The Project Asylum

Advent Brochure Page 6

magnetic system. The voice coil is suspended in “magnetic fluid” (ferro-fluid) in the magnetic gap. This, plus the use of anodized aluminum for the tweeter voice coil bobbin, allows for highly effective heat dissipation that permits the driver to radiate very high levels in the 10,000 Hz region without danger of thermal damage. (See the box on “The New Advent vs. The Original Advent” for the importance of increased high-frequency energy in this region.) Other factors include a very careful choice of cone size and weight as part of the system concept, to provide enough output and enough efficiency without the need for an overelaborate and over- expensive magnetic structure. The tweeter assembly is flush-mounted on the front panel to minimize unwanted reflections from the front of the enclosure and consequent response irregularities at random points in a listening room. To prevent damage to the cone in normal use around a household, it is protected by a special grille behind the grille-cloth itself.


It wasn’t generally realized until a few years ago that the effective high-frequency response of a speaker depended on the total amount of high-frequency power radiated in several directions from the speaker-not just along the narrow axis directly in front of the speaker. The sound perceived by a listener across the room from any loudspeaker is made up more of indirect sound reflected from room surfaces than of direct radiation from the speaker. If high- frequency power is not spread out in proper proportion to the more easily-spread middle frequencies of music, the overall sound will range from “overbrilliant” to “raspy,” depending on how much high-frequency power is going out along the speaker’s axis. It will not sound right under any conditions.
What makes this question of appropriate dispersion a difficult and complex one is that the dispersion itself is not enough. The kind of design chosen for a high-frequency driver, and particularly its diaphragm, must be capable of handling and radiating power-enough of it to provide not only for the tremendous high-frequency content of some kinds of musical material, but also for the loud levels at which many people want to reproduce that material at home.
Many present systems that were designed for good dispersion of high frequencies do not relate it well enough to the requirement for high-frequency power, and some provide their performance only up to the point where the demands of music begin to get heavy. Many systems that do justice to string quartets do not do the same justice to cymbals, snare drums and brass.

                                  The New Advent Loudspeaker.

The Advent High- Frequency Driver

The Crossover and
High-Frequency Balance Switch.

The single crossover network between low-frequency and high-frequency drivers is a simple LCR design that is also used for “contouring” of electrical input to the requirements of the system’s design across the frequency range. The con- touring action at various points in the frequency range represents a careful choice of octave-to-octave musical balance based on some fifteen years of experimenting with a wide range of recordings of improving but still variable quality.
The overall octave-to-octave balance, a critical concept that no other manufacturer to our knowledge fully explores, was chosen on the basis of exhaustive listening both to recordings and to wide- and narrow-band noise inputs. Although ours is not the only possibly “right” choice, We think you will find it convincing over the widest range of musical material.
  A factor that still varies widely in recordings is the overall high-frequency characteristic - a function both of the amount of high-frequency musical material present and of the amount of extraneous noise and distortion present along with (or instead of) it. To provide for the range of characteristics that exists, a three-position switch on the rear panel of the

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