Mark K's Speaker Pages
...when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science...Lord Kelvin
Midrange Group 3 test data- Arum Cantus AC130mk2 SB15NRXC30-8 Skanning C-Quenze 15H 520613SD Tang Band W5-1685
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Midrange-er, midwoofer test data
The drivers, and the most current links I could find are listed above. For brevity, I'll refer to them as the AC, TB, SB, and Skanning.
Impedance
Magnified impedance curve.
Nearfield frequency response
FR open frame(dipole) at 0.25m.
Nonlinear distortion at 0.25m, five tone, then triplets centered at 150, 400, and 800 Hz.
Nonlinear five tone distortion.
Skanning in black, compared with the TB.
Skanning in black, compared with the AC
The AC and TB hold their own compared to the Skanning. Yes, the Skanning is better. But not by much...
Now, is the TB or the AC better. See below. The TB is now in black, and the AC in red
So, it's a bit of a wash. A statistical dead heat.
What about the SB? Again, here is the Skanning in black with the SB in red.
Well, that's a bit of a disappointment. As far as low end brute excursion, both the TB and the AC beat out the SB. I guessed the Skanning would, and does, but it's suprising to see the AC and TB beat out the SB.
At 150 Hz
Uh, oh. Higher order distortion for the Skanning. What???? Below is a redo at 1dB less
What gives? It's lead resonance. Just very light pressure on on of the leads makes this go away. More on this later.
OK, the other 3-the TB, followed by the AC and the SB.
Well, look at that. The Skanning is and should be the best, though marred by a lead resonance. The SB is next, followed closely by the AC. The TB lags a little here.
At 400 Hz
All are acceptable, though the SB and Skanning are statistically better.
At 800 Hz
Well, again, the Skanning and SB are excellent, closely followed by the TB then the AC.
Conclusion
And the winner is...well, no one.
The Skanning is the best. Still, the lead slap/resonance is unexpected for such a premium driver. The SB is a fantastic midrange, rivaling the Skanning. Unfortunately, the low end performance is bested by the Tang Band and the Aurum Cantus. Conversely, the AC and TB have excellent low end performance and nice FR curves, but lag behind a little bit in midrange distortion performance.
I can put up with some flaws in an inexpensive driver, and so the Tang Band and the SB probably represent the best value. The AC did suprisingly well, but is also priced a little bit higher.
I wish I had a Scan Speak 5 midwoofer (I have a 5" pure mid, which may compare favorably to the SB but might not be the best on the low end) to compare.
Actually, I wish AC, Tang Band, or SB would charge an extra $50 and use it to improve the motor structure and cone structure. I really think they could come up with a driver that would give equivalent performance to a Scan Speak or Skanning for half the price.
Well, now it's time to mail back the drivers. I happen to own the Tang Bands, so will likely stick them in a small sealed box and see what happens.
As an aside-I have additional measurements on the Skanning and wanted to do additional measurements on the other drivers. But frankly, I don't have enough time to do them currently, and have already held onto the drivers longer than I should have. If anyone is really interested, I will post raw Praxis files for additional measurements of the Skanning. Does this mean that the data is incomplete. Well, I think there is enough here to get the basic flavor right, so to speak.