AudioCircle
Industry Circles => Tortuga Audio => Topic started by: tortugaranger on 8 Sep 2015, 09:04 pm
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I've been working with a customer who is looking for a set of custom speaker cabinets that utilize a curved laminated cabinet shaped like a boat hull...hence "boathull speakers". These will be milled out of baltic birch plywood and finished naturally showing the thin laminate look of this fine hardwood plywood. The top, bottom and baffle will be veneered. The pics below don't reflect the external "look" of the final version but the structure and shape are accurate.
Once we get these done I may build a similar but larger mid-size cabinet suitable for a Audio Nirvana full range driver.
Anyone interested in something similar feel free to contact me. Keep in mind these are not low cost cabinets. I won't do these in MDF - the dust is terrible even with a good vacuum system.
Here are a few CAD pics. The last one is a top view with the top removed showing the internal brace located between the 2 drivers.
(http://www.audiocircle.com/image.php?id=127657)
(http://www.audiocircle.com/image.php?id=127655)
(http://www.audiocircle.com/image.php?id=127654)
(http://www.audiocircle.com/image.php?id=127656)
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I am looking for a pair of cabinets for an Audio nirvana 15 inch classic driver. The Audio Nirvana cabinet designs suggest a 5.6 cubic foot bass reflex box. I don't know if this design would be appropriate or not. I have already spoken with a couple of cabinet makers but I would like something really special.
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In your design, are the front baffles Baltic birch plywood, or could another material be used? Specifically, I'm curious about using Plyboo (bamboo plywood) with matching tops and bottoms.
Thank you.
Michael
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I am looking for a pair of cabinets for an Audio nirvana 15 inch classic driver. The Audio Nirvana cabinet designs suggest a 5.6 cubic foot bass reflex box. I don't know if this design would be appropriate or not. I have already spoken with a couple of cabinet makers but I would like something really special.
Experts say this 5.6 box is not suited to the TS pars from this driver, but if its for guitar use...
I would suggest the Super10Alnico to stick with manudacturer.
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I am looking for a pair of cabinets for an Audio nirvana 15 inch classic driver. The Audio Nirvana cabinet designs suggest a 5.6 cubic foot bass reflex box. I don't know if this design would be appropriate or not. I have already spoken with a couple of cabinet makers but I would like something really special.
I had roughed out a layout for a 12" Audio Nirvana the other day which ended up with a ~48" tall boathull stack. Obviously the 15" driver would need a wider baffle. Something like 18-20". I think the 12" boathull had a 20" depth. If I wider then baffle to accommodate the 15" driver the volume per slice will go up probably from 200 sq inch to over 250 which will reduce the height several inches. To keep total height up towards 48" would have to reduce the depth. Definitely doable. And it would definitely be something really special.
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Experts say this 5.6 box is not suited to the TS pars from this drivers, but if its for guitar use...
I would suggest the Super10Alnico to stick with manudacturer.
One thing I have noticed looking at the Audio Nirvana's is the Qts vary considerably depending on whether you go with Alnico or Neodymium. On the 15" driver it's 0.98 and 0.34 respectively. That's going to have a huge impact on optimum size. The optimum volume on the 15" Alinco's is enormous. Neo's are more reasonable.
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Why the 15'' model?
The best TS data in this brand are the new Classic10Alnico, which VAS also big.
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In your design, are the front baffles Baltic birch plywood, or could another material be used? Specifically, I'm curious about using Plyboo (bamboo plywood) with matching tops and bottoms.
Thank you.
Michael
Yes, the approach with veneer is use baltic birch but no reason you can't go with bamboo ply without veneer. We have some 1/2" bamboo ply in our shop and for the most part it mills ok. It does have a tendency to chip out along the cut edge but worst case that can all be milled out. For that matter we can make the whole thing out of bamboo but it's pricey stuff. Cost us $500 to land 2 4x8' sheets of 1/2" - almost half of that was commercial trucking so it pays to buy in volume. You'd want 3/4" or 1" for baffle material etc.
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Why the 15'' model?
The best TS data in this brand are the new Classic10Alnico, which VAS also big.
Not sure if "bigger is better" applies here but that's probably the thought behind it.
I've had Super 8 Alnico's running in mid size ported box for a few years now and I think they're amazing. Have not tried their newer Classic line without the whizzer cone. Do you think the Classic's are superior to the Supers?
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I think the lack of whizzer cone prevent the beaming.
The Classic line seem a upgrade from the Super.
Definitely I prefer the Classic Alnico, mainly the 10'' model.
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Here is a link to a similar project albeit done for GR Research drivers:
http://www.audiocircle.com/index.php?topic=79983.0
Best,
Ed
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Not sure if "bigger is better" applies here but that's probably the thought behind it.
I've had Super 8 Alnico's running in mid size ported box for a few years now and I think they're amazing. Have not tried their newer Classic line without the whizzer cone. Do you think the Classic's are superior to the Supers?
Hi,
Here is a comparison Super10Alnico x Classic10Alnico for your evaluation,
you will note Super are stronger at bass and hi freq while Classic is smoother.
Also smoother at the Impedance chart.
(http://www.audiocircle.com/image.php?id=127976&size=xlarge)
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I think the lack of whizzer cone prevent the beaming.
It does not... but it is likely the highs will be rolled off on a 6.5" or larger driver without a whizzer.
