I thoroughly compared the specs between these two speakers and the currently available alpha 6A and made an informed decision to ignore them. If the Alphalites suck I'll buy the 18 sounds.
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I thoroughly compared the specs between these two speakers and the currently available alpha 6A and made an informed decision to ignore them. If the Alphalites suck I'll buy the 18 sounds.
Assembly:
Once I sanded/filed/routed down the tenons to fit the mortises assembly went pretty smoothly. The pieces assembled nicely with a mallet and the bracing didn't require any clamping or any manual locating whatsoever. Some inaccuracy was introduced when I filed down parts of the tenons but it didn't seem to make much difference. I applied loads of PL premium to all joints and drove them home. It should be noted that PL premium is NOT a great glue for joinery like mortise and tenon or box/finger joints becase it's viscous and doesn't really flow into the joints that well. This can cause problems with air sealing in the cabinet. For that reason I caulked along the interior seams to compensate and create a seal.
Even with the difficulties I had with the mortise and tenon and exterior box joints I would still do it that way again. In fact I would do full box joints along the entire exterior. The cabinet is tremendously rigid and stout, I had not difficulty whatsoever getting all the pieces in the right place, and the box joints look fabulous with the finishing I'm doing.
Lesson learned: I had difficulty removing the PL premium in areas where finish needed to be applied. This was a problem around the exterior box joints and especially the area where the baffle meets the sides. I got overzealous and caulked a ton of PL along the baffle/side joint. I do not recommend doing this. Only caulk joints along the interior. If you have PL that oozes out of the joints I actually found it to be better to just leave it in big globs rather than try to wipe it up while its wet. It might clean better with solvent on a rag but I used paper towel and it smeared. Then when it dried it was difficult to clean up the smeared material. I ended up paintstakingly scraping with a chisel and sanding. When I made the rack case (not pictured yet) I just let the globs dry in glob form. Then when I went to clean them up they all came up in big pieces much easier. Takeaway: PL premium is hard to clean up so either use a solvent rag or leave the globs and chisel them later. Don't smear it. Wear nitrile gloves and expect to use a ton of paper towels to clean up.
Here is the back panel bracing installed. Note the caulking.
Here is the back panel viewed from the outside. Note the water stains and visible tenons. This all ended up cleaning up very nicely after sanding. The tenons are very visible in the finish but I don't mind. If anyone asks about them it just gives me an opportunity to brag that I know what a mortise and tenon is.
Here is the damping foam. It's not shown but I also put foam in the mid chamber. The foam was too tall and would have pressed against the backs of the mid range drivers so I just cut the tips of the foam peaks off with a knife until it cleared the drivers. I attached the foam with spray adhesive. Make sure to spray some adhesive on a test piece of foam to make sure that it doesn't dissolve the foam.
Lesson learned: I think it would be better to cut all the pieces to size then set them aside and install them after assembling the cabinet. This design calls for several bracing pieces that span across the inside of the cabinet. I made these braces but forgot about them when I installed this foam. I have had to remove several pieces to make room for the interior bracing.
Here is the box all clamped up. I installed the back last and I designed the mortise and tenon features with this assembly order in mind. You need to be careful with this type of joinery or you can accidentally make a box which is impossible or very difficult to assemble. It was kind of difficult to glue the back piece in.
Lesson learned: If I could go back I would design the cabinet so that the last panel to install is butting up against a perpendicular surface not a parallel surface. In my design I installed the back panel last but it had to slide into place between the sides, top, and bottom. This smeared the PL premium. I plan to caulk along the inside after finishing before installing the drivers so it's probably not a big deal but it could be improved.
Here is the 5/16" round over. This was my first time using a router. It went pretty well but I would recommend getting more practice first. I burned a few spots by going too slower but it sanded out. The vertical edge shown here looks good but the other side is ratty from the water jet and the ratty edge was difficult to follow with the router bit. I ended up sinking the router too far in at one point. Oh well.
