yet ANOTHER DIY Unity, and a spreadsheet for figuring the wood cuts

Very cool. This is something I eventually want to try myself. I am an applied mathematician by background, so I should be able to figure it out.

You are the man! I was dreaming of this yesterday and here it is. Thank You. Looking forward to seeing some great results. What mids are you using?

Oh man, you are going to break me A inexpensive DIY CD and this could be the budget buy of the century.

bwaslo, iirc much of the 'magic' in the synergy horn is in the crossover and getting the phase right, whatever 'right' means in this context. cowan tried a number of different crossover networks, but chose the one provided by danley. any thoughts on why the danley network was preferred?

Thanks for contributing that spreadsheet, bwaslo, that's a real treat for us all! I hope your build goes well- looking forward to it.

John

Cool, Bill. I like the tandem driver mount. I'm guessing 1 hole per driver? How big are the holes?

John

"No idea, but I don't know what Danley's crossover is."

iirc cowan posted the final design on his site. dug it up...attached. passive crossover networks are like hieroglyphics to me. just by looking at the crossover, i couldn't tell if it is phase linear, power response linear, or any other kind of linear. :-) all i know is that cowan experimented with a number of different designs including at least one by mckinney, yet he settled on the attached.

maybe you or someone else have a perspective on why it seems "to work"?

LTD, it had to do with the XO iterations Danley himself was working on. When the Unity first came out the XO still needed some adjustment and the version that Cowan used is the final iteration to ensure optimal phase and time alignment for that combination of drivers.

First of all, nice work on the spreadsheet!

Now I see a couple of errors on the angles at which edges have been cut off. Just wondering if those errors were done in construction, or whether they are in the spreadsheet?

On the second horizontal flares, the edges look at if they got cut off the wrong way.

The mids seem to typically have less extension than simulated, so it's a good idea to aim for a bit more than you actually need. Bit of a pest if you hope for 1k and you get 900 Hz!

Also see that famililar hump at the bottom end.

One tricky aspect of the angles is that I don't actually end up with the angles I intended. I might start with say 80 degrees initially, but then I start working with the throat flaring and modifying the mouth slightly and what results might be 77.4 degrees.

You also might want to consider attempting to mitre the edges rather than doing butt joins. I did butt joins on the first two and found they were a pain in the butt.

It helps with painting. If you do butt joins then the ports for the mids end up going through edges of sheets, which is awkward and you have problems with getting the insides of the ports smooth.

Looks really good Bill.

To prop up your high end you might try a little infill between the area under the cone. Makes quite a difference. More trapped air acts like a high frequency filter. Less air will push up your top end.

Sacrifices to the driver gods!

Think plastic wrap and your driver lives to woof another day. With the cone mold short enough to allow decent excursion you will get closer to your goal.

Mark

You might find that bondo or something similar may wor better.

Most wood fillers that I can think of will crack and kind of split when they are laid up in any useful thickness.

An automotive filler is fast and happy as a pig in mud when it comes to a heavier plug type of setting.

Just some fuud 4 thot.

Mark

Nice stuff Bill! Even if the plug idea doesn't buy you too much more, you still seem to be comfortably at a 2k xover which opens up some options.

It's hard to tell from the photos - what are the dimensions of your horn? guessing 16"x10" or thereabouts?

Are you entertaining thoughts of trying some woofers on the flare for a 3-way Unity, or are you thinking of just augmenting with a conventional woofer?

These Unity builds are great!

Keep it up... thanks for sharing.

There is a trade-off involved here with making the chambers smaller - you tend to get less acoustic filtering, hence higher distortion. If you look at the original Unity kit, it had very low distortion. For home use with capable compression drivers, I question what is achieved in pushing up the crossover point. I'm aiming to go a little higher, around 1.2 - 1.5k whilst keeping the acoustic filtering for low distortion. In so doing, that's pushing things just a little bit further than my S2, aiming for a bit more headroom.