Making some 2397 horns.

[Lee in Montreal]

Yesterday was a slow day, so I did some research and started drafting some 2397 horns, with datas from JBL and independent sources. The target is a set of horns to be produced thru CNC machining and requiring the minimal "human intervention". I was thinking mixing wood (top and bottom "saucers") and aluminum (fins, sides and flange), while using plastic is not out of the question. My question is in regard of material, as the original 2397 were made from wood (at least I believe it was 100% wood). Will the aluminum separators/fins be okay over the original wood? Or will using aluminum produce high frequencies that will be too sharp? I am currently mainly enquiring about resonance of materials.

TIA

[Mr. Widget]

I can send you CAD data for 2397s that is likely more accurate than the drawing you posted. In addition I made the ribs with built in tenons that are far more secure than the dowels that JBL used. Send me a PM if you are interested.

Alternatively, if you do a bit of searching on this site you will find numerous postings of my drawings and others' that are based on my drawings.

As for your question about high frequency ringing... as long as your fins are well mated to the tops and bottoms any ringing should be adequately damped.


Widget

[speakerdave]

. . . . My question is in regard of material, as the original 2397 were made from wood (at least I believe it was 100% wood). Will the aluminum separators/fins be okay over the original wood? Or will using aluminum produce high frequencies that will be too sharp? I am currently mainly enquiring about resonance of materials . . . .

The top and bottom of the original are particle board.

[Lee in Montreal]

I can send you CAD data for 2397s that is likely more accurate than the drawing you posted.

Hi Widget

Some measurements are not marked on the drawing, but are actually used. As I work electronically, I can take measures wherever I want. The fins can use dovel pins, but if they are aluminum, then the holes will most likely be threaded to screw both faces. There are many, many ways to fasten both halves.

Nonetheless, I'D be interested to see what you came up with as I was able to calculate the expanding ratio between the fins (and it look very nice), but it seems to flatten out after the fins. The Smith horns have fins to the edge.

Here's my email: massivebrakes(at)gmail.com

Thanks

[totaltech]

G'Day All,
Here a some pics of a pair of shith horns (which the JBL's are based on), that are in progress at the moment!
The beer can on one of the pics is to show scale to a mate who wasn't sure of their size!

Cheers

Rob

Hi Widget

Some measurements are not marked on the drawing, but are actually used. As I work electronically, I can take measures wherever I want. The fins can use dovel pins, but if they are aluminum, then the holes will most likely be threaded to screw both faces. There are many, many ways to fasten both halves.

Nonetheless, I'D be interested to see what you came up with as I was able to calculate the expanding ratio between the fins (and it look very nice), but it seems to flatten out after the fins. The Smith horns have fins to the edge.

Here's my email: massivebrakes(at)gmail.com

Thanks