I'm sure it has happened. They range in quality from crap to very desirable.
With all the effort involved in this proposed build you should not just slap a cheap driver in.
A 1/2 line is esentially a sealed box with a shape such that the rear wave can be completely absorbed before the reflection can come back thru the horn.
FRs engineered for sealed box with bass extension are few, the 1st one that comes tomind is the "cheap" SEAS 8" FR. or a BetsyK (maybe). The box volume should be that needed for a lowish Q sealed box (i'd target 0.58), and the length on the order of a 1/2 w/l of the lowest frequency of interest (box resonance is a good target). The taper will allow it to be shorter than if it was a straight line.
dave
as Dave mentioned earlier I think, this is not the type of enclosure to slap a $50 driver into
even if you're planning on breaking each layer of tapered circles into arcs to allow for nesting of machined parts to increase yield, there will be a huge amount of plywood and many hours of machine running time, not to mention quite possibly wear on tooling, unless diamond coated
I guess it's my commercial shop background, but anytime I use the CNC for speaker projects, I try to keep run time to a minimum - we're not allowed to assume that it costs nothing to run a $150,000 production machine for several hours just because it's a "side job"
all that said - good luck and keep us posted
From the offset, my design was "A 1/2 line is esentially a sealed box with a shape such that the rear wave can be completely absorbed before the reflection can come back thru the horn."
Though I wasn't aware of the technical name I have measured the reflection to be 2.75m. So with my little knowledge, this should be sufficient to absorb the rear wave energy with a volume of 43L. (I am still working out the internal surface area) - Any thoughts on this idea is welcome.
Why an I building these monsters, I have played and installed a few AV systems over the years, though I have a better understanding of Video compared with Audio.
I have a pair of CCM663's, which are not cheap - $750(ChrisB), and have a sound quality to my liking. (Note, not being an audiophile, my comparisons will be less than you!)
Looking at natural form from an artistic point, I noticed that horn or spiral are the preferred shape in nature, the cochlea being an example.
This is when I thought that combining the drivers I have, my design skills and the fact that CMC milling is only $70 per hour, I am able to make a amazing looking speaker which hopefully will sound great to.
With regards to material required, I have been able to nest a pair using 4 sheets of 18mm ply. This I don't believe to be a great deal in relation to the final dimension of H90cm x W30cm x D60cm
Though I wasn't aware of the technical name I have measured the reflection to be 2.75m. So with my little knowledge, this should be sufficient to absorb the rear wave energy with a volume of 43L. (I am still working out the internal surface area) - Any thoughts on this idea is welcome.
Why an I building these monsters, I have played and installed a few AV systems over the years, though I have a better understanding of Video compared with Audio.
I have a pair of CCM663's, which are not cheap - $750(ChrisB), and have a sound quality to my liking. (Note, not being an audiophile, my comparisons will be less than you!)
Looking at natural form from an artistic point, I noticed that horn or spiral are the preferred shape in nature, the cochlea being an example.
This is when I thought that combining the drivers I have, my design skills and the fact that CMC milling is only $70 per hour, I am able to make a amazing looking speaker which hopefully will sound great to.
With regards to material required, I have been able to nest a pair using 4 sheets of 18mm ply. This I don't believe to be a great deal in relation to the final dimension of H90cm x W30cm x D60cm
I believe what you are trying to do is very similar to the principle behind the B&W Nautilus. They have a nautilus like spiral in order to absorb the back wave. I believe they use a plywood truss frame covered with fiberglass. There have been some DIY efforts at cloning this too.
B&W has quite a few videos on YouTube explaining the concept behind the shape. The red speaker above is a Nautilus impaired copy - different from B&W in number of drivers.
B&W has quite a few videos on YouTube explaining the concept behind the shape. The red speaker above is a Nautilus impaired copy - different from B&W in number of drivers.
Last edited:
I have seen these (red Copies) as well as the B&Ws which put me off at the beginning as I didn't want my build to be a clone. But, I got into this because I wanted to build something which was challenging.
I have to say, I really don't like Lluis Pujol design, it looks to top heavy and not aesthetically suited to my taste. Also, I noticed last night the Nautilas has squished the diameter of the circle as it archs round. I wouldn't want to question this as B&W spent 5 years developing as well as having an open cheque book.
Now thinking about it, my design was formed from logic. I have no intentions in ruining the form by adding additional drivers above the main shape. Thus I came up with the conclusion of using a Ceiling speaker as this has both a combined woofer and tweeter.
I have been wondering if the finished product will be best suited to listeners of classical, of jazz?
I have to say, I really don't like Lluis Pujol design, it looks to top heavy and not aesthetically suited to my taste. Also, I noticed last night the Nautilas has squished the diameter of the circle as it archs round. I wouldn't want to question this as B&W spent 5 years developing as well as having an open cheque book.
Now thinking about it, my design was formed from logic. I have no intentions in ruining the form by adding additional drivers above the main shape. Thus I came up with the conclusion of using a Ceiling speaker as this has both a combined woofer and tweeter.
I have been wondering if the finished product will be best suited to listeners of classical, of jazz?
