I just aquired a truck-load of some very neat, unused baltic birch ply. It is made for Mercedes transport truck flooring. I plan on doing a little research on this stuff and post the results here.
I played around with it a bit yesterday and this eveing this is what I know so far:
The quality of this material is higher than I've ever seen in any plywood(more on this when I post some pictures tomorrow)
The sheets have about 3'x5'' of useable area per panel ( these are pre-fab with holes drlled here and there, the 3'x5' section is with out holes). I ripped some of these to make the 3'x5' 'clean' panels and I also ended up with a lot of useable 12"x 24" sections.
The plys are much thinner than in standard Baltic Birch.
It is extremely strong and stiff for it's thickness of 7mm. strength test in a different thread.
Due to the mere 7mm thickness, the panels are quite flexy over a large area, therefore not so good for speakers with large panels, very well suited for bookshelf or small monitor type cabinets.
The face is covered with a very hard, smooth resin, the back with the same resin but it is textured and has some type of fine abrasive mixed in with it. This was made to be reversable depending on the type of duty the truck was to serve. The colour is an almost black cherry that is actually quite appealing, a few people have seen it in my shop and asked if I could make cabinetry out of it for them - based on the finish alone.
You can hit it with a hammer and not damage the finish. There are limits, of course.
Wood glue, contact cement and weldbond would not adhere well to the finish. I tried laminating two of these yesterday, I tried sanding, face to face, back to back...not so good ...but I did make a small (5"x5") cube with bevel(mitre) joints all around, so the contact areas were edge to edge, I assembled it with wood glue and a couple hours later I was throwing it at the floor trying to break it apart, it withstood the rough treatment admirably.
Although the standard type glues did not work well on the resined sides, plain clear silicone worked with acceptable results, and I had great results with some industrial adhesives like Sika-Flex.
Since I have the capability for making repeatable, accurate cuts quickly, I'm thinking of putting together some flat packs for a DiyAudio Reference monitor kit... if we can come up with a design we can agree on. These would be cheap because the wood cost me a symbolic amount, I have enough for at least fifty pairs of cabinets if kept small by design. The total cost would be composed of a symbolic something for my time and effort, a donation to the forum, and shipping...I could probably keep it at around $20 a pair plus ship, give or take.
Also, if anyone interested in helping with this project wants to check the material, I'll send out samples if you cover shipping.
I played around with it a bit yesterday and this eveing this is what I know so far:
The quality of this material is higher than I've ever seen in any plywood(more on this when I post some pictures tomorrow)
The sheets have about 3'x5'' of useable area per panel ( these are pre-fab with holes drlled here and there, the 3'x5' section is with out holes). I ripped some of these to make the 3'x5' 'clean' panels and I also ended up with a lot of useable 12"x 24" sections.
The plys are much thinner than in standard Baltic Birch.
It is extremely strong and stiff for it's thickness of 7mm. strength test in a different thread.
Due to the mere 7mm thickness, the panels are quite flexy over a large area, therefore not so good for speakers with large panels, very well suited for bookshelf or small monitor type cabinets.
The face is covered with a very hard, smooth resin, the back with the same resin but it is textured and has some type of fine abrasive mixed in with it. This was made to be reversable depending on the type of duty the truck was to serve. The colour is an almost black cherry that is actually quite appealing, a few people have seen it in my shop and asked if I could make cabinetry out of it for them - based on the finish alone.
You can hit it with a hammer and not damage the finish. There are limits, of course.
Wood glue, contact cement and weldbond would not adhere well to the finish. I tried laminating two of these yesterday, I tried sanding, face to face, back to back...not so good ...but I did make a small (5"x5") cube with bevel(mitre) joints all around, so the contact areas were edge to edge, I assembled it with wood glue and a couple hours later I was throwing it at the floor trying to break it apart, it withstood the rough treatment admirably.
Although the standard type glues did not work well on the resined sides, plain clear silicone worked with acceptable results, and I had great results with some industrial adhesives like Sika-Flex.
Since I have the capability for making repeatable, accurate cuts quickly, I'm thinking of putting together some flat packs for a DiyAudio Reference monitor kit... if we can come up with a design we can agree on. These would be cheap because the wood cost me a symbolic amount, I have enough for at least fifty pairs of cabinets if kept small by design. The total cost would be composed of a symbolic something for my time and effort, a donation to the forum, and shipping...I could probably keep it at around $20 a pair plus ship, give or take.
Also, if anyone interested in helping with this project wants to check the material, I'll send out samples if you cover shipping.
I'll send one out to you tonight,Dave, you tell me how it looks when it gets there.
7L ...of the top of my head...8 x 12.5 x 5, that's about the max I'd go strictly because beyond 8x12 the panel may get too flexy without bracing. I have a 7x11 panel in my hands now, I can very slightly bend it using my knee as the fulcrum... about 1mm deflection , end to end. When I knock on it the resonace f is very high for a piece of material this size, sounds like a block of hardwood. There is also the option of using a dowel to brace the large panels, not the most effective, but works.