Once I sanded/filed/routed down the tenons to fit the mortises assembly went pretty smoothly. The pieces assembled nicely with a mallet and the bracing didn't require any clamping or any manual locating whatsoever. Some inaccuracy was introduced when I filed down parts of the tenons but it didn't seem to make much difference. I applied loads of PL premium to all joints and drove them home. It should be noted that PL premium is NOT a great glue for joinery like mortise and tenon or box/finger joints becase it's viscous and doesn't really flow into the joints that well. This can cause problems with air sealing in the cabinet. For that reason I caulked along the interior seams to compensate and create a seal.
Even with the difficulties I had with the mortise and tenon and exterior box joints I would still do it that way again. In fact I would do full box joints along the entire exterior. The cabinet is tremendously rigid and stout, I had not difficulty whatsoever getting all the pieces in the right place, and the box joints look fabulous with the finishing I'm doing.
Lesson learned: I had difficulty removing the PL premium in areas where finish needed to be applied. This was a problem around the exterior box joints and especially the area where the baffle meets the sides. I got overzealous and caulked a ton of PL along the baffle/side joint. I do not recommend doing this. Only caulk joints along the interior. If you have PL that oozes out of the joints I actually found it to be better to just leave it in big globs rather than try to wipe it up while its wet. It might clean better with solvent on a rag but I used paper towel and it smeared. Then when it dried it was difficult to clean up the smeared material. I ended up paintstakingly scraping with a chisel and sanding. When I made the rack case (not pictured yet) I just let the globs dry in glob form. Then when I went to clean them up they all came up in big pieces much easier. Takeaway: PL premium is hard to clean up so either use a solvent rag or leave the globs and chisel them later. Don't smear it. Wear nitrile gloves and expect to use a ton of paper towels to clean up.
Here is the back panel bracing installed. Note the caulking.
Here is the back panel viewed from the outside. Note the water stains and visible tenons. This all ended up cleaning up very nicely after sanding. The tenons are very visible in the finish but I don't mind. If anyone asks about them it just gives me an opportunity to brag that I know what a mortise and tenon is.
Here is the damping foam. It's not shown but I also put foam in the mid chamber. The foam was too tall and would have pressed against the backs of the mid range drivers so I just cut the tips of the foam peaks off with a knife until it cleared the drivers. I attached the foam with spray adhesive. Make sure to spray some adhesive on a test piece of foam to make sure that it doesn't dissolve the foam.
Lesson learned: I think it would be better to cut all the pieces to size then set them aside and install them after assembling the cabinet. This design calls for several bracing pieces that span across the inside of the cabinet. I made these braces but forgot about them when I installed this foam. I have had to remove several pieces to make room for the interior bracing.
Here is the box all clamped up. I installed the back last and I designed the mortise and tenon features with this assembly order in mind. You need to be careful with this type of joinery or you can accidentally make a box which is impossible or very difficult to assemble. It was kind of difficult to glue the back piece in.
Lesson learned: If I could go back I would design the cabinet so that the last panel to install is butting up against a perpendicular surface not a parallel surface. In my design I installed the back panel last but it had to slide into place between the sides, top, and bottom. This smeared the PL premium. I plan to caulk along the inside after finishing before installing the drivers so it's probably not a big deal but it could be improved.
Here is the 5/16" round over. This was my first time using a router. It went pretty well but I would recommend getting more practice first. I burned a few spots by going too slower but it sanded out. The vertical edge shown here looks good but the other side is ratty from the water jet and the ratty edge was difficult to follow with the router bit. I ended up sinking the router too far in at one point. Oh well.
Last edited:
- Feb 12, 2006
- 61,067
- 5
- 221,115
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
A hand held router can sometimes develop a mind of its own. They are deceptively simple yet can be frustratingly difficult.
A question for the team:
I bought some nice and not inexpensive Guilford of Maine / Duvaltex grille cloth for this project. Immediately after I bought it I realized that it may not be a great idea because of the excursion of the woofers and how much air they'll be moving. Has anyone had trouble with this? I'm building a stout wood frame with plenty of bracing to stretch the fabric over and I'm planning to attach it with six #10-24 screws through the grille frame into pressed-in T-nuts in the baffle. I'm thinking about cutting a name plate out of brass like the concept render shows and placing it between the woofers which I figure will help hold the fabric down.
