Galeons - SB13 MTM

[donradick]

http://www.sbacoustics.com/index.php/products/oem-only/sb13pfc25-08http://www.parts-express.com/pe/show...umber=264-1028

[donradick]

Re: Galeons - SB13 MTM

The SB13 drivers required an irregular shaped cutout. I used nottaway’s method:
http://techtalk.parts-express.com/sh...r-Shape-Driver
It worked pretty good, but of course there were complications. I found that I had a really hard time lining up the template on the baffle, so I got some Lexan and cut an opening the same size as the driver and scribed the lines on it.

Since I wanted the drivers as close as possible, I mounted the tweeter, covered it with a bit of TP and blue tape, and just cut the face of it when I cut the recess for for the woofer. Sort of “white-knuckle” and not to be recommended, but came out pretty good in the end.

I got some flat cut cherry veneer from Tapease, and researched finishing. Several of the “masters” recommended General Finishes ARM-R-SEAL gel coat, but I wanted something a bit warmer. In the end, I’d heard about the tendency of cherry to blotch with stain, so I decided to just use only the gel coat. They came out really, really nice. About 7 coats and I figured I was done. Typical sub-standard camera work by me.
https://lh4.googleusercontent.com/-N...rch-3coats.JPG

[donradick]

Auguest 11, 2013 UPDATE:
Looks like I forgot a 2 ohm resistor for the tweeter in the crossover schematic.
Correct crossover picture uploaded

[greywarden]

Re: Galeons - SB13 MTM

That's some really nice looking plywood.

[donradick]

Re: Galeons - SB13 MTM

That's some really nice looking plywood.

They probably have it at HD in FLA - reasonable price - about $38 a sheet IIRC

[thekorvers]

Re: Galeons - SB13 MTM

Nice job Don! You are getting pretty good at this.

How do they sound?

[[email protected]]

Re: Galeons - SB13 MTM

very nice writeup Don. Did you find that using two of the sb13 helped you get a f3 od 35? i might have to get two more and do a mtm.

[donradick]

Re: Galeons - SB13 MTM

Nice job Don! You are getting pretty good at this.

How do they sound?

Thanks! I am increasingly reluctant to "blow my horn" on my designs, but I would say these
are very smooth, have a very wide soundstage, and play bass with real authority.

[donradick]

Re: Galeons - SB13 MTM

very nice writeup Don. Did you find that using two of the sb13 helped you get a f3 od 35? i might have to get two more and do a mtm.

Well, according to the model, using 1 should get you there, but with a MTM, you can crank them up real nicely. I am really, really digging that nice paper sound.

[bkeane1259]

Re: Galeons - SB13 MTM

Don...this is very cool. Do you have any subjective observations on the DCR alignment? Anything in particular that stands out as a positive or negative??

Just to satisfy my selfish curoisity, I'm wondering if you can determine if there is any midrange leakage from the ports. Since they are rear-mounted, is there any way you can do a quick and dirty sweep measurement??

Really good job on the overall build!! :applause:

[Wolf]

Re: Galeons - SB13 MTM

I'm not Don, Bryan, but I feel it allows the driver a bit more Xmax protection by spreading the tunings out over a broader range.
It did wonders on the W3-517S1 project I built. That little 3" still only could take so much though...

Later,
Wolf

[jonlem]

Re: Galeons - SB13 MTM

Wow, might have to skip my Maurbacs build and go for these, hard to keep up lol. That low end extension is very attractive considering the same size foot print as the Maurbacs. Don, what are your thoughts in comparing the 2 speaker designs? I am looking for a set of garage speaker....

[scottsehlin]

Re: Galeons - SB13 MTM

Nice work Don, This looks like a high-value, well-executed design with a thorough design write-up. I would be curious to hear them. I did a project a long time ago with some Def Tech buyout 5.25" woofers that helped give me a healthy appreciation for what a good paper cone driver can do in the mids.

[johnnyrichards]

Re: Galeons - SB13 MTM

I echo Scott's sentiments on this project, and would like to point out one of the advantages of an MTM with slightly shallower slopes - that off-axis in the horizontal performance is very nice, indeed.

FYI: I would have probably voiced mine closer to the surface mount curve

[donradick]

Re: Galeons - SB13 MTM

Don...this is very cool. Do you have any subjective observations on the DCR alignment? Anything in particular that stands out as a positive or negative??

Just to satisfy my selfish curoisity, I'm wondering if you can determine if there is any midrange leakage from the ports. Since they are rear-mounted, is there any way you can do a quick and dirty sweep measurement??

Really good job on the overall build!! :applause:

Thanks Bryan - the DCR really helps to improve midrange clarity, especially when you crank 'em up. It's spooky to hear all this volume, and
the woofers are hardly moving. I do not notice the dip around 90Hz at all.
I'll be happy to run a sweep on the rear port - I do expect some midrange oout of it, since it's directly behind the tweeter.