Thinking about going from sealed to ported sub to gain about 5db

Discussion in 'Audio/Video & Home Theater' started by Vdubchaos, Nov 2, 2012.

  1. Vdubchaos

    Vdubchaos Lifer

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    I currently have the following components in my Passat

    12" Kenwood W3013PS 4ohm (400RMS) in Atrend E12S B Box Series Sealed Box (about .8 Cubic Feet) pushed by Kenwood Kac-7205 (500RMS @4ohm).

    I was going thru the manual and noticed that bigger ported Box can gain me good 5db (which I assume is pretty significant). See below:

    [​IMG]

    My set up sounds great currently (AMP does overpower the sub and its set to about 60-70 gain /no bass boost crap), but I wouldn't mind more deeper/powerful bass. Also I wouldn't mind building a new Box (already have MDF board and it would be a cool project for me and my boys.

    I guess the question is, would it be worth it to go from Sealed box to Ported and from .8 cubic feet to 2+ cubic feet as per below.

    [​IMG]

    Based on my speaker manual it seems like I''m current;y on the low end of the cubic feet for Tight bass. Guessing going to a much bigger box and switching to Ported box can gain me significant difference.

    Any thoughts?

    TIA
     
  2. alkemyst

    alkemyst No Lifer

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    I'd gut it all and go to JL or some higher end gear if you really want SPL.
     
  3. Vdubchaos

    Vdubchaos Lifer

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    no

    I had JL Audio W6 and Fosgates amps/12s as well. Difference in sound is slight and price difference is EXTREME. Also I'm not upgrading my battery/alternator or amp.

    My Sub cost me $45 bucks, amp about $115. Can't really beat that when it comes to bang for the buck.

    I'm fine with the set up, just wondering about the benefits of going ported/bigger proper box. Again I don't NEED more power but building a box would be free (I already have MDF/carpet).
     
  4. kornphlake

    kornphlake Golden Member

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    The ported box looks like it would sound really boomy, even more so with cabin gain. I'd stick with the sealed box.
     
  5. joetekubi

    joetekubi Member

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    Looked closely, that that Kenwood driver has 15mm xmax - usually the limiting factor. I say go for. If you don't like the ported box for some reason, you can always drop it back in the sealed box. One tip - ported systems have no "resistance" below the port Hz, so you might want to use a high pass filter (if possible) on your amp for 20-30Hz to protect the driver.
     
  6. Vdubchaos

    Vdubchaos Lifer

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    please explain

    I don't understand.

    Run High Pass on the Amp?

    I'm not really worried about pushing the Sub too hard. Amp won't be turned up more than 60-70% and I use no Bass Boost and usually adjust it accordingly if I hear/notice distortion.
     
  7. alkemyst

    alkemyst No Lifer

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    Bro...do you always attack everyone that knows more than you?

    XMAX is a HUGE thing.

    your amp turned up 60-70% normally does say a lot though.
     
  8. sdifox

    sdifox No Lifer

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    xmax = how far the cone will move. Bigger xmax= more air moved. You can go to bigger enclosure but keep it sealed.
    The driver you picked has a Frequency Response Range of 34-300Hz. You should filter out the frequencies below 34 and above 300. So high pass 35Hz and low Pass 295Hz kind of setup.

    85 db makes it low efficiency, you need to go to bigger enclosures. use calculator to figure out what you need. Parts-express says xmax=15.1mm.

    http://www.parts-express.com/pe/showdetl.cfm?partnumber=267-4356


    http://www.bcae1.com/spboxnew2.htm

    calculator recommends sealed internal dimension of 12"x12"x18" so 1.5 cubic feet box.
     
    #8 sdifox, Nov 2, 2012
    Last edited: Nov 2, 2012
  9. Vdubchaos

    Vdubchaos Lifer

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    And where do you see me attacking?

    Explain then

    Ok, can you explain how this matters or what it effects?

    I still don't get it, why?

    I understand.

    I believe my amp has a filter.

