npdang
08-22-2005, 09:37 PM
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.
http://diymobileaudio.com/pics/hm100z2/fr.JPG
Looks like poor transient response around 4-5khz, possibly due to cone breakup.
Very clean, fast decay.
http://diymobileaudio.com/pics/hm100z2/decay800.JPG
Some energy storage here at 1.8khz.
http://diymobileaudio.com/pics/hm100z2/decay1800.JPG
Very fast decay.
http://diymobileaudio.com/pics/hm100z2/decay3000.JPG
Some stored energy at the cone breakup point, yet still fairly benign. Excellent dampening.
http://diymobileaudio.com/pics/hm100z2/decay5000.JPG
Clean decay, with some minor issues present.
http://diymobileaudio.com/pics/hm100z2/waterfall.JPG
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...
http://diymobileaudio.com/pics/hm100z2/200dis.JPG
http://diymobileaudio.com/pics/hm100z2/400dis.JPG
http://diymobileaudio.com/pics/hm100z2/800dis.JPG
Getting better...
http://diymobileaudio.com/pics/hm100z2/3000dis.JPG
Finally, distortion below 1%.
http://diymobileaudio.com/pics/hm100z2/5000dis.JPG
Impedance curve, looks like typical edge resonance at 1.2khz.
http://diymobileaudio.com/pics/hm100z2/impedance.JPG
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.
http://diymobileaudio.com/pics/hm100z2/klippel1.JPG
T/S parameters:
http://diymobileaudio.com/pics/hm100z2/klippel2.JPG
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
http://diymobileaudio.com/pics/hm100z2/fr.JPG
Looks like poor transient response around 4-5khz, possibly due to cone breakup.
Very clean, fast decay.
http://diymobileaudio.com/pics/hm100z2/decay800.JPG
Some energy storage here at 1.8khz.
http://diymobileaudio.com/pics/hm100z2/decay1800.JPG
Very fast decay.
http://diymobileaudio.com/pics/hm100z2/decay3000.JPG
Some stored energy at the cone breakup point, yet still fairly benign. Excellent dampening.
http://diymobileaudio.com/pics/hm100z2/decay5000.JPG
Clean decay, with some minor issues present.
http://diymobileaudio.com/pics/hm100z2/waterfall.JPG
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...
http://diymobileaudio.com/pics/hm100z2/200dis.JPG
http://diymobileaudio.com/pics/hm100z2/400dis.JPG
http://diymobileaudio.com/pics/hm100z2/800dis.JPG
Getting better...
http://diymobileaudio.com/pics/hm100z2/3000dis.JPG
Finally, distortion below 1%.
http://diymobileaudio.com/pics/hm100z2/5000dis.JPG
Impedance curve, looks like typical edge resonance at 1.2khz.
http://diymobileaudio.com/pics/hm100z2/impedance.JPG
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.
http://diymobileaudio.com/pics/hm100z2/klippel1.JPG
T/S parameters:
http://diymobileaudio.com/pics/hm100z2/klippel2.JPG
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
