xcortes wrote on 03/07/08 at 00:10:51:

Hi. I'm new to this forum. I just downloaded the plans for the imperial horns with the idea of adding two to my yard. My intention is to use them with a set of 350hz edgarhors on top crossing them maybe at 500hz. I have searched the forum but there's many questions to which I have not found answers yet. Hopefully you can help me: 1. Why two drivers? 2. Which drivers are recommended? What about JBL 2226s? Altec 416-8Bs? 3. Would you suggest MDF or plywood? 4. What efficiency should I expect? 5. Can I use them with passive crossovers or you recommend biamping? Thanks, xavier

And now for the simple answer to your questions:

1)  Because for some unknown reason (or a known reason that nobody who knows has shared) two different speakers playing together can sound better than either one is capable of by itself.  Obviously power handling increases and efficiency increases also.

2)  The two recommended drivers are a Peavey Scorpion (Parts Express P/N 294-313) and a Goldwood GW15120 (Parts Express P/N 290-397).  If you look at the specs of these two drivers, I believe the more important ones to keep in mind are an Fs around 40-50 hz and a Vas around 4-5 cubic feet.  Also, for any horn loaded system, the Fs/Qts product should be high (greater than 100, 150 is better).  As far as your specific drivers go, I have never tried either one of them.  The JBL looks like it might work well, but the Altec's huge Vas and low Fs might indicate it wouldn't do so well.

3)  Plywood unless you are a world class weight lifter in constant need of a workout.

4)  Probably better than you ever got before.

5)  Either way.  Personally I prefer passive, but they have to be good quality.

Dan