"forstner"?
but even a few broomsticks or dowels might not be sufficient - I'd probably suggest a 50-75mm wide piece of plywood, oriented as a vane in the mouth
Lae2,
A while ago, I posted a slightly altered plan to eliminate any impact of
ply thickness. See the post here -
http://www.diyaudio.com/forums/full-range/140862-sachiko-build-thread-7.html
Prasad
A while ago, I posted a slightly altered plan to eliminate any impact of
ply thickness. See the post here -
http://www.diyaudio.com/forums/full-range/140862-sachiko-build-thread-7.html
Prasad
Bamboo Plywood and Resonance
I have just spent hours reading more stuff on DiyAudio about Sachiko, Hiro, and wood. Also, I had a good day in the market. A sizable investment in Greek shipping may fund Hiro. Anyway, in all of the bantering about building material and Renaissance frequencies I have not seen much said about bamboo plywood other than Dave taking it under consideration.
So I studied bamboo plywood construction. As near as I can tell there is no direct comparison to counting the plies of traditional plywood. But let me ask this. Would the resonant frequency of a 4X8 piece of .75" bamboo plywood be higher that the resonant frequency of a same sized piece of 13 ply Russian Baltic birch? Further, is it expected that the vertical and horizontal directed bamboo plywood would have significantly different resonant frequencies to the point of influencing which to use for a cabinet? Frankly, I am considering the fossilized stuff.
I may sell my Greek stock and build Hiro with 1" bamboo sides, top, bottom, baffle, and back. And 3/4" panels to maintain the horn dimensions.
Bamboo plywood resonates with me. I drive a spaceship. My last 80 mile drive to Allentown was at 92 mpg. I drove 12 miles to Lowes the other night and parked at 96 mpg. I am kind of green and feeling bad about building class a amplifiers. But maybe I could live with myself if I built Hiro with bamboo plywood. Could I expect the cabinets to have a higher resonant frequency and the sound to be less coloured (colored for us Yankees)?
I have just spent hours reading more stuff on DiyAudio about Sachiko, Hiro, and wood. Also, I had a good day in the market. A sizable investment in Greek shipping may fund Hiro. Anyway, in all of the bantering about building material and Renaissance frequencies I have not seen much said about bamboo plywood other than Dave taking it under consideration.
So I studied bamboo plywood construction. As near as I can tell there is no direct comparison to counting the plies of traditional plywood. But let me ask this. Would the resonant frequency of a 4X8 piece of .75" bamboo plywood be higher that the resonant frequency of a same sized piece of 13 ply Russian Baltic birch? Further, is it expected that the vertical and horizontal directed bamboo plywood would have significantly different resonant frequencies to the point of influencing which to use for a cabinet? Frankly, I am considering the fossilized stuff.
I may sell my Greek stock and build Hiro with 1" bamboo sides, top, bottom, baffle, and back. And 3/4" panels to maintain the horn dimensions.
Bamboo plywood resonates with me. I drive a spaceship. My last 80 mile drive to Allentown was at 92 mpg. I drove 12 miles to Lowes the other night and parked at 96 mpg. I am kind of green and feeling bad about building class a amplifiers. But maybe I could live with myself if I built Hiro with bamboo plywood. Could I expect the cabinets to have a higher resonant frequency and the sound to be less coloured (colored for us Yankees)?
Nice looking. I see that the edges can be decorative frames rather than something in need of a veneer. Is your decision based on sonics or aesthetics? Are these cabinets more "neutral" than a Baltic birch version? I predict that they would be. Indeed do they have a higher resonant frequency? I can't tell in this particular case whether that is vertical or horizontal grain?
Expensive, yes. But I am looking at over 500.00 to get 4 sheets of 13 ply Russian B/BB Baltic birch shipped to my doorstep. Local lumber companies tell me that that is a good price - 125.00 per 4X8 sheet shipped. I might as well see if I can find a closer vendor for the bamboo that would be reasonable for a warehouse pickup. I am also looking into finding a cabinet maker to broker a purchase.
Sonics are better. Stiffer & lighter (a guess i haven't actually confirmed that).
Another...
As well a manufacturer Scott & i are working with is using bamboo,
dave
Another...
An externally hosted image should be here but it was not working when we last tested it.
As well a manufacturer Scott & i are working with is using bamboo,
dave
Wow! That is sweet. This has more clearly a look of vertical grain. I don't how you/Chris got the inner/outer plies of the sides to match up with the top and bottom unless you went to single ply. Neat. It would be even more aesthetic if there was a way to continue with a uniform thickness for the vent borders. It looks like the rearward ply is uniform. I don't know how you did that. But, it sure looks good.