Has anyone had experience with the fabric stretching or tearing? If it fails for whatever reason I'll build a metal grille but I've already got the fabric so I may as well use it.
I bought some nice and not inexpensive Guilford of Maine / Duvaltex grille cloth for this project. Immediately after I bought it I realized that it may not be a great idea because of the excursion of the woofers and how much air they'll be moving. Has anyone had trouble with this? I'm building a stout wood frame with plenty of bracing to stretch the fabric over and I'm planning to attach it with six #10-24 screws through the grille frame into pressed-in T-nuts in the baffle. I'm thinking about cutting a name plate out of brass like the concept render shows and placing it between the woofers which I figure will help hold the fabric down.
Has anyone had experience with the fabric stretching or tearing? If it fails for whatever reason I'll build a metal grille but I've already got the fabric so I may as well use it.
I can take screenshots and post more details about the design process if you're interested. Fusion can be frustrating. The key for me has been to figure out how to use external references for top-down design. This process is simple in programs like solidworks but Fusion requires you to take some extras steps to do the same thing. I was also frustrated to learn that the free version has a paywall for for the export command to export DXFs to send to water jet or laser. At least the "export body" function is included for those of us into the 3D printing game.Excellent work and attention to detail.
Fusion360 has a steep learning curve.
Home laser cutters keep coming down in price. Still more than the $600 you would have paid for the laser cutting job. Perhaps a thin layer of particle board attached with double sided tape would have worked as a sacrificial protective layer when cutting. Although it’s easy enough to sand off the rough bits.
Moist BB plywood has a way of warping. Best to assemble the cabinet soon after cutting.
I get into trouble when I do woodworking in any living space.
The free version paywalls were unknown to me till I hit them. I’m trying to learn FreeCAD, it’s getting better all the time.
I'll check out FreeCAD. You can get around the "ten editable documents" paywall in Fusion by creating multi-body parts. This 151566 cabinet has like 40 parts but because I made them all in one file it only counts as one editable document. This is especially useful for 3D printing since there's no limit on exporting STLs or STEPs.
Best grill cloth I ever used is actually "Pet Screen" for doors and windows. It's a very strong material made for patio screen doors and windows. Virtually indestructible. I used it on my fEARful 15/6. Cannot be torn and will look like brand new practically forever.
I've also painted different designs on it...
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Some fabrics can be pre-stretched before installation.
I lay down the grille cloth on a table, put the baffle or frame over it, then clamp the assembly down. pull the edges over and staple. Some fabrics can be heat shrunk after installation. A delicate process to get it even and without waves. I like to blow hot air from a distance to shrink it tight. I heat the oven, open the door and hold it in front moving back and forth. Some people use a blow drier or a heat gun. Too hot with a heat gun and ping, you get a hole. I’ve never tried heat lamps but they would work.
A frame that the grille cloth mounts on can help with speaker excursion. The frame is then installed onto the cabinet. There are velcro type snaps that can be used. They hold firmly. A stick frame can be built. Ampeg did that. A frame cut from a single piece of baltic birch works well. A waste of wood but the result is excellent.
Poplar strips around the outer edge can increase the grille cloth offset if the cloth is going over the baffle.
One way for grille frame attachment.
Invalid Link Removed
- Feb 12, 2006
- 61,067
- 5
- 221,115
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
I've built the grille frame from nice straight poplar furrings cut down to like 1/2" wide by 7/8" tall so that the grille will be recessed by 1/8". I left a gap of 1/4" all the way around between the frame and the sides of the baffle opening. I considered venting the grille a number of ways:
- Bass drum O's in the corners. I could even get shiny brass colored ones.
- Route reliefs into the back side of the grille frame to allow air to escape from behind the grille around the sides
- small standoffs between the grille frame and baffle to allow air to escape around the sides
- Feb 12, 2006
- 61,067
- 5
- 221,115
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
If the cabinet design needs to be vented for performance, than making it sealed is as big of a problem.
