Curved Satements Monitors, Round 2!

[Ironman129]

So earlier this year I attempted to make the monitors using kerf cuts to curve the cabinets and had less than optimal success. I've since moved and started a new job, so now that I've settled a bit I wanted to give it another shot. I'll try bending 1/4" hardboard to see if it works out any better. Here the work so far.

[Sylvan]

Cool! I might end up doing something very similar for my next build. I didn't read your old thread though. How did you pick your curve? Just went with what "looked good"?

[Ironman129]

Cool! I might end up doing something very similar for my next build. I didn't read your old thread though. How did you pick your curve? Just went with what "looked good"?

I don't remember if it was a member here or on the PE forum that suggested twice the depth of the cabinet for the curve radius. I loosely followed that advice and chose a curve radius of 24"

Crossovers:
First time with these. Well it's my first time making my own speakers so I guess that goes without saying! I remember there was a thread that talked about spacing between the components of the crossovers. Do mine look ok? Also I believe it is recommended that you do all the connections on the back side of the board correct? They will be placed on their side along the the curved sides of the lower part of the woofer cabinet.

That being said I am trying to figure out the padding for inside the the woofer cabinet. I have 2" wedge foam. I can't fit that and the crossovers in there. Since the sides are curved and the crossovers are not there is going to be some space there. I have plenty of the 1" flat foam for the mid tunnel. Should I cut that in half and adhere to the sides behind the crossover boards? Should I also put it on the forward facing part of the woofer brace?

Thanks for the help.

[Ironman129]

Too Restrictive?

Here's what the upper woofer cabinet would look like. Would the foam restrict air flow too much to the top of the cabinet? Also, do I want to start it 1" back like in the mid tunnel? Thanks again!

[john trials]

That foam doesn't look too restrictive around the mid tunnel. It looks pretty nice, actually.

For the crossovers, there is no need to make the connections on the rear of the board. Check out some others : http://www.htguide.com/forum/showthread.php4?t=36810

For the positioning of the inductors, here is some info: http://www.troelsgravesen.dk/coils.htm

For the 2" foam inside the woofer area, it's going to be like a 3D puzzle, getting it in there with the crossover. The main thing you do NOT want to do is cover up the crossover. Resistors get hot and need an open area to dissipate heat. Since you don't have the sides on your enclosures yet, you will have an easier time figuring it all out. Making your crossover board/layout more compact might help things, and remember, you can always put components on both sides of the board, if that helps make things smaller or improves the layout. See my Statement Monitor crossovers in the above link (post #13). I positioned the tweeter circuit on one side of the board, and the mid circuit on the opposite side.

What are those monster caps in your crossover?

[Ironman129]

What are those monster caps in your crossover?

They are auto-grade caps that I picked up at digi-key. All the values are the same, but it was recommended that I use them because they would add more depth and clarity. It wasn't that much more expensive so I figured I might as well.

I could easily fit them in the tweeter compartment, but I couldn't get them out once I put on the sides. I also don't think I could put the on the same board and fit them through the woofer cut out.

Had a couple of set backs. I couldn't figure out why my cuts weren't matching up and discovered that just because the table saw blade or bench top disc sander are angled to 0*, that doesn't mean it's square. I'm redoing some of the braces. I would like to have the crossovers finished and all the cut outs done by the weekend. Maybe start putting on the sides.

[BeerParty]

A couple of quick questions for you:

How much did you increase the height of the cabinet to compensate for the lost volume of the curve?
How wide is the back of the cabinet with the curve?

[BeerParty]

Here's what the upper woofer cabinet would look like. Would the foam restrict air flow too much to the top of the cabinet? Also, do I want to start it 1" back like in the mid tunnel? Thanks again!

While I don't believe it would hurt anything, you don't need to put the wedge foam on the outsides of the mid tunnel. The 2" wedge foam is only necessary where the woofer driver can 'see' the cabinet, so any surface visible from the woofer hole. So the bottom of the outside of the mid tunnel is the only place you'll need 2" wedge foam around the mid tunnel.

If you review my build thread (link below), you'll see that I only put foam in the tweeter and woofer section of the cabinet. Jim pointed out that I didn't need to put foam into the tweeter section of the cabinet, only in the woofer section.

[BeerParty]

I'll try bending 1/4" hardboard to see if it works out any better.

If the hardboard doesn't work well, you could try some 1/4" Neatform Bendy MDF.

[BeerParty]

Crossovers:
First time with these. Well it's my first time making my own speakers so I guess that goes without saying! I remember there was a thread that talked about spacing between the components of the crossovers. Do mine look ok? Also I believe it is recommended that you do all the connections on the back side of the board correct? They will be placed on their side along the the curved sides of the lower part of the woofer cabinet.

+1 with John - no need to make your connections on the back side of the board. In fact I would suggest that you NOT do this, as having the components and the connections visible on the front of the board will make diagnosing crossover issues much easier.

[Ironman129]

A couple of quick questions for you:

How much did you increase the height of the cabinet to compensate for the lost volume of the curve?
How wide is the back of the cabinet with the curve?

It was recommended that I don't make any changes to the baffle, so I left it alone. That meant I had to increase the depth, which I did to 13". Curt said that since it was within 10% of the original design it shouldn't have any noticeable difference to the the SQ.