Cali Plywood - Fossilized
It looks to to like Dave's bamboo speakers might be built with Cali Bamboo. As it turns out, there is a Cali warehouse about 40 mi from me. That removes hundreds of dollars in shipping costs. The price becomes not all that much more than shipped Russian Baltic birch. So far, I see this as really good news for me. Just being able to source something that is possibly appropriate is a relief.
I am looking at the Cali Fossilized .75 for the sides, back, top, and baffle. It comes in 4X6. How convenient to have a 72" height ready to go for Hiro/Sachiko. I am hopeful that I could get by with a couple of 4X6 and a single 4X8 of the carbonized. I do not yet know if this plywood is 18mm or 19mm. The fossilized version might be milled in which case it could be 19.05 mm. That would be great for following Scott's and Dave's blueprints out to several decimals of precision. I will find out on Monday.
The organization of the wood is shown by clicking on one of the images.
Bamboo Plywood
This is more expensive than Russian 13 ply Baltic birch but it looks like the finishing work might be much easier. No veneer work, both sides equally prepared, and sand in an oil. The nature of the construction suggests to me that voids are not a concern. The outside walls, inside walls, and deflectors should all match up nicely. Maybe natural fossilized walls paired up with carbonized baffle, deflectors, and panels. I must think about a cut sheet. Time to fire up the vector drawing software (Illustrator in this case).
The less than enthusiastic reception for using MDF or HDF as cabinet material gives me pause about using the fossilized bamboo plywood. The fossilized version is suppose to be especially dense. Anyone have thoughts about the sonic implications?
It looks to to like Dave's bamboo speakers might be built with Cali Bamboo. As it turns out, there is a Cali warehouse about 40 mi from me. That removes hundreds of dollars in shipping costs. The price becomes not all that much more than shipped Russian Baltic birch. So far, I see this as really good news for me. Just being able to source something that is possibly appropriate is a relief.
I am looking at the Cali Fossilized .75 for the sides, back, top, and baffle. It comes in 4X6. How convenient to have a 72" height ready to go for Hiro/Sachiko. I am hopeful that I could get by with a couple of 4X6 and a single 4X8 of the carbonized. I do not yet know if this plywood is 18mm or 19mm. The fossilized version might be milled in which case it could be 19.05 mm. That would be great for following Scott's and Dave's blueprints out to several decimals of precision. I will find out on Monday.
The organization of the wood is shown by clicking on one of the images.
Bamboo Plywood
This is more expensive than Russian 13 ply Baltic birch but it looks like the finishing work might be much easier. No veneer work, both sides equally prepared, and sand in an oil. The nature of the construction suggests to me that voids are not a concern. The outside walls, inside walls, and deflectors should all match up nicely. Maybe natural fossilized walls paired up with carbonized baffle, deflectors, and panels. I must think about a cut sheet. Time to fire up the vector drawing software (Illustrator in this case).
The less than enthusiastic reception for using MDF or HDF as cabinet material gives me pause about using the fossilized bamboo plywood. The fossilized version is suppose to be especially dense. Anyone have thoughts about the sonic implications?
What a wonderfully parsimonious and succinct statement. Thanks. I just finished reading over 500 posts in the building materials thread. I wish you would have nailed it in that discourse. I hope that o'l cross bones is still lurking about. I kind of like him.
I imagine that you have seen the Green Glue animations on panel dampening (or damping). Kind of fun. They make a statement about green glue and speaker cabinets but then I can not find any relevant application notes. I am a little confused about why one might want to take a stiff wall and glue a joint with flexible compound. I can understand gluing panel layers but not joints between panels. I am going to interview a Cali "specialist" on Monday. Poor guy. Glue is on the top of my list. Maybe I can get some closure. Thanks for your comment.
I imagine that you have seen the Green Glue animations on panel dampening (or damping). Kind of fun. They make a statement about green glue and speaker cabinets but then I can not find any relevant application notes. I am a little confused about why one might want to take a stiff wall and glue a joint with flexible compound. I can understand gluing panel layers but not joints between panels. I am going to interview a Cali "specialist" on Monday. Poor guy. Glue is on the top of my list. Maybe I can get some closure. Thanks for your comment.
Try Fessenden Hall in Lancaster Pa. They have a "exterior" grade birch ply in both 19mm and 25mm 4X8 sheets which i'm told are void free just not furniture grade, don't know haven't seen it.
