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NHT Speaker Clone Project: VR-3

post #1 of 81
2/23/09 at 8:54pm
Thread Starter 
Here's my build thread to duplicate the VT-3 setup from NHT.

The original VT-3 system had an upper chamber using two 6.5" woofers, one 5.25" midrange, and one tweeter. The lower compartment had two 10" subwoofers.

Link to a review:
http://ultimateavmag.com/speakersystems/11/

Well, as luck would have it, my last subwoofer built just so happened to use twelve of the exact 10" subwoofers from the VT-3. I believe that I have the bass portion nailed down.

So, that leaves me to build the upper front compartment, which is pretty much exactly like the matching VC-3 center and the VR-3 surrounds. I contacted Jack Hidley and he was able to get all the exact drivers, the original crossover, and even the build plans! http://home.comcast.net/~jhidley/

I have the finalized outside dimensions for the upper compartment and the center channel. The original had laminate over 3/4" mdf. Jack went to work and decided that 1" mdf could be used with no laminate and get the same strength, which of course would also be easier. Plus it would allow for roundovers, which he believes should sound better.
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post #2 of 81
2/23/09 at 8:55pm
Thread Starter 
Here's the full page of plans I got for the center channel:



I also have the plans for the mains as well.
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post #3 of 81
3/13/09 at 6:55pm
Thread Starter 
Okay, time to update this thread. I'm going to go into a bit more detail about this build because I know there are others that are going to be building this as well. Plus, Jack mentioned that he may eventually have a very similar speaker kit to this one if he gets enough interest.

I got some of the components for this build last week, and got the rest of it today. Jack had to cut the aluminum tweeter heatsinks which took extra time.

So here's what I have for each kit: Keep in mind, it also came with some screws, fiberglass, and some other needed parts, but this is the main stuff.



You can see the aluminum bar for the heastsink over between by the crossover. That attaches to the back of the tweeter.

The sun kinda made the speakers look a little funny, but it is what it is.
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post #4 of 81
3/13/09 at 7:19pm
Thread Starter 
I had my 1" mdf cut into two 4'x4' sections so it's easier to handle. The nice thing about this enclosure is that it's 24" tall. So basically, if you cut your sides for one box, you make one swath at 8 5/16" and then cut that into 24" lengths. Then mark those two pieces as "box 1". So even if you're off a little on your next cut, it won't matter, the sides for Box 1 should be identical. I did the same thing for the top/bottom as well. I didn't cut all the pieces for 3 boxes, and then shuffle them up and hope they all were exactly the same.

I cut the top and sides to the exact measurements needed. But I cut the front and back an extra 1/16" larger on each side, so basically added an extra 1/8" to Length and Width. The flush trim router bit will smooth that out later, and allows for a little play when you finally get it all together.

I happen to have some really nice corner brackets to use to get the box nice and square. They aren't really needed, but they might help. I used regular Titebond wood glue for the job.




Then I clamped the heck out of the box!!! Yes, it looks like a bit of over kill!

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post #5 of 81
3/13/09 at 7:25pm
Thread Starter 
I know the Titebond directions say you can take the clamps off after about an hour, but I don't chance it and just leave it 24 hours. Then the backs went on.

Here's the overhang on the back that I was talking about (the front has the same overhang). It's not the best photo, but you can see it.




That slight burn on the wood was because that was my first sheet on the table saw and it's not so easy to steady a 4'x4' sheet of 1" mdf by yourself on the first swath! But I knew it was going to be flush trimmed anyway.

Obviously, that bottom piece of mdf isn't part of the enclosure, that's just the top of my "bench".
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post #6 of 81
3/13/09 at 7:39pm
Thread Starter 
The next task I chose was to go ahead and flush trim the rear panel. I used a 1" flush trim bit for the router, but I should have bought a longer bit. It worked just fine though, but a 1.25" would have been quicker.

After I ran the flush trim bit over it, I decided to use the smallest roundover bit I had on the back. It might have been less than 1/4", I can't recall. If I was going to use veneer, I would have left it square. But they will be painted, so I thought a slight roundover looked better.

