Minerva Monitor: "Patience my ass, I'm going to go build something!"

[benthe8track]

Would love to see a Wilson Ardent!!

[JonMarsh]

Yeah, I'm hoping Steve builds these some day- I think they'd be cool. I've got someone I'm going to try to get interested in this concept....

[sdl2112]

Great work guys :T I'm just wondering what you will do with all theses speakers. Jon, you are going to need another shed to set up a museum of speakers :B

[Steve Manning]

Great work guys :T I'm just wondering what you will do with all theses speakers. Jon, you are going to need another shed to set up a museum of speakers :B

Your right Scott ...... I'm not nearly as bad as Jon and I'm already wondering where to put stuff. I guess there are worse forms of addiction to have .....

[TEK]

This is where I see the finished design .......

[ATTACH=CONFIG]25243[/ATTACH]

[ATTACH=CONFIG]25244[/ATTACH]

With such a large woofer box, and wide baffel, have you (and Jon) evaluated the possibilities to go up to for example 2 x 10" or 2 x 12"?

[Steve Manning]

ALuminum Trim

Got the aluminum trim back for the cabinets, from the welder today .... here are some pictures.

Needed to do some clean up of the weld areas, this is what they looked like to start ....



A file was all that was needed to get the excess removed. One side done .....



All four sides filed ....



Half way done ......




The frames will need a little tweaking to adjust the fit and then some polishing and sealing before they are completely done. So far it looks promising though.

[Steve Manning]

With such a large woofer box, and wide baffel, have you (and Jon) evaluated the possibilities to go up to for example 2 x 10" or 2 x 12"?

Hey TEK .... The way it sits at the moment these should get down into the low 20's. The base section is actually only 2 cu ft, which is not all that large really and the cabinet is only 14" wide. It could handle a 10", but not a 12" driver.

[JonMarsh]

As Steve is getting at, it's really all about the complete system tuning and the compatible drivers. The 10" PR's on the back give a fair amount of radiating area for the low frequencies, but they will kick in only on the very low frequency stuff. We're not trying to make PA speakers, after all, but a wide range home music system.

OTOH, this cabinet is significantly larger in volume- each 9" waver and 10" PR requires about 30-35 liter, (60-70L total) where as the total volume sealed for the Wavecor Ardent isn't much more than 40L.

Let's look at the anechoic response potential predicted by Unibox, which I find to be fairly accurate. First, the predicted SPL vs frequency for 60L setup for the two drivers and two ScanSpeak PR's:




Now, under those same conditions, the driver and PR excursion:



The SW223BD02 is comfortably under it's Xmax limit, though the PR will be pushing pretty hard by the time you get down to 23 or 24 Hz. For this size box, that's some pretty respectable LF extension. This is anechoic, for one cabinet; with boundary reinforcement one should see about 6 dB more output. :T

[Steve Manning]

More glue on hand from Amazon ....... cabinet parts are next in line for that process. Got stuff separated into cabinet lots and did a test fit on some dowels. Have decided to run a drill bit through the holes to make thing a little easier and took a few pictures of what the cabinet will look like.

[kevinm]

Probable noob question incoming -

Steve - when you translam like this, are the tolerances so good with a little sanding/scraping, the surface is perfectly smooth/uniform? Or is the subtle unevenness just part of the translam character?

[knowledgebass]

Probable noob question incoming -

Steve - when you translam like this, are the tolerances so good with a little sanding/scraping, the surface is perfectly smooth/uniform? Or is the subtle unevenness just part of the translam character?

Sand until smooth. Fill small holes and ply inconsistencies as you would with a grain filler on open grain woods (epoxy works).

[Steve Manning]

Probable noob question incoming -

Steve - when you translam like this, are the tolerances so good with a little sanding/scraping, the surface is perfectly smooth/uniform? Or is the subtle unevenness just part of the translam character?

I've never done one that was cut on a cnc, the other one I did I cut all the pieces by hand. With the dry fit I did today, I think there should be a lot less sanding this time around. As knowledgebass already mentioned, it will be smooth when done. I'm hoping for a minimum of voids, but there are going to be some. I used some cyanoacrylate the last project I did, to fill in some tear out issues that worked very well. I'll have to asses things when I get to that point.