Also i've a good wholesale source of Russian Baltic Birch located not too far over the bridge from Philly in NJ. Last time i bought a 1/2 pallet of 5x5's and had planned to do a group buy with a guy in DC when i get the time to coordinate it and assuming the cost are still good. I'll keep you posted if it's something you may be interested in.
4X8 13 ply Russian Baltic Birch is offered here.
Buy Baltic Birch Plywood Hardwood Lumber Wholesale Price NY NJ PA
Thanks for the suggestion. Fessenden Hal is also on my list to call because I think they are an Appleply distributor. Plus, they are only about 50 mi from me. At this point I am very much interested in the bamboo plywood. I like the green aspect. Plus, it seems that I might be able to finish it to a good result without much expense or time. Further, it may have sonic advantage. Rather than being green I could be patriotic with Appleply. I want to do something soon. I just received a shipment of FETs that puts me closer to building amplifiers.
I have read scattered posts from your Hiro adventures but I have yet to read a post that describes your construction of Hiro. Did you do a diagonal cut on 60" BB? I am also interested in your approach to panel A. I am having someone else cut the wood. I may keep panel A simple for the cutter and then retrofit a speaker brace. I am thinking of designing an adjustable dual point system that would couple the speaker to the A panels by metal points having balanced pressure contacts.
I am still confused about the reasoning for a pliable gasket between the speaker and the baffle. If left to my own devices, I would have made a gasket from Masonite. Why strive to make a rigid connection with the chassis at Panel A while using a pliable coupling at the baffle. I don't get that. It seems that the pliable gasket would soften energy transfer. Then again, maybe a rigid coupling at panel A gives the best of two worlds. Because of less recoil, the speaker's motor is more devoted to sound production and, at the same time, the baffle vibrates less because of a soft gasket. I don't know. Dave refers to push/pull but I don't know that push/pull applies to air. It is push more and then push less. If I remember correctly from a million years ago, there is still back pressure during rarefaction. Thus, I like the idea of the speaker braces on panel A.
I think I read that you have auditioned Sachiko but I did not see anywhere that you commented about Hiro compared to Sachiko. I have not decided on panel width yet but 9" is likely. The AudioTalk thread on Sachiko further convinces me to build Hiro.
That you are nearby also encourages me to build Hiro because I could, with your invite, evaluate my work at some point. As I recall you have a more high-end driver than the 168eS.
In the beginning I was simply looking for a pair of efficient commercial speakers so that I could get on with amplifiers. This speaker binge has got a little out of control for me.
Pit, has the Russian ply risen to the quality of Finnish ply or succumbed to the mediocrity of Finnish ply?
Might you have a comment on the sonic implications of bamboo plywood. Snake oil? Tea Bag recommended that I get out the duct tape and cardboard boxes. I suspect that this is good advice. Speaker building was not in my plans beyond the practical conclusion of having a decent pair of efficient speakers. I can't stop myself from wanting to understand some little bit about what I am hoping to achieve.
AFAIK the bamboo ply we used was made in California. If you can afford the downsides (cost & care) go for it. Beaytifuk & beautiful sounding.
By the time the driver is tightened down, the gasket is not pliable. A bit of decoupling from the baffle wouldn't hurt... the baffle is the weakest panel and most audiable if excited. Masonite would be less effective than no gasket
dave
Yes, Yes and used the slant rather than steps to fit a 5' piece of BB for the back panel and cut down on weight some. I left a very small gap on the optional braces and closed the gap with a cork sheet that i got at staples. Used many clamps and no screws or nails. I've a compound sliding miter saw, contractors table and lightweight panel saw so the cuts were easy. For now i'm using the foam strip gasket supplied with the drivers but will prob change that at some point because it's so thin. I put eichmann cable pods at the back behind the driver. I'd like to veneer them with something nice at some point. Again if funds permit and assuming i don't become more interested in something else as i only have two rooms which are large enough for them and just. I'd like to build something that'll couple with the smaller rooms too. Always entertaining the idea of doing a Austin166 but the only walls that will reflect the bass are the same two rooms i alternate the Hiro between.
I'm using the limited ed 166es-r which has some definite advantages over stock and is different than the E∑ series. More flat across the bw and higher 95.5db sensitivity with large 1.982lb colbalt lanthanum magnet. It's a shame they didn't give it a cast chassis but i'd say they put the money in the right places on this one. Cost was around the same as the E∑.
