Question about the Polk MM1240 SVC subwoofer...

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jon s
jon s Posts: 905
edited June 2013 in Car Audio & Electronics
I was able to get a Polk MM1240 subwoofer (single voice coil) real cheap. I have a spare Dayton Audio 250-watt plate amplifier which I am not really using. I was thinking of building a HT subwoofer with the driver.

Question is whether I should build a vented or sealed system. After punching the TS parameters, it appears the sub is somewhat designed for a sealed cabinet. Does anyone have any opinions or experience with this driver?
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  • MacLeod
    MacLeod Posts: 14,358
    edited June 2013
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    Sealed is my favorite. Sound better and more forgiving of design flaws and such. Ported boxes are louder but only at a certain frequency that theyre designed for but the problem is that they tend to roll off on front and back of that frequency so it wont be linear.
    polkaudio sound quality competitor since 2005
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  • jon s
    jon s Posts: 905
    edited June 2013
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    I know what you mean... I like sealed designs as well, they just sound tighter. Luckily, the amplifier has a 3dB boost switch @ 35Hz. That should level out the bottom end. Don't know if 250-watts will be enough. i would think so since the driver is rated for 425-watts. But with 250-watts, the output is "only" 109-dB. My other 15" DIY sub models at 119-dB, quite a diffference.
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  • philr168
    philr168 Posts: 91
    edited June 2013
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    I made mine with two 15" momo's powered by a carver pm900 bridged and it will shake the house.
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  • WLDock
    WLDock Posts: 3,073
    edited June 2013
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    When I was researching the MM drivers it seems they can play fine either way...I think you have almost try both sealed and ported to know what really is going to work for your situation. Anyway, I ran across this post:

    http://www.avsforum.com/t/1440186/polk-momo-mobile-monitor-speakers-whats-the-deal

    The OP really tore the driver apart literally and verbally....but another poster had great success with a sealed system. IMO, the beauty of DIY is that you can play around. For the home, I would build the ported box but make provisions to be able to seal it and reduced the enclose volume if needed.
    2.2 Office Setup | LG 29UB55 21:9 UltraWide | HP Probook 630 G8 | Dell Latitude | Cabasse Stream Amp 100 | Boston Acoustics VS 240 | AUDIORAX Desk Stands | Mirage Omni S8 sub1 | Mirage Omni S8 Sub2
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  • arun1963
    arun1963 Posts: 1,797
    edited June 2013
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    jon s wrote: »
    I know what you mean... I like sealed designs as well, they just sound tighter. Luckily, the amplifier has a 3dB boost switch @ 35Hz. That should level out the bottom end. Don't know if 250-watts will be enough. i would think so since the driver is rated for 425-watts. But with 250-watts, the output is "only" 109-dB. My other 15" DIY sub models at 119-dB, quite a diffference.

    99% of music has no information in the sub 40hz range. HT will have some information sub 40. But low end in most recordings is ~70hz. My issue with the ported box is the roll off after the frequency the box is tuned for. Makes it tough to integrate with your mid bass driver, cause most mids won't play down that low with any authority.

    250 watts should be fine. If you like cranking the sub a bit then you may want a little more power. Hook it up and see if you need more.
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