Bought a Speedster kit. Now what?

[Browncoat]

I'm a complete newbie to DIY, I don't know much about hifi, and I don't have an electronics background. What could possibly go wrong?

Anyways, I cracked open my Speedster kit, and I have a couple questions (if these are really stupid questions, feel free to point and laugh )

• If I'm reading the components correctly, the kit includes 2x 100 Ohm resistors, but I was expecting 2x 10 Ohm. Am I off in the weeds?
• The kit has 2x 2.7uF caps, but the crossover specifies 2.2uF. Is that difference significant?
• Two of the four 4.7uF caps are Audyn Q4, and the other two are Bennic XPP. Does it matter which goes where?
• How sensitive is cabinet volume? For example, if I add some tack strips for a removable front or back, do I need to calculate the volume of those strips and adjust the cabinet size accordingly?

Thanks for your advice!

[Bill Schneider]

Things do go wrong, and I think you have valid concerns about some of the issues. 100 ohm vs 10 ohm is significant. The cap difference of 2.7uF vs. 2.2 uF is over 20 percent, and that's too much.

I'd contact the supplier and express your concerns. I'm sure it's just human error. It's fortunate that you went through the contents to find this.

About volume - I'd feel comfortable within 10 percent of the specified volume, but if you can do the math, there's no reason not to make accommodations for things that might change it. Just keep the baffle width the same as the design, and keep the driver position as specified. It's usually safe to go deeper with a box when you need more volume.

[Browncoat]

Cool, thanks for the advice! I emailed the supplier about the components, so hopefully I can get those straightened out soon.

I happened to have some 1/2" MDF lying around that I veneered a year ago and never used, which I think will work nicely for the cabinets. I don't have any more of that veneer, so I think the front will have to be something different. I've seen some people use solid wood for the front--does that cause any problems when glued to an MDF box? Don't those materials move at different rates?

I found enough time to build a sled out of scraps and start a practice box yesterday. It would be more DIY to build a circle jig, but I think I'll be lazy and buy one

[Bill Schneider]

I don't have any more of that veneer, so I think the front will have to be something different. I've seen some people use solid wood for the front--does that cause any problems when glued to an MDF box? Don't those materials move at different rates?

Yes, the two materials WILL expand at different rates with humidity changes. With small boxes, you might get away with gluing them on. However I'd avoid that in case I was one of the unlucky ones.

Instead, glue some small triangular blocks of plywood in the box corners, and screw the baffles to them. Screws passing through clearance holes in the baffles allow for movement and could prevent splitting.

[Browncoat]

Good to know. I took your advice and used triangles on my practice box, which was a worthwhile exercise. I'll probably tweak a few things on the next try.

[Steve Manning]

Good to know. I took your advice and used triangles on my practice box, which was a worthwhile exercise. I'll probably tweak a few things on the next try.

[ATTACH=CONFIG]26517[/ATTACH]

Browncoat ...... with Bill's great idea about attaching the baffle with screws you could take it one step further if you want to hide the screws. Put some threaded inserts into the backside of the baffle and then run machine screws from inside the cabinet through the triangles to secure the baffle. This is more for aesthetics, (don't mind my OCD) but it looks like you have the room to do it.

[Browncoat]

That's a good idea. I'm willing to live with some screws, though, because I want a removable panel to allow for inevitable mistakes. Which brings up another question: do most people solder the drivers, or do they use clips to make them removable?

BTW, the speaker pictured in your avatar looks fantastic, and gives me another idea of how I might finish these...

[doubleTrouble]

do most people solder the drivers, or do they use clips to make them removable?

Soldering will keep best possible contact for years, clips may oxidize and become unreliable after some 10 years.
Everything I want to work forever I solder.

[Steve Manning]

BTW, the speaker pictured in your avatar looks fantastic, and gives me another idea of how I might finish these...

Thanks for the kind words

[Browncoat]

Soldering will keep best possible contact for years,

Thanks, solder it is!

I don't remember where I saw it, but I noticed that one maker recessed the woofer by cutting the tweeter surround. Not sure if I'm brave enough to try that, but it looked pretty slick. Anybody here have experience doing that? Looks like the surround is aluminum, and I'm using a solid carbide cutter, but I've never tried doing something like that before.

[Bill Schneider]

I haven't done it before, but I'd try it.

In a previous job back in the 80s, we used carbide cutters in routers to trim large aluminum parts. They needed to fit into a steel drum. When the aluminum cylinders were formed, they had high spots that the router leveled handily. I suspect that the die cast aluminum used in the tweeter frame would be even softer than the 6061 T6 alloy that we used.

Just wear gloves and serious eye protection because of the hot, sharp metal chips. Cover the sensitive parts of the tweeter too.

[Pknaz]

Thanks, solder it is!

I don't remember where I saw it, but I noticed that one maker recessed the woofer by cutting the tweeter surround. Not sure if I'm brave enough to try that, but it looked pretty slick. Anybody here have experience doing that? Looks like the surround is aluminum, and I'm using a solid carbide cutter, but I've never tried doing something like that before.