Steve

[JonMarsh]

Nice to see how well those pieces are fitting- expected, but still nice! :T

[Steve Manning]

Productive day in the garage ....... had to go with plan B on the aluminum trim. I was a bit concerned with the trim pieces fitting once they were welded. Even though they were setup in a jig, they were still essentially bent by hand. As such trying to tweak things to get them to fit was just not working. So I've decided to remove a section of the trim on the bottom of the cabinet so I can make adjustments. Things will look essentially the same from all angles, except the bottom.

The plan was to cut a around the circumference for the trim to sit in. Now I had to modify it with a start and stop point.

The high tech. jig, scrap boards and carpet tape .....





New rabbeting bit set up to go ....



Rabbet cut ....

[Steve Manning]

Marking the squared out finish ....



After a little chisel work .....





All cabinet pieces are rabbeted at this point ....

[JonMarsh]

Looks pretty good- doing some of what you do best, adapting and finessing! :T

[TEK]

Lookd really good Steve. Thanks for sharing the pictures as well as the process.
You are doing some really impressive work! Especially interesting to see how you combine different materials. Not to often seen in the DIY work, so I think this pushes the DIY to yet another level!
I went back to the initial post and looked at the target picture:


I'm a bit curious about how you will proceed.
Will the side panels be painted wood? How will you treat the bamboo? And how will you keep the paint and treatment for the bamboo away from the metal strips?

[Steve Manning]

Lookd really good Steve. Thanks for sharing the pictures as well as the process.
You are doing some really impressive work! Especially interesting to see how you combine different materials. Not to often seen in the DIY work, so I think this pushes the DIY to yet another level!
I went back to the initial post and looked at the target picture:
[ATTACH=CONFIG]25266[/ATTACH]

I'm a bit curious about how you will proceed.
Will the side panels be painted wood? How will you treat the bamboo? And how will you keep the paint and treatment for the bamboo away from the metal strips?

Thanks TEK ..... the side panels are going to be "painted" with a tinted Waterborne Pre-Catalyzed Lacquer, where as the main body is clear. You can get this stuff in pretty much any color you want that regular paint comes in. The base lacquer is white instead of the regular clear. From the samples I've seen it looks like paint when your done. I will be putting a couple of clear coats on top of it.

As far as keeping paint away from trim, etc., I'm planning on keeping the pieces separate until the finishing is done, then do a final assembly. I think trying to keep bleed through from happening would be a royal pain.

Steve

[TEK]

I did it that way on my In-Kahn-Neatos for my livingroom.
It worket out great, but I did have some issues when applying pressure to glue the pices together. As the paint was done the pressure caused a pattern to form in the paint. Had to do quite a bit of polishing to get it away. On the second one I applied all pressure inside the cutoffs for the elements so that there were no visible pressure mark.
Just a heads up.

[Steve Manning]

I did it that way on my In-Kahn-Neatos for my livingroom.
It worket out great, but I did have some issues when applying pressure to glue the pices together. As the paint was done the pressure caused a pattern to form in the paint. Had to do quite a bit of polishing to get it away. On the second one I applied all pressure inside the cutoffs for the elements so that there were no visible pressure mark.
Just a heads up.

Appreciate the heads up TEK ....... I've been giving that a little thought already. Actually I started putting something "soft" between my clamps and the wood prior to tightening things down. The idea behind this is to make sure you don't dent the wood with the harder surface of the clamp. I ran across that suggestion over at http://www.thewoodwhisperer.com/, the guy has a lot of helpful tips and what not's on his site. I'm also thinking of seeing if I can get some screws in place on the inside of the cabinet to pull things together instead of using so much clamping pressure, we'll see if I have enough room through the speaker openings.

[TEK]

Thanks for the link Steve. Will see if I can get time to read through his site.

You can probably use clamps if you are able to divide the pressure over the whole surface, using both hard wood as well as soft fabrics to protect the paint.
However, any "soft" you put between have to be something that does not make any trace of it. I used some painters mats made of wool like material and that caused me to get a lot of small marks in he paint.

[Steve Manning]

Cabinet One Glued

Spent the day gluing up the first cabinet. Split things up into three sections to deal with open time for the glue, etc. I think if you had a second person working with you it could be done in two steps vs. three. Where is that Jon when you need him ...... :B

The first glue up ....





At the end of the day .....






Now comes a bit of clean up ......

