

    MaddoxBay Full Member

    Can you check my numbers on WinISD…


    4 TB 8’s in a 2 cuft chamber tuned to 29.80 Hz on 400 watts.

    3 – 3” ports 29.63” each

    Box dimensions: 34.5” (w) x 11.5” (h) x 14.5” (d), after sub and port displacement 2 cuft.


    The highest group delay is 20.157ms @ 27.45 Hz. From there it rolls off quick.
    The highest port velocity is 21.287m/s peak @ 26.19 Hz.

    The Transfer Function Magnitude isn’t flat but a wide curve. -3dB is @ 36.84 Hz. Will the increase in cabin gain help?



    Any other thoughts or suggestions?

    Would I be better with a 35 Hz tuning?
     
    MaddoxBay, May 25, 2004
    #9
  10. fugyaself

    fugyaself Full Member

    Yes you can stuff a port with poly. Just make sure you have both ends covered with chicken wire or something to hold it in. I havent really seen any calculations or known figures on how much to use to change tuning. Kind of hard to do due to the unlimited sizes of ports you can use to get the same tuning.
     
    fugyaself, May 27, 2004
    #10
  11. MaddoxBay

    MaddoxBay Full Member

    Is there a way to check the tuning frequency?

    Is it possible to use a DMM and test tones or something?

    If so I guess I could keep adding poly fill until I get the desired tuning frequency and still have an adequate port area…
     
    MaddoxBay, May 27, 2004
    #11
  12. geolemon

    geolemon Full Member

    Good thinking on the port stuffing idea. B)
    Unfortunately, I don't believe the stuffing nets you much. :(

    Here's one alternative thought, might work for you:
    If you make the enclosure larger, your ports will be shorter.

    But I wouldn't sweat the port length.. ports can be bent using PVC elbows very easily. ;)
     
    geolemon, May 28, 2004
    #12
  13. geolemon

    geolemon Full Member

    Yes, you can check your tuning frequency with a frequency generator feeding tones into your amp... or even a test CD with a lot of test tones on it.

    Keep your volume at a constant setting as you test... something that is fairly loud, but not so loud that you risk bottoming out the subs.

    As you go lower in tuning frequency, you'll initiallly see your excursion keep increasing and increasing...
    ...then at some point, you'll notice it begin to decrease again.
    It'll reach some point where the cone motion seems to be nearly nonexistant. That's your tuning frequency.

    And if you keep going, below the tuning frequency, you'll see excursion again increases dramatically.
    Be careful... you don't want to play very low below your tuning frequency - it's easy to unload your sub and bottom it out! :eek:
     
    geolemon, May 28, 2004
    #13
  14. MaddoxBay

    MaddoxBay Full Member

    Thanks for all the help so far…

    I want to get started soon but I want to have everything all planned out before I even begin to start.

    Thanks again,

    MaddoxBay
     
    MaddoxBay, May 28, 2004
    #14
  15. MaddoxBay

    MaddoxBay Full Member

    Thanks for all the help…

    I got my box built this weekend and got them installed temporally just to hear how they sound.

    4 TB8’s in 2cuft @ 35 Hz on a Opti 1000.1 @ 4 Ω

    With about 100 watts or less per sub I am already happy with the subs. They sound great and get low for eight inch subs. :jawdrop: The output isn’t all that bad either for the power they are getting. I will wire the subs to 1 Ω once the components are installed and see how they do with about 200 watts each.

    The setup is fine for my daily driving at 100watts though… It still needs some tweaking but I am very happy with the subs. I just need to get the crystal components in to finish up the budget install.

    I will have some pics later…

    Thanks for all the help, I am very happy :yes:
     
    MaddoxBay, Jun 14, 2004
    #15
  16. geolemon

    geolemon Full Member

    Very cool! I want to play with some myself. B)
     
    geolemon, Jun 14, 2004
    #16
  17. MaddoxBay

    MaddoxBay Full Member

    It’s a really impressive sub for the price. I haven’t had much listening time yet but I am extremely pleased with them so far.

    There is a lot of tweaking to do but I am very happy with them. In fact I am thinking about just using two of them and putting them in 2 cuft and tuned to around 29 – 30 with about 200 watts each. I should have plenty of head room @ 2 Ω and I hope they will blend in with the Crystal CPe60s components that I will be installing soon ran by an Opti 100.2

    I hope this works out well; I have very little money involved. I have tried to keep this on a very low budget and I am happy so far ($400).
     
    MaddoxBay, Jun 14, 2004
    #17