Then I used an orbital sander to really clean up the joints/seams. I also used 150 grit sandpaper to very lightly go over my tiny roundovers by hand.

Here's how that all turned out. This is the back of the box:





And here's a close up of the edges:


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post #7 of 81
3/13/09 at 8:08pm
Thread Starter 
Next I cut a piece of drawing paper to the dimensions of the baffle and drew out exactly where the drivers were going to go. The woofers are in the same position for the center and the mains, so I just made one drawing, but I drew out both places for the mids and all three places for the tweeters on the same piece of paper. I can send this paper to anyone that may need to lay out the baffle. It was real easy to mark the center hole for each driver this way.

The hardest part of this build will likely be the tweeter mount. So I wanted to cut that first, because if that gets messed up, there's no reason to cut anymore holes in that baffle!

Here's why it's hard: There are no screws on the front, it sits back into a recess and gets held in place from the back of the tweeter. Well, the difference between the tweeter through hole and the recess is only 1/16". So you can't mess up! I tried this 2 times on a seperate board, then went ahead and gave it a final run.

I wrote down the exact hole I used on my circle jig if anyone is interested. Mine was set at 1 15/16" for the outer recess hole and 1 7/8" for the cut through hole. Obviously, everyones jig could be slighly off, so you would run a trial first. The recessed area is 4.5mm deep. Yeh, I actually got it right too!

Here's how it turned out: Keep in mind, I haven't done any light sanding yet.




I should mention that the inner hole is slightly too small at the size I listed for the jig. But you can't move it up any bigger, or the tweeter will fall through. So after you make the cut, you need to sand the inner circle down.

NOTE: When sanding it down, you must sand from the back of the baffle. If you sand from the front, you may smooth out that nice little lip that holds the tweeter in place. I learned from that mistake, luckily it was on a trial piece. I just used a tiny piece of 150 grit that wrapped around my index finger.

Honestly, after my trial run, it wasn't that hard. I was overly worried about it.
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post #8 of 81
3/13/09 at 8:15pm
Thread Starter 
Here's a real good tip that probably saved my butt on the tweeter cut out. After you cut all the way through your hole, the spinning router can jerk over a litle bit because the circle you just cut can now freely slide around. The router could dig into the side of your hole. Not good.

To keep that from happening, you should nail down the inside of the circle, then clamp the rest of the baffle to the work bench. That way, nothing moves, even if you cut all the way through.

I used a nail gun, but you could use finishing nails. Just make sure you counter sink them so the router doesn't get hung up.

This photo shows my center hole for the circle jig, and how I nailed each circle down.





When your baffle is also clamped down, everything stays put until you're done spinning that router.

See:

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post #9 of 81
3/13/09 at 8:22pm
Looking real good so far. You are much better taking your time and measuring 2,3,4 times to make sure that things are cut properly than screwing a piece up and having to scrap it. This should turn out very nice.

What is the tally so far for all of the drivers and crossover components?
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post #10 of 81
3/13/09 at 8:27pm
Thread Starter 
The outer circle on the woofer was done at the 7" mark on my jig and fits perfect. Then I set it at 6.5", then 6 1/16" to clean away the recess area. It needs to be 3mm deep, just like the midrange. So it would make sense to set the router depth and make sure you knock out all of the recessed areas on the woofers and mids at the same time.

I made my midrange recess at 5.75" for the outer portion. I think I may have been able to go 1/16" smaller, so you might want to check that. It looked good, but the more I see it, I think 1/16" smaller could have worked.

Then I made the woofer through hole cut, which happens to be 5.75".

Next I did the midrange through hole at 4.75".

Obviously, if your building this kit, you should test out your own jig measurements, I'm just giving a starting point to look at.



Here's a close up of 3mm deep recess:




And my 3 front baffles!!!!