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It does not... but it is likely the highs will be rolled off on a 6.5" or larger driver without a whizzer.
So remove Super10Alnico whizzer will be a great tweak?
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So remove Super10Alnico whizzer will be a great tweak?
No, I think you need a whizzer on a larger single driver. You can see the classic 10 is very rolled off, I couldn't deal with that but I suppose some like it.
Morten, nice cabinet! I have access to a Shopbot CNC router which I am very excited about. Going to be making waveguides and cabs out of stacked ply... :)
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No, I think you need a whizzer on a larger single driver. You can see the classic 10 is very rolled off, I couldn't deal with that but I suppose some like it.
Morten, nice cabinet! I have access to a Shopbot CNC router which I am very excited about. Going to be making waveguides and cabs out of stacked ply... :)
OK thanks for your evaluation.
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Yes, the approach with veneer is use baltic birch but no reason you can't go with bamboo ply without veneer. We have some 1/2" bamboo ply in our shop and for the most part it mills ok. It does have a tendency to chip out along the cut edge but worst case that can all be milled out. For that matter we can make the whole thing out of bamboo but it's pricey stuff. Cost us $500 to land 2 4x8' sheets of 1/2" - almost half of that was commercial trucking so it pays to buy in volume. You'd want 3/4" or 1" for baffle material etc.
Bit off topic, but relevant to baltic birch and veneering....
These are 3/4" (19mm) baltic birch dipoles that I built to Siegfried Linkwitz's LX521 design. The top parts and bridge are hand veneered using hide glue and French polished by moi, because I'm a traditionalist. The dark wood is solid Cocobolo rosewood. The feet at the bottom of the bridge are Goncalo Alves. The bass dipoles are also baltic birch and are painted in black milk paint.
Craig
(http://www.audiocircle.com/image.php?id=128002)
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A few pics of the custom set of "boathull" speakers we're making for a customer. These are 0.32 cubic foot cabinets for a 2-way design. These will look very cool when finished. The baffle and top/bottom will be veneered in zebra wood to compliment that striped laminate look of the baltic birch. Took a bit of trial and error on laying out the boathull toolpaths but after the first few we adjusted the layout/spacing and it went smoothly. Always nice working with wood. :thumb:
After building the initial stack but without ends and before sanding. The peppering you see is part of the plywood color variations and are not voids. Very few voids in the baltic birch plywood and what few their are will fill in nicely and disappear.
(http://www.audiocircle.com/image.php?id=130912)
The first boathull stack - 17 layers. Each glued and power nailed. Extremely strong/rigid even without baffle, ends or internal brace.
(http://www.audiocircle.com/image.php?id=130913)
Tried to maximize utilization of the wood while maintaining the integrity of the sheet to keep it clamped down in place while milling. The lower right corner area shows initial attempts at getting even more utilization but this proved unworkable as adjoining pieces would not hold together during milling.
(http://www.audiocircle.com/image.php?id=130914)
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Suhweet! Digging it! I know it's not easy! :thumb:
Best,
Anand.
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Thank you for posting the update. This had slipped my mind. (happens to me a lot it seems)
I like how this looks, but I don't have a clue how much this might cost for a pair. Are you comfortable putting a probable cost for the pair in this thread either or in a PM? A ballpark price is fine at this point. My next pair of speakers will have 6.5" to 8" midwoofers in a two-way monitor. Im still debating different speakers' merits.
Michael
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Thank you for posting the update. This had slipped my mind. (happens to me a lot it seems)
I like how this looks, but I don't have a clue how much this might cost for a pair. Are you comfortable putting a probable cost for the pair in this thread either or in a PM? A ballpark price is fine at this point. My next pair of speakers will have 6.5" to 8" midwoofers in a two-way monitor. Im still debating different speakers' merits.
Michael
We're still asessing the material and shop hours needed to build these boathull cabinets but even these small cabinets eat up close to $200 of raw materials. Then there's the custom CAD design work and toolpath layout, CNC time, jig building, assembly, sanding, veneering and finishing.
There's also the inefficiency of custom one-off designs vs. the more efficient production building of a fixed design.
For budgeting purposes figure on at least $1k for a small custom pair sans drivers or crossovers and that's probably optimistic. :o
There's a good reason nearly all speakers are simple rectangular boxes of mdf.
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Zebra wood veneer selected for the top, bottom and baffle. Should look quite sharp when done with both the horizontal and vertical lines and complimentary wood tones.
(http://www.tortugaaudio.com/images/boathull_zebrawood.jpg)
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Nice photos. Just a idea:
The best enclousure shape is the sphere, do
you wouldnt like to make spherical enclosures
with resin or fiberglass?
It seems less expensive.
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Nice photos. Just a idea:
The best enclousure shape is the sphere, do
you wouldnt like to make spherical enclosures
with resin or fiberglass?
It seems less expensive.
While a sphere may be indeed be acoustically ideal, I find the whole idea of making big resin/fiberglass "beachball" enclosures very unpleasant and aesthetically unsatisfying. And while the material costs may indeed prove to be less than wood I suspect the labor costs would be higher when you start talking about building up layers. Plus you'd be working with harsh stinky stuff. And as I think about it, achieving a flawless smooth sphere could be tough to accomplish in practice. Perhaps someone with a background in fiberglass boat building and/or bodywork would have a better sense of how this could be done effectively.
