DM-1, Dreams Wideband AMT Driver
Most commonly used by hi-fi industry today for making the ribbon tweeters (also used by M&D’s pleated Dreams AMT drivers), the etched aluminum circuitry is laid on a very thin 0.025mm (1.0mil) polyimide (also known as Kapton) film as the substrate to constitute the voice diaphragm; due to the outstanding characteristics of polyimide such as extremely light weight, high temperature resistance (180-250ºC), excellent durability, and so forth.
However, from M&D’s own study, we found that the attached mass and hardness of the present polyimide substrate could still amount to certain obstruction for perfect diaphragm movements during sound reproduction. In order to further cut down the substrate moving mass and enhance the pleated diaphragm compliance, after long research, M&D has developed the unique technique and craft to further reduce the substrate to only one-half of its original thickness. This successful development allows us to apply the rare, super-thin 0.0125mm (0.5mil) polyimide material in re-formulating our new Dreams series voice diaphragms.
Not only this 0.5 mil super-thin polyimide itself incurs much expensive production cost, the higher level of skilled craftsmanship throughout the entire manufacturing process of the Dreams diaphragm are painstakingly time consuming. However, this innovative breakthrough has been proven worthwhile; the new DM-1 Dreams AMT wideband driver exhibits significant improvement over the original version on operating bandwidth, transient response, and sound quality characteristics.
Constructed with 42 micro elements, forming a 15 micron (0.0006“) aluminum ribbon in thickness, attached onto the super-thin 0.5 mil polyimide diaphragm and pleated into shape, then meticulously fixed onto the acoustic frame; this symmetrical ribbon array directly pumps out (or draws in) a sufficient quantity of air driven by the musical current signal, responding to high dynamic, acoustic power, pushing wideband frequencies down to lower than 700Hz! Thanks to the micro weight of each ribbon unit that is less than 10% of the moving mass compared to a typical 1” dome tweeter, the Dreams DM-1 driver yields a high frequency and high transient response to 25 KHz.
The DM-1 is therefore, a true 5 octaves wideband driver responsible from 700Hz up to 25 KHz, and has a large composite diaphragm that constitutes over 50 times the driving surface of a 1” dome tweeter. Needless to say, very high SPL output with low FMD pollution throughout the entire operating bandwidth is guaranteed.
The whole diaphragm is sunk into an extremely strong magnetic loop which utilizes 21 units of NdFeB magnets forming a curvature, creating a sophisticated and expensive structure to ensure proper operation of the driver, thereby yielding a satisfactory ±30 degree horizontal dispersion (-5dB) characteristic within a 700Hz to 8KHz bandwidth. Vertical dispersion is low, effectively avoiding undesirable reflections from ceilings and floors for better clarity and imaging under all listening conditions. 
The new DM- has a higher impedance design over the original driver, typical DC impedance is up to 5.6 Ohms (±0.3 Ohms). DM-1 is completely coherently resistive throughout the entire audio band, without resonance, and without inductive or capacitive contributes. This perfect impedance characteristic provides a highly stable operative platform for the power amplifier; it also facilitates much simpler and more efficient crossover network design.
The DM-1 has an efficiency of 85dB/2.83V/1m on average, and can easily match woofers through a simple crossover network. In addition, the DM-1a has a very steep roll-off slope at the low frequency end. While input signals are lower than 700Hz it will not cause distortions nor “click“ noise; it simply does not respond in this fashion due to its mechanical attenuation. The DM-1 is the most advanced curved shape wideband modular driver utilizing AMT technology ever made! The module measures 130mm (H) x 144mm (W) x 42mm (D), and the steel frame, 5mm in thickness, is extremely rigid and heavy-duty in construction with each module weighing up to 1.6 Kg (3.5 lb). Different from an assembly line produced product, the manufacturing process of the Dreams module is both time and labor intensive, requiring extensive hours and hours to assemble and test. Rather than just a simple, mass-produced, assembly line manufactured tweeter, the Dreams driver requires utmost dedication in both precision technology and artistic craftsmanship throughout its creation. 
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