Description
Overview
The Master Series M6 mid-woofer is a high stroke, low distortion high output mid-woofer. This speaker features high stroke, low distortion, wide bandwidth, and high power handling. It features a 51mm / 2” voice coil diameter for high power handling and motor force.
The M6 mid-woofer features a split-gap design which provides ±8.7mm of linear excursion, allowing for displacement equal to many 8 inch woofers. The high linear stroke features a flat BL curve for exceptional dynamics and impact.
The M6 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 intermodulation distortion for a much more open and natural midrange.
The M6 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 M6 basket 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 mid-woofer can fit into shallow locations, enabling creative positioning for best acoustical performance.
Crossover Frequency and power handling
The M6 mid-woofer is a wide bandwidth, high stroke speaker. A low pass crossover should be set no higher than 3500 Hz. The actual value should be selected based upon the paired tweeter, midrange, or full-range speaker.
The bottom end is robust, and can often forego a subsonic filter. The following table summarizes general guidelines about a subsonic filter. 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 | Not necessary | Not necessary | Not necessary | Not necessary |
| 100W | Not necessary | Not necessary | Not necessary | Not necessary |
| 200W | 100 Hz | 80 Hz | 70 Hz | 60 Hz |
| 400W | 170 Hz | 135 Hz | 110 Hz | 100 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 | 86 dB @ 1W, 1m (89 dB @ 2.83Vrms, 1m) |
| Resonant Frequency (Fs) | 65 Hz ±10% |
| Total System Q (Qts) | 0.75±15% |
| Equivalent Volume Air (Vas) | 8 liters ±15% |
| Motor Force (BL) | 5.8 N/A ±10% |
| Inductance (Le) | 0.110mH±5% |
| DC Resistance (DCR) | 3.8 Ohms ±5% |
| Moving Mass (Mms) | 21 grams ±10% |
| Electrical Q (Qes) | 0.95±10% |
| Mechanical Q (Qms) | 3.5±15% |
| Diaphragm Surface Area (Sd) | 133 cm²±2% |
| Linear Excursion (Xmax) | 8.7mm one way ±5% |
