Minimal Energy Storage

Loudspeakers are essentially energy converters. They convert electrical energy (the amplifier's signal) into acoustical energy (sound). This involves many highly complex functions and the design of drivers, crossovers and cabinets must balance sometimes conflicting requirements.

Colouration is a catch-all phrase for a variety of problems that afflict loudspeakers. As electro-mechanical devices, they are naturally prone to electrical and mechanical resonances. Poorly controlled mechanical resonances in the drivers and cabinet panes, and electrical resonances in the crossover can grossly affect their acoustic performance.

Mechanical resonances, essentially, are the result of energy storage and delayed release. They are the result "springiness" in the materials. Some of the input power, instead of being converted directly into sound, will be stored in the materials to be released late, sometimes after the original signal has been removed, sometimes at a different frequency and always in an uncorrelated way. Even low-level resonances, which might not be overtly objectionable, can mask detail and cause tone and timbre to take on an unnatural character.

Traditionally, engineers have added damping to lower the Q, the "quality", of the resonance in question. At best, this approach can result in colouration-free loudspeakers at the cost of lower efficiency and limited dynamic range. At worse, the Q of resonance will be lowered, without an accompanying reduction in amplitude. The resonance, while looking smoother on a frequency response curve, will now affect a larger part of the musical spectrum and will be more audible.

Angstrom loudspeakers have benefited from a different line of thinking..........
Resonances have been carefully designed out of the system, while the structures are designed for maximum rigidity.
 

 
 


→ woofer diaphragms are light and rigid. Drivers are carefully designed to move resonances out of the frequency band in which they will be used. This allows the diaphragm to react quickly and accurately to musical signals it is reproducing.

→ steep, 4th order, crossover slopes are utilized to attenuate the out of band resonances beyond audibility. Designing high order crossovers such as these can be problematic, and engineers have traditionally avoided them because of their complexity and high parts cost. Angstrom has utilized the latest technologies in digital data acquisitions and circuit analysis techniques to model crossover/driver combinations. Thus, all Angstrom loudspeakers use network topologies previously restricted to the most esoteric loudspeaker systems.

→ cabinets are built of the best materials and are rigidly braced for structural integrity. The cabinet must provide a stable, platform which the drivers use to launch sound. Any "give" in the cabinet translates directly to loss of detail and unwanted resonance problems. Angstrom's staggered array bracing consists of a series of open "shelves" used transversely in the cabinet in much the same way an airplane wing is braced. These divide the outer enclosure into a series of small rigid panels that resist movement much more readily than a large panel. Furthermore, the braces are staggered unevenly, to ensure that no small panel will be harmonically related to any other. Some models employ open air braces in various configurations strengthening the cabinet and not reducing internal volume.

→ several different damping materials are strategically deployed inside the cabinets according to the specific function they are to perform. They work in conjunction with the braces to make the cabinet a rigid, new-anechoic structure. Angstrom uses Roxul extensively for cabinet damping. Roxul is a spun stone wool product used in construction as a sound insulation sound barrier. Roxul actually traps reverberant sound in trillions of tiny internal chambers.

→ baffles and grilles are an especially important part of the loudspeaker cabinet. On many designs, grilles have been an afterthought. Most engineers just hope that the grille will have the least possible ill-effect on the sound. Angstrom loudspeakers incorporate a special arrangement whereby the grille and baffle are parts of an integrated system working together to provide a smooth acoustic transition from the drivers to the listening room. Angstrom's front baffle boards, on which the drivers are mounted' are made of Ranger board MDF, ranging in thickness from 2 cm to 5 cm. This seemingly small detail produces an inherently stronger, more rigid, cabinet with a much lower resonant frequency. Some models have baffles made from Angstrom's exclusive acoustic-roc. Acoustic-roc
is unique, made from 70% St. Laurent cement and 30% cellulose fibre mated to 3/4" ranger board MDF with a special neoprene glue. Other models incorporate a new baffle made from ranger board MDF and coated with Lamineer. This a new process that actually powder coats the MDF baffle with a rock hard finish which is virtually inert.
 

 
 
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