My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

[SoundEx]

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[bullittstang]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

*****REVISED 8/28/2015***** after receiving some good input from judges and attendees at this year's MWAF. I was told they didn't have enough mid-bass punch and too much lower bass (muddy?). So I went back to the drawing board and revised the XO focusing on increasing the BSC (went from 3db to a 4.5db average in the 300-500 region) and reworked the XO to get the flattest response while keeping the XO count within reason. I still have a 2nd order on the woofer and 3rd on the tweeter. The updated XO resulted is a much better overall tone and smooth sound and I can listen for hours without any fatigue. But another important factor I considered was that they needed to play any kind of music and still have no fatigue, which now they do - MP3, FLAC, Pandora, even youtube sounds good. I have updated the pictures and some graphs to the new design and removed the previous version, because I don't think it merits retention. I will continue to update the graphs as I get them converted to pics.
Thanks for everyone's input at MWAF, it was a great learning experience and showed me just how much more I have to learn about this hobby.

[bullittstang]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

updated a few pics and added two new graphs on post#4 showing the PCD SIM and Actual OmniMic Graphs...I couldn't believe how close they are, you can barely tell the gray (actual) line is there. Still working on getting some more professional final pics posted.

Updated out the XO schematic in Post#4. As I learn more, I get better, so this updated XO is a much better sounding version (granted I only change the woofer capacitor from 7.5uF to 12uF)

[bullittstang]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

The 45's look great. I think i will try this on my next build. Is it 1" mdf or does the 45's make it seem thicker. Did you use screws or nails or battons to secure it? I figure if you use decent quality veneered ply you can skip alot of the veneering process. Was it difficult to get the back and from on with those being 45'ed as well? Im wondering if you jist cut everythibg to size and mocked it up to verify it fits then used the 45 on the table saw.

It's just 3/4", but the camera angle and 45 does make it seem larger. I just set my table saw at 45-degrees and measured all the panels on the long side.
(Ex. I cut the first 45 just taking off an 1/8" or less, then set the fence at the desired outside measurement and run it through with the 45 side running down the fence. So if you put your tape measure on the "long" side it should read you panel measurement, i.e. 7" needed, tape measure should read 7")
I just used Tite-Bond regular glue and did the top, bottom and one side, then the brace, back and other side, then the front. I always go back and run a small bead of glues along all the interior edges, so any minor "misses" on the gluing will get a good bond after that.
Yes, you could totally get away with using Birch or Oak veneered ply and cut out 4-5 hours of the veneering process. Some people don't like 45's because there isn't any "edges", but from seeing and reading on here, most of you guys like the solid look... me included.

[Mike220]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

The 45's look great. I think i will try this on my next build. Is it 1" mdf or does the 45's make it seem thicker. Did you use screws or nails or battons to secure it? I figure if you use decent quality veneered ply you can skip alot of the veneering process. Was it difficult to get the back and from on with those being 45'ed as well? Im wondering if you jist cut everythibg to size and mocked it up to verify it fits then used the 45 on the table saw.

[bullittstang]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

they look fantastic! I was going to guess beeswing Makore before I saw the last post. Yep, 1/66" is pretty thin. 1/42" definitely give you a little wiggle room, and you can even put a very small, hand sanded round over on the corners.

Do you love the SB26's as much as other folks on the forum? I've been wanting to give them a try. My favorites are the NE19VTT's so far, but the venerable XT25BG's are awesome too.
nikkoluvr

They are very nice, while I don't have much reference since this is only my 5th build and 3rd different kind of tweeter I've heard for an extended period. I was looking at the XT25BG's in small frame format, but Jeff recommended these, and I certainly trust his opinion. They are very easy to work with, which for me was a real help in the design aspect. They sound good and easy to design a XO for, that's a check and check moment. For $35/ea, you really can't go wrong with them as long as you like the look.

I've been eye balling the redwood burl he has. The option for paperbacking a burl is crazy it adds like $100! There are so many veneers to choose from on that site it is insane. I go there an just browse a lot trying to get ideas. How was the shipping of the brittle stuff? Did it come in a large box I assume he couldn't bend it at all? Also, what glue method did you use contact cement, cold press, heat lock etc.?

