Originally Posted by xtremerevolution
What do these numbers mean?
- FS : 31.6 Hz
- Qts : 0.45
- Qes : 0.49
- Qms : 5.64
- VAS : 21.9 L
- Mms : 187.4 g
- XMAX: 19mm one way
And for the following, what does "yields F3 of 50 Hz" mean? What is Qtc alignment?
- 1.25 - 1.5 cubic feet tuned to 30 - 35 Hz
- Yields F3 in the mid to high 20s
- 0.55 cubes for 0.707 Qtc alignment
- Yields F3 of 50 Hz
Fs = Also called F0, measured in hertz (Hz). The frequency at which the combination of the moving mass and suspension compliance maximally reinforces cone motion. A more compliant suspension or a larger moving mass will cause a lower resonance frequency, and vice versa. Usually it is less efficient to produce output at frequencies below Fs, though motion below Fs can cause uncontrolled motion, mechanically endangering the driver. Woofers typically have an Fs in the range of 13–60 Hz.
Qts = Qts is a measure of the driver'* tendency to resonate at Fs, based on its overall characteristics.
Qes = A measure of the driver'* tendency to resonate at Fs, based on its electrical characteristics, like magnet strength, magnetic circuit characteristics, etc.
Qms = A measure of the driver'* tendency to resonate at Fs, based on its mechanical characteristics, like surround compliance, the compliance of the spider, weight of the cone, etc.
Vas = The volume of air that has the same compliance ("springiness") as the driver'* suspension. Because less air is more "springy" than more air, a large Vas represents a "loose" suspension
Mms = Measured in grams, this is the mass of the cone, coil and other moving parts of a driver, including the acoustic load imposed by the air in contact with the driver cone.
Xmax = Linear (one-way) travel of the cone. Xmax is used to determine the maximum linear SPL capability of the driver, and can be defined in a number of ways.
F3 = Is the frequency where the response (loudness) is down from the reference level by 3 dB.
Qtc alignment = value for the damping provided for a driver in a sealed enclosure. Denotes the enclosures ability to control the driver response at resonance. Qtc = 0.707 is the optimum value for sealed enclosures, providing flattest response and highest SPL for deep bass extension.
Let me know if you have any questions on any of the explanations, I can go further into detail if needed.