Leaderboard

General Box building: Measure three times, cut once. Gorilla glue will stain your hands for a couple of days, but it'll destroy your mdf if You try to dismantle the box. The glue joint literally has more tensile strength then the wood. Glue like a clean surface, take 5 seconds to wipe off the saw dust. Be sure to set any adj. saw blades to 0 or 90 degrees unless otherwise needed. You'd be amazed how much a 10* list will fudge up your corner. Pick up two or four of these: http://img.photobucket.com/albums/v492/Njc...uip/90brace.jpg 90* or corner braces. Will save You 10 - 30 minutes per box. When pre-drilling pilot holes into the edge of a board, use a slight countersink. this will make for easier finishing of the box (carpet, bondo, paint) and in theory gives the screw more holding power. When cutting the mounting hole for a speaker, be SURE to use the proper cutout size, an extra 1/8" may not sound like much, but it's too much. If You don't like unsightley wires hanging out of Your port, drill (2) holes into a hidden surface of the enclosure, JUST BARELY larger then your speaker leads. If You are having trouble feeding the wire through, spray it down with some WD-40 or similar. Once the wire is long enough (will reach ~12" out through the baffle), silicone the holes. When mounting a speaker, be sure to screw @ a level angle. 90* from the surface. If You are off by 30-45* You could very well skip through the edge of the wood & end up splitting the wood -or- even damaging the speaker possibly. If You do a proper job cutting Your mdf and using the gorilla glue, You will not need and silicone or caulk on the interior seams. The same goes for foam tape around the speaker cutout. Port length, less is more. The shorter that Your port is, the less 'intrusion' upon the acoustic energy in the box. This will help with port noise, spl, transient, and cone control. When building an enclosure for more then one speaker, try to place the port or any openings as central as possible... I have seen woofers over exert simply because they were mounted over the port, vs others that were not. Slot ported woofer enclosures with the port on one end and two (or more) woofers side by side: Depending on the equipment and power levels, You will tend to see "servo-ing" of the woofers - the woofer closet to the port excurting more then the further one. If this becomes a reoccuring problem, try a loading board. A vertical board (1/2 the width of the woofer) directly behind the woofer closeest to the port. There are many variations of a loading board, this is simple a rule of thumb to start with. When working with smaller baffles & mulitple drivers - dont be afraid to get the baskets touching each other. BUT, if You do, be sure to rotate the woofers in a fashion that the screws are not within 3-5" of each other. Otherwise that area could suffer some weakening. When builing slot ported boxes with 'labyrinth' ports, be sure to account for the full length of the port. By that, I mean keep in mind that each 180* bend will have a length of 2x the width of the port. The 9:1 port area ratio... Try to stay under it. The more surface area or perimeter of the port area, the more likely You are to suffer from Laminar Flow - the air on the outer edges of the port opening slowing down and the air in the center of the port area speeding up. This is why round ports are best - minimal perimeter. As far as SPL numbers - 45* reflection boards in the corners DONT ALWAYS help, sometimes they may hurt. Sometimes You may need 30* boards, You may need 70* boards, experimentation helps. I've found the method that helps most often is to: cut a cardboard tube in half (from a 1" dia. mailing tube to a 8" diam. concrete tube); tack it into the corner; fill the gap created with pretty hot resin or epoxy; once the pour is cured, pull the cardboard off and sand the pour smooth as possible. Simple rubber stips on the bottom of the box will go along way toward keeping the box from sliding around in the vehicle. when double-walling a box or baffle, try to interlock the ends of the panels with the adjacent panels. makes for a stronger corner. when making a box that has the port on the far end of the baffle, try not to put the woofer on the far opposite. generally dead middle to 2/3rd's positioning will yield a higher score then a woofer then is butted up against the far wall. When making a box with variable tuning, I find it much easier to make a port 'plate' rather then a port plug, or swappable port. To bring a 10"x8" port down to 8"x8", simply make a plate that is 2"x8" that can screw over -or- be flushed into the port opening to reduce area. This will change Your tuning more easily and quikly... and it's generally easier to "make pretty" then a fully swappable port assembly. IMO - nothing more then 15 sq in of port per cu. ft. is necessary for music or daily. No less then 7 sq in though. Use at least 1 5/8" screws for 3/4" mdf. When painting a box with out bond'ing it, be sure to sand down the showing cut edges well, then spray with automotive "high build" primer. All thread > all for bracing. Use a double baffle & BIG washers where it'll be bolted though. This will help structural integrity as well as allowing You to "sink" the nut flush - therefore hiding it. Inverting drivers raises cooling efficiency, but the only by a negligible amount. I can't think of anything else at the moment... it's early still. Hope this helps. -Nick