I totally agree with you, going online to "find" veneer results in a lot of head-spinning and indecision. I went back and forth on Curly Eucalyptus, Makore and Teak, but thought for the price I couldn't resist getting a really high-end looking veneer on the cheap. They just rolled it about 12" in diameter with paper between the sheets and put in in a pretty big box with packing paper all around. It was split on the ends, but only about 1-2", so I still got 80+" out of each sheet and the width was completely usable. It is fairly flexible, especially if you wet it slightly with some distilled water, just brittle on the edges when it dries out.
I used the iron-on method (1st time using this process too) with Tite-Bond Premium. I put 2 coats on the MDF, letting each coat dry for about 45-60 minutes, then 1 coat on the veneer letting it fully dry at least 45 minutes. Then with a dry (no water in the iron) and running it at "wool" setting (highest, no-steam setting). I laid the pre-cut veneer pieces on the box exactly where I wanted them and ironed them on, which only takes 2-3 minutes on each panel. Followed up with a veneer scraper to make sure it was fully adhered, especially the edges. Also found out if you wipe the veneer with just a little water, it kept it pliable even with the iron on it (iron tends to dry it out and it really wanted to crack/split) Only real issue with that was if you didn't let the glue completely dry, it acts like contact cement and when they touch, it's down for good. I used almost half of a quart of the Tite-Bond to do both boxes and used 2 sheets of the 5 sheets of veneer. So I have enough veneer to do at least another pair of monitor speakers.

Glad to answer any questions, I was kind of "flying by the seat of my pants" on this build. Since I was new to testing, new to designing a XO, new to 45-degree cabinet joints, new to raw veneer and new to the iron-on veneer method. So just a couple new things I now have in my arsenal for future projects.

[Mike220]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

I've been eye balling the redwood burl he has. The option for paperbacking a burl is crazy it adds like $100! There are so many veneers to choose from on that site it is insane. I go there an just browse a lot trying to get ideas. How was the shipping of the brittle stuff? Did it come in a large box I assume he couldn't bend it at all? Also, what glue method did you use contact cement, cold press, heat lock etc.?

[nikkoluvr]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

they look fantastic! I was going to guess beeswing Makore before I saw the last post. Yep, 1/66" is pretty thin. 1/42" definitely give you a little wiggle room, and you can even put a very small, hand sanded round over on the corners.

Do you love the SB26's as much as other folks on the forum? I've been wanting to give them a try. My favorites are the NE19VTT's so far, but the venerable XT25BG's are awesome too.
nikkoluvr

[bullittstang]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

Nice work on your first build. Is that sapele veneer?

Thanks for the kind words.

Yes, it's "Mottled Sapele" I got on clearance from veneersupplies.com. Great deal at $34 for 5 sheets of 11-1/4"x84", after book-matching and shipping it was $47. The only downside with it, was how thin it was cut. At 1/66" thick, it was very brittle and easy to get cracks and/or chip-out. Since it was on clearance, he didn't offer to paper-back it, or an option of a 1/42" thickness. Even a little bit thicker would have made using it a lot easier.

I love the look of it though and I think it was worth all the "issues" and difficulty I had working with it.

[Mike220]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

Nice work on your first build. Is that sapele veneer?

[kenny_k]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

Very attractive build you got there.

[[email protected]]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

Very nice build and write up as well.

[bullittstang]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

***Revised 8/28/2015*** with updated graphs

Here's all the Curves and plots.
Raw FR Curves - tweeter, woofer and Both


Final FR Curve at 27-inches at 1/24th octave


Distortion at 1/24th octave


Tweeter Only


Woofer Only

[bullittstang]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

***Revised 8/28/2015***
Crossover is pretty straight-forward, 2nd order on the woofer and 3rd order on the tweeter. It helps to have some quality components to work with.


Here is the SIM Graph (Black) versus my Actual OM measurement (Orange)



Here is the SIM with the reverse null


Impedance Graph
SB Build_Impedence Graph.pdf

[bullittstang]

Re: My First DIY Build - SB15NRX30-8 & SB26STCN-4 (pic heavy)

Not the best pics, since I was using an iPhone camera. Trying to get my sister in law (a professional photographer) to take some "completed" pics, but that hasn't happened yet.

These are with either 2 or 3 coats, so not completely finished yet.



Picture of the OLD XO board, will update once I get the new version completed


Couple pics of the "finished product" next to my Nano Neo's build. So far I have built the Nano Neo's, the OS's (TM and MTM versions), the CLASSIX II's (in Walnut veneer, same Arm-R-Seal finish and flat black baffle) and these.