1. Welcome to TalkBass 2014! If you're new here, we just went through a major site upgrade. Please post all concerns and bugs to the Forum Usage Issues forum. We will be monitoring that forum. Thank you for all of your feedback.

    The TalkBass iphone/android app is NOT WORKING currently. We're working on it. Tapatalk IS working, so if you need to use an app, use Tapatalk. Try using your browser though - TalkBass is now 100% responsive to your phone/tablet screen size ;)

    Please read the TalkBass 2014 FAQ for lots of great info on the new software.

Building a Lightweight Cab for a 10" Polk

Discussion in 'Amps [BG]' started by swamp_bass, Nov 20, 2013.

  1. swamp_bass

    swamp_bass I love it when a groove comes together Supporting Member

    Joined:
    Nov 20, 2013
    Likes Received:
    0
    Hi, all!

    I've been picking up information by lurking here a bit, and now decided to crawl out from under my rock and show myself.

    I'm playing on a loaner Rumble 60 combo, and it's time to get my own. After trying out an assortment of amps/cabs at the nearest Guitar Center, I came to the conclusion that my taste outweighs my budget.

    I inherited a gently used Polk MM1040DVC from a friend, and I'm in the process of building a lightweight, portable cab for it. I've built many subwoofer boxes in my past, but all of them were heavy and dense. This is my first foray on the lighter side.

    [​IMG]

    Haven't decided yet if I'm going to paint it or cover it with rat fur. I've also gone without a tweet for now, but might add one depending on how much it needs one in my sound check.
  2. will33

    will33

    Joined:
    May 22, 2006
    Likes Received:
    6
    Disclosures:
    Use of this field for any other purpose is prohibited
    I'm not too familiar with Polk but aren't they mostly home hifi type stuff?
  3. swamp_bass

    swamp_bass I love it when a groove comes together Supporting Member

    Joined:
    Nov 20, 2013
    Likes Received:
    0
    Both home Hifi and car. This one is made for car audio applications.

    It's original home was in a custom box under the back seat of a Dodge Ram. I'm giving it a more breathing room in a sealed enclosure with a box Q of about 0.6
  4. wcriley

    wcriley

    Joined:
    Apr 5, 2010
    Likes Received:
    0
    Disclosures:
    Uncompensated endorsing user: fEARful
    It's a car subwoofer.
    With an upper limit of ~200Hz, I can't imagine it sounding very good as a stand alone bass guitar driver.
  5. Woodstockz

    Woodstockz

    Joined:
    Sep 23, 2011
    Likes Received:
    0
  6. swamp_bass

    swamp_bass I love it when a groove comes together Supporting Member

    Joined:
    Nov 20, 2013
    Likes Received:
    0
    On paper it stops at 200Hz, but I've spent the better part of my life making crossovers to cut out the 500-1KHz midrange coming out of subs that were rated similarly.

    When I tried the Polk in its original unlined box with the amp notched up at 10KHz, it gave the Rumble 60 a run for the money, complete with steely string slides and fret noise. This makes me suspect the high frequency response extends well above 200, with a very gradual rolloff at that.

    Only one way to find out! ;)
  7. swamp_bass

    swamp_bass I love it when a groove comes together Supporting Member

    Joined:
    Nov 20, 2013
    Likes Received:
    0
    I paid $50 for my friend's radio, sub, and amp. The radio's in my truck, and the sub and amp are basically free fodder in storage.

    Can't beat economy of a friend's clearance sale!


    By the way, that Eminence has all the hallmarks of an efficient woofer, right down to the tiny Xmax. I guess being new to bass amps, I'm coming from the dark side, but I'd rather risk a little extra mid scoop - or the complexity of switching to multiple drivers - than build a bass box that can't put out good volume at low frequencies.

    Perhaps I just need to learn the hard way why nobody else uses these in this application, but I gotta try, especially when the materials and speaker are practically free. At worst, I'll have a nice sub box. At best, I'll achieve my goal of a portable 10" bass cab that kicks butt.
  8. will33

    will33

    Joined:
    May 22, 2006
    Likes Received:
    6
    Disclosures:
    Use of this field for any other purpose is prohibited
    Not to rain on your parade but we can save some future disappointment if we back up here just a bit.


    The car audio sub.......the signal that comes from playing the radio and playing the bass are 2 extremely different things. Recorded music is very compressed and controlled. The live bass has incredibly high transients that place serious demand on the speakers. That car woofer with its soft suspension will not handle anymore than a very small amount of power before it bottoms out or tears itself apart.