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Just curious why cut the "Brace" in a separate panel to insert? Why not just make it a single piece simply cutting it into the same piece of ply used for that external "U" as well? Seems you would end up with an even more solid construction, and simply remove the fitment variations in the end.
Thanks
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Just curious why would you cut the "Brace" in a separate panel to insert? Why not just make it a single piece simply cutting it into the same piece of ply used for that external "U" as well? Seems you would end up with an even more solid construction, and simply remove the fitment variations in the end.
Thanks
An excellent point! Although once properly glued in place a conforming brace would be arguably indistinguishable from an integral continuous "slice" from a structural standpoint. The real answer in this instance is I didn't know exactly where the internal brace was going to be located since there's still some back on forth on a few design details so a flexible "put it anywhere" brace was the way to go. As it turns out I may need to redesign the brace to accommodate the port so good thing it's not already permanently built into the stack or glued in place.
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I agree... I guess though with a larger cabinet it would be a big time saver to just cut multiple braces using them integral to each piece if you know they will be out of the way. Nice cabinets.
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Any shape that reflects back-waves back towards the driver(s) is a less desirable than one that directs the back-waves away from the driver. The back-waves will transmit through the driver (the thinnest, most acoustics transparent part of the cabinet - except for a port), causing a muffled/delayed copy of the front-wave to smear the intended sound. Non-parallel front/rear baffles is one solution.
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I was surprised that Ellipson were still going - although for recent times their speakers are spherical, the ones I remember from the dim and distant past were in fact elliptical (hence the company name)
https://s-media-cache-ak0.pinimg.com/originals/0d/17/29/0d1729f8acfaf27aee1dcbfc69131e4a.jpg
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I agree... I guess though with a larger cabinet it would be a big time saver to just cut multiple braces using them integral to each piece if you know they will be out of the way. Nice cabinets.
Next time around, we'll definitely take this approach. :thumb:
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I was surprised that Ellipson were still going - although for recent times their speakers are spherical, the ones I remember from the dim and distant past were in fact elliptical (hence the company name)
https://s-media-cache-ak0.pinimg.com/originals/0d/17/29/0d1729f8acfaf27aee1dcbfc69131e4a.jpg
Wow fantastique enclousure, its 6'' fullrange, fiberglass?
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I was surprised that Ellipson were still going - although for recent times their speakers are spherical, the ones I remember from the dim and distant past were in fact elliptical (hence the company name)
https://s-media-cache-ak0.pinimg.com/originals/0d/17/29/0d1729f8acfaf27aee1dcbfc69131e4a.jpg (https://s-media-cache-ak0.pinimg.com/originals/0d/17/29/0d1729f8acfaf27aee1dcbfc69131e4a.jpg)
I have to say, these may be the ugliest speakers I've ever seen. For me personally, even if these were the best sounding speakers ever made, I'd cringe every time I opened my eyes and had to look at them. Something right out of the 1960's Jetsons. I like contemporary styling by OMG these are awful. :lol:
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I have to say, these may be the ugliest speakers I've ever seen. For me personally, even if these were the best sounding speakers ever made, I'd cringe every time I opened my eyes and had to look at them. Something right out of the 1960's Jetsons. I like contemporary styling by OMG these are awful. :lol:
Definitely from the 60's visually, in shape and color. I like modern designs of that time period but you're right Morten, these are down right ugly IMO!
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I know this is picky but..... why are these called "boat hull construction"? Aren't boat hulls constructed with longitudinal strips?
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I know this is picky but..... why are these called "boat hull construction"? Aren't boat hulls constructed with longitudinal strips?
It's not the construction method per se, it's the cross sectional shape (minus a keel, bow and stern...but I digress). I'm big on boats and I think "boathull" sounds way cooler than concave, parabolic, or some other geometric adjective. Take a boat, chop off it's bow and stern, cut a hole in the deck, mount a driver, stand it up on end....boathull speaker. :thumb:
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It's not the construction method per se, it's the cross sectional shape (minus a keel, bow and stern...but I digress). I'm big on boats and I think "boathull" sounds way cooler than concave, parabolic, or some other geometric adjective. Take a boat, chop off it's bow and stern, cut a hole in the deck, mount a driver, stand it up on end....boathull speaker. :thumb:
:D Very cool. Your speakers, if left unveneefred will have the same cool look as some of the Penaudio speakers which have a similar laminated look.
Just curious if true "boat hull" construction would be easier or sturdy enough for speakers. I may be mistaken but the Swan Diva speakers apparently are constructed this way.
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Many boats are designed with ribs for strength, though not pure/continuous ribbing.
This construction method is very reminiscent of AC's own Vapor Audio.
Note that Gallo (the original "round sound" guys) use a special fill material to cut down on the back-wave reflections in their sealed designs.
A modern 2-way spin off the spherical shape can be found in the ported Munro Sonic Egg 100 and 150 speakers.
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http://www.audiophilia.com/hardware/waveform.htm
A business assoc. had a pair of these back in the day....dam good sound.
the spherical & elliptical shape has been around for a few years.
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http://www.audiophilia.com/hardware/waveform.htm
A business assoc. had a pair of these back in the day....dam good sound.
the spherical & elliptical shape has been around for a few years.
I remember hearing the Waveform Mach Solo. Wasn't terribly impressed, but the room was a near perfect cube (and as you'd guess the bass was boomy). :roll:
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http://www.audiophilia.com/hardware/waveform.htm
A business assoc. had a pair of these back in the day....dam good sound.
the spherical & elliptical shape has been around for a few years.