Power conditioners in general do nothing good, and can cause problems with some amps too. I have discussed this in detail, you might search the forum for these discussions.
I finished the last coat of lacquer and built up the grille. The lacquer and finish looks dazzling even without sanding and polishing but I'm not really happy with how the grille came out so I've come up with some modifications. It looks really nice from the front but I didn't want to wrap the fabric all the way around to the back so I stapled it to the sides of the stick frame. With the 1/4" gap I can see the staples and even some of the bare pine if I get the perfect angle. I bought enough fabric for four tries so I should be good there. I'm going to try to cut my stick frame pieces down so that they're 3/4" tall by 3/4" wide with six 1-1/8" tall standoffs - one in each corner and one at each midpoint of the long side - so that the entire frame floats above the baffle. Then I'll be free to wrap the fabric around the back of the frame and it will have a 3/8" air gap all the way around to hopefully avoid stretching the fabric, chuffing, or impeding excursion of the woofers while still maintaining an 1/8" offset/in-set from the front of the cabinet. I still think that six T-nuts and #10-24 screws are my preferred attachment method whether I go with fabric or metal in the future.
Test fit of the grille and brass corner guards. The grille fabric is not trimmed so it looks kind of bunched up in places. The fabric is Guilford of Maine Duvaltex fabric in "Tidepool" color. I initially wanted a purple color but I couldn't find a color that I liked (the closest was a maroon) so I went with green to get that "pool table" look. The corner guards are made by Gerstner. I chose them because they are shiny brass and they make both three leg and the two leg versions shown here. I did NOT choose them because they were affordable. I bought some cheaper not-as-shiny brass corner guards from Rockler which are larger but only available in 3 leg version. I like the Gerstner ones more despite the smaller size. I would have to modify the Rockler ones to fit on the front of the cabinet. I 3D printed a jig with the same geometry as the corner shown below so that in theory I could cut a leg off and hammer the edge to hook around the corner. I may still try it. The mostly laminar reflections in the lacquer let me know that it *should* be thick enough to sand flat and polish into that "glass" finish that I'm looking for. Yes I know that the finish will not be glassy after the first time taking this cabinet to a gig
Close-up of the visible staples in the side of the grille. Unacceptable!
Modifications to the grille frame. Note the reliefs cut in the mid brace and top stick to fit around the driver mounting flanges. It doesn't seem to need angled corner braces but it might after I thin it down. I'll update later if that turns out to be necessary.
The 16/4 cable and screw terminal Neutrik connector came in so I believe there's nothing standing between me and completing this project except time and effort. I'll make detailed posts about finishing, wiring, and review/final thoughts in the coming weeks.
I'm hoping to work on it more this Sunday and maybe a little during the week if possible. It's really coming together nicely.
Test fit of the grille and brass corner guards. The grille fabric is not trimmed so it looks kind of bunched up in places. The fabric is Guilford of Maine Duvaltex fabric in "Tidepool" color. I initially wanted a purple color but I couldn't find a color that I liked (the closest was a maroon) so I went with green to get that "pool table" look. The corner guards are made by Gerstner. I chose them because they are shiny brass and they make both three leg and the two leg versions shown here. I did NOT choose them because they were affordable. I bought some cheaper not-as-shiny brass corner guards from Rockler which are larger but only available in 3 leg version. I like the Gerstner ones more despite the smaller size. I would have to modify the Rockler ones to fit on the front of the cabinet. I 3D printed a jig with the same geometry as the corner shown below so that in theory I could cut a leg off and hammer the edge to hook around the corner. I may still try it. The mostly laminar reflections in the lacquer let me know that it *should* be thick enough to sand flat and polish into that "glass" finish that I'm looking for. Yes I know that the finish will not be glassy after the first time taking this cabinet to a gig
Close-up of the visible staples in the side of the grille. Unacceptable!
