DM-5, 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 mil) 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 (0.5 mil) polyimide material in 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 newly developed, large DM-5 AMT wideband driver has significant improvement transient response, and sound quality characteristics.
Constructed with 28 heavy-duty 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 400Hz and the Dreams DM-5 driver yields a high frequency and high transient response to 20 KHz.
The DM-5 is therefore, a true over 5-octave wideband driver responsible from 400Hz to 20 KHz, and has a very large composite diaphragm that constitutes over 85 times the driving surface of a 1” dome tweeter into this slim-shaped, large AMT sound reproducer. This unique driver is therefore, allowing for high power handling capability, high SPL output with ultra-low FMD pollution throughout the entire operating bandwidth over the smaller AMT drivers.
DM-5’s large diaphragm is sunk into an extremely strong magnetic loop which utilizes 28 units of large NdFeB magnets creating a sophisticated and expensive structure to ensure proper operation of the driver, thereby yielding an excellent ±30 degree horizontal dispersion characteristic within a 400Hz to 10KHz (-5dB) bandwidth. Vertical dispersion is low, effectively avoiding undesirable reflections from ceilings and floors for better clarity and imaging under all listening conditions; this sharp vertical dispersion characteristic may also be beneficial for building the line-array tower to cut down sound interferences between the drivers.
DM-5 has typical DC impedance at 5.2 Ohms (±0.2 Ohms) and 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. DM-5a has a very steep roll-off slope at the low frequency end. While input signals are lower than 400Hz it will not cause distortions nor “click“ noise; it simply does not respond in this fashion due to its mechanical attenuation.
Each DM-5 module measures 222mm (H) x 90mm (W) x 32mm (D). Its iron frame is extremely rigid and heavy-duty in construction with each module weighing up to 1.5 Kg (3.3 lb). The DM-5 has an average efficiency of 87dB/2.83V/1m within the mid-range band; for 2-way speaker, a crossover point higher than 650Hz is recommended by M&D.
This versatile DM-5 Dreams AMT driver may be designed for the sealed chamber or open-baffle (di-polar) applications; by line-up several drivers together, DM-5 can also be the perfect wideband transducer to build one’s line-array speaker system for absolute hi-fi reproduction.
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 AMT driver requires utmost dedication in both precision technology and artistic craftsmanship throughout its creation. 
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