Waveguides and horns

[jzagaja]

Ok. let's go with the driver...

 

[3GGG]

Can anyone comment on how the Fane 8m will go with a JMMLC200 with a 125mm opening?
I will use a 3lt (approx) rear chamber for the driver.

http://www.diyaudio.com/forums/multi-way/185681-my-le-cleach-horn-build-15.html

 

[cka3o4nuk]

Hello dear comunity
just interested from what distance aceptible to listen e-jmlc horns
Horns
Horns

now i building Yuichi Arai A-290

 

[jzagaja]

Spun aluminum domes - first trial. Plate thickness is 0.1mm, corrugations and cracks appears quickly.

 

[Ed LaFontaine]

Spun aluminum domes.

Use less tool pressure & make more passes to arrive at the finished profile. As the profile develops, change to a larger live center pressure pad (reverse profile) to better distribute the torsional forces.

 

[MikeR]

Spun aluminum domes.

Use less tool pressure & make more passes to arrive at the finished profile. As the profile develops, change to a larger live center pressure pad (reverse profile) to better distribute the torsional forces.

Sounds like advice from a guy that has spun a little aluminum over the years!

 

[jzagaja]

Better use a roller? Smoother surface, more uniform thickness, higher tensile strength. Below Ti diaphragm with TiN coating for benchmark.

 

[noah katz]

Spun aluminum domes - first trial. Plate thickness is 0.1mm, corrugations and cracks appears quickly.

I expect results are very sensitive to alloy and temper - did you use one recommended for that process?

 

[jzagaja]

7up aluminum can (side) that why it doesn't want flow again - was deeply drawn and oriented.

 

[noah katz]

Ah

Now if you could find out what's a suitable type for deep drawing, or try annealing the can material.

Or try cutting the material from the bottom, as it's closer to the final shape.

 

[jzagaja]

New phase plug parts.

 

[jzagaja]

New driver almost ready, magnetizing left. White adapter for 18sound NSD1095N.

 

[dnewma04]

The NSD1095N is currently my favorite 1" compression driver. Are you modding the phase plug on it?

 

[jzagaja]

I mod Polish driver (D800Ti) with Fresnel phase plug and NSD1095N diaphragm. 18sound driver uses hybrid phase plug.

 

[gedlee]

Jacek

If thats is supposed to be a Fresnel phase plug then each open section should be of equal area. Somehow that just doesn't look right. Are you sure that eaach opening has equal area?

 

[jzagaja]

I'm aware they aren't equal. I've used centroids from your paper and maybe in a wrong way.

 

[jzagaja]

I did typo in the first ring from diaphragm side but all in all 3D print is limited on wall thickness and we must take it into account - this 3D print is rough. No problem with a new one and for example 0.5 inch.

 

[gedlee]

Well you need to review the patent again, because the concept of equal areas for all of the channels is critical, just as the concept of a Fresnel pattern also have equal areas. If the ares of the channels are not equal in area and equal in length the the wavefront at the aperature will not be constant, i.e. "flat". This is the central point of the patent.

So if you have three channels then the area of each channel must be exactly 1 / (3 * compression ratio) of the total area of the diaphragm.

The "centroids" tell you the locations for the channels, centroids match centroids, but nothing about their widths. The widths are defined such that each channel has an equal area and covers corresponding Fresnel areas of the diaphragm.

 

[jzagaja]

Divided by compression ratio.

 

[jzagaja]

So you have good eyes for details
Compression ratio is 1:3