[dar47]

Ya. I think i would have tried to clean the 1/3 sections before joining them but it must have been fun to stack them all right away.:T

[JonMarsh]

Cleanup... now if only that were just sugar frosting or maple syrup. OTOH, that wouldn't hold the wood together very well... :W

Oh, and I've been here all day long, vacuuming, doing laundry, feeding and walking the dog, working on the APx500 manual, searching for test data files so I can finish Ron's crossovers, and of course, goofing off for a few minutes pondering unicorns...

Nice progress Steve... this is DEFINITELY when it feels like progress is happening!

[Steve Manning]

Cleanup... now if only that were just sugar frosting or maple syrup. OTOH, that wouldn't hold the wood together very well... :W

Oh, and I've been here all day long, vacuuming, doing laundry, feeding and walking the dog, working on the APx500 manual, searching for test data files so I can finish Ron's crossovers, and of course, goofing off for a few minutes pondering unicorns...

Nice progress Steve... this is DEFINITELY when it feels like progress is happening!

I wish it were, it would pull less skin and hair coming off my arms 8O

[IslandHydro]

So, how did the alignment turn out? I would think the dowels would only do just so so (at maintaining alignment) when you're looking at that many stacked pieces. I'd guess that when clamping pressure was applied (and glue began to flow) there would be a tendency for the whole stack to 'swim' a bit. How square do you think it ended up overall, and how much sway (variation between pieces)? I love the concept, if it works well I think it'd be something to try!

[JonMarsh]

I think by only doing a third of the stack up at a time, Steve is mitigating the "swimming issues". But let's see what he says...

[Steve Manning]

So, how did the alignment turn out? I would think the dowels would only do just so so (at maintaining alignment) when you're looking at that many stacked pieces. I'd guess that when clamping pressure was applied (and glue began to flow) there would be a tendency for the whole stack to 'swim' a bit. How square do you think it ended up overall, and how much sway (variation between pieces)? I love the concept, if it works well I think it'd be something to try!

I'll let you know when I scrape the glue off ..... though with that many dowels I think (hope) it won't be too bad.

[Steve Manning]

Well the glue has been scrapped off ..... loads of fun to be had there 8O

This is what it looked like after that was done. Alignment looked pretty good.





Then spent some time with a scrapper and some rough sand paper ( 50 & 80 grit) on the sander and got a couple of sides semi smooth. Sanding this end grain is like sanding steel. It's going to take a bit of work to get it finalized, even though the alignment is good.

[dar47]

I'd say that's better then a slap in the belly with a wet fish! :T

Are you going to sand smooth or skin the surface with epoxy or something first?

[sdl2112]

That's fast Steve...although you may not have the same feeling :E Looking good, are you thinking satin or gloss finish...my top is the same construction and right now I'm thinking a natural wood sheen.

[Steve Manning]

I'd say that's better then a slap in the belly with a wet fish! :T

Are you going to sand smooth or skin the surface with epoxy or something first?

Now that one I have not heard before Darrell ...... I'm going to sand smooth and then hit it with a coat or two of sanding sealer/shellac, then apply the finish. There are a few voids/tear outs that I was not expecting, so they will need to be filled some where in that process as well. I have a bag of bamboo sawdust so I might throw that in with some epoxy to take care of the voids. Tear outs I've found CA works very well.

[Steve Manning]

That's fast Steve...although you may not have the same feeling :E Looking good, are you thinking satin or gloss finish...my top is the same construction and right now I'm thinking a natural wood sheen.

Thanks Scott ..... your right I'm not feeling the same thing, though this is moving along pretty well compared to the last tranlam project I did. The final finish will be satin, though I'm going to lay down a couple of coats of gloss first and then finish with a coat or two of satin to finish.

[JonMarsh]

Today's money quote:

Sanding this end grain is like sanding steel.

Don't you just love this LBL stuff?!? Not quite as bad as hard rock maple could be, definitely a bit stouter than MDF!

It's looking pretty good, Steve- starting to resemble speaker cabinets!

Just imagine, if you were doing this at speaker building boot camp, they would be making you scrape all the glue off with just a tooth brush... it could be worse, you know!

[Steve Manning]

Today's money quote:



Don't you just love this LBL stuff?!? Not quite as bad as hard rock maple could be, definitely a bit stouter than MDF!

It's looking pretty good, Steve- starting to resemble speaker cabinets!

Just imagine, if you were doing this at speaker building boot camp, they would be making you scrape all the glue off with just a tooth brush... it could be worse, you know!