I once owned a pair of Mach Solos long ago, buying one of the last full price pairs before John had his "closing up half price sale" in September 2000. I wish I still had them. But they were large and I needed to get small, so I sold them. I thought, and still think, of them as the best designed speakers to ever come along. There was nothing fancy about the drivers though, and that was a real pity.
Since then, nobody has designed a speaker with any of the design features that made these so good.
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I have to say, these may be the ugliest speakers I've ever seen. For me personally, even if these were the best sounding speakers ever made, I'd cringe every time I opened my eyes and had to look at them. Something right out of the 1960's Jetsons. I like contemporary styling by OMG these are awful. :lol:
The Jetson's comment cracked me up :lol:
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This is way off topic - for which apologies. But if you want to see ugly, try this for size:
http://www.6moons.com/audioreviews/westernelectric/2.jpg
Made by Electronluv http://www.electronluv.com/ . All of their stuff looks like a lesson in anatomy.
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This is way off topic - for which apologies. But if you want to see ugly, try this for size:
http://www.6moons.com/audioreviews/westernelectric/2.jpg
Made by Electronluv http://www.electronluv.com/ . All of their stuff looks like a lesson in anatomy.
Beauty is in the eye of the beholder. This is a good excerise in form following function design.
But domestically acceptable? - Not so much :roll: :wink: :duh:
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Now that we have our CNC router/mill up and running again I've been able to move our 0.32 cubic foot boathull speaker cabinets closer to completion.
The baffle has now been bonded to the body. While not visible in these pics we lined most of interior with heavy felt. Being our first boathull build we had to figure things out along the way. Note the clamping cradle. Without that cradle it would have been tough clamping on to a curved surface. :scratch: The zebra wood veneer is turning out to be an outstanding match for the baltic birch laminate body. Fine sanding and poly oil finishing comes next. Note that the speaker terminals are not yet installed. These speakers will use an external crossover and will be set up for bi-amping.
I'll post one final set of pics once they are completely done.
(http://www.audiocircle.com/image.php?id=134916)
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Here are pics of the finished "boathull" 0.32 cubic foot speaker cabinets. Made of milled baltic birch plywood with zebra wood veneer on top, bottom and baffle. Body is ellipsoid (boat hull) in shape - 1 inch thick walls. Finished in about 10 layers of gloss poly oil.
Woofer is a Scanspeak Revelator 15W/8530K00
Tweeter is a Scanspeak Revelator D2905/990000
Customer wanted these built without crossovers so unfortunately I'm not going to get to have a proper listen before shipping them out...but that was the arrangement. They are set up for external crossover/bi-amping.
There's a reason most speaker cabinets are simple rectangular boxes - cheap and easy. These are neither. Very unique and quite stunning to look at. Each cabinet is unique with its own laminate pattern depending on the random nature of the baltic birch in the plywood.
Our next build will be a set of floor standers, probably 44 inches tall, 13.5 inches wide with 10" Audio Nirvana full range drivers. Considering making those with continuous integral baltic birch all the way around - no separate front baffle to attach. That build will become our standard design.
Please contact me if you, or anybody you know, is interested in a set of custom make cabinets using this construction technique. At this point we're only planning to build these to order.
(http://www.tortugaaudio.com/images/boathull_front.jpg)
(http://www.tortugaaudio.com/images/boathull_frontandback.jpg)
(http://www.tortugaaudio.com/images/boathull_leftside.jpg)
(http://www.tortugaaudio.com/images/boathull_top.jpg)
(http://www.tortugaaudio.com/images/boathull_rear.jpg)
(http://www.tortugaaudio.com/images/boathull_topcorner.jpg)
(http://www.tortugaaudio.com/images/boathull_rightside.jpg)
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Morten - those are things of pure beauty! Truly superb
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"Considering making those with continuous integral baltic birch all the way around - no separate front baffle to attach. That build will become our standard design.
Please contact me if you, or anybody you know, is interested in a set of custom made cabinets using this construction technique. At this point we're only planning to build these to order."
Very interesting idea! I'll tuck this away till I'm more ready to consider this for myself. Thank you, Morten.
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Morten - those are things of pure beauty! Truly superb
Thanks. They came out better looking than I'd hoped for. The zebrawood veneer really complimented the baltic birch laminate. Also, the hardwood ply took on a really nice look after a few coats of finish. I tried both satin and gloss but the gloss won out. Probably around 10+ layers of poly oil - I lost count. :thumb:
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We just posted an article on the boathull speakers on our website. It can be found here: http://www.tortugaaudio.com/custom-boathull-speaker/ (http://www.tortugaaudio.com/custom-boathull-speaker/)
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We just posted an article on the boathull speakers on our website. It can be found here: http://www.tortugaaudio.com/custom-boathull-speaker/ (http://www.tortugaaudio.com/custom-boathull-speaker/)
You're certainly right in the article about rectangular box speakers. Back 25 years ago I was Tech Director of Wharfedale, the UK speaker company. And the thing that dictated the size of a particular speaker was how the cutouts fitted with minimum waste out of 8 x 4 sheets. The sheets were veneered on one side, and a high speed router cut an 90 degree V almost all the way through, but not quite. So the box would fold up with glue down the V, and the veneer wrapping round the edge. At that point we were shipping 50,000 pairs of Diamond 4 each year alone - and that was only one model. We even vacuum formed the cones, wound the voice coils and built every darned driver right on the shop floor. This was a big factory!
