mate if you could send the instructions i would be very apreciative thanks mate
I'm trying to find the original in Japanese, but this is the thread that got me started:
AAAACCCCKKK!!! neophyte question: basic enclosure types
It was worth a Master's class in design... it quickly turned to OB's and then ends with my first pair (which I am listening to right now.) This is the thread about putting together my first pair (which are way more complex than they need to be, but the family likes the way they look).
OB's are essentially just a flat board with a driver mounted almost in the middle. The baffle is just there to keep the front sound waves from interfering with the back sound waves. (the front and back waves are out of phase, and they cancel each other out) The bigger the baffle, the more bass.
In post #10 in the above thread Mike posts a graph that shows the effect on the low end as the baffle gets larger. Basically, bigger is better but your family may not be ok with having half the room blocked off by 2 4'x8' sheets of plywood. The dimensions that I posted above are about the best balance I think.
Below is a simple exploded view.
--The line is the baffle, just a flat board. It can be plywood, drywall, whatever. Of course, the heavier and less resonant the better, but for prototypes cardboard would even work.
--Moving left is the speaker-- I like OB's the best with one full range speaker. But I don't have a pair of good full range drivers right now so....
--Moving left a bit more you see a small baffle at the top and a small driver. *Note: that baffle needs to be there whether you are using a second driver or not. It really tightens up the mid range, a LOT.
--Most of the designs you will see have the mid and tweeters facing forward. I prefer to have them facing up- the soundstage and the image then extends up to the ceiling and back to the rear wall. Huge, open, spacious and natural imaging.
--the next item to the left is just a board for the baffle to rest against. It's cut so that the bottom sits flat on the floor and the baffle itself leans back at a 10 degree angle. On my prototypes it was just hacked out with a sheet rock knife and baffle was just duct taped onto it so it wouldn't fall over.
The whole thing ends up being embarrassingly simple, and the sound is extraordinarily. Mine is still populated with drivers from midrange consoles from the '60s.
Bass really does roll off-- they do work best with a sub (as long as the sub is very subtle it won't wonk up the imaging)
Obviously they can be very cheap. My next set will be made of only drywall $5.78 per sheet. The drivers, again, cast offs from consoles.
***** EDIT****** I just found the link and the original instructions!!!!:
http://members.myactv.net/~je2a3/open.htm
Hope this helps
Mike