Never listened to the Sachiko, you may be confused by tubeguy#?'s dialog with me only i go to south Florida and iirc he's more central so that hasn't happened. A local HiFi shop has or had a pair of C&C Abby's which is the closest i've come to other Fostex driver based designs. I never got around to stopping in for a listen because i know i'm not about to buy anything there. It's not as though he can carry mine plus the pair won't fit in the car so i can't compare the two. I don't think it's fair to compare them to set-up's i've heard at shows. I can say they're better than the proac resp 1sc i used to keep in the bedroom and my other vintage speakers, i'm glade i ordered the drivers even though i had to go with such a large box. I had considered the swan turkey or whatever it is called 'till i read of that design's problems. I'd like to save my comments on sound 'till i feel they're fully broken in and i have more here to compare and contrast.
The basic design were interesting enough for T.C. to do a double ben and J.C. to put out a line. The physical size is imposing but i'm sure you won't regret building them.
I'm using the limited ed 166es-r which has some definite advantages over stock and is different than the E∑ series. More flat across the bw and higher 95.5db sensitivity with large 1.982lb colbalt lanthanum magnet. It's a shame they didn't give it a cast chassis but i'd say they put the money in the right places on this one. Cost was around the same as the E∑.
Never listened to the Sachiko, you may be confused by tubeguy#?'s dialog with me only i go to south Florida and iirc he's more central so that hasn't happened. A local HiFi shop has or had a pair of C&C Abby's which is the closest i've come to other Fostex driver based designs. I never got around to stopping in for a listen because i know i'm not about to buy anything there. It's not as though he can carry mine plus the pair won't fit in the car so i can't compare the two. I don't think it's fair to compare them to set-up's i've heard at shows. I can say they're better than the proac resp 1sc i used to keep in the bedroom and my other vintage speakers, i'm glade i ordered the drivers even though i had to go with such a large box. I had considered the swan turkey or whatever it is called 'till i read of that design's problems. I'd like to save my comments on sound 'till i feel they're fully broken in and i have more here to compare and contrast.
The basic design were interesting enough for T.C. to do a double ben and J.C. to put out a line. The physical size is imposing but i'm sure you won't regret building them.
For those that live in the USA and Canada, don't forget Appleply. IMO it is a higher quality plywood than baltic birch and comparably priced. I also have had good luck with enclosures made from asian 'mahogany' plywood (Luan, Meranti, et al Shorea sp) as well as marine grade fir ply.
Oops. Must've missed the earlier post, allow me then to second the suggestion of appleply.
Oops. Must've missed the earlier post, allow me then to second the suggestion of appleply.
Follow-up on bamboo plywood
The Cali bamboo plywood is readily available in PA. The .75" size is indeed .75" or 19.05 mm. Thus, no redrawing or compromising of Dave's drawing. It was suggested to me that non-fossilized 4X8 could be used for a table top with simply 4 support posts and would not flex if you jumped on it. That seems to be a bit of claim. Get out the transducers for that. The fossilized is even more stiff, is 4X6 rather than 4X8, but nevertheless workable with standard woodworking tools. The edges are said to be clean from the factory such that essentially none of the 72" length would be lost to finishing for the fossilized; convenient for Sachiko and Hiro. The surfaces are equally finished on each side. The weight of the 4X8 is approximate 85 lbs. I am still working on determining the weight of the fossilized 4X6. I imagine it will be heavier per sq foot.
I am drawing cutsheets to maximize the 4x6 size with maybe a 4x8 to create a two-tone version. I need help with that kind of thought. Now I need to find someone to cut the wood, place an order, and things will be shaping up.
The Cali bamboo plywood is readily available in PA. The .75" size is indeed .75" or 19.05 mm. Thus, no redrawing or compromising of Dave's drawing. It was suggested to me that non-fossilized 4X8 could be used for a table top with simply 4 support posts and would not flex if you jumped on it. That seems to be a bit of claim. Get out the transducers for that. The fossilized is even more stiff, is 4X6 rather than 4X8, but nevertheless workable with standard woodworking tools. The edges are said to be clean from the factory such that essentially none of the 72" length would be lost to finishing for the fossilized; convenient for Sachiko and Hiro. The surfaces are equally finished on each side. The weight of the 4X8 is approximate 85 lbs. I am still working on determining the weight of the fossilized 4X6. I imagine it will be heavier per sq foot.
I am drawing cutsheets to maximize the 4x6 size with maybe a 4x8 to create a two-tone version. I need help with that kind of thought. Now I need to find someone to cut the wood, place an order, and things will be shaping up.
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