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You're certainly right in the article about rectangular box speakers. Back 25 years ago I was Tech Director of Wharfedale, the UK speaker company. And the thing that dictated the size of a particular speaker was how the cutouts fitted with minimum waste out of 8 x 4 sheets. The sheets were veneered on one side, and a high speed router cut an 90 degree V almost all the way through, but not quite. So the box would fold up with glue down the V, and the veneer wrapping round the edge. At that point we were shipping 50,000 pairs of Diamond 4 each year alone - and that was only one model. We even vacuum formed the cones, wound the voice coils and built every darned driver right on the shop floor. This was a big factory!
50,000 speakers month!! Now that's production with a capital "P". Good times!
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50,000 speakers month!! Now that's production with a capital "P". Good times!
It was per year, but still a big number. We used to make close to a quarter million drivers each year to feed the speaker production.
You will be not at all surprised to find that Wharfedale (and Quad too) are now owned by the Chinese.
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Here's a CAD rendering of the full range boathull speaker cabinet. Note that unlike the initial bookshelf design the baffle will be integral and not a separate attached panel.
(http://www.tortugaaudio.com/images/enclosure_crosssection_13.5x18.jpg)
(http://www.tortugaaudio.com/images/enclsoure_height_13.5x18.jpg)
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Cool... I'd put a flat spot for the binding posts so they can be side-by-side and build bracing and damping into the design too...
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Yes, those binding posts might be awfully difficult with large, maybe stiff, speaker cables.
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Yes, those binding posts might be awfully difficult with large, maybe stiff, speaker cables.
I don't understand the concern here regarding large/stiff cable. Not that I disagree, I simply don't comprehend how the over/under binding post configuration might pose a problem especially if they're sufficiently spaced that would be somehow less of a problem if they were side by side.
Also, to Craig's earlier comment, creating a sufficient flat spot on the given curvature to allow for side-by-side binding posts has its own issues. First, keep in mind that the walls here are 1.5 inches thick. Let's say we create a flat spot sufficient for binding posts 3 inches apart. Given the degree of curvature those posts would have to be considerably longer possibly exceeding available lengths of most/all binding posts. Flat spots would also create a more complex surface to smooth and finish properly. Anything is doable of course but need a very compelling reason to create new problem in order solve a problem that may not be one (or that I don't recognize as a problem - yet).
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I've now tested the Audio Nirvana 10" Classic driver in a conventional rectangular 2.8 cubic foot cabinet with mixed results. The level of detail and clarity coming from this driver is really amazing...outstanding in fact. But....the amount of mid/low level bass has so far been disappointing. It produces bass but not as much especially when I compare it to the 8" Super running in a much smaller 1.5 cubic foot cabinet which produces impressive bass. I've been discussing this with Dave at Audio Nirvana who is baffled (no pun intended) by this since his experience suggest the bass with the 10's and bigger cabinet should be yuuuuge!
Until I can resolve this performance issue, I'm not going to produce a boathull cabinet for the 10" Nirvana Audio driver. On the other hand, perhaps the smaller 8's in a 1.5 cabinet is the way to go. Smaller and better fit for most living rooms but will need a stand to get the driver up to ear level.
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One acronym - DSP (Digital Signal Processing) has most definitively solved the lack of mid/low bass with the 10" Audio Nirvana full range drivers in the 2.8 cubic foot cabinet. I secured a miniDSP 2x4HD ($190). This is their latest and most updated model and is reportedly far more powerful than the original 2x4 ($80). I used it to add a +3-5 dB low end shelf boost starting at 200 HZ and below and this immediately filled out the weak low end. Remarkably effective. All the bass/slam you could reasonably ask for while retaining the phenomenal coherency and detail of the Audio Nirvana Classic full ranger driver. I do realize that for some audiophiles the use of digital anything is nothing short of audio blasphemy but while the luddites gnash their teeth I will be enjoying the hell out of these full ranger speakers.
I located the 2x4HD between the DAC output and the amp. In this configuration the 2x4HD converts the analog into digital, manipulates the data digitally, and then converts it back to analog. So essentially I have a DAC-ADC-DAC in this instance. This is obviously not ideal but it was the simplest way to get the 2x4HD up and running. The 2x4HD also accepts Toslink or USB digital input so my next step is to take my DAC out of the loop and check performance with the 2x4HD by itself as a DSP/DAC. I understand they make a model that you can put upstream of your DAC as well - the nanoDIGI2x8K ($155). This would keep all processing in the digital domain with no additional ADC/DACs within the unit.
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I've received a few inquiries on the full range boathull speakers so here's an update.
My default starting point for this project was to use Audio Nirvana's 10 inch Classic full range driver a their plain vanilla 2.8 cubic feet (~79 liter) cabinet with a 6 inch port and no port tube, just the ~0.75 wall thickness of the front baffle. It was never my intent to actually use this as the final cabinet, only to use it to guide to next steps. The final cabinet design will be a stacked "boat hull" shape using layers of milled baltic birch. Thus the entire cabinet except for the tops and bottoms will be sanded and clear finished baltic birch edge grain. The walls will be ~1.5 inch thick laminate with periodic cross bracing. Stiff, stiffer, stiffest. You won't be hearing this cabinet, just the driver. :thumb:
I've run several cabinet design calcs which more or less conclude that the ideal cabinet for this driver would be ~ 12 cubic feet with an F3 well under 30 Hz. A monster size box that is too big to be practical for what I'm looking for. Hence the 2.8 cubic feet box which when you see it standing there in front of you still looks plenty big. 40" tall by 12" wide by 13.5" deep.
