2 drivers in OB

[Kensai]

2 drivers in OB Post #1
I have small OBs in my office rig running 6"x9" bicone fullrangers. I happen to have a few extra drivers, and I was wondering if there would be any benefit to mounting a pair of them in each baffle?

I have them mounted vertically, to improve horizontal dispersion, so I would have them mounted side by side. I'm assuming you would want one mounted facing forward and one backward. What would this do for me?

Would I want them wired in phase (bipole) or out of phase (dipole)? Would I want damp the high frequency output of the rear facing driver (remove the whizzer, add mass to the cone, etc.)?

Any enlightenment on this subject would be greatly appriecated.

Thanks,
Kensai

[planet10]

2nd one front firing, wired in phase with a series inductor to get a 1.5 way. Maybe excise the whizzer. You'll have to play with inductor value. You should get more bass with less distortion at the cost of maybe a bit of loss of coherency just above the 0.5 woof XO.

dave

[Kensai]

And the lower I might make such an xover the less problem I'd have with coherence loss, right?

Kensai

[planet10]

Yes, but where also needs to play against where the OB roll-off starts and the smaller the baffle the higher that is.

dave

[Kensai]

So, that sounds like about the right place to place the xover, then. My baffles are 16" wide and 20" tall. Any idea where that might start rolling? I'm guessing its quite high.

Kensai

[planet10]

I'd guess in the 250-400 Hz range. Driver Q & inductance also plays a role, but this is -- typically -- in the area of flattest impedance which will make things easier.

dave

[Kensai]

Thanks, Dave

I figure adding inductors will raise the Qts of the second set of drivers enough to make a bit more of a hump in the bass response. This is likely a good thing.

Now, is this the best possible use of a second set of drivers? And is it worth the bother/expense?

Kensai