The crossovers are designed so that the woofer and tweeter are in proper phase when they are mounted as designed, I'm not sure I'd recommend having the woofer and tweeter both flush mounted.

[wkhanna]

............. we used carbide cutters in routers to trim large aluminum parts......

if one were to cut the surround (notwithstanding Pknaz's concerns regarding the effect to phasing on this specific project) carbide tooling would not necessarily be required. High Speed Steel (HSS) cutters (end mills) are typically significantly cheaper & would be quite sufficient since the material is not excessively hard & tool life would not be an issue.

also, HSS is not as brittle as carbide & is a bit tougher; e.g. will be less likely to break.

Harvey Tool has been a good source of metal cutting end mills for me professionally, along with McMaster-Carr & MSC.

[Browncoat]

Thanks for the advice everybody! I think I'll punt on the recessed woofer and save the fancy stuff for a future project

I made a little progress on the cabinets (I wiped some mineral spirits on the outside to get an idea how dark these will end up):

[Browncoat]

Does this layout make sense? I was thinking about making connections underneath--that might give me some more room to solder?

[Pknaz]

Thanks for the advice everybody! I think I'll punt on the recessed woofer and save the fancy stuff for a future project

I made a little progress on the cabinets (I wiped some mineral spirits on the outside to get an idea how dark these will end up):

[ATTACH=CONFIG]26521[/ATTACH]

That is going to look fantastic!

[Browncoat]

That is going to look fantastic!

Thank you! I'm having fun working on them.

I got a little cocky and assembled one of the crossovers before I tested it, so of course I had to do some rework. Fortunately, nothing was past the point of no return

[Bill Schneider]

If you did any rework, it's not obvious from this view.

I can tell you are detail-oriented because all the labels are facing upward.

Looks good!

[Paul K.]

And all labels oriented in the same left-right direction!:T
Paul

I can tell you are detail-oriented because all the labels are facing upward.

Looks good!

[Browncoat]

Thanks. And now I know you guys are detail-oriented, 'cause you noticed

[Browncoat]

Crossovers are done, and the carcasses are nearly complete. I'm going to do black baffles, because I don't have any more of this veneer. In fact, I barely had enough to complete these boxes :P

[Browncoat]

Dumb question: is it OK to round or miter the outside edges of the baffle?

[Bill Schneider]

If I understand your question correctly, yes. Round-overs and chamfers are OK.

It's done more often than not, and it can help tame baffle-edge diffraction issues.

[Pknaz]

Looking fantastic!

[Browncoat]

Thanks! I might be the slowest builder ever, but I'm still plugging away.

I was calculating the enclosure volume the other day, and couldn't figure out why my numbers were so wacky. Eventually I found the problem--I made the cabinets too wide! Since I had nothing to lose, I cut a section out of the middle of both cabinets, and glued them back up. Looks like I might actually pull it off. The veneer grain just happened to be going the right direction, so the seams are essentially invisible.

I finished the baffles tonight (aside from some kind of edge treatment), and tested the speakers as a pair. These things are really small, so my expectations were modest, but they surprised me. In fact, it's kinda ridiculous how good they sound. Well done, Mr. Carmody.

[wkhanna]

good progress....:T

..our motto around here for many of us is, "Slow work takes time!"

we do like photos, a lot, too.:W

[Steve Manning]

Looks like your moving right along actually ....

[Browncoat]

good progress....:T

..our motto around here for many of us is, "Slow work takes time!"

I like that--I think I'll be using that in the future

Finishing will take a while, but you can kinda see what I'm going for here:

[Bill Schneider]

Very nice!

That's a handsome combination!

[wkhanna]

i V much like the flat chamfer on the baffles.
round-overs are more common, but i feel the look of yours integrates well with how the driver bezels overlap.

[---k---]

Very nice. The veneer came out beautiful.

[Browncoat]

These didn't really turn out how I planned, but I wanted to finish the project and move on to other things, so I pushed through. Maybe someday I'll make new boxes with lighter wood and skip the paint, but for now I'll just enjoy listening to them .

[JonMarsh]

These didn't really turn out how I planned, but I wanted to finish the project and move on to other things, so I pushed through. Maybe someday I'll make new boxes with lighter wood and skip the paint, but for now I'll just enjoy listening to them .

[ATTACH=CONFIG]26738[/ATTACH]

That's probably a good pragmatic plan for now! :T

[Bill Schneider]

Most builders would die to have something that looks that nice. Tame those regrets!

[scottvalentin]

I agree with Bill, those look really beautiful! Enjoy the music!

[TEK]

I agree as well, those looks very nice.
The fact for most of us is that we often focus very mutch on something that we see as flaved, but that nobody will actually notice on a regular basic.
"good enough" is often more than that :-)

[wkhanna]

those are V nice.

you should be proud of them.
your workmanship is both V evident & superb.

[Browncoat]

Thanks for the kind remarks! It was a fun project. I'm already looking for some excuse to build the Carreras or Solstice kits.