With a 6 inch port the design calcs call for a port tube length in the 8-12" range. I currently have no port tube other than the 0.73" baffle itself. I've experimented with an 8" quick and dirty port tube made of stiff thick walled paper rolled into a tube reinforced with duct tape. Ugly as sin but fairly solid. Did some with and without listening and my conclusion was the port tube was not noticeably effective. Quite possibly a proper tube would lead to a different conclusion. By my hunch is that while a longer tube may provide incremental benefit it would be rather modest at best and adds additional sonic complexities.
After further playing around with the miniDSP together the Room Eq Wizard ("REW") software (http://www.roomeqwizard.com/ (http://www.roomeqwizard.com/)) and a real time analyzer (RTA), I've arrived at the following adjustments and thoughts.
1) The 10" Audio Nirvana Classic benefits greatly from the application of a high shelf PEQ starting at 400 Hz with -6 dB reduction in gain. Some might call this a form of baffle step compensation.
2) Whether it's the driver, the room, or combination of both, there was a noticeable boominess in the mid-bass. After running REW and loading the adjustment filters into the DSP, the boominess was completely gone. The filter was a fairly complex peak followed by big notch. Huge plus and a snap to implement with REW and the miniDSP.
3) Overall bass satisfaction benefits from adding a low shelf PEQ boost from 100 Hz down with a +2 to +3 dB gain. Adjust to suit. Cranking it up further really pours on the bass.
4) After further work with the DSP, RTA etc. it's quite clear that de-emphasizing the 2.5-5k range by ~2 dB resulted in enormous improvement by smoothing out a somewhat overly bright presentation in this audible range. This wasn't obvious based on the RTA but the benefits were most clearly evident while listening to live tracks and switching this filter in/out of the mix.
I should add that the room these speakers are in is arguably on the large size. Vaulted ceiling central great room with integral kitchen area. Plus the speakers are at least 3-4 foot out from the wall. In a smaller room with speakers closer to the walls the above adjustments may not prove optimal. Which only goes to further support the efficacy of DSP in achieving optimal performance. One size rarely fits all.
While further tweaking of the DSP may yield yet more improvements, this full range driver in a plain vanilla box with a DSP in front of the amp is producing the best sound I've ever heard from a speaker. Or let's say as good a sound as I've heard from any speaker regardless of price including anything I've heard at shows.
This presents a quandry in terms of how to best package this together. One the one hand, offer the 10" boat hull full range speaker together with a preconfigured DSP in a separate box? Or...make this a powered speaker with integral DSP?
Regards,
Morten
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DSP solutions don't seem to change quite as fast as DACs, but they still change often enough that I don't know that I'd make the preconfigured DSP the only option. Some might want to use that DCX2496 they have sitting in the closet...
DSP performed on a computer front end source component is not uncommon either. For example, I implement the needed driver EQ for my active speakers by defining the points in RoomEQWizard and then saving a convolution filter at its highest resolution setting, which I then import into HQPlayer where it convolves the filter with the music stream, upsampling everything via poly sinc filters to my DAC's native DSD128 input rate. (HQPlayer runs on my modded Mac Mini, fronted by Roon for the sake of its impressive interface, and I have an analog line level crossover handling the frequency splitting duties between drivers.)
Note that you may want to talk to potential customers about the amp with which they intend to pair these speakers if you don't integrate an amp. Perhaps the impedance is benign, but +5 dB of boost at lower frequencies may put undue stress on an amp that is marginally sized, if otherwise spectacular. Avoiding that potential challenge is one advantage to the powered speaker configuration...
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DSP solutions don't seem to change quite as fast as DACs, but they still change often enough that I don't know that I'd make the preconfigured DSP the only option. Some might want to use that DCX2496 they have sitting in the closet...
DSP performed on a computer front end source component is not uncommon either. For example, I implement the needed driver EQ for my active speakers by defining the points in RoomEQWizard and then saving a convolution filter at its highest resolution setting, which I then import into HQPlayer where it convolves the filter with the music stream, upsampling everything via poly sinc filters to my DAC's native DSD128 input rate. (HQPlayer runs on my modded Mac Mini, fronted by Roon for the sake of its impressive interface, and I have an analog line level crossover handling the frequency splitting duties between drivers.)
Note that you may want to talk to potential customers about the amp with which they intend to pair these speakers if you don't integrate an amp. Perhaps the impedance is benign, but +5 dB of boost at lower frequencies may put undue stress on an amp that is marginally sized, if otherwise spectacular. Avoiding that potential challenge is one advantage to the powered speaker configuration...
Thanks for the input. All very good points worth considering. I suspect there's no "one way" that fits all scenarios here. I do intend to secure a version of the miniDSP that operates entirely in the digital domain and apply the same filters upstream of the DAC and compare efficacy to the downstream analog domain version I'm currently working with.
Your EQ and active crossover approach sound interesting. I've not worked with HQPlayer yet. I've no doubt that DSP will eventually become the norm especially in computer based audio where it's a natural fit upstream of the analog.