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post #11 of 81
3/13/09 at 8:36pm
Thread Starter 
Quote:
Originally Posted by tsloms View Post

Looking real good so far. You are much better taking your time and measuring 2,3,4 times to make sure that things are cut properly than screwing a piece up and having to scrap it. This should turn out very nice.

What is the tally so far for all of the drivers and crossover components?

Thanks, I've been lucky so far with no major mistakes....knock on wood (or mdf)!

The tally was about $150 per kit. I did buy the Jasper jig circle cutter from Parts Express. I got the one for small holes and the other one for large holes.....in a bundle package for a decent price.
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post #12 of 81
3/13/09 at 8:43pm
Thread Starter 
So today I used a 1/2" chamfer bit on the back side of the cutouts.



I set the plunge router up just a slight bit for the tweeter so that it didn't get the full 1/2" chamfer. But the rest of the drivers did get the full 1/2".

I was going to use hurricane nuts to attach the drivers to the mdf. I even bought 100 from PE. But I've never used them before, and didn't want to experiment on these.

Keep in mind, this is my first speaker build besides my subwoofer, so I didn't want to chance messing it up. If I used the hurricane nuts, the recess holes for them probably would have been cut out prior to the chamfer bit being used.
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post #13 of 81
3/13/09 at 8:49pm
Thread Starter 
And that brings me up until now.

Tonight I used diluted wood glue and painted everything inside and out to seal up the mdf. I taped off the front baffle where it would be glued to the box. I read that I should keep the glue off that area, so I did.

I just mixed up 2 cups of wood glue to 1 cup of water. But ya know, I did squeeze in just a bit more glue for fun. Probably about 1 tablespoon more?

No doubt that you guys are dying for a picture of my sweet gluing technique!

Sure thing:

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post #14 of 81
3/13/09 at 9:18pm
Very nice. I take it you're not using the rear firing 5.25" mid and soft dome tweeter that the VT-3 has.

Out of curiosity, what was the cost of these per speaker from Jack?
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post #15 of 81
3/13/09 at 9:27pm
Thread Starter 
Quote:
Originally Posted by geoffstgermaine View Post

Very nice. I take it you're not using the rear firing 5.25" mid and soft dome tweeter that the VT-3 has.

Out of curiosity, what was the cost of these per speaker from Jack?

No, just the front portion, pretty much a VR-3 and VC-3 setup, and I already have the VT-3 subs in my basement as well.


I can't recall the actual price per driver. Somewhere in the range of $14 each. But the crossover and tweeter were a bit more, which brought all of it up to $150 per VR-3 or VC-3 kit.
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post #16 of 81
3/13/09 at 9:40pm
Great Job so far Eric, and what a bargain these kits from Jack are. The crossovers are clearly very well built as well.
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post #17 of 81
3/14/09 at 6:59am
Thread Starter 
Yeh, I was a bit surprised at how nice the crossovers were. The tweeter crossover is on the back of the terminal cup. I'm thinking about unscrewing that from the terminal cup and mounting it directly inside the box and just running seperate posts into the enclosure. It will make for a much easier installation as well as a clean look. Not sure just yet.
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post #18 of 81
3/14/09 at 7:27am
Erich,

Very impressive. It looks like you're a seasoned, professional speaker box builder. It's hard to believe that these are your first, except for your already legendary (12) 10" 083 VT3 subwoofer build. Great job! And I for one greatly appreciate all the little details you've documented in your build thread.
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post #19 of 81
3/14/09 at 7:56am
Thread Starter 
Yup, first time. The box construction isn't too hard. But if I had to build the crossovers, it would have made this job very difficult for me. I know as much about building crossovers as your typical 10 year old! So it would've been a major learning curve.

And honestly, after seeing these, I'd be a bit worried about trying to build something like that in a future project.
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post #20 of 81
3/14/09 at 9:15am
They don't have to be pretty, just functional.
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post #21 of 81
3/14/09 at 11:05am
Thread Starter 
Digital Desire, I don't have the equipment to measure the exact properties of all the components either. I may try to learn more about it this year though.
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post #22 of 81
3/20/09 at 3:41pm
Thread Starter 
The makings of the inner baffle. These had to be built from 1/2" mdf. This was the easy stuff....