Back is 7" wide on the outside

If the hardboard doesn't work well, you could try some 1/4" Neatform Bendy MDF

One of the criticisms when I did the kerf cuts was that it wouldn't be structurally sound and create voids in the cabinet. Some said I would have to fill the cuts with bondo, others said it might not be noticeable, so that's why I am trying to bend the 1/4" MDF. Thankfully the scrap pile at home depot is always full of peices of MDF that only cost $.50. That's also how I got a 4'x4' piece of peg board. While redoing cuts takes up a lot of time, at least it isn't costing me a whole lot!

While I don't believe it would hurt anything, you don't need to put the wedge foam on the outsides of the mid tunnel.

I'm not planning on putting the wedge foam in up upper part or outside the mid tunnel. That pic was just showing how much space is available from the woofer cabinet to move up to the port. Since I am already reducing the flow with the curve, I didn't know if wedge foam would restrict it too much. Also, am I supposed to start 1" back like in the mid tunnel?

[BeerParty]

I'm not planning on putting the wedge foam in up upper part or outside the mid tunnel. That pic was just showing how much space is available from the woofer cabinet to move up to the port. Since I am already reducing the flow with the curve, I didn't know if wedge foam would restrict it too much. Also, am I supposed to start 1" back like in the mid tunnel?

Ah, I understand your questions now. I had the same concern when I put the foam in my cabinet, but the foam doesn't appear to restrict the openings at all (at least, I have not noticed any problems).

You don't need to start the foam 1" back from the woofer like you do in the mid-tunnel, as long as you are not putting any on the back-side of the front baffle. I believe the 1" gap behind the mid is to make sure that the foam doesn't rub up against the driver in the small opening; the area on the front baffle around the woofer should leave plenty of space between the woofer and the foam.

[BeerParty]

One of the criticisms when I did the kerf cuts was that it wouldn't be structurally sound and create voids in the cabinet. Some said I would have to fill the cuts with bondo, others said it might not be noticeable, so that's why I am trying to bend the 1/4" MDF. Thankfully the scrap pile at home depot is always full of peices of MDF that only cost $.50. That's also how I got a 4'x4' piece of peg board. While redoing cuts takes up a lot of time, at least it isn't costing me a whole lot!

I have never used the bendy MDF, so I didn't know if the kerfs in it would be deep enough to create a problem. I just tossed it out there in case your current approach doesn't work.

[BeerParty]

It was recommended that I don't make any changes to the baffle, so I left it alone. That meant I had to increase the depth, which I did to 13". Curt said that since it was within 10% of the original design it shouldn't have any noticeable difference to the the SQ.

You should be fine. But for future reference, I believe it is OK to change the height - the critical things not to change on the baffle are the width and the spacing between the drivers.

[Ironman129]

I LOVE my circle jig. It was so much easier than when I was doing it by hand with a rotary tool! Back half of the baffle is finished. I'm hoping to finish the crossovers today and get all the padding in the woofer cabinet.

[Ironman129]

So with the over sized caps i can fit it inside, but I can't move them in and out of the woofer cut out. That means I can either try and make a removable baffle or pray that everything will work and I wont have to make any changes to the the crossovers once it's all put together. Any suggestions?

[Jim Holtz]

So with the over sized caps i can fit it inside, but I can't move them in and out of the woofer cut out. That means I can either try and make a removable baffle or pray that everything will work and I wont have to make any changes to the the crossovers once it's all put together. Any suggestions?

Make sure you have a way to get to the crossovers for trouble shooting if necessary. :B

The cabinets look great so far!

Jim

[Ironman129]

Well, I have 2 options that I can see. I can have a removable side panel, or removable base. For the side panel, I I wouldn't put glue on the woofer brace or below on one side, then after gluing the 3, 1/4" hardboard sides, use a jigsaw to cut out a bottom panel, line it with speaker gasket, then screw it s back on. I would then have a removable sled panel that would allow access if the crossover.

Option 2, and the one I think I will most likely use, Make the base removable. Glue up the sides and finish the cabinet, then cut off the base, 3/4" from the bottom and again, line the edged with speaker gasket and screw back to the cabinet. I will have to counter sink them so the bottom is flush, but I think that would be the least noticeable option.

[Ironman129]

I think I found a solution. As long as I take them out and put them in in a specific order, I'm good. Mids CO first, then woofer, and finally tweeter. Now I can move forward with putting on the sides and padding the woofer cabinet!

[Ironman129]

Previously I had my crossovers on two boards. Woofer and tweeter on one board and mids and a second. Because of the spacing problem I had to break it up in to three, each having their own board. I can now get everything in and out of the woofer cutout. Enjoy the updated cross over pics! :P

[Ironman129]

Still have a long way to go, but have been making progress. For the sides I did two 1/4' mdf and one 1/4 birch. I still have a lot of sanding to do, but those pics are with the XOs in, so I know everything fits.

[impala454]

Looks awesome! :T

[JonMarsh]

Looking pretty good! Solid progress! :T

[Ironman129]

So I've been listening to them for a couple of weeks now. They sound great! I added an Epic 12 sub in an 18" cube powered by the BASH 300s amp for movies and am REALLY impressed. I used the 3/4" roundover on the sides and continued that into the curve. I am happy with how they turned out but am still trying to figure out how I am going to paint them. I used the birch ply but with sanding it, the wood grain does not show up where it is sanded.