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DIYMA Founder
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Discussion Starter · #1 · (Edited)
Nominal spl @ 2.75vm = 87.5db. Pretty good for a 4" mid. All measurements are taken unbaffled in free-air which explains the roughness in the response. The drop below 1khz is also due to the unbaffled loading. The yellow curve is good up until 1khz, for those interested in the low end performance. Note the peak at 5khz, which is consistent in all the measurements. Excellent off-axis performance all the way out to 5khz.



Looks like poor transient response around 4-5khz, possibly due to cone breakup.

Very clean, fast decay.


Some energy storage here at 1.8khz.


Very fast decay.


Some stored energy at the cone breakup point, yet still fairly benign. Excellent dampening.




Clean decay, with some minor issues present.



All distortion tests taken at 96db @ 1m, which represents a fairly good real world listening volume.

I started at 200hz, trying to find a suitable highpass point for this driver. After reaching 800hz, I realized this driver has rather significant second order distortion throughout and doesn't really reach an "acceptable" level until 5khz.

You can see at 200hz, this driver exceeds 10% total harmonic distortion. That's pretty bad...





Getting better...



Finally, distortion below 1%.



Impedance curve, looks like typical edge resonance at 1.2khz.



Appears that the voice coil is centered too high. CMS and BL symmetry is not bad at all though, and if the centering problem were corrected could lower second order distortion significantly. Inductance curve looks poor.

Xmax about 2.5mm 1 way.



T/S parameters:



Strong points of this driver:

1. Affordable
2. Superb off-axis performance to 5khz
3. Good dampening of cone breakup

Negatives:

1. Very high distortion
 

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Premium Member
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57 Posts
If you have the time, would it be possible to give a brief interpretation for those of us who are "graph challenged"? I've read the tutorials and have a vague idea of what I'm looking at. Being a philosophy major didn't prepare me for this!

:confused:

Your overall SQ impressions and recommendations after a speaker has been tested, perhaps in the review section, would be a real help and appreciated.

It's been said before, but deserves to be said again, Great forum!
 

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DIYMA Founder
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4,757 Posts
Discussion Starter · #5 ·
I'm reserving comment until all the data is complete and accurate.

This driver so far, does not perform all that well. Rather high second order distortion at all frequencies up to 5khz. Some energy storage issues around 4-5khz. However, good efficiency for such a small driver.
 

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Would be great to know as well like cdj mentioned a little in depth explination for the graphically challenged person like myself to understand the distortion graphs and such.
 
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