After I finished building those, I sealed them with diluted wood glue as well.

I did a trial "dry run" by sliding them in with no glue, I just used a clamp to pull the enclosure sides together to hold it in place while I measured exactly where it had to go. Then I traced the inner chamber on the sidewalls so I would know where to start applying glue. Rubbed glue on the sidewalls and the innerbaffle, then it slid right where I needed it. Double clamped the baffle sides and it was good to go.




And here it is in place:

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post #23 of 81
3/20/09 at 4:05pm
Thread Starter 
Now came the hard part! Figuring out where to drill the hole for the heat sink to fit in. It's small and needs to be directly behind the center of the tweeter cutout......5" away.

This is a different NHT speaker, but this is the general idea (E is the heatsink):





There are a couple issues with this. #1, it has to be exact. #2, my front baffle was made 1/16" larger all around to allow for flush trimming later. So when you figure out where the hole needs to be drilled, and take off the baffle, then the baffle needs to be glued exactly where it was when you lined up the tweeter hole in the first place.



My first thought: Cut a piece of cardboard the size of the tweeter and poke a tiny hole in the middle. Lay that in the cutout and shine a bright light on the cardboard. It should let light in just through the middle hole projecting the target on the inner baffle. Nope, the light scatters too much. I tried a laser, but moving the laser angle just a little bit threw off the target hole too much.

So I then found a small spray paint can cap that was the exact size of the tweeter cut out. I poked a tiny hole in the middle and ran a plumb bob through the cap, through the tweeter hole and it marked my target just right. Obviously, your work bench needs to be level.

If I took the baffle off at this point, I'd have no idea how to line it up later when it had to be glued. So while it was clamped together (no glue), I just drew straight lines from the baffle down the outside of the enclosure on all sides. That way, I could just line up the marks and know I was correct. It worked good.

After drilling the hole, I wanted to double check to make sure it was going to fit okay. I reclamped the baffle, installed the tweeter, and made sure everything was where it should be. Turns out, I did have to shift my baffle a very tiny amount, but this was nitpicking a bit. I got paranoid and decided my pencil lines needed to be more accurate. I ran painters tape over the baffle to the sides. Then used a razor blade to cut the tape at the seam. NOW it could easily be lined up later when gluing!

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post #24 of 81
3/20/09 at 4:10pm
Thread Starter 
Here's my center channel after using a flush trim router bit to clean up the baffle overhang:

This one is ready for the roundover bit!

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post #25 of 81
3/22/09 at 5:21pm
Thread Starter 
Well, I was able to use a roundover bit on the sides today. All 3 enclosures are now ready for paint.

I just used a 3/4" roundover bit versus the 1". Jack said it would be okay when I first ordered the kits, so I'm not worried.

I still need to lightly sand the edges and seal them with diluted wood glue, but they look pretty good right now......for my first speaker build anyway. I'm happy with how they turned out so far.




Can anyone give any pointers on how to paint these? I have some primer, but it's white. Will that hammered black Rustoleum show the white color through the thin parts of that finish? The hammered paint leaves some areas thick with paint, and other areas are very thin. So I'm wondering if you can see the primer color through those thin layers? If so, I will need to use grey primer I guess.

Also, can you apply more than one coat of that kind of finish or will it look a bit rough?
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post #26 of 81
3/22/09 at 6:48pm
Quote:
Originally Posted by Erich H View Post

I just used a 3/4" roundover bit versus the 1". Jack said it would be okay when I first ordered the kits, so I'm not worried.

You had mentioned before that a 1" roundover would come pretty close to the tweeter in the center-channel cabinet. I see what you mean. Since I already have a 1" roundover bit, I will first test to see just how close it comes to the c-c tweeter by drawing the tweeter on a scrap piece of the MDF before rounding over the edge with my 1" radius bit. Thanks for saving me some serious headaches!

