Below is the data obtained from Klippel (LSI only) testing of the Scan Speak Illuminator 12mu in 4 ohm version. This 4.5″ midrange driver has the goods to deliver hefty bass for a nearfield, compact system or excellent midrange as part of a farfield speaker due to it’s excellent linear stroke (at 5.1mm one-way). The use of shorting rings here help to lower IMD driven distortion (higher frequency distortion caused by pushing the driver to higher excursion levels). To date, this is the best midrange driver I have tested and lives up to the Scan Speak name.
For Frequency Response measurements, please visit ZaphAudio.com (linked here) and scroll down to Sept 22, 2011.
Thiele-Small Parameters
| Re | 3.2947 | ohms |
| Fs | 74.3 | Hz |
| Qes | 0.3906 | |
| Qms | 6.2385 | |
| Qts | 0.3676 | |
| Zmax | 55.9197 | ohms |
| Le | 0.1052 | mH (@ 1khz) |
| Vas | 3.9555 | L |
| Sd | 5857.538 | mm^2 |
| BL | 4.7691 | N/A |
| Cms | 811.5327 | um/N |
| Kms | 123.2362 | N/m |
| Mms | 5.7625 | g |
| Sens | 87.8233 | dB @ 1w/1m |
Large Signal Analysis (LSI)
| Displacement Limits | thresholds can be changed in Processing property page | ||
| X Bl @ Bl min=82% | 6.1 | mm | Displacement limit due to force factor variation |
| X C @ C min=75% | 5.1 | mm | Displacement limit due to compliance variation |
| X L @ Z max=10 % | >6.4 | mm | Displacement limit due to inductance variation |
| X d @ d2=10% | 15.7 | mm | Displacement limit due to IM distortion (Doppler) |
| Asymmetry (IEC 62458) | |||
| Ak | 10.55 | % | Stiffness asymmetry Ak(Xpeak) |
| Xsym | -0.52 | mm | Symmetry point of Bl(x) at maximal excursion |
| Power Series | |||
| Bl0 = Bl (X=0) | 4.7976 | N/A | constant part in force factor |
| L0 = Le (X=0) | 0.15811 | mH | constant part in inductance |
| C0 = Cms (X=0) | 1.3196 | mm/N | constant part in compliance |
| K1 | 0.00364 | N/mm^2 | 1st order coefficient in stiffness expansion |
| Xpse | 8.6 | mm | =-Xpse < X < Xpse, range where power series is fitted |