The biggest pain is that I'm hearing my belt sander whisper to me from under the work bench .... "Use me, Use me" and that usually never ends well. The scrapper is working pretty well though. I'm thinking about trying a hand plane on some test pieces to see how that does with this stuff. I'm expecting tear out, but I have a high angle setup on one of them to deal with that, so we shall see.

[JonMarsh]

Belt sanders fall under the Spiderman rules: With great power, comes great responsibility... (and a big opportunity to screw up).

I'm pretty good with my DeWalt and Porter cable random orbital sanders, and Arabnet disks; that I feel like I can control, including down to the coarse stuff. It's a setup that works for me, an admitted wires and sparks guy.

[Steve Manning]

Belt sanders fall under the Spiderman rules: With great power, comes great responsibility... (and a big opportunity to screw up).

I'm pretty good with my DeWalt and Porter cable random orbital sanders, and Arabnet disks; that I feel like I can control, including down to the coarse stuff. It's a setup that works for me, an admitted wires and sparks guy.

Look close in the bottom right corner you will my Poter Cable with Arabnet disk attached. I picked up a sample pack of different grits to give them a try. I have the 80 grit on it at the moment.

[Hank]

You guys are really going for bamboo! My son in NYC told me Sunday that he may want me to build some speakers for him. I thought I was through with that, but if he insists, I may just try LBL.
You might want to try these new sanding discs from an obscure little company: http://www.3m.com/3M/en_US/company-u...3948891&rt=rud

[Steve Manning]

You guys are really going for bamboo! My son in NYC told me Sunday that he may want me to build some speakers for him. I thought I was through with that, but if he insists, I may just try LBL.
You might want to try these new sanding discs from an obscure little company: http://www.3m.com/3M/en_US/company-u...3948891&rt=rud

Thanks for the recommendation Hank

[Steve Manning]

So while Jon is out west chasing Unicorns ..... I've made a little progress on things here is the shop. At present I'm gluing up the side panels for the cabinets, (there two layers of lbl each). While the glue is drying on one I've cleaned up three sets of others I decided to take a look at the scale of the stand vs the cabinet. It always seems to be different in real life than in a drawing ........

First three are of the stand. At this point the top and bottom sections are glues together as is the center two layers of the vertical. The vertical outside pieces are just press fit together.







Here is the stand with one of the outside layers sitting on it. I figured putting the entire cabinet up there with no bolts was not going to work very well 8O





All in all though the cabinet profile is "chunky" I think the scale is not too bad.

[Steve Manning]

Also finished rough cleanup of the first cabinet Tuesday. Inside and out are sanded to 80 grit. I also did some tests using my hand plans on the lbl and it worked rather well. To get it to this point was ~ 7 hrs of work.

[ergo]

FIY AudioXpress has published test data for the Wavecor woofer we are using here.

http://audioxpress.com/article/Test-Bench-Wavecor-SW223BD02-8-75-Subwoofer.html

[JonMarsh]

Also finished rough cleanup of the first cabinet Tuesday. Inside and out are sanded to 80 grit. I also did some tests using my hand plans on the lbl and it worked rather well. To get it to this point was ~ 7 hrs of work.

Looking very nice, Steve- you're making some great progress while I chase down the Unicorns and Tesseracts. I guess we each have our crosses to bear... :W

Got your email about glue, will take care of that shortly.

I did get a good all day training with PLECS software yesterday, but I sure could have done without the drive to and from Menlo Park; I spent about 4-1/2 hours on the road yesterday.

http://www.plexim.com

And also found out the big scope has shipped- be here next Wednesday if UPS does their job properly.

[JonMarsh]

FIY AudioXpress has published test data for the Wavecor woofer we are using here.
http://audioxpress.com/article/Test-...Subwoofer.html

Thanks for the link! Clipped to Evernote!

[Steve Manning]

Looking very nice, Steve- you're making some great progress while I chase down the Unicorns and Tesseracts. I guess we each have our crosses to bear... :W

Got your email about glue, will take care of that shortly.

I did get a good all day training with PLECS software yesterday, but I sure could have done without the drive to and from Menlo Park; I spent about 4-1/2 hours on the road yesterday.

http://www.plexim.com

And also found out the big scope has shipped- be here next Wednesday if UPS does their job properly.

I see you have the rainbow part for the Unicorns taken nicely care of .......

I think I should have just gone ahead and ordered the 55 gallon drum of glue, the way this is going.

Lovely California driving ..... what is that ~ 45 mile drive from Danville :E