Modifications to the grille frame. Note the reliefs cut in the mid brace and top stick to fit around the driver mounting flanges. It doesn't seem to need angled corner braces but it might after I thin it down. I'll update later if that turns out to be necessary.
The 16/4 cable and screw terminal Neutrik connector came in so I believe there's nothing standing between me and completing this project except time and effort. I'll make detailed posts about finishing, wiring, and review/final thoughts in the coming weeks.
I'm hoping to work on it more this Sunday and maybe a little during the week if possible. It's really coming together nicely.
- Feb 12, 2006
- 61,067
- 5
- 221,115
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
The material needs to wrapped around and stapled on the back side, stretched taught and even. No way will stapling on the side work acceptably.
I finished my polishing regimen on the rack case to test it out. Here is the result compared to the (currently) unpolished cabinet:
Here is the full process from raw wood up to this finish:
Lessons learned:
Here is the full process from raw wood up to this finish:
- Sand from 80 to 220 grit
- Clean with tac cloth
- Rub/spray with distilled water to raise the grain
- Re-sand to 220 grit
- Clean with tac cloth
- Two coats sprayed on Transtint walnut dye diluted in distilled water
- Two coats sprayed on Zinsser Sealcoat dewaxed Shellac (absolutely must be dewaxed)
- Rub with something. I used 0000 steel woold but I would NOT recommend it because it left steel bits all over the finish. If I did it again I'd use a scotch brite pad.
- About a dozen or so coats sprayed on Watco clear gloss lacquer to get a thick buildup
- Occasional sanding between coats to keep things flat. I think this is of dubious usefulness and probably just makes things take longer. If I did it again I'd just slap lacquer on as thick and fast as I could without it running.
- Dry hand sand from 120 to 400 grit to level out the lacquer (worst step imo)
- Wet sand from 1000 to 2000 grit with random orbital sander and mineral spirits
- Rub with Maguiar's M105 ultra cutting compound with compounding foam pad with random orbital sander
- After this step it was very shiny and I felt like I could have stopped here. I already had the wax so I applied the wax but it didn't make a lot of difference. The M105 pulled a lot of weight.
- Clean up M105 with microfiber cloth
- Hand apply Maguiar's carnauba wax with foam applicator
- Buff out carnauba wax with random orbital sander with finishing foam pad
- This made minimal difference but it smells and feels nice
- Fingerprints are a problem
Lessons learned:
- Don't use steel wool to smooth out finishes. It leaves little steel bits all over the finish. Use a scotch brite pad.
- Dont press hard when cleaning up dust with tac cloth. It leaves a residue which will interfere with the next layer of finish. Press lightly. If you get residue on the surface you can clean it with mineral spirits as mineral spirits will dissolve the residue but won't affect the lacquer.
- Sanding between lacquer coats has minimal benefit if you're planning to sand it flat later. I would just slap the lacquer on as thick and fast as possible. Applying lacquer was absolutely the most time-consuming part. It took weeks.
- Build a booth if you're worried about debris and insects getting stuck in your finish. I personally didn't care because I figured the dark dye would cover that stuff up and I knew I'd be sanding and polishing anyway. I sprayed outside and wore a lot of PPE and didn't have any issues. Spraying after rain was nice because the rain knocked down the dust.
- Carnauba wax didn't make much difference in the finish. It was easy to apply and remove with the random orbital sander so I don't regret it but if I did it again I'd probably skip it.
The nice thing about lacquer is it’s easy to tough up when damaged.
Perhaps it depends on the product but I’ve found that too thick can cause a problem. The top layer can harden and trap solvent underneath. The finish can remain soft for a long time. To resolve this, the manufacturer recommended sanding the top to open up the finish.
When I apply lacquer to tweed, for example, thicker layers work better because it absorbs into the cloth and dries from on top.So if your wood os porous, a thicker first layer works well.
For water based polyurethane lacquer, some manufactures do not recommend sanding between coats.
That's the benefit with lacquer, it doesn't need sanding between coats, it dissolves into itself. Obviously you have to wait for the flash off time between coats.
