edeit Posted November 9, 2009 Share Posted November 9, 2009 A question for all of you out there. I am building a new set of Cornwall cabinets and would like to know peoples' opinions on whether I should build them out of veneered MDF or veneered plywood. Quote Link to comment Share on other sites More sharing options...
Mike Dubay Posted November 9, 2009 Share Posted November 9, 2009 My most recent Cornscala build used veneered MDF. I personally find MDF a much more 'dead' material of construction, less prone to resonance and vibration. I have been more satisfied with my MDF projects than my plywood projects. The down side is that MDF is much more dense than plywood, so will cause the project to be very heavy. My split Cornscalas tip the scales at 130 lbs each. This does not mean that well designed speakers can use plywood and sound excellent. Just that my preference is MDF. Good luck on your build. Quote Link to comment Share on other sites More sharing options...
Mike Dubay Posted November 9, 2009 Share Posted November 9, 2009 Oh, by the way, welcom to the forms with your first post! Quote Link to comment Share on other sites More sharing options...
CallMeJoe Posted November 9, 2009 Share Posted November 9, 2009 I am preparing to build a pair of Forte cabinets, and intend to use plywood. I find it preferable to work, as MDF goes to obnoxious dust during cutting or routing. It's also easier to repair plywood if your cabinet ever gets dinged; filling voids in crumbling MDF can be a terrible exercise in futility. As for undesired resonances, I am "growing" the cabinet slightly to maintain a stock interior volume while adding significant internal bracing to stiffen the box. edit: excuse the poor manners, please. Welcome aboard! There aren't that many members here junior to yours truly... Quote Link to comment Share on other sites More sharing options...
edeit Posted November 9, 2009 Author Share Posted November 9, 2009 This is good info; thanks gentlemen. I'm not too concerned with the weight as they are gonna be heavy regardless. May even opt to put handles on them. I've worked a lot with MDF and it is dusty and isn't forgiving if you lose a chunk (bondo time). My main concern is if by using MDF will I be killing any desired resonances? I'm not a speaker designer so maybe my concern is unfounded. Quote Link to comment Share on other sites More sharing options...
Carbon_66 Posted November 9, 2009 Share Posted November 9, 2009 The MDF is cheaper and easier to machine precisely. It is heavier and has better dampening properties, but this can easily be overcome by bracing or doubling the Ply. My main concern is when edge screwing MDF. Your pilot hole will need to be larger to prohibit splitting which decreases clamping force. MDF is much harder and the screw will act like a wedge and create bulges. Plywood is softer and the screw will create deeper threads without splitting. Either way, I would always do a few scrap mock-ups for pilot hole diameter selection. Looking forward to the build thread. [H] Quote Link to comment Share on other sites More sharing options...
CallMeJoe Posted November 9, 2009 Share Posted November 9, 2009 ...My main concern is if by using MDF will I be killing any desired resonances? I'm not a speaker designer so maybe my concern is unfounded. IMHO, any cabinet resonances are entirely undesired. A cabinet can be designed to enhance the driver performance to a certain degree (porting a cabinet to enhance woofer response, etc.), but for the most part the cabinet itself should be neutral. You may note that most speaker designers take measures to eliminate resonances rather than produce them. Quote Link to comment Share on other sites More sharing options...
bliss53 Posted November 10, 2009 Share Posted November 10, 2009 MDF works great with pocket screw joinery. The Kreg jig is available at most Lowes stores. The system has a special self tapping screw that was designed for MDF. I have glued the joint and used the screws as a clamping method and then backed out he screws for reuse. I have tried to break the glue joint and the joint remains while the MDF breaks first. See this site: http://www.kregtool.com/index.php Quote Link to comment Share on other sites More sharing options...
bliss53 Posted November 10, 2009 Share Posted November 10, 2009 In my limited experience MDF sounds a little dead. The plywood produced a livelier sound in the mid bass sounds. I have only compared with Heresies boxes. I liked the standard klipsch plywood box better. On the other hand I have noticed that a center brace in the standard cornwall cabinets tightened up the clarity in the same mid bass tones. Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted November 14, 2009 Share Posted November 14, 2009 What Pete said. I use a similar approach with 3/4 plywood. I use a brad nailer to hold/clamp the pieces while the glue cures. It's really the glue that holds, once it sets up good you really don't need the screws or nails. This assumes clean straight edges though. Quote Link to comment Share on other sites More sharing options...
dollar bill Posted November 15, 2009 Share Posted November 15, 2009 I am mainly a all ply guy, partly for reasons stated above, partly because I am into pro gear, but also just for crazy hippie style reasons, of feeling that woodgrain, through and through, has Soul and sawdust and glue(MDF), doesn't. Veneer, while beautiful is just as it sounds, a thin skin to cover up what is really underneath. Anyone that has ever done any woodworking, from that bowl in shop class to building a house, probably feels that same connection. Even the differences of using a axe over a chainsaw or hand tools over electric, there is a connection between you and the wood( No not that kind of wood!). *No substances were used during the creation of this post. Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted November 16, 2009 Share Posted November 16, 2009 *No substances were used during the creation of this post. Yah... Right.... [H] Just kidding!!! Quote Link to comment Share on other sites More sharing options...
bliss53 Posted November 16, 2009 Share Posted November 16, 2009 Just to clarify, the pocket screws have the advantage of drawing the parts together for good glue contact. When using a nail gun with a but joint I usually have to clamp the pieces to assure that the nails hold the joint tight and in alignment. I am probably to picky. I generally use a nail gun when I am securing rabbit or dado joints because there is some alignment built into the joint and there are more glue surfaces. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted November 19, 2009 Share Posted November 19, 2009 I would most likely prefer to build a cabinet like that out of Baltic Birch plywood, it machines well and is very stiff, as well as being less fragile than MDF. For a smaller cabinet, or one that isn't likely to be moved much, MDF is what I will generally use. You can also see if you can get MDO ( medium density overlay ) from your wood supplier. Also, I am not a fan of the 'MDF' smell or outgassing when a vented enclosure is in operation. I have used it for vented enclosures, but I have also taken care to seal all of the MDF with urethane as well as a primer to keep it from outgassing. MDO is generally used for road signs or concrete forming because of it's smooth nature and waterproof glues. http://www.canply.org/english/products/overlaidplywood.htm Quote Link to comment Share on other sites More sharing options...
hklinker Posted November 19, 2009 Share Posted November 19, 2009 The Cornwall I was built of plywood, but the Cornwall II & III is made of veneered MDF, so Klipsch engineers must not feel that it makes much difference. I personally like the naturalness (is that a word?) of plywood. As far as the resonance factor, if you remove the back of a Cornwall I, you will see that they made the squawker depth so that the K-55 pressed against the backboard. When you tighten the screws you will see a slight bow in the backboard. This design was not accidental, it made the backboard an active component in the cabinet. Good luck with your project, and welcome to the forums! Herb Quote Link to comment Share on other sites More sharing options...
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