Quote:
Originally Posted by Matthijs  Did you have a look at the cabinet suggestions on the eminence site? |
good suggestion lets look at that
Cab design PDF. after playing around with the driver in WinIsd, Eminence suggested setup for med vented cab sounds
good.
Vb of 2.5 cubic ft and tuned to a
Fb of 50hz
Eminence suggest using
Round 2x4" ports,
shelf ports and triangle ports are garbage to me, and i agree with the round port choice. placing evenly spaced 4" ports closely to the driver can end up giving you a wide box.
I prefer 4 evenly spaced 3" ports placed close to the driver, because with 4 ports you can use more smaller more convenient sizes. And still get a decent port velocity that 2 larger ports would give you. aside from a few other reasons I dont care to discuss.
I hate boxes that are too small for heads, if i remember a rack is 19" wide and with 1/2 ply case would be about 20"
so i went with 20" wide, then for height to get a aesthetically pleasing ratio used the good old Golden Ratio. look it up, it works so well. But yet so many ugly cabinets fail to use it. anyhoo
so 20" wide 32" 3/8 tall for a true vertical alignment, not some annoying squat looking thing with horrible offset drivers trying to make it smaller. Depending on how much baffle setback you want for a grill and the thickness of your wood. the depth will give you the final size, to give you the needed airspace.
Shooting for 2 separate compartments for each woofer will help keep up with standing waves and will make the 4 ports dedicated to each driver more accurate. And add a good brace to the center of the cabinet. blah blah blah with 1/2 inch of set back and 1/2 inch front and rear baffle. I decided 18.5 inches of depth.
So if you measure the actual internal measurement of one of the compartments at 15" x 19" x 17" you get 2.8 cubic feet.
subtract the volume of the driver, bracing and ports you should be around the recommended 2.5 cubic feet.
4 x 3" ports with a correction factor for a single flared end should be 9.5 inches in length to get you close to 50hz
I think i went higher to 51hz for error factor so real world tune should be around 49 to 52 hz both 1to 2hz above or below the drivers Fs.......cool. I dont care to argue about tuning,
Eminence actually tunes below Fs for this driver, Except for the med cabinet is tuned higher most likely for power handling, but not to high which would make it boomy and annoying in such a small airspace of 2.5
basic drawing, i hate thin looking goober cabinets, so with 1/2" or 12mm ply, you simply add another 1/2 x1/2 layer to the inner edges of the cabinet to give it a beefy 1inch look, plus it will add supporting edge all the way around the front baffle.
this is a incomplete drawing obviously, not showing bracing or the 2 separate compartments.
the LFA's are going to need Hf drivers, no point in trying to wedge them into this cabinet, it is purely dedicated to having enough volume for the LF drivers and to provide very accurate symetrical evenly spaced ports for each driver. A simple HF box can be added later and contain the realated drivers and crossovers.
each driver needs 69liter netto (2.4cft) and a 1x102mm (4'') pvc pipe, 65 mm long
