wheelie bin system questions |
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samsavenger
Registered User Joined: 15 September 2010 Status: Offline Points: 10 |
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Posted: 12 November 2010 at 5:45am |
Hi all,
I'm planning on making a portable system out of a 140L wheelie bin. I have a 4* tk2050, 2x 7ah 12v batteries, 2x eminence beta 12a drivers and a bunch of assorted car speakers. I had an idea of mounting one or both of the eminence drivers firing downwards on a plywood board wedged about half way down and venting the bottom of the bin on 3 sides to create a sort of bandpass enclosure, then mounting 3 kenwood 6x9" car speakers in the top half of the enclosure firing outwards to take care of the mids and highs. Would this type of design work? or would the eminence driver(s) cancel out the kenwood speakers in the top half of the enclosure? Also... obviously wheelie bin plastic is not noted for its sonic qualities... but will this inevitable sound muddy or will I lose efficiency due to the pliable plastic type material? |
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rich_gale
Old Croc Joined: 18 February 2008 Status: Offline Points: 2697 |
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it'll probably end up sounding better than srm450's. they're not that much more sturdy than a wheelie bin. personally, id just bolt a sheet of 12mm ply onto the inside front face to strengthen the main baffle. then use the beta 12's direct firing with a tweeter like the apt150 doing the highs. the beta will be fine up to 5khz.
6x 9's are a waste of time for anything like this imo. plus they will want a separate enclosure so the 12's dont interfere with them
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REFLEX ALL THE WAY.... (however, im playing with horns again...) That ok Mister Valiant? :)
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Saturnus
Old Croc Joined: 13 July 2010 Location: Copenhagen Status: Offline Points: 2025 |
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I agree with the above. Ditch the car speakers. They are probably ranged in quality between stinking crap and smelly crap anyways. You get much better sensitivity and sound quality from the betas, just add some tweeter horns, which could be piezos if you're on a budget.
Edited by Saturnus - 12 November 2010 at 8:17am |
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sonofalesbian
Young Croc Joined: 16 May 2010 Location: Leeds/MCR Status: Offline Points: 1219 |
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ive build a system out of a bin before, my advice to to make sure your speakers are mounted on a wooden baffle and then that should be attached to the bin, the plastic realy isnt suitable for holding the drivers in place, it can also get a bit rattly if you pump seriose power into it. make sure you get some pictures of your build up though!
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www.brotherhoodsoundsystem.co.uk
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sonofalesbian
Young Croc Joined: 16 May 2010 Location: Leeds/MCR Status: Offline Points: 1219 |
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www.brotherhoodsoundsystem.co.uk
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sonofalesbian
Young Croc Joined: 16 May 2010 Location: Leeds/MCR Status: Offline Points: 1219 |
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that was mine, the 15" woofer is in its own ported enclosure but i ran out of time to make a chamber for the 6" woofer so i just slammed it in there and hoped for the best. the battery and amplifier are inside the bin above the bass enclosure. (85ah battery and 500w car amplifier)
if i were to do it again i would use a 12" instead of the 15" for bass (i only used that one because it was knocking about)
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www.brotherhoodsoundsystem.co.uk
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slaz
Old Croc Joined: 27 November 2009 Location: London E2 Status: Offline Points: 2713 |
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Yeah - I like the idea of wheelie bin as enclosure too :-)
Based on intuition rather than experience, I'd say :- If there are sizeable areas of flat panels in the plastic, you could get some quite "nasty" resonant modes in there. Would prob help quite a bit if you can get some material like bituminous felt to dampen the panels (would need to be bonded tightly to the panels - dunno what kind of glue etc.). Use bracing struts too - should help. Plastic/ABS enlosures can be very rigid, but this is achieved by virtue of the shape - curvature and ridges will greatly enhance the rigidity. 2 x 7Ah will prob give you fairly limited run-time if you figure on driving the 2050 hard into 4R loads. 2 x 17Ah - would be better - at the cost of some weight of course - but then - if the batteries are located at the bottom of the bin (close to the wheels) it should achieve better stability and wheelability. I'd agree with mounting drive units on plywood sub-baffles if at all possible ... Let us see if you get around to doing it :-) |
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subbass
Old Croc Joined: 30 March 2009 Location: bristol Status: Offline Points: 1683 |
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never ever ever ever ever ever ever ever ever ever use 6*9s!
total waste of power and space!
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samsavenger
Registered User Joined: 15 September 2010 Status: Offline Points: 10 |
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yeah I think I'll do away with the 6x9 idea, I just need something cheap to give decent response above 2k hz... I figured a wheelie bin isn't gonna sound fantastic anyway, but perhaps I'm wrong if it's done correctly. I have some mid range/tweeters from some old hifi speakers with will probably sound better anyway, I might even be able to recycle the crossovers.
How about the idea of loading the eminence driver into the bin on a piece of MDF facing downwards (or diagonally downwards) and venting the bottom? I figured if it was tuned more of less correctly it wouldn't be all that different to a bass horn or bandpass enclosure... Would this work? I was hoping to achieve some sort of omnidirectional effect and dividing the vents over 3 sides of the bin... |
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sonofalesbian
Young Croc Joined: 16 May 2010 Location: Leeds/MCR Status: Offline Points: 1219 |
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why bother with venting 3 sides of the bin? unless your going to have mids and hi's on all three sides its abit pointless.
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www.brotherhoodsoundsystem.co.uk
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samsavenger
Registered User Joined: 15 September 2010 Status: Offline Points: 10 |
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^ I was thinking maybe I would if it worked alright...
I'm really just keen to experiment a bit I think... does anyone have any experience making a scoop out of a wheelie bin?.. haha |
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sonofalesbian
Young Croc Joined: 16 May 2010 Location: Leeds/MCR Status: Offline Points: 1219 |
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by all means make a scoop out of the bin but venting three sides isnt the best thing to do. bass is omnidirectional anyway...
my advice is build the first one as you have described but only use one face of the bin, then if you feel you need to rebiuld one using all three sides then do it.
i found that cutting the bin material took a while to do and was quite labouriouse aswell, so the less you have to cut the better!
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