I think if we keep a speaker kit really cheap there should be no excuse for many forum members to own a reference set up, we already have the cheap, repeatable gainclone, maybe we can settle on a cheap, readily available source too.
This way at least a number of us can have the same, good, resolute system that can be used to compare anything from recordings to cables to whatever tweaks we want to try...the only difference will be our ears. That's the dream, anyway. This has been mentioned on this and other forums many times, but I haven't seen it ever go through. Maybe DiyAudio can be the first.
7L ...of the top of my head...8 x 12.5 x 5, that's about the max I'd go strictly because beyond 8x12 the panel may get too flexy without bracing. I have a 7x11 panel in my hands now, I can very slightly bend it using my knee as the fulcrum... about 1mm deflection , end to end. When I knock on it the resonace f is very high for a piece of material this size, sounds like a block of hardwood. There is also the option of using a dowel to brace the large panels, not the most effective, but works.
I think if we keep a speaker kit really cheap there should be no excuse for many forum members to own a reference set up, we already have the cheap, repeatable gainclone, maybe we can settle on a cheap, readily available source too.
This way at least a number of us can have the same, good, resolute system that can be used to compare anything from recordings to cables to whatever tweaks we want to try...the only difference will be our ears. That's the dream, anyway. This has been mentioned on this and other forums many times, but I haven't seen it ever go through. Maybe DiyAudio can be the first.
Oh, If we kept the size at ~1L (3"tb or Hi-Vi) it would be pretty cool IMO. This way I could keep very close tolerances and use a drill press for the driver hole (I have some big forstner bits), overall cost would be less, ie. the shipping would be cheap, I could satisfy a lot more demand (multichannel anyone?), the drivers are cheaper.
Keep in mind, we're not out to build the best loudspeaker in the world, but a good sounding one that we can all use to test ideas...surely, they'll have to sound good and look proffesional but tha main goal is to have a reference, of course, purchases for non-reference use will be accepted
.
I have some generic 3"ers kicking around, I'll build a pair of little boxes tonight and take some pictures, just so everybody can have an idea of what the finished design may look like.
Keep in mind, we're not out to build the best loudspeaker in the world, but a good sounding one that we can all use to test ideas...surely, they'll have to sound good and look proffesional but tha main goal is to have a reference, of course, purchases for non-reference use will be accepted
. I have some generic 3"ers kicking around, I'll build a pair of little boxes tonight and take some pictures, just so everybody can have an idea of what the finished design may look like.
Hehe, yeah, the roads are awful this year...Main St. is 4x4 access only
I shipped a sample panel to David just now. They accepted it without packaging, $2.45 lettermail.
I'm off to the shop to knock-up( ) a couple little enclosures, I'll post results in a couple hours. The cool thing about mitre joints is that no clamping will be necessary for assembly, just tape and glue for perfect joinery.
I shipped a sample panel to David just now. They accepted it without packaging, $2.45 lettermail.
I'm off to the shop to knock-up(
) a couple little enclosures, I'll post results in a couple hours. The cool thing about mitre joints is that no clamping will be necessary for assembly, just tape and glue for perfect joinery.
Illusus said:
I think that is more reasonable... ~6x10x16 cm inside (ignoring the space the driver takes up).
The Auratone Tim was playing with is another candidate. The FE8xs might also be a consideration... also the Adire AV3. We should copile a list. A simple sealed cabinet wouldn't give the lowest bass, but the most consistent given driver-to-driver variation.
i think good but affordable is a laudable goal.
These would also make good 'puter speakers.
If we can choose one driver and an ameniable driver vendor a volume discount can probably be negotiated.
dave
"sounds a bit big for me" - those were approx golden ratio exterior dims.
Other stuff- My thoughts exactly. Bass extension shouldn't be a priority here anyway, midrange and hf resolution should be the main goal.
"These would also make good 'puter speakers."
Funny you should mention that. When I was heading out to put a couple boxes together I grabbed my crummy Cambridge Soundworks 'puter speakers and built around their drivers. ~2" driver, .5L boxes. They came out well, it took me about an hour of work, all my tooling was set up for a different project so I spent another hour taking down jigs etc.
These are so darn cute
I snapped a couple pics(the pics look a little wierd, the perspective is exaggerated).
This hard resin coating is not the easiest to work with, it's easy to chip with a saw, I used a fairly fine blade and it worked fine when I went really slow, a finer blade would make a clean cut easily but I didn't feel like changing blades...or going slow, so the edges show a little.
The tape and glue assembly is so easy with these, whatever glue squeezes out, let it dry and it just flakes off the resin coated outside. One could do the assembly on a kitchen counter with no tools other than glue, some masking tape, and a screwdriver for mounting the drivers.
While I was waiting for glue to dry, I spray-painted a sample with standard automotive paint, I scuffed the face with scotch-brite before applying paint, it adhered well to the resin.
BTW, the drivers sound much better than they did in the plastic-fantastic cubes they originally came in.
Other stuff- My thoughts exactly. Bass extension shouldn't be a priority here anyway, midrange and hf resolution should be the main goal.
"These would also make good 'puter speakers."
