First Speaker Build!

[j-wes]

Hello all, I've been wanting to build my own speakers for quite a while and have finally started building. I was looking for a design that was very small (4 or 5" woofers) and would fit comfortably on the small desk in my dorm room. I played around with designing my own and some already made designs and finally decided on Paul Carmody's Speedster build.

https://sites.google.com/site/undefinition/speedster

This is the build I am primarily following and what I hope my speakers will look like in the end.

http://techtalk.parts-express.com/showthread.php?225266-Paul-Carmody-s-SPEEDSTER-build-thread

I'm about halfway done at this time but I'll take a couple posts to get you up to speed.

 

[j-wes]

I decided to put my own twist on the speakers by making a pair with external crossovers and boxes that are a mini version of the main cabs. This was due to the fact of me never assembling a crossover before and size restraints in the box. The woofer magnet on those tang bands are huge and I wanted to make sure I could get the inductors to go in the proper placement positions. Having the external boxes will also help get the tweeters to ear level as I plan on spiking the main boxes on top of the X-over boxes (an extra 3 1/2" inches of height).

I started out with a 4' x 8' sheet of 3/4" birch ply from menards. I opted for the cheeper sheet but I am now slightly regretting not paying the $20 for the higher grade sheet after some of my cuts splintered the veneer, oh well. I readjusted the measurements due to using 3/4" instead of 1/2" and I got everything laid out so my grain would travel uninterrupted in the correct directions. I used a cheaper table saw for my cuts and they actually turned out pretty good.

 

[StevenZ]

Very cool, have always been interested in these neat little speakers.

 

[j-wes]

Holes are drilled for the binding posts. Checked the fit and the posts weren't long enough. Darn. I took a bit out of the backside and now they fit good. The outside holes will be the inputs to the crossovers. Then the highs and lows are connected up to the second sets of bindings in the main cabs.



This is what the two cabs will look like. The 45 degree angles all fit together nicely.

 

[j-wes]

I got the crossovers built. It was pretty easy once I figured out the best way to lay everything out. Everything got soldered together and hot glued to the bottom of the crossover box.



Once that was done I glued both sets of cabs. I laid the pieces flat and used painters tape to hold the edges in place. Then I flipped them over, added glue to the edges, folded them up, and hold them with a strap. Looks like they turned out pretty good.



Up next is building a circle jig for the router so I can start cutting out the front faces for the drivers

 

[StevenZ]

Good progress. Have you decided on a finish?

 

[j-wes]

I want something that's going to accent the wood grain and pop with the black faces. I'm thinking maybe something with a hint of red like a lighter mahogany color. I've got plenty of scrap pieces to test on when the time comes.

 

[StevenZ]

Cool idea. I used to have some red dye stain that was very expensive but really made any woodgrain pop with a deep 3-D effect. Can't remember where I got it from or even how much it was but that's going to look great for your speakers (red and black).

I'm curious what size room these are going in and what electronics you will use on them.

 

[j-wes]

Room size is pretty small at something like 10 x 10' and placement is not going to be optimal since it's a shared dorm room. They are going to be set up on my desk so near field listening for the majority of playing time. Hopefully I will be using a new NAD d3020 but that hasn't been acquired yet. I've got a little dot iii tube headphone/pre amp and a pair of akg q701's that round out the rest of my home away from home hifi setup.

That stain sounds pretty interesting, I'll have to see if I can find something like it.

 

[Lavane]

Very nice! I've used tape on the cut lines when I used the cheaper plywoods with good results. I once had a few sheets of oak veneer plywood that were so dry and dusty. It splintered badly. Using the tape took care of the splintering. I'll be waiting to hear how those sound. I've built a couple PE speakers and they sound great!

 

[elnaldo]

Keep in mind that at some high sound levels, the resistors on the crossover will get hot. I say this in case you hot glued the resistors, they could melt the glue. Try to keep them apart from the wood, a 1/2" space will be enough, and glue the caps and coils, not the resistors.

 

[j-wes]

Lavane, I thought about this after the fact. I will have to try it on the next project

Elnaldo, I've never heard anything about that before but it makes sense. Since these will be pulling mostly near field listening duty I think I am safe this time but I will certainly keep that in mind in the future.

 

[elnaldo]

Lavane, I thought about this after the fact. I will have to try it on the next project

Elnaldo, I've never heard anything about that before but it makes sense. Since these will be pulling mostly near field listening duty I think I am safe this time but I will certainly keep that in mind in the future.

It's true, for near field listening you should be OK, but take a look at this random google images...
http://smg.photobucket.com/user/tonyfromsuffolk/media/neat2.jpg.html
http://cd8ba0b44a15c10065fd-24461f3...aforums.com/attachments/1/5/4/5/8/3/74761.jpg
http://www.classicspeakerpages.net/IP.Board/uploads/monthly_04_2008/post-101828-1207804691.jpg

 

[j-wes]

Last night I got the holes cut on the front baffles. I thought I was going to have to build circle jig but the audio gods were on my side. Turns out the mounting holes on the router were what I needed, right to the millimeter. I cut the head off a screw and used it as a pivot to router out the circles. Everything fit dead on.

 

[j-wes]

It's been a while since the last update but I have been very busy getting things done on this build. Continuing from the last post, I picked up a 45 degree router bit and did both the outside edge of the baffles and around the backside of the woofer to give it some room to breathe.



On the cabs I veneered the back edge with iron on strips of birch. The trick was to leave the corners un-ironed and then use a razor blade and a hammer to get a nice 45. Of course I didn't get good at trimming the veneer until I was on the last cab.





Then I installed my t-nuts and did a test fit of the baffles. Looking good so far

 

[Binkman]

:thmbsp:

 

[StevenZ]

You're almost done!

 

[j-wes]

The backs got glued in and I started staining. Ended up going with golden pecan which I had left over from refinishing a pair of advent heritage.





For the baffles, I used bondo to fill in any large gaps and then put about four coats of primer on with light sanding in between. Then they got 4 coats of flat black spray paint. In retrospect I should have used a solid piece of wood instead of ply and I could have avoided a lot of the gaps and uneven sections that I had to deal with. At this point I was pretty excited and forgot to take pictures.

Last night I got everything put together. Drivers fit in snug but good and everything looks pretty good. I added stuffing but I think I got a little carried away. I'll probably play around with the volume. It's not quite as much as how it looks in the picture but I still think I went a little overboard.

 

[StevenZ]

Nice! Are those external crossovers? This is shaping up to be a very nice build. I agree about using hardwood for the front baffle, would have added a nice touch.

 

[j-wes]

Finished

Speakers are all set up on my desk and wow do they look good. My parents just gave me the NAD d3020 that I'm running with them now as a birthday gift and it fits perfect on the desk. I've heard lots of good things about it and so far I am impressed. As for the speakers, I am equally impressed. Things seem well balanced and crisp and there is certainly a large bass presence. Right now there is a bit of slop in the lower midrange but my guess is it will go away as the drivers break in.

Overall, a job very well done. I will post some more pics when the lighting is less yellow.