Austin A166

Mr Pass recommended the the Fostex FE166E as a nice driver to get my feet wet with full range speakers. After looking at back loaded horns I would like to build Ron's Austin A166. I see Layertone built his by laminating CNC pieces together. Is there a drawing available to submit to a cabinetmaker with a CNC Router? I can make the standard one but the rounded horn section of the CNC version looks very appealing. I have to admit I am pretty jazzed about this as well as my Pass F4 I plan to drag out my 300b set amp to drive them. Any recommendations on padding or stuffing on it, or any other mods for that matter.


Thanks
Bill
 
A166 drawing

By Tony you mean layertone ? Ron are you ok with some else using them? Do they sound as good or better than regular version. I see Layertone is in Sacramento, I would gladly pay for time and materials if you were willing an it was ok with Ron to cut them, and of course the stars align and the creeks don't rise. These things look so cool in the laminated version.

Thanks

Bill
 

ronc

Member
2003-03-08 2:22 pm
1. Yep/ (layertone)
2. Yep. Never heard the curved version. I have the standard version in SC and will install the EnABL drivers on my next trip home.
3. I would email Tony.

As i have posted recently i have kinda gotten away from SD FR Big BLHs. and moved to more two way systems. A bass BVR( a Scott design) and more of a waveguide OB or an waveguide on the front and an IB on the rear of the WB driver (my design). To me it just makes more sense than trying to make a single driver do the whole spectrum. Add to the fact that there is less group delay and i can time align the XO point and have a more simple build. Again , it just makes sense, besides ,despite what others think, i have never been a purist.

ron

(the hardest thing you can do is to make something simple)
 
A166

I have made 2 way systems and have been greatly pleased by them, 3 way with passive crossovers just get to complex. MTM are nice have one of them. Just wanted to try a single driver with horn maybe add a tweeter with simple cap for crossover. I think it is said somewhere amps like the F4 work better without crossovers and it would be an excuse to revisit my set amp, may put regulated DC on the filament and try to eliminate some hum.

Bill
 
A166 laminations

I guess the prefered material is Baltic burtch plywood. Has anyone tried using solid pieces of plywood for the strait sections of the pipe and glued them to laminated plywood that has been routed to shape for the curved sections? Would it change the tuning of the horn to use the existing dimentions from the current plan and just round the ends?

Thanks
Bill
 

bobmar

Member
2005-10-06 6:27 pm
curved bends

A auto muffler is designed to not allow the sound to reflect around the bends.
It seems it would matter, the shape of the turns and flow of the sound, but is a little chaos allowable?

Full size drawing
A full size drawing is an advantage because you can turn it over and do the opposite side and it matches. I used mylar and poked holes for the points. I found it difficult to do, but fun.
There is a discrepancy in Dave's drawing in respect to Ron's rev G drawing [10/9/05] where the 2nd turn at the 45 degree position is .2 inch too full so that if you try to get a transition from 4.05" to 4.46",that half way point wants to remain 4.05"rather than 4.20"...[4.05"is at the 180, 4.20"@ 45 degrees,4.46" @ 12 o'clock]
The points on the rev G are given as : [x7.58,y44.58] and [x5.7, y42.81] If you connect those two points you will get a line that will diminish the thickness of that piece of ply wood to .50".
[Well, I feel better, having said that...].....Bob
 

ronc

Member
2003-03-08 2:22 pm
Sorry! Those dwgs were made from an old version of Turbo Cad, The actuals were taken from my rather crude wave form programming, Turbo Cad ,at that time, did not have a point lock and i never use a grid. The reported dimensions may be incorrect, but the profile is not. I lost the original Dwgs awile back in a windows crash, so i cant reference them.

ron
 

bobmar

Member
2005-10-06 6:27 pm
166 drawings on planet 10

Actually the drawings are very good. They were much clearer in the upper area and generally easier to follow. I just used them both. There is only one other measurement that was off and that was the length of divider board that terminates at the 2nd turn. It is given as 36.35"and the x,y co-ordinates give that as [x6.98, y37.93] . The 37.93 includes the bottom piece of wood, so [.7 --37.93 =37.23 ].That works out pretty well with the dimensions given for the turn.
I should have mentioned the discrepancies a long time ago.

Bob
 
A166 curves

I am still thinking of making the curved pieces out of routed laminated plywood and gluing them with biscuits to the strait pieces, more for aesthetics and to experiment with a different construction technique. What dimensions should I be careful not to alter ? I will buy phase plugs for drivers any other mods for improvement? Is there any benefit to placing any dampening (wool felt) behind driver?

Thanks
Bill
 

bobmar

Member
2005-10-06 6:27 pm
important dimensions

I made two 166 A's. The second set was better than the first. It's hard to know in advance where the difficulties lie, but all the dimension are important and in drawing the plans you realize just how exact you need to be......Rons notes : no. 4 , is good advice. Using spacers at the turns. Example:On the 1st turn, If you cut thin masonite to the dimensions, 1.92" x7.9" and 2.45" x7.9", plastic tape the edges, so they come out when the glue is dry. you can put it together in a square way. With one side open and the majority of the build is finished, you can check your dimensions on the turns. I actually used epoxy mixed with sand on the turns. It seemed necessary in the 2nd turn where the plywood was .5" , but having done this I'd still advise following the plans and not making the job more difficult than it already is.
damping is not a plus in this design.
Bob
 
Re: important dimensions

bobmar said:
I made two 166 A's. The second set was better than the first. It's hard to know in advance where the difficulties lie, but all the dimension are important and in drawing the plans you realize just how exact you need to be......Rons notes : no. 4 , is good advice. Using spacers at the turns. Example:On the 1st turn, If you cut thin masonite to the dimensions, 1.92" x7.9" and 2.45" x7.9", plastic tape the edges, so they come out when the glue is dry. you can put it together in a square way. With one side open and the majority of the build is finished, you can check your dimensions on the turns. I actually used epoxy mixed with sand on the turns. It seemed necessary in the 2nd turn where the plywood was .5" , but having done this I'd still advise following the plans and not making the job more difficult than it already is.
damping is not a plus in this design.
Bob

Agree with using spacers on the turns, it certainly made things easier. I found the Austins to be a pleasure to build, and they certainly sound amazing. Here's a shot before I did any final sanding and finishing.

hd009.jpg
 

ronc

Member
2003-03-08 2:22 pm
The smooth bends have nothing to do with extended range. It has to do with efficency and wave front distortion.

I have yet to see a pipeline have square changes in direction, there are 90 degree smooth elbows. The difference between a fluid and air is density of the mass. If you dont think air is dense then hold your hand out the window at 100 mph.Now as it changes from a slug to a wave ,things change.

In a square turn the wavefront (as it rounds the bend) first expands, then compresses then expands again then compresses again. Anytime you compress a slug of air you convert some of the energy to heat which is a loss of efficency.

Anyway a BLH is nothing more than a high tuned BR with a big ole expanding vent that depends on TL and horn action.
ron