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Thanks for the input. All very good points worth considering. I suspect there's no "one way" that fits all scenarios here. I do intend to secure a version of the miniDSP that operates entirely in the digital domain and apply the same filters upstream of the DAC and compare efficacy to the downstream analog domain version I'm currently working with.
Your EQ and active crossover approach sound interesting. I've not worked with HQPlayer yet. I've no doubt that DSP will eventually become the norm especially in computer based audio where it's a natural fit upstream of the analog.
Siegfried Linkwitz came to the same conclusion. All of his designs right from the 1970's used analog active crossovers. Until a year or so ago, when DSP technology evolved to a level of sophistication and quality that made it the method of choice. So the LX521.4 and LX-mini family designs all use miniDSP based algorithms http://www.linkwitzlab.com/ . In particular they enable driver EQ that is impractical even with analog active.
I have the LX521 with analog crossover, but given the cost effectiveness of the 4x10 I might upgrade. Need another two channels of amplification though to do that.
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In particular they enable driver EQ that is impractical even with analog active.
Not to mention passive EQ!! I wouldn't want to attempt what I've done using the miniDSP with either active or passive. It might be doable via active but it would end up being very complex and costly to design/build in smaller quantities. Not to mention that the development time would take months rather than a few hours with the miniDSP.
I owned a Behringer DEQ2496 a few years back. It worked OK but was a real bear to configure. I had to devote hours each time just to figure out how to use it. By comparison the software that comes with the miniDSP is quite straight forward and relatively intuitive. I also think the miniDSP is much more powerful.
I've heard nothing but good things about the LX521.
I just ordered the miniDSP nanoDIGI 2x8 K which is all digital in/out. The only beef I have with it is it doesn't have USB input, only SPDIF and Toslink. I'll post an update when I've given it a spin.
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We've been evaluating the Audio Nirvana 10" classic drivers in plain vanilla 2.8 cubic feet cabinet for a few weeks now. With appropriate tuning of the response curve via DSP these drivers are really quite spectacular. Great solid tight bass and amazing detail. Sublime with great recordings and merciless on badly recorded material.
Before making a final decision we're going to also audition the Audio Nirvana 12" Super driver. The 12's should further improve both the bass and the mid range quality. Since it uses the same ALNICO magnet size as the 10's, expectations are a somewhat more relaxed and toned down upper end. Also, due to the size of this driver the physical depth of the speaker cone, we're opting for the Super model with the whizzer cone on these 12's. The whizzers will help the dispersion with the deeper cones on the 12's which might otherwise be a bit to beamy.
Once we've evaluated the 12's we'll make a final decision on driver and cabinet size. The CAD pic below shows the prototype cabinet size with the 12's. It would be 16" wide x 17" deep x 41" tall and be roughly 3 cubic feet in volume. Oh, and the walls are 1.5 inches thick including the top and bottom. PLUS there's longitudinal X & Y bracing running internally between the driver opening and the baffle opening. A most stiff rigid beast of a cabinet that will also be a beautiful head turning piece of audio gear artwork.
(http://www.audiocircle.com/image.php?id=141924)
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Having tried the 10" Audio Nirvana Classic in our test cabinet, I decided it wasn't quite good enough for what we are looking for. Good but not great. So we moved on to the 12" Audio Nirvana full range driver. Except this time it was the Super and not the Classic. The Supers have the whizzer cone. The concern being that with the a full range driver as large and deep as the AN12S there would be horizontal dispersion and beaming issues with the classic which has no whizzer.
Even though we only have a dozen hours on the 12" so far, it really delivers especially in the mid-bass and with vocals which just come across so naturally. We are still tweaking the response curve with a DSP to optimize the sound quality and the results are really wonderful. The 12" really projects sound efficiently and we noticed we tend to run these turned down further than the 10's. Bass is good as well.
The pic below is speaker sausage making at its finest. This is just a test cabinet and obviously not a boat hull. Note the round covers on the right side which is where the 10" drivers used to be. The 12's just wouldn't fit so we rotated the cabinet 90 degrees and made new openings for the 12" driver and port. The cabinet is 14" wide and 12" drivers only have about 3/4" room on either edge.
We are going with the 12's. Next step is to build our first full size 3 cubic foot boathull cabinets for these 12" drivers.
(http://www.tortugaaudio.com/images/AN12S_TestCabinet_2.8.jpg)
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Time to give up and move on. After numerous iterations with various full range drivers of various sizes in various cabinets together with extensive listening and tweaking the equalization via DSP I've come to a conclusion and a decision.
My conclusion is that while full range drivers show promise and can sometimes hit the mark (I've owned/used them for several years now) they tend to: a) be beamy/shouty, and/or b) be a bit too bright, and/or c) have weak bass with the larger drivers (which have the best mids/voicing by the way) unless you use refrigerator size cabinets. Nothing unique or new about these observations if you've ever worked with full range drivers. I'd hoped to thread the needle on all those issues and find a perfect happy place where it all just fit together into something superlative. Couldn't get there. Time to move on.
Meanwhile I've just auditioned some high end Scanspeak drivers in a 2-way configuration (woofer/tweeter) using external crossovers and biamping and OMG do these sound smooth and sweet in moderately sized 1.5 cubic foot towers. The search for drivers is officially over!