The most important is to put the subwoofer in the enclosure spiral. The shape of the housing of other speakers, are of less importance. Even better results can be obtained by placing the subwoofer outlet to the floor.
All the best
RK
I believe what you are trying to do is very similar to the principle behind the B&W Nautilus. They have a nautilus like spiral in order to absorb the back wave. I believe they use a plywood truss frame covered with fiberglass. There have been some DIY efforts at cloning this too.
B&W has quite a few videos on YouTube explaining the concept behind the shape. The red speaker above is a Nautilus impaired copy - different from B&W in number of drivers.
If by "they" you mean B&W, no they don't use plywood space frame / fabric shell. Several years ago there was a very thick & highly detailed glossy "coffee-table art" book on describing the technical research, driver and enclosure "breakthroughs" and manufacturing production processes for the entire Nautilus line. I think fewer of us will have had the opportunity to hear the statement products than the 800 series, and for those of us who have, regardless of our assessment of the performance / value, it's hard not to be amazed by the investment and commitment involved.
To be entirely honest, of the half dozen or so models of the 800 series I've heard since their debut at local showroom, the one I liked most was the 805 before the Diamond tweeters.
An externally hosted image should be here but it was not working when we last tested it.
excerpted from their website, so excuse the "market-speak"
Bowers & Wilkins' search for the best possible quality in production means that we devote a great deal of time and care to specifying materials and components – and then to finding suitable specialists to make them. For the Nautilus™ body we engaged the services of Raceprep, a specialist company which is expert in the formulation of fibre-reinforced composites. Because of its complex shape, Raceprep engineers make the Nautilus™ shell almost entirely by hand, using a resin which has been identified by computer analysis as perfect for its purpose – ensuring maximum strength and durability. The same attention to detail has been applied to the finish for the Nautilus™ shell. Bowers & Wilkins' paint and lacquer system is imported directly from Germany, where it is supplied only to the leading names in the luxury car industry, such as Porsche and Mercedes Benz.
xrk971: no worries, with each solar orbit it becomes far easier to get confused - it happens to me daily
buy I think the material is much thicker and denser than carbon fiber racing monocoque type construction
Sparrowlegs:
by all means don't let notorious naysayers such as myself dissuade you from this very ambitious project - it's just that I noted in my first post this thread ( #10), this seemed like rather a lot for a first time builder to chew on
buy I think the material is much thicker and denser than carbon fiber racing monocoque type construction
Sparrowlegs:
by all means don't let notorious naysayers such as myself dissuade you from this very ambitious project - it's just that I noted in my first post this thread ( #10), this seemed like rather a lot for a first time builder to chew on
Last edited:
Several technologies to make it perform. Each of them is arduous.
In the case of individual products are more opportunities. The housing is formed from the skeleton of glass fiber and then filled it with plastic putty (for example). Otherwise, create a form and later another castings. Most of the work is for cleaning and polishing all before painting.
In the case of individual products are more opportunities. The housing is formed from the skeleton of glass fiber and then filled it with plastic putty (for example). Otherwise, create a form and later another castings. Most of the work is for cleaning and polishing all before painting.
Hi Guys, Dean and Chris.
Thank you for your comments, they are now in the process of being cut, so I can't wait to assemble. From a technical point of view, I believe that there will be much room for improvement, particularly with regards to the type of drivers used.
I have adjusted for final design because of this. As these are prototypes, I have adapted the head so that different drivers can be easily screwed off and on, allowing for testing once permitted.
Thank you for your comments, they are now in the process of being cut, so I can't wait to assemble. From a technical point of view, I believe that there will be much room for improvement, particularly with regards to the type of drivers used.
I have adjusted for final design because of this. As these are prototypes, I have adapted the head so that different drivers can be easily screwed off and on, allowing for testing once permitted.
Well here's something to throw into the mix. I will have the first pair of logarithmic spiral transmission line speaker made from wood completed within a week or so. I would be interested in an exchange, which could suit all parties. For example, my cabinets for range of drivers for example. Or a testing time... etc etc.
I would be welcome to all avenues of opportunities?
Haha you guys are funny. It is pretty hard finding out the TS Parameters if you don't have the equipment - T-S Parameter Calculator Nor, if the manufacturer doesn't provide a data sheet.
Though, I going to work this out, but I have read from various resources, that - EBP relationship to type of cabinet enclosure is - "A rule of thumb only. Your results may vary."
Honestly, what I designed wasn't based on the driver calculations, it was based on the fluid dynamics, and wave reflection. Also working out how to make a really difficult shape from wood.
I am aware though the drivers I'm going to be using were intended in a sealed enclosure, then I can't see the problem with testing them in my prototype.
Does no one reverse engineer? Or take the point "not just a science but an art"?
Though, I going to work this out, but I have read from various resources, that - EBP relationship to type of cabinet enclosure is - "A rule of thumb only. Your results may vary."
Honestly, what I designed wasn't based on the driver calculations, it was based on the fluid dynamics, and wave reflection. Also working out how to make a really difficult shape from wood.
I am aware though the drivers I'm going to be using were intended in a sealed enclosure, then I can't see the problem with testing them in my prototype.
Does no one reverse engineer? Or take the point "not just a science but an art"?
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.