Finalized my 3way design

[bbcmp1979]

So i've been playing with this design for quite some time and it's probably as flat as i can get it to. I"m upcycling the RS180s-8 and RS28f from the Natalie P build for this. Instead of using the Dayton rs drivers for the mids (rs150, rs125, rs100, etc...), I've opted to use the peerless buyout from partsexpress instead, and I could definitely use all peerless drivers but wanted to keep the rs180s-8.










and I've ordered the xover parts from erseaudio



Cabinets dimensions is 49" x 9" x 18.5", MTM section is sealed w/ .75 ft^3, and the ported section is ~ 3ft^3.



Now I just need to come up with a name for it...and pick up some mdf ...

[TacoD]

Wow nice project. What measurements did you use for your filter simulations?

[bbcmp1979]

They are all manufacturer specs measurement.
I used SPLcopy for SPL and ZMA data, then ResponseModeler to generate an inbox and BSC before importing the data to PCD for the simulation.

[bbcmp1979]

Impedance dipped down to 3.4 ohms at the lowest point for the tweet. Which any good 4ohms amp should be able to handle.

[cjd]

Where'd you get those z-axis numbers? They don't look right - which, assuming you've extracted and are using minimum phase for modeling, means you won't get nearly the phase alignment you think you have.

If you didn't do minimum phase, it's even less likely things will line up as expected.

C

[bbcmp1979]

CJD,
Good catch, I completely forgot the zoffset and kept them at .025 for the longest time.

The original design was for a quad of rs180s from Pete over in partsexpress. He was kind enough to send me the sim offset mostly for the rs180s which were about .025. After many rev from 2.5way to a 3way, the z-offset for the rs180 remained on my sim. I also looked at the peerless 3way design from Pete which also used the same z-offset.

http://techtalk.parts-express.com/showthread.php?t=219069&page=2

However, the peerless 831735 is about .5" shorter then the rs180, I could measure both the rs180 zoffset to get more accurate sim. I did a quick offset sim from .015 to .025 for the peerless and phase came in much better. There weren't much changes to the sum response , but phase wrapping is better with C10 ranging from 24uf - 30uf.

As for phase, i used the RM3 to exptract minimum phase in a simulated box. Not sure how accurate that maybe until i get a measuring gig.

For now, it look like i might build it as is. If they sound right then I probably needs lot of help.

[bbcmp1979]

I also looked through the Best Z-offset est http://techtalk.parts-express.com/sh...light=z-offset and it looked like I should be in the ball park keeping them @ -.025. I will dropped the C10 down to 30uf though.

[David G]

Your bracing could be better.
I'd use full shelf cross-braces, i.e. pieces with 4 circular holes cut in them.