Time to proceed with new 1.5 cubic foot boathull cabinets for the Scanspeaks. :thumb:
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Time to give up and move on. After numerous iterations with various full range drivers of various sizes in various cabinets together with extensive listening and tweaking the equalization via DSP I've come to a conclusion and a decision.
My conclusion is that while full range drivers show promise and can sometimes hit the mark (I've owned/used them for several years now) they tend to: a) be beamy/shouty, and/or b) be a bit too bright, and/or c) have weak bass with the larger drivers (which have the best mids/voicing by the way) unless you use refrigerator size cabinets. Nothing unique or new about these observations if you've ever worked with full range drivers. I'd hoped to thread the needle on all those issues and find a perfect happy place where it all just fit together into something superlative. Couldn't get there. Time to move on.
Meanwhile I've just auditioned some high end Scanspeak drivers in a 2-way configuration (woofer/tweeter) using external crossovers and biamping and OMG do these sound smooth and sweet in moderately sized 1.5 cubic foot towers. The search for drivers is officially over!
Time to proceed with new 1.5 cubic foot boathull cabinets for the Scanspeaks. :thumb:
There are very few satisfying single drivers ime... Louis at Omega makes ones you'd probably like, as would Feastrex and AER, but they are proprietary or very expensive. AER drivers in Lamhorn cabinets are the best I've ever heard, but $19k retail.
Many have had good results from adding a woofer (and tweeter) to a full range driver, allowing the full range to cover most of the frequency range, say 250 to 400 Hz on up. Depending on the driver a super tweeter could be a good idea too.
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Many have had good results from adding a woofer (and tweeter) to a full range driver, allowing the full range to cover most of the frequency range, say 250 to 400 Hz on up. Depending on the driver a super tweeter could be a good idea too.
I played around with this a little as well. In the end I concluded there were better solutions that were not as costly. Most really good full range drivers are pricey to begin with given the huge ALNICO or Neodymium magnets they typically have. Add a decent woofer and tweeter plus crossovers etc. and you've paid for a whole loaf but only eating the center third plus buying two more to make up for it...and the knives to slice it all up. Ok, enough with the food analogy. :lol:
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Sounds like you might have skipped the most important meal of the day.
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Sounds like you might have skipped the most important meal of the day.
The midrange meal? Yep, that's important! :lol:
IMO, full range drivers can make for amazing extended midrange drivers and the cost is well worth it, crossovers are often simpler as well. The Lotus Audio Grenada is one of the best speakers I've ever heard, but the cost of the drivers is also jaw-dropping. This is Omega's big advantage, the proprietary drivers are amazing and you get the entire speaker for less than the cost of many other drivers. If going for bare drivers AER is not cheap but they are probably the best and prices are reasonable vs Feastrex (expensive but awesome) and Voxativ (horribly overpriced and over rated) When done right and paired with a good SET amp a full range driver can make conventional speakers sound a bit dull and boring.
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The Audio Nirvana drivers are just OK. Their prescribed cabinets are horribly under braced and have been for years (since David Dicks changed the name of his company to get a "fresh start").
If I were going through the effort to build nice cabinets, I'd:
- Go with a design with a bit more imagination than sealed or ported.
- Consider internal and external diffusion of sound waves (an egg is probably the best shape).
- Use really good drivers (not just nice off the regular shelf drivers that lots of decent speakers use).
- Have a well designed room for them to be used in (the biggest mistake nearly all audiophiles make).
- Use materials that are acoustically inert (like synthetic resins).
- Use a swarm (search Audio Circle) of subwoofers and limit bass output of the mains to say 80-120 Hz.
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It just occurred to me that traditional headphones usually have 1 driver each ear. Obviously it seems a single full range driver is more practical in headphones. If you can do one driver well, there is no need to mess with crossovers and phase and other multi driver complications. So is it correct to say that the performance of most headphones is more like that of single driver full range speakers?
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It just occurred to me that traditional headphones usually have 1 driver each ear. Obviously it seems a single full range driver is more practical in headphones. If you can do one driver well, there is no need to mess with crossovers and phase and other multi driver complications. So is it correct to say that the performance of most headphones is more like that of single driver full range speakers?
+1.
So is it correct to say that the performance of most headphones is more like that of single driver full range speakers?
I cant say ''most'' as the cheaps but certainly a good headphone are similar to FR drivers, a great HP is much more detailed than a FR, let alone speakers with xovers.
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Hi, those enclosures sure are beautiful. When I saw the word boat hull it grabbed my eye. Andy Paynor from Rockport Maine came out with a mega priced large speaker. I can't remember the name without looking it up but it was about 10 years ago when I first saw it. It might of been the Anteries. Rockport is just outside a town called Rockland which is a famous boat town. I grew up in Maine and worked around boat yards . His 300 pound enclosure reminded me of a boat hull except it was made out of fiberglass like a modern sail boat. At first he broke into the audio field with a mega priced turntable, Rockport Technology. Being a transplant and living in Rockport I know he got that idea from his love of sailing and the idea of his enclosure by being around boats. Do a knuckle rap test on any fiberglass hull and you will understand. That speaker won awards for being the best by both Stereophile and Absolute Sound. Although using the finest drivers like Dynaudio or Scanspeak when I saw the article about him boat hull was the first thing that came to my mind as his enclosure was just that. If I'm not mistaken I think some of his help were boat builders from Rockland.....The Tortugas are beautiful! Boat hull and speakers grabbed my eye. I hope I didn't ramble too much. ...thanks Mark Korda