Quote:
Originally Posted by Erich H View Post

I'm happy with how they turned out so far.

You should be. They look great! Those are some seriously good-looking cabinets. With your eye for detail, I know they will look pretty marvelous with the finish.

Quote:
Originally Posted by Erich H View Post

Can anyone give any pointers on how to paint these? I have some primer, but it's white. Will that hammered black Rustoleum show the white color through the thin parts of that finish?

You need to seek wisdom from Master Shinobiwon (Kinobi?). I am but a padewon-learner. However, I have had a little experience with with the Hammered finish spray paint. About a year ago I converted some dark-grey shelving racks into a test rack for some electronic equipment where I worked at the time. Before assembling the shelves, I painted them with Rustoleum Hammered-Black spray paint. As you indicated above, you could see the dark grey in the thinned areas of the hammered finish. If you choose to go with the hammered finish, I highly recommend a dark grey primer.

Quote:
Originally Posted by Erich H View Post

Also, can you apply more than one coat of that kind of finish or will it look a bit rough?

Good question. I sprayed a little touch-up in a few places on those metal racks. While I did not notice a concentration of "hammer-blows" effects in the touched up areas, I did notice that I could no longer see the dark grey of the primer in those areas. The effect was not nearly pleasing as it was where you could see the dark grey of the primer. To even things out, i ended up re-spraying larger areas where I had touched-up, again with the hammered black, and it looked okay. That was my experience with the Hammered Black finish.

Also, in order to protect the hammered finish, I sprayed two or three coats of a clear ummm...either laquer or enamel. I forget now.

If you seal the hammered finish with a clear topcoat, you need to know that there are some things that will make the clear topcoat krinkle.

Temperature will cause weird problems, maybe krinkle. Not just the ambient temp. at the time you spray, either. Keep the cans of spray paint indoors if your garage will get cold overnight, so the paint inside the can will not be cold. That may not be a necessary precaution--I'm no expert--but it certainly won't hurt anything.

One krinkle-avoidance step you can take is to spray the clear topcoat before the hammered paint cures completely. The hammered finish can will tell you when the paint should be dry enough to accept another coat--should be about one hour--that's the time to spray the clear topcoat. If you miss the one-hour mark, you have to wait the full 48 hours for the paint to fully cure before spraying the topcoat, or you run the risk of krinkling the finish.

I hope this helps.
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post #27 of 81
3/22/09 at 8:13pm
Thread Starter 
Thanks, that does help. Ya know, I'm curious how it would look if I sprayed the on white primer, then painted the entire cabinet a lighter blue......then did the hammered black.

I wonder if the cabinets would have a slight blue tint sort of like the individual drivers do?

I may try that on some spare mdf.



By the way PassingInterest, the 1" roundover should be okay. I debated about buying one, and I know you said I could borrow yours. But I figured that a 3/4" could be used more on other future builds, so I just bit the bullet today and bought one. If you decide to go with the 3/4", let me know, I'll send you you mine to use.
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post #28 of 81
3/22/09 at 8:44pm
Incredible details and workmanship...They are going to look fabulous!
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post #29 of 81
3/22/09 at 9:02pm
Quote:
Originally Posted by Erich H View Post

If you decide to go with the 3/4", let me know, I'll send you you mine to use.

I appreciate that. I'll let you know.

Black & Blue...I have to admit that you've got me curious how that would look. Definately experiment on some scrap and post the pictures for us.

If you're trying to get a pretty close color match to the cones for your first coat (not counting primer), you could take a driver to Home Depot or Lowe's and have them do a computerized color match in the paint department. But, you'd have to brush-on the paint, unless you have the means to spray the paint that they mix for you.

Just a thought.
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post #30 of 81
3/23/09 at 2:50am
Great thread. Love all the pics along the way. I'm sure you're going to enjoy them. NIce work on the cabinets

KG
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AVS › AVS Forum › Audio › DIY Speakers and Subs › NHT Speaker Clone Project: VR-3