Open baffle design help

[fin1bxn]

I just received my EV SP12b drivers today and am torn between building the Karlson K12 cabinet or going open baffle.

I figure if I try the open baffle and dont like it I can always cut the wood to make the cabinet.

Looking for opinions, also if I do a OB i was going to use 48 high 24 wide, I wanted to know where should I cut the Hole? In the center or is listening hight ok (About 3/4)

Here are the specs
fs - 41
vas CFT - 6.27
qms - 5.9
qes - .69
qts - .623
re 9
le mH - 1.2
eff - 94.5

Thanks
Bob

[hitsware]

I'd put it in the center of the 24" dimension
(12" each side")
~30" from 1 end of the 48" dimension
BUT !
Put it on the floor on the 48" side I.E.
48" wide 24" high tilted up towards the
listening position.
(for better bass (this gives a shortest
diameter of 48" (Fb~90Hz) rather than
Fb~180Hz (shortest diameter 24"))

[chris ma]

Use the EDGE program to find the location of the hole..

[Kensai]

Getting it closer to the floor gets you more bottom end, but you will definitely need to tilt them to radiate toward your listening height. As for the the rest, its really more about the baffle width than the height, and you do not want equal distances from driver center to any 2 edges as that will cause either a hole or a peak at the frequency defined by the distance the front and back waves travel to meet at the 2 points that are identical. Generally I would suggest just go with listening height mounting vertially and then put the driver into the outside third of the horizontal space on either side (so that there is maximal separation between channels)

Kensai

[opnly bafld]

Originally posted by hitsware
I'd put it in the center of the 24" dimension
(12" each side")
~30" from 1 end of the 48" dimension
BUT !
Put it on the floor on the 48" side I.E.
48" wide 24" high tilted up towards the
listening position.
(for better bass (this gives a shortest
diameter of 48" (Fb~90Hz) rather than
Fb~180Hz (shortest diameter 24"))

I agree with this.
Measurements I have seen indicate more problems with frequency response when the driver is offset left or right vs. centered.

Except, since you more than likely will want bass augmentation regardless of whether you place the baffle 48'w or 24"w, I would suggest 24"w(or less~18") for much better imaging and soundstage IMO.

Lin