Funny you should mention that. When I was heading out to put a couple boxes together I grabbed my crummy Cambridge Soundworks 'puter speakers and built around their drivers. ~2" driver, .5L boxes. They came out well, it took me about an hour of work, all my tooling was set up for a different project so I spent another hour taking down jigs etc.
These are so darn cute
I snapped a couple pics(the pics look a little wierd, the perspective is exaggerated). This hard resin coating is not the easiest to work with, it's easy to chip with a saw, I used a fairly fine blade and it worked fine when I went really slow, a finer blade would make a clean cut easily but I didn't feel like changing blades...or going slow, so the edges show a little.
The tape and glue assembly is so easy with these, whatever glue squeezes out, let it dry and it just flakes off the resin coated outside. One could do the assembly on a kitchen counter with no tools other than glue, some masking tape, and a screwdriver for mounting the drivers.
While I was waiting for glue to dry, I spray-painted a sample with standard automotive paint, I scuffed the face with scotch-brite before applying paint, it adhered well to the resin.
BTW, the drivers sound much better than they did in the plastic-fantastic cubes they originally came in.
Attachments
With the 2" drivers, could the side be the front? With those big posts it is a bit of a caricature... needs to be mated with an amp that is too...
dave
An externally hosted image should be here but it was not working when we last tested it.
dave
I could have mounted the drivers on the narrow side, but I opted for for the other, I laughed a little because in this orientation the ratios reminded me of the big old cerwin vegas I once owned.
The binding posts do look silly,
, 'caricature' did come to mind, but I stuck them in for fun, I'll remove them eventually and just run some leads directly to the drivers through the holes and seal them.
They would look really cool with that amp or similiar. It would look something like what one could imagine Tim Burton's office system to be.(man, that last sentence is funky...damn that night cap)
The binding posts do look silly,
, 'caricature' did come to mind, but I stuck them in for fun, I'll remove them eventually and just run some leads directly to the drivers through the holes and seal them. They would look really cool with that amp or similiar. It would look something like what one could imagine Tim Burton's office system to be.(man, that last sentence is funky...damn that night cap)
My "letter" arrived today ... except for the tiniest bit of corner damage on 3 of 8 corners (only on the finished side) it looks to have passed thru the Canadian postal system unscathed. The "not shape enuff saw" glitches on the waffle face dwarf that by a whack.
BTW, the material looks to be OUTSTANDING. I will pass along to Chris for his opinion...
dave
BTW, the material looks to be OUTSTANDING. I will pass along to Chris for his opinion...
dave
Take a look at the long edge, if you haven't already, it has a seam in it, that's a pretty nice seam! I chose that piece for you so you can see how much detail they put into the construction.
Regarding my little test boxes. After thinking about what I built, I don't think I built them to encourage any excitement about a kit... I should've built them to look good, and build trust in my abilities, not just see how well the stuff was to work with. Still, they sound good.
This weekend I'm going to make some new boxes with a more aesthetic shape. They'll have the sides, top and bottoms made of the S-BB but I'll make the baffle and back from 1/2 or 5/8 BB with round over edges.
Anyway, I have the facilities to make nice flat packs for a kit, be it made of 'S-BB' or anything else. I'd definitely like to take advantage of them.
If there is an interest for a 'reference' kit I'll do it, if not maybe it'll be something for the market-place.
Regarding my little test boxes. After thinking about what I built, I don't think I built them to encourage any excitement about a kit... I should've built them to look good, and build trust in my abilities, not just see how well the stuff was to work with. Still, they sound good.
This weekend I'm going to make some new boxes with a more aesthetic shape. They'll have the sides, top and bottoms made of the S-BB but I'll make the baffle and back from 1/2 or 5/8 BB with round over edges.
Anyway, I have the facilities to make nice flat packs for a kit, be it made of 'S-BB' or anything else. I'd definitely like to take advantage of them.
If there is an interest for a 'reference' kit I'll do it, if not maybe it'll be something for the market-place.
I plan to do that by making a box 'frame' with mitre joints out of the superPly then simply closing it by gluing the bb front/back to it. The 'frame' will have mitred joints but the face and back edges will be flat(butt joint), so glue will work. I think this description makes sense...but then again I'm still playing with dosage
. I would've drawn a quick facsimilie of the concept but I just set up this 'puter...don't have my proggies on it yet (it's not a mac)It seems the w3-871 is pretty well liked, HiVi b3s seems ok too. Something small, readily available, inexpensive and very resolute in the mid-hi band are the obvious demands.
Something bigger (driver/alignment) is possible as well for a little extra cost...I have a good supply of 5/8"BB at wholesale cost...but I don't want to list too many options as that just causes indecisiveness.
Only problem I see with the superPly is the finish, sure it's durable and looks ok, but it may not be everyone's cup o' tea, and ther's no way to change it other than paint. With BB face and back that problem is not so severe, the baffle and back can be stained or veneered and finished to the end user's liking.
Seriously, if a good majority of interested parties can agree on driver and alignment, whatever it may be, I can make the kits with very little overhead.(I belive I'm repeating myself)
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