measure compression driver exit angles

[mga2009]

Hi,

How do you measure a compression driver's exit angle?

I want it to matched to my horn, but I can't find it in my CD's specs.

It's a Denovo Audio DN-250 compression driver, the one that came with many DIYSOUNGROUP kits. It's a threaded 1-3/8 18TPI, neodymiun tiny CD.

No problem if I have to take it apart.

Thanks!

 

[TNT]

Never done it. But.... remove the "tube". Take a piece of paper and roll it to a tube. Insert into the hole of the removed tube. Now if the opening is not a cylinder, you should be able to twirl the paper tube into fitting both the output and entrance section of the CD. Once you think that the now more cone shaped paper roll fits perfectly both the entrance and exit hole, fixate it with some tape.

Once paper is taken out, flatten it on a table and you should see the none parallel sides. Extract angle by using a protractor or some fancy trigonometry.

My 2 €c spontaneous guesswork :-D

Good luck!

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[mark100]

I've made a small angle finder using two cut-short popsicle sticks, and a thumb tack as the pivot. Then compare angle found to a protractor.

Doesn't work if bug screen, phase plug too big for sticks etc (use thinner sticks)

(Fwiw, i don't find angle matching to matter much if any, measurement and audible wise.....)

 

[mga2009]

Well, it seems I overstepped myself...

First of all... what angle I am trying to measure?

I attached some pictures of my driver.

 

[GM]

I give up! Can't find any info on it. 🙁 Doesn't look like it's got a proper throat.

 

[TNT]

It seems the CD has like a tube as exit so comparing the red marked side walls of that tube and the centerline, they are parallel and therefore your exit angle i zero degrees!? If it had an angle it would look like e.g. pic 2 and it had been 11,8 degrees.

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[mga2009]

Thanks for the help! At least now I know what to measure.

I am inclined to think this compression driver is just a "tube like" exit... which sucks...

Cheers.

 

[TNT]

Yes, 0 deg. There seem to be a phase plug (the black nob) in there - all may not be lost 😉 - its there to fix the outgoing wave etc.

But it doesn't look like a top performing product I have to admit... 😉

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