This patent is really rich. Just beyond words. Right from the opening the BS meter is off the charts:
"According to implementations of the invention, new and improved transducers (a woofer for example) are specifically designed to match or more closely match the mass of the musical instrument producing the music. For example: a woofer is designed to be highly compliant with very low moving mass and a low resonant frequency. Existing known obscure transducers that were never intended to be applied in speakers for this purpose work and have been used experimentally to prove the concept. New transducers may be designed to further extend and prove the concept. For example,
current copper-clad aluminum windings of existing transducers could be
replaced with copper-clad beryllium windings to significantly reduce the mass of a transducer."
Omg, because they use beryllium in tweeters it must be better, it must be lighter, of course people will replaced aluminum in voice coil windings. Why do we use aluminum? Because it's cheap, has excellent thermal conductivity, relatively good electrical conductivity, and low density. Beryllium has inferior electrical conductivity and thermal conductivity, but lower density. It is not remotely cheap. But given that it has even less electrical conductivity and thermal conductivity than aluminum it would be a poor material to make coil windings out of, nevermind actually fabricating the coil given the toxicity of pure beryllium. Note that if you actually use a beryllium-copper alloy and not just copper-clad beryllium you do get a very strong metal, but the conductivity is still well down from straight copper.
A table:
Element: __________ Electrical Conductivity _______ Thermal Conductivity ________ Density
Beryllium __________ 2.5×10^7 S/m ______________ 2.01 W/cmK __________________ 1.848 g/cc
Aluminum _________ 3.8×10^7 S/m ______________ 2.37 W/cmK __________________ 2.702 g/cc
Copper ____________ 5.9×10^7 S/m ______________ 4.01 W/cmK __________________ 8.96 g/cc
Silver (for fun) _____ 6.2×10^7 S/m ______________ 4.29 W/cmK __________________ 10.5 g/cc
Here's another great blurb to go with the image below (also from the patent):
"FIG. 8 illustrates the benefits of embodiments of the invention. FIG. 8 shows a frequency response chart of an input signal superimposed on frequency response charts of a relatively high-mass transducer and a relatively low-mass transducer. Both transducers used for the frequency response charts are efficient transducers and have linear frequency responses extending to 18 kHz. The input signal is an 800 kHz triangle input, with the fundamental frequency represented by the largest peak. As can be seen from the respective graphs, the relatively low-mass transducer achieves a frequency response that is significantly closer to the original source signal. In contrast, the relatively high-mass transducer is unable to reproduce the original source signal, with a strong low-pass filtering effect being visible, resulting in nearly 10 dB attenuation in the upper frequency ranges. Thus, FIG. 8 illustrates the high-mass transducer's inability to reproduce higher frequencies and the resultant loss to the ear of perceived overtones."
So a triangle, which has a mass approaching half a kilogram, is producing a fundamental at 800 Hz, but the patent says the transducer has a moving mass less than that of the instrument producing the fundamental? So if everything up to a 30" subwoofer has a moving mass less than the triangle, then this patent thinks it's covering any array of drivers except massive subs? If the driver needs to be lighter to produce the harmonics of the instrument, why do we care about the multiple-order harmonics of an instrument vastly heavier than the supposed tweeters that the patent is intended to reference? How this graph was created is beyond me- were the drivers driven with only the fundamental signal from the triangle?? If a tweeter that measures as linear and another different tweeter are both sent a signal to produce a 3 kHz signal, they had better both produce it at the same volume if they have the same sensitivity, regardless of whether the fundamental originated from a triangle or whatever. This is so mind-bogglingly stupid it's insulting.