Description
Overview
The Master Series M3 midrange is a high stroke, low distortion wideband midrange. This midrange has high stroke, very wide bandwidth, and high power handling. It features a 38mm / 1.5” voice coil diameter for high power handling and motor force.
The M3midrange features a split-gap design which provides ±4.5mm of linear excursion, about double of most 75mm/3 inch midranges. This lowers distortion over the operational range and allows a mid to play at least half an octave lower in frequency, allowing better imaging and sonic cohesion.
The M3 has multiple copper shorting rings within its magnetic structure. These features result in exceptionally low inductance at all operational frequencies and across stroke. This further extends bandwidth as well as reduces motional inter-modulation distortion for a much more open and natural midrange.
The M3 uses a thermo-fused woven, strand-oriented-chain hardened polyolefin cone. This cone features very high strength due to the strand orientation of the polyolefin monomer chains, and exceptional internal damping from the polyolefin itself. The thermal fusing ensures an air-tight surface without degrading the woven feature and strand orientation. The result is a cone with over 600 MPa of tensile strength, vastly superior internal damping as compared to carbon and glass fibers, and a density of just 0.9 g/cm3 , approximately 40% that of carbon fiber.
The M3basket is also extremely open and holds the motor structure at the rear, so that basket-based reflections back up to the cone are minimized. Use of a shallow split gap motor structure and custom tooled basket, surround, cone, and spider result in a very shallow mounting depth so the midrange can be placed as high as possible within a vehicle, to raise the stereo image up near the head of the listener.
The M3 comes with a chemically etched steel grille featuring an anti-resonant hole-pattern with size of opening optimized for dispersion. The grille is mounted to the midrange with a friction-fit gasket ensuring vibration-free operation and eliminating visible screws.
Crossover Frequency and power handling
The M3 midrange is a wideband, high stroke speaker. A low pass filter for blending with a tweeter would be dependent upon the tweeter and location of tweeter and the M3. As the M3 naturally rolls off above 12 kHz, it can often be used as a near-full-range speaker without a low pass filter applied.
The following table summarizes general guidelines for a high pass filter for use with the M3. As noted above, this is not a hard-and-fast set of limits, and the final installation needs to be considered when setting actual crossover values and gains.
| Power | 6dB/Oct | 12dB/Oct | 18dB/Oct | 24dB/Oct |
| 50W | 250 Hz | 225 Hz | 200 Hz | 160 Hz |
| 100W | 400 Hz | 300 Hz | 250 Hz | 225 Hz |
| 200W | 450 Hz | 350 Hz | 325 Hz | 300 Hz |
| 400W | Not Recommended | Not Recommended | 400 Hz | 350 Hz |
Note that with lower power applications, these frequencies may be adjusted down; with higher power, you may need to adjust the frequencies up. Again, the actual implementation of the entire system needs to be considered when installing these products. A small sealed chamber behind the midrange can increase mechanical power handling, but may negatively impact thermal power handling.
Thiele Small Parameters
| Nominal Impedance | 4 Ohms |
| Nominal SPL | 84 dB @ 1W, 1m (87 dB @ 2.83Vrms, 1m) |
| Resonant Frequency (Fs) | 149 Hz ±10% |
| Total System Q (Qts) | 1.3±15% |
| Equivalent Volume Air (Vas) | 0.5 liters ±15% |
| Motor Force (BL) | 2.7 N/A ±10% |
| Inductance at 1 kHz (Le) | 0.08 mH ±5% |
| DC Resistance (DCR) | 3.3 Ohms ±5% |
| Moving Mass (Mms) | 4.7 grams ±10% |
| Electrical Q (Qes) | 1.6±10% |
| Mechanical Q (Qms) | 6.3±15% |
| Diaphragm Surface Area (Sd) | 39 cm²±2% |
| Linear Excursion (Xmax) | 4.5mm one way ±5% |
