Adhiraj
Active Member
Taking off from my previous thread
http://www.hifivision.com/diy/11991-soundlogic-atma.html
This is the first part of my 4 way build project , the foundation of the speaker , the Subwoofers. Initially I tried a clamshell Isobaric design using 4 x Car audio 12 inch subs from Hertz , but had to ultimately ditch that idea because I ended up completely frying one of the subs by being a little too frisky with the gain knob on the Crown :sad: BUT on the upside , I now had an excuse to get something better , much much better . Thus , Dayton Reference HF12 , 4 ohm versions , total landed price at $ 200 per piece from PE. I must say that these damn things weigh a ton ! and they look good. And Boy do they sound sweet.
The basic design mandate behind the Cabinets was to engineer something seriously overbuilt . It is constructed using a box in a box concept , with 3 dimension shelf bracing , all of which were inter connected (criss crossing) .Braces were offset using the Golden ratio , this was done to achieve different compartment sizes within the box, as a result , no two panels have the same resonant frequency and pipe resonances within the box along with standing waves get taken care of.Further a angled wave deflector panel was employed behind the woofer , this too was asymmetrical in shape ,this helps taming standing waves.
The materials used were MDF and BWR Grade AA rated Club Premium Green ply. The ply used was so hard I had to specially buy a tungsten carbide blade for cutting .Blades that were being used to regularly cut bwr grade ply and block board failed miserably when it came to this.I guess Club premium really is premium.Very solid stuff that.
The first box is made from the ply 19mm in thickness , each of the panels of the box apart from the top and bottom is of a different size i.e. no two panels are the same length . This was achieved using an overlapping butt joint .This was employed to keep the resonant frequencies of each panel different from one another. The bracing is made from MDF 19mm and the outer box is also made from 19mm mdf, the baffle is three layers thick , ply-mdf-ply , all glued together using fevicol .The cabinets total wall thickness is about 30mm . Steel screws were used along with fevicol for panel jointing and bracing installation.
Interior damping and absorption was achieved using a mix of 3m floor mat (the thing with squiggly lines) 1 inch black acoustic foam , jute fibre matting , glass wool , and regular polyfill .
They weigh roughly 80 kilos each. I say roughly because no one has ever attempted to lift one , they may find out the actual weight posthumously.
Currently being powered by Crown XLS 1500 pushing 500 watts in stereo 4 ohms . Im running them up to 180 Hz using the amps in built XO . They sound dry , flat and very very musical .
Looking for finishing suggestions ~ help!
Shows the inner shell
Top view of the 3 dim bracing , clearly shows the offset .
Another look , this time with the holes cut
Mirror image braces for the dual subs
Braces inserted and interior treatments being done
Closer look at the wave deflector panels (in blue)
And shes ready , fully loaded , awaiting final finishing , grill and baffle padding.
http://www.hifivision.com/diy/11991-soundlogic-atma.html
This is the first part of my 4 way build project , the foundation of the speaker , the Subwoofers. Initially I tried a clamshell Isobaric design using 4 x Car audio 12 inch subs from Hertz , but had to ultimately ditch that idea because I ended up completely frying one of the subs by being a little too frisky with the gain knob on the Crown :sad: BUT on the upside , I now had an excuse to get something better , much much better . Thus , Dayton Reference HF12 , 4 ohm versions , total landed price at $ 200 per piece from PE. I must say that these damn things weigh a ton ! and they look good. And Boy do they sound sweet.
The basic design mandate behind the Cabinets was to engineer something seriously overbuilt . It is constructed using a box in a box concept , with 3 dimension shelf bracing , all of which were inter connected (criss crossing) .Braces were offset using the Golden ratio , this was done to achieve different compartment sizes within the box, as a result , no two panels have the same resonant frequency and pipe resonances within the box along with standing waves get taken care of.Further a angled wave deflector panel was employed behind the woofer , this too was asymmetrical in shape ,this helps taming standing waves.
The materials used were MDF and BWR Grade AA rated Club Premium Green ply. The ply used was so hard I had to specially buy a tungsten carbide blade for cutting .Blades that were being used to regularly cut bwr grade ply and block board failed miserably when it came to this.I guess Club premium really is premium.Very solid stuff that.
The first box is made from the ply 19mm in thickness , each of the panels of the box apart from the top and bottom is of a different size i.e. no two panels are the same length . This was achieved using an overlapping butt joint .This was employed to keep the resonant frequencies of each panel different from one another. The bracing is made from MDF 19mm and the outer box is also made from 19mm mdf, the baffle is three layers thick , ply-mdf-ply , all glued together using fevicol .The cabinets total wall thickness is about 30mm . Steel screws were used along with fevicol for panel jointing and bracing installation.
Interior damping and absorption was achieved using a mix of 3m floor mat (the thing with squiggly lines) 1 inch black acoustic foam , jute fibre matting , glass wool , and regular polyfill .
They weigh roughly 80 kilos each. I say roughly because no one has ever attempted to lift one , they may find out the actual weight posthumously.
Currently being powered by Crown XLS 1500 pushing 500 watts in stereo 4 ohms . Im running them up to 180 Hz using the amps in built XO . They sound dry , flat and very very musical .
Looking for finishing suggestions ~ help!
Shows the inner shell
Top view of the 3 dim bracing , clearly shows the offset .
Another look , this time with the holes cut
Mirror image braces for the dual subs
Braces inserted and interior treatments being done
Closer look at the wave deflector panels (in blue)
And shes ready , fully loaded , awaiting final finishing , grill and baffle padding.
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