1 12" sub or 2 12" subs...

Discussion in 'OT Technology' started by cRaZe, Jul 21, 2004.

  1. cRaZe

    cRaZe 3rd world slummin

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    ok i've done more homework and i've decided my pioneers are not suitable anymore and neither is the bandpass box they are in.

    I've narrowed it down to the Infinity kappa perfect 12.1 DVC

    RMS rating is 350W rms, peak 1400W, Impedance Dual 4 ohm voice coils, recommended Sealed box volume 1.0 cu. ft.


    im sure most of you experienced guys know that subwoofer, it seems that it gets RAVE reviews all over the internet and over at www.carreview.com it has over 200+ reviews with 5 star ratings making it the #1 rated sub on that website.

    I did the calculations on my rockford fosgate amp 360 a2 and bridged it will put out 340 rms @ 4 ohms.

    (listed [email protected] so formula is 170 * 2 = [email protected] bridged) correct?

    so the power is definately ready to be tapped if i wire 2 subs in series to the bridged amp.

    what i want to know is, my preference is SQL but SPL is not a bad thing either.

    what is the overall difference between 1 and 2 subs in the sealed box?

    whats the estimated % increase in SQL and SPL?

    the car is a 2004 hyundai tiburon which is a hatchback so trunk rattle is not going to be a problem.

    would i inside the car stand to gain a lot more with that extra sub or is that extra sub more for letting people outside of the car hear your bass...

    i listen to all kinds of rock mostly .
     
    Last edited: Jul 21, 2004
  2. cRaZe

    cRaZe 3rd world slummin

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    the amp is only 4 ohm mono stable bridged but not 2 ohm mono stable bridged.

    hence the reason i need the dual voice coil sub if i want 2 of them in series to get the end result 4 ohm amp load.

    am i wrong? am i confusing myself...

    www.sounddomain.com has a really useful subwoofer wiring guide thats basically a ohm calculator for series and parallel given the # of subs and impedance of the subs as variables.

    im just trying to see also if i DO choose two subs that i wont need a new mono amp and that what i have now is good.
     
  3. merlinski

    merlinski and I'm his friend, Jesus

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    Have you bought the subs yet? If not, you should see if it comes in a DVC 2 ohm version.

    If you wire 2 subs, you'll only be sending 170 watts to each one. That amp would be much better for one sub if you could wire the sub for 4 ohms.
     
  4. realest00

    realest00 New Member

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    hmm, this sounds familiar...
    http://forums.offtopic.com/showthread.php?t=1187848

    2 subs in a sealed box would give you a 3db increase. This increase is about the same as using a PROPERLY BUILT ported box. With 340w you should only be looking at a single sub application.

    I would really recommend the Image Dynamics IDQ12v2d2 over the Infinity.
     
  5. cRaZe

    cRaZe 3rd world slummin

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    yea i know its familiar but at that point i hadn't done any homework so now with figures in hand i wanted to start a new thread...

    im going to sell all that stuff i got (100% profit :cool: ) and make it a much cleaner setup... i read about bandpass boxes and i do realize that they suck at accurately putting out bass at all frequencies instead of just one loud ass muddy tone..

    ill look into the sub recommendation of yours.

    what makes you prefer it over the infinity?
     
  6. cRaZe

    cRaZe 3rd world slummin

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  7. 04

    04 Guest

    Actually, bandpass enclosures are not all bad. BUT, the vast majority of the car audio prefab ones you hear are. They really have a bad stigma attached to them, even though they can be made to be quite good :hs:
     
  8. 04

    04 Guest

    2 subwoofers in a sealed box would give you a theoretical 3dB gain only if they received the same amount of power as one did. But if you wire them in series, your output will be closer to 0dB gained, and in parallel it would be closer to 6dB.

    With 340 watts I see no reason why he couldnt use a dual woofer setup if he has the space for it.

    And the ported enclosure only gets and extra 3dB around the tuning frequency. The gain gradually rolls off as you increase in frequency through the passband.
     
  9. 04

    04 Guest

    Yes it should be around 340 watts.

    The difference would be dependent on many factors. Such as wiring configuration, and amplifier power output.

    If you simply take a single woofer with say 100 watts, and then take another of the same woofer and give it 100 watts too, you will see a gain of near 6dB if the soundwaves are closely correlated (which they usually are for bass)

    Percentage wise, the increase is 100 percent for sound pressure levels (not subjective loudness). Sound quality wouldnt really improve except at high volume levels.

    IMO one subwoofer would probably be fine if you listen to rock and the car is a hatchback. However, if you want to blast your music really loud, I suggest going with two.
     
  10. 04

    04 Guest

    You could also run two 2ohm single voice coil subwoofers in series, or two 8ohm dual voice coil subwoofers in parallel to acheive a 4ohm nominal load. The DVC setup (for two woofers) would only be suitable if you bought woofers with dual 1ohm coils, or dual 16ohm coils, or dual 4ohm coils.
     
  11. XR250rdr

    XR250rdr OT Supporter

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    I'll throw a wrench in the discussion. The 360a2 has been known to bench in 500W RMS range @ 4 ohms mono. Two Perfects would run fine on that amp. But for the price of two Perfects I'd look at the Adire Brahma. And there is the Adire Tempest too cheaper than a Perfect and will perform on par with two of them in about the same airspace.
     
  12. cRaZe

    cRaZe 3rd world slummin

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    ive heard of adire.. they make some good home theater stuff which im more into.

    WTF though 500 rms @ 4 ohms mono???

    its 90x2 @4 ohm ... how does it suddenly jump 410 watts?

    so basically ive got my hands on a really good amp already.

    on ebay the kappa perfects go for 220-240 / pair.
     
  13. cRaZe

    cRaZe 3rd world slummin

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    wait the temptest is a 15" sub according to the adire website?

    i thought 15's weren't known for SQL but more for SPL .. ?
    .

    The Brahma 12 has a bandwidth from 18 Hz to 2 kHz. Fs of 28 Hz, Qms 5.1, Qes .47, Qts 0.43, Re 1.3 Ohms per voice coil, Vas 38L, Sd 436 cm2, 1600W RMS. MSRP $379 each.

    the power ratings on those don't seem like they would work with my amp .. 1600 RMS :eek3:
     
  14. 04

    04 Guest

    A 15" subwoofer can have as good or better bass quality than a smaller diameter speaker. At low frequencies, the cone diameter is not the deciding factor for sound quality.

    You could run the Brahma off a 100 watt amp if you wanted to :)

    1600w is the maximum reccomended power. If you used a large sealed box, you may only need a couple hundred watts to get the driver to full excursion at low frequencies.
     
  15. XR250rdr

    XR250rdr OT Supporter

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    4 ohms mono is also known as 4 ohms bridged. Its rated at 360W x 1 @ 4 ohms bridged. The older RF amps were known to be quite underrated. I have seen several birthsheets for that amp close to 500W.

    Thanks 04. As for the Brahma on 100W, Dan Wiggins used to run one on 100 or 150W, cant remember which.
     

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