    Spl will be very low (not much loud coming out per watt going in).

    It also won't produce hardly any of the harmonics that give our instrument its tone and timbre and sense of pitch.

    All these make it the wrong tool for the job, even as a dedicated subwoofer.


    The chipboard box.......not very stucturally sound. Could resonate badly which will rob the sound of energy. Also just heavier than needed and suseptible to moisture damage. A good quality grade of plywood would be a much better choice.


    That said, don't get discouraged! You've got the stuff there, it cost very little, so finish building it and play it! It will make some sound, and you will have learned a whole lot in the process you can apply toward making your next speaker. Nobody can stop at just one. :)


    Some people may come in here and tell you what you're doing is all wrong and you should just buy something instead.......don't listen to them....just continue on with your project. The knowledge you gain from this will be worth more than any speaker. Nobody learns anything from getting it right.
  9. Bassmec

    Bassmec

    Joined:
    May 9, 2008
    Likes Received:
    1
    Disclosures:
    Proprietor Springvale Studios
    @86 dB 1 watt one metre rolling off gently above 200 Hz you had better be in a very quiet reggae band mate.:bassist:
  10. will33

    will33

    Joined:
    May 22, 2006
    Likes Received:
    6
    Disclosures:
    Use of this field for any other purpose is prohibited
    Sounds like you've got some experience in car audio. You can use that knowledge to help understand all the differences here. For one, in a bass rig, you won't be getting any cabin gain to help the output.
  11. swamp_bass

    swamp_bass I love it when a groove comes together Supporting Member

    Joined:
    Nov 20, 2013
    Likes Received:
    0
    If I get a van, I can get both. Just gotta find a reggae band that likes playing in a used VW microbus.
  12. wcriley

    wcriley

    Joined:
    Apr 5, 2010
    Likes Received:
    0
    Disclosures:
    Uncompensated endorsing user: fEARful
    I like your attitude and sense of humor, swamp_bass.
    Go for it!
  13. Bassmec

    Bassmec

    Joined:
    May 9, 2008
    Likes Received:
    1
    Disclosures:
    Proprietor Springvale Studios
    If the 10" driver was an Eden XST 10" the quoted SPL would be around 99dB 1 watt 1 metre, so if you need to double your amplifier power for each increase of 3dB.
    You see the problem here?.:bassist:
  14. will33

    will33

    Joined:
    May 22, 2006
    Likes Received:
    6
    Disclosures:
    Use of this field for any other purpose is prohibited
    +1
  15. Woodstockz

    Woodstockz

    Joined:
    Sep 23, 2011
    Likes Received:
    0
    +1. Go for it. I never discourage experimentation.

    Eventually, you may want to expand your testing.
  16. swamp_bass

    swamp_bass I love it when a groove comes together Supporting Member

    Joined:
    Nov 20, 2013
    Likes Received:
    0
    Thanks for the input, folks. Based on the discussion so far, I'm no longer wondering if I'll need to add a tweet (at the very least).

    I took a drive to Rat Shack to see if they still carry tweeters, but as expected that chain is in its death throes and has become little more than a Best Buy "mini-me." Gone are the high priced, but mid quality tweets, mids and woofers of yesteryear.

    Time to order one on MCM/Parts Express. I have room to fit a 2" tweet in the corner of the face. The trick here will be to avoid the slippery slope and end up in a situation where I'm throwing money into a dog. If that dog won't hunt with a tweet and a simple LC crossover, then I'll move on to one of the full range speakers recommended here.

    Wish me mucho luck! I got a lucky feeling, I tell ya!
  17. Woodstockz

    Woodstockz

    Joined:
    Sep 23, 2011
    Likes Received:
    0
    You are showing your age. If you remember speakers from Radio Shack, then you must be old...


    ...about as old as me.
  18. swamp_bass

    swamp_bass I love it when a groove comes together Supporting Member

    Joined:
    Nov 20, 2013
    Likes Received:
    0
    I've managed to out myself my first day in the forums! :eek:
  19. will33

    will33

    Joined:
    May 22, 2006
    Likes Received:
    6
    Disclosures:
    Use of this field for any other purpose is prohibited
    Hey now......I've still got a pair of Realistics with electrostat tweets I hang on to in the back of the storage unit that I swear I will get around to refurbishing someday. :D
  20. will33

    will33

    Joined:
    May 22, 2006
    Likes Received:
    6
    Disclosures:
    Use of this field for any other purpose is prohibited
    Actually, with the lower output of the sub, you might be able to use a soft-dome tweet or something nice sounding like that.

Share This Page