[chrislittle]

Hi, I just bought four Celestion drivers from Parts express for $49 apiece and I want to use them in an 18"x48" OB with a Dayton 8" full range point scource. Acording to the Martin King site I'm withgin the 6 to 10 db range between the fullrange and the woofers in paralell. I don't think I have the software to run the programs I have found recomended on this site to predict the dipole peak, so I'm just using a formula I found on the site 1126x12/2xRadius inches. For Radius inches I'm using 1/2 width + 1/2 width. I know there are other issues like the floor and the vertical measurement, but can this formula get me into the ballpark where I can start the LP an octave below, and the HP an octave above, and then manipulate the component values by ear to find a balance?

I have also seen a really interesting OB where they used 8 layers of 3/4" plywood to make a 6" think baffle which increases the width measurement by 12 inches without actually changing the width. Does anybody have a take on either of these ideas?

Thanks, Chris

[mcgsxr]

Welcome to the site Chris, and sounds like you have found something fun to experiment with.

From my experience, having only ever tuned by ear, I am sure you can get a feel for the experience by ear, and then decide if you want/need to explore taking the next step, or if it is just not for you.

For my experimental baffles, I used piano hinge to attach wings of various widths.  Easier than making the baffle thicker, though I suspect I know why they tried that too.

I found running active much easier than exploring using passive components.  I used a small tube amp for my main drivers, and a subwoofer plate amp for the subs.  I eventually bought a small active Xover to try to optimize the experience.

I also found that using the subs in the main baffle muddied the mids, regardless of Xover frequency, but I understand the appeal of 2 baffles vs 3 or 4!

Good luck with it, let us know how you make out.

[Alan]

Cool project! I'm doing something similar.

As Mark mentioned, perhaps easiest to run the Dayton without crossover and a plate amp for the bass.

I'm using minidsp, an excellent solution. Here's a guide http://www.hifizine.com/issues/minidsp-tutorials/

If you really want to do a passive crossover, this should put you on the right path
http://www.diyaudio.com/forums/multi-way/189847-introduction-designing-crossovers-without-measurement.html

Have fun with it!

[chrislittle]

Thanks for the comments!

I'l post when I build.

I'm pretty sure I want to do everything passive though. I have had bi-amp systems before but I went through a simplification during my last couple of speakers and I don't really want to go back. Had I realized that I would get into open baffle speakers while I had my bi-amp system I might have stayed with it, but now that I have simplified I want to stay that way.

Like mentioned I have also read in other places too that the Daytons sound pretty good full range. So I really only need to focus on a crossover point for the woofers.

Is there a way though that I can predict what the natural roll off of the daytons is in my particular baffle?

Is it right below the dipole peak which I figure is around 440, or is it closer to the driver Fs 37? Based on what I have read it seems like it would be between 100 and 440.