sub box - mdf vs polycarbonate

corpse

Founding Member
Jan 23, 2001
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chicago area
i currently have a sub box made of 3/4" mdf, housing 2 10's.. I'm going to redo the box - it's currently a very tight fit bolt in design that goes in the backseat on my 69 fastback, I'm going to change it to a slide in style so I can easily take it out at the race track..

I was thinking about doing it out of polycarbonate (Lexan), and was curious what the pro's n con's are.. I know the plastic route is more expensive, but money isn't an issue. My priorities on this are 1) sound quality, and 2) weight. Any idea how much the proper thickness polycarbonate would weigh compared to the 3/4 mdf??

Also, maybe someone can help with a design a little. Currently, the subs face outward, visible when the back seat is down. Because I want this removable EASILY, I need to change the design.. You can see the rough speaker fit here http://corpse.stangnet.com/stereo.htm
Maybe a design where the subs face up or down? I just want to rig it up so I can pop out a few "safety" pins (or a few thumbscrews), and slide the box out.
 
I have used 3/4 inch mdf, 1 inch mdf and 1/2 inch plexiglass. I have to say that I am somewhat partial to 3/4 inch mdf. Not only is it simple to work with but it just gets the job done. It is kinda heavy, but weight will always be an issue when installing a system. I am currentyl making a fiberglass enclosure to go inside my spare tire well, which is a lot lighter, but will probably be hard to remove. At least if you make a simple design out of mdf then you can remove it when you need to. I have some pics posted of my two prior trunk designs, if you want to look they are here... http://www.sounddomain.com/memberpage/484771/3 but those are not really easy to remove at all.
 
If the box is going to be small and sealed, or under 1000 watts, a properly braced 1/2" MDF enclosure will work fine for those 10's (unless they're like XXX's or Brahmas or something). Also, void-free Birch plywood is a MUCH better choice for enclosures, but it's a bit harder to work with and more expensive than MDF. Wood is definitely the way to go, just avoid particle board like the plague that it is, and make sure all your edges are well-finished and you'll be fine.

Another option is to make the box out of Sonotube and paint the inside of it with fiberglass resin. I don't mean making a "tube" enclosure, but one like the old JL Microsubs. Where it's a hemispherical shape. The tube is structurally strong as hell (that curve/dome thing), and it's a lightweight material.
 
What type of box design should I be looking at if I wanted the subs to lay flat within the box? I'm really only familiar with building plain ol sealed boxes and simple ported boxes.. After doing some more research, it seems I may want to do a fourth-order bandpass enclosure? But all the pics I saw is where the speaker is vertical - and my sizing problem is going to prevent me from having the speaker vertical in the box, it needs to be horizontal in the box.. The speakers are eclipse 8710's powered by a directed 600d amp.

Thanks!