Feel free to ask questions. I'll do my best to answer.

Friday, August 26, 2011

Large Driver Cone Treatement

the Eminence Delta ProA.

Yes, their response graph is optimistic.

Prior to any treatment, the one's polar response looked like this:

I didn't do the other one out of sheer laziness.
After one round of stiffening and surround damping treatment I got these:

after the next round those went to these respectively:

another round makes

into this:

and this:

into this:

Time elapse on these showed similar results, but I didn't save the graphs or the drivers.

Cone Treatments Demonstrated To Work (Time Elapsed)

one driver over the initial curing as of June 9,2010:

Same driver in slightly different measuring conditions today June 22, 2010:

Prior to any treatment:

The Mod Podge Hard Coat still has 2 more weeks prior to full cure as of this graph where the Aleen's is well beyond its stated curing time. 

Cone Treatments Demonstrated To Work (Geometrical Stiffening)

Polar after large dust cap added:



The other driver:

Cone Treatments Demonstrated To Work (Surround Damping)

Here's that same driver after damping the rim 3 times with the Aleene’s® Flexible Stretchable™ :


Average of Polar

Here's another driver start to finish I did all the same things to:



Next up, Geometrical stiffness.

Cone Treatments Demonstrated To Work (Stiffening)

Here's the new driver prior to cone stiffening treatment with Mod Podge® Hard Coat:

and after:

The impulse before:

and after:

Average of polar response before:

and after:

So what do we get?  A higher rim resonance, deeper notch(es), reduced efficiency, and a little better impulse response.

Cone Treatments Demonstrated To Work (Damping II)

Check out this same driver's impulse responses from the exact same angles.  Here's just the first and the last:


Then the first and last polar response average:


You can see that the weight has apparently reduced efficiency.

Cone Treatments Demonstrated To Work (Damping)

OK, here's a super cheap FRer's polar response from 11.25 degrees to 90 degrees in 11.25 degree steps straight out of the box:

Then I teated the surround with Aleene’s® Flexible Stretchable™ :

That was more change than I had expected--and for the better!  So I tried again:

Notice that the rim resonance is down 6dB from the original after just 2 treatments!  I though it could get no better, but figured what the heck, throw another slab on. This time I also added some yellow glue around the rim of the cone:

Another improvement so I did the same again:

OK, so in many respects this one is starting to look worse.  I figured there was still a change and I should now just see where it goes.  I didn't want to see worse again, so I didn't add any more yellow glue to the rim and damped the whole cone.

and again:

and yet again:

That's where I stopped for a listen.

I'll follow this up.