    "High-pass (12 dB per octave) and low-pass (24 dB per octave) filters variable from 50 to 200 Hz"
    Taken from:
    http://www.kenwoodusa.com/Car_Entertainment/Amplifiers/KAC-7205

    Also under Specifications I found the following
    Low Pass Filter Frequency
    (-12 dB/oct.)
    50 Hz - 200 Hz (variable) Low-Pass Filter Frequency

    Also it will be around 90db once it's in a proper size ported box, as per the posted manual screenshot.
     
    #9 Vdubchaos, Nov 2, 2012
    Last edited: Nov 2, 2012
  10. sdifox

    sdifox No Lifer

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    a subwoofer's job is to push air. More air = louder sub.

    Your amp does not have a high pass filter, or at least they didn't list frequency range for it if it has one. You need to filter out anything lower than 35Hz before you feed it to the amp, then use the low pass filter and set it to like 70 or 80Hz. What is your main speaker's diameter?

    The site I linked to recommended a 1.5 ft^3 sealed box for this driver based on its Fs and Qes specs. You can use it to calc a ported enclosure too. Ported enclosure would have to be bigger to maintain output.




    http://www.diyaudioandvideo.com/Calculator/Box/
    http://www.diyaudioandvideo.com/Calculator/SealedPorted/

    that one also says sealed is better.
     
    #10 sdifox, Nov 2, 2012
    Last edited: Nov 2, 2012
  11. Vdubchaos

    Vdubchaos Lifer

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    It does have a high pass filter. I think Kenwood just didn't update the site properly. If you look at other similar amps on the left side they all have High Pass Filter specs listed under Specifications tab.

    Sub? It's 12". It's the only speaker hooked up to this amp.

    I thought I had to filter out low pass, not high. I'm getting confused again.

    Mids and Tweeters are hooked up to a Monsoon that came with my car (premium package). I have 6.5" Component Kenwoods.

    The site I linked to recommended a 1.5 ft^3 sealed box for this driver based on its Fs and Qes specs. You can use it to calc a ported enclosure too. Ported enclosure would have to be bigger to maintain output.[/QUOTE]
     
  12. sdifox

    sdifox No Lifer

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    reason I am asking what your main speaker size is because you need to figure out the crossover frequency. The high pass filter is used to filter out frequencies lower than 35Hz to protect your subwoofer driver. If you say your amp has a high pass filter, set it to 35 or 36Hz. Anything above 35 or 36Hz will make it through and set the low pass Filter to around 80Hz so that combined filtering effect means only 36-80 Hz signal makes it to your sub.

    The driver is best used in a sealed box, you can go ported if you really want to.

    the pictures you linked is recommending 1.2 sealed, why are you looking at 0.8?


    Interesting read.
    http://uk-mkivs.net/forums/t/170419.aspx
     
    #12 sdifox, Nov 2, 2012
    Last edited: Nov 2, 2012
  13. Vdubchaos

    Vdubchaos Lifer

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    I thought High Pass filter was for high frequencies and Low filter for low.

    Here is a pic
    [​IMG]

    I don't believe High Pass is adjustable

    What makes you say "is best used in a sealed box"?

    .8 is what I currently have (sealed)

    I want to go to 2.0 Cubic Inch Ported
     
  14. sdifox

    sdifox No Lifer

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    High pass = higher than x frequency it gets pass, so it is used to filter out lower frequencies of the signal :p
    Also, filters efficacy is sloped, not a straight cut off. This means on a high pass 35Hz, you will still get some 35, 34,32, etc, but attenuated.
    You need to look at the spec graph to know what the slope looks like.

    Can you find out what is the high pass frequency on the amp?


    read this

    http://uk-mkivs.net/forums/t/170419.aspx

    It explains the basics.
     
    #14 sdifox, Nov 3, 2012
    Last edited: Nov 3, 2012
  15. Vdubchaos

    Vdubchaos Lifer

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  16. Howard

    Howard Lifer

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    You can open up a whole new world to people if you show them what the frequency response is like in their car.
     
  17. joetekubi

    joetekubi Member

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    Yep, those look like they should work.

    On the other hand, you are not a 16 year old teenager who might
    turn the amp all the way up, and add some bass boost.

    If you listen to your car system at moderate volumes and are not addicted
    to bass-heavy electronica music, you should be fine without the additional
    high pass filters.

