Cornwall III

[jwc]

Doc, I agree with your post. "loss of extension to gain SPL". I also agree that the curve looks funny. However, this same type curve is obtained with several different K33's. I know I am running the software right because when I put in different eminence woofers, the curve will match what is posted by parts express with their suggested cabinet volume and ports.

You know, the WinISD program by default wants the K33 in a Large cabinet like 9 cubic feet to get a flat response. And yes, there is loss in SPL.

Back to the main topic:

Michael, if you find out any info on the port change so far, please chime in. I am going to assume the cabinet structure/volume is the same. You seem to be the front runner on this topic so I am bumping these questions of you.

Also, maybe I missed the standing wave explanation on this thread. I heard right away about the problem on the older CW. But what exactly is the standing wave and what is this doing to the audio listener. Also, is this a function of the cabinet....tall...shallow....wide. I just ask because I wonder if it could be an issue for us Cornscalars who have made more "boxy" cabinets.

jc

[JSharp]

Well that shows I don't know

squat about making a mold! What I would like explained

is why it would cost so incredibly much. Especially if you have a

metal K-600 or plastic K-601 from which to make the mold. I guess

I just do not see exactly what is so hard and/or labor intensive about

it.

Are you thinking of casting new horns

from a cast mold of the original part? An injection mold means

squirting liquid plastic into a cavity the is machined from expensive

tool steel. A mold for a horn would require lots of moving parts,

called slides, that need to move out of the way, as the mold is opened,

in order to remove the part. Think of the horn itself as airspace

surrounded by steel. Hard to explain without seeing it. I will attach a

picture of a simple mold core and cavity. It is a highly skilled

profession (5 year apprenticeship in the U.S.) we make decent money for

that skill, so the labor rate is high in the U.S. Also, steel prices

have a huge impact on the final cost. Steel is in high demand these

days due to demand issues forced by the rapidly increasing Gross

Domestic Product of China. Basically they need more steel, so we all

pay more for it. I hope I am making sense here.

Actually, if you did the tool with the part line at end of the horn

mounting face, the whole part is "in draft" so you wouldn't need any

slides. Of course the part might want to hang on the core as it shrank

and the tool opened and depending on the curvature and surface texture,

you might never get it off. [] It would make for a pretty deep

tool. And if you had to use a collapsing core you're talking big

$$$

The problem I think is cutting the cavity. You'd need to make the

cavity in 2 pieces to allow you to get down inside the cavity and

finish it all the way to to the throat...

--

Jim - who has designed a few injection molded parts and worked in a tool and die shop in a former life...