Eminence Lab12 in an open baffle.

[ashok]

Anyone used a LAB12 in an open baffle sub ? Maybe a H or U frame ?
The Qts is rather low but that doesn't seem to deter some people.

Just had a Kilomax Pro18 in my hands for a day ! This sure should sound good in an open baffle. Qts was just over 0.5 . Fs was about 27 Hz I think ( measured). Felt terrible to let it go without some experimentation..... belonged to a friend who eventually put it into a reflex box !

[Rademakers]

I've tried it without baffle to speak off for a while but found the result rather disappointing. It needs lots of power, with 300 Wrms continuously (just below clipping) it was barely making a difference in my room. I've used an 18" with a Qts of 0.29 with far more succes then that. Perhaps I'm just expecting to much, is there much difference to be gained with an H or U frame as opposed to free baffle?

Best regards Johan

[ashok]

Hi Rademakers,
Yes the H and U baffle will make the driver go lower. However they also cause resonance at a higher frequency as they are (large) ducts attached to the speaker. The frequency depends on the dimension of the H or U baffle. So a steep rolloff above the upper useable frequency is required.
The plain large baffle is easier to use though it's too large for many rooms.

Maybe you should use an 18x18 inch baffle on the 12 inch and then compare it with your 18 inch driver ? It might be easy to rig up a U frame. Just have a inverted U with a front panel. No panel on the bottom but make sure it is well sealed with the ground/carpet. Typically 18 inches deep. Frontal maybe 14x14 inches. If you do try this let us know what happened.
Cheers.

[Rademakers]

Do you have picture of a typical u-frame? Not sure that I got it right,

I will probably make it a bit bigger then that and rectangular in shape, I suppose the first is better, the second just will have to do.

Best regards Johan

[ashok]

You can look at the Thor subwoofer box. That's what a U frame looks like. The rear end B is "open" and the inside is filled with sound absorbent to damp the box resonance. ( the box shown here has a closed rear end !).The front end has the driver. The front panel need not be much larger than the driver. The depth is the critical factor.The absorbent is critical also and you need to find out how much is required by trying it out. You will find that several U frame subs mentioned on this forum are about 19 inches deep ( driver to rear open end ).