    BTW, "high pass" nomenclature confused me for many years. I would convert "high pass" in my mind to "low cut".
     
  18. alkemyst

    alkemyst No Lifer

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    Well in all fairness we'd need to know the rest of his setup and what he is wanting to accomplish. Boom cars are a 16 year old thing only. This is more readily seen by use older folks in friend's home theatres with $2000 in subwoofers for a $750-1000 home theatre that arrived in one box :)

    The system I had estimated for my M3 comes out to about $6k, it would BOOM or be major on SQ depending on settings. I will probably go lower end and be at about 75-80% of it.
     
  19. Vdubchaos

    Vdubchaos Lifer

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    No, amp won't be turned up all the way. It will go up to about 75%-80% as long as there is no distortion.

    I don't turn up my radio more than 80% as my insides (Monsoon amp + 6 1/2 inch Kenwood Components x2) distort at anything past that. At 80% they sound nice and clear (I think amp is rated at 200RMS). I have my treble/midrange all at stock level). Sounds great and I'm leaving this as is.

    I do like heavy bass though and I do listen to just about every kind of music you can imagine (minus Country/dubste hehe).Mostly Rock, metal, 80s Rap, 90s hip pop, 80s Dance/freestyle etc so plenty of low frequencies.
     
  20. Soccerman06

    Soccerman06 Diamond Member

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    Ok I did you a favor, I created a response simulation of your sub with a few others that are out there at 400w peak power. My first concern is a EPB of 27.5 is way down into the sealed only area. My second concern is the excursion seen at about 23hz with ported, anything below that will be near bottoming out the woofer and may or may not happen in music.

    I threw in some other subs to give you reference to higher end stuff (note: they arent limited to the 400w amp), however the ixl is only $200 so Id consider it a very high cost/performance ratio.

    spl
    [​IMG]

    excusion
    [​IMG]
     
    #20 Soccerman06, Nov 3, 2012
    Last edited: Nov 3, 2012
  21. Vdubchaos

    Vdubchaos Lifer

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    THanks!!!

    But I'm struggling to understand what all that means. :oops:

    When you say EPB is way down in sealed box, guessing that's a bad thing? And you are referring to my current sealed box correct?

    Sorry for newb question.
     
  22. Howard

    Howard Lifer

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    EBP is only a guideline for what type of enclosure is suitable.
     
  23. Ketchup

    Ketchup Lifer

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    From my experience, you will get more sound at certain levels (aka range of notes), depending on the port size and placement.

    Personally I don't like it. Most people who listen to rap go with ported, since all those bass frequencies are about the same. I like hearing the different notes (of a bass guitar, for example) at the same volume level.

    I got the best-sounding results when using a sealed box that was sized according to the power and sub size I was using.
     
  24. Soccerman06

    Soccerman06 Diamond Member

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    Basically what howard said, it stands for efficiency bandwidth product, and the lower the number is the more suited it is for a sealed system. Anything below 50 is recommended to be sealed.
     
  25. Vdubchaos

    Vdubchaos Lifer

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    So I finally finished building the box. This thing is HUGE. About 3x the size of my sealed box.

    It's also HEAVY. I didn't weigh it but it must be at least 40-50lbs.

    I used an entire 6x4 sheet of MDF 3/4 inch board.

    I took my time letting the glue set and sealing it on the inside and outside (also letting it cure for over 2 days). I also didn't use a speaker terminal, just drilled a hole > ran a speaker wire thru it and sealed it up with silicone.

    Just put the speaker in yesterday, installed the FMOD (30hz) on the RCA on the amp side and readjusted the gain (using Multimeter and 60hz tune) just to make sure everything was nice and dandy. Bass Boost stayed all the way down as always and EQ/Treb/bass on the head unit is default.

    First impression. It's a big difference. I can finally hear higher end bass much better than before (before it was just ......flat/almost non existent). Puny would be a better word I guess.

    As for the low end bass, it is much deeper and stronger now. Heck it feels/sounds better with the seats up than it did with the sealed box+ the seats down.

    I would say the chart I posted in the OP from Kenwood is pretty much on point.

    I'm pretty happy with the results and again I would like to thank everyone for warning be about the none existent subsonic filter on my amp.
     
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