DM-2a, the Super Tweeter
Most commonly used by hi-fi industry today for making the ribbon tweeters (also used by M&D¡¯s pleated Dreams 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-a 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-a diaphragm are painstakingly time consuming. However, this innovative breakthrough has been proven worthwhile; the new DM-2a super tweeter exhibits significant improvement over the original DM-2 version on operating bandwidth, transient response, and sound quality characteristics.
The DM-2a is therefore, a super tweeter based on Dreams AMT technology that mainly designed to respond upon the HF band, from 7KHz up to 35KHz; DM-2a may also be used as the wideband driver (such as on our Maximus-Mini+ speaker), ranged from 950Hz to 35KHz with proper alignments.
DM-2a¡¯s voice diaphragm is built by 38 units of light weight micro elements, has a total moving dimension 15X over a typical 1¡± dome tweeter, yields a much lower FMD pollution and higher power handling, high SPL output capability than the conventional super tweeters. Total 8 units of NdFeB magnets have been structured into the heavy metal to form the magnetic loop; each DM-2a unit is sized ¦µ 100 xD 28mm (¦µ4.0¡±xD1.1¡±) and weights about 0.5 Kg (1.1 lb), very solid and durable.
DM-2a has a typical DC impedance at 4.5 Ohms (¡À0.3 Ohms), completely resistive to whole audio band, without resonance, without inductive or capacitive contributes. This perfect impedance characteristic provides a highly stable operation to power amplifier.
While used as the wideband driver; however, DM-2a requires proper test instruments for the complicated system level alignment. For DIY applications without having sound-level tester, DM-2a is therefore recommended only to be used as the standard super tweeter within the 7KHz to 35KHz frequency range, with an average output efficiency for over 90dB/2.83V/1m to the case.
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.