Enclosures
The Milestones cabinet consist of two enclosures, one for the woofer, and one for the midrange and tweeter.Bass reflex enclosure
In 1973, in the Journal of Audio Engineering Society, Richard Small published an article called “Vented-box Loudspeaker Systems”, where vented loudspeakers are modeled as fourth order high-pass filter. Vented loudspeaker design became more predictable, though still quite complicated. Another approach for designing vented speaker systems is taken by Friedemann Hausdorf of Visaton.In our case the enclosure dimensions are fixed, because they are inspired by the Avalon Opus Ceramique. The inner dimensions of the cabinet (taking in consideration the thickness of the wood) are 9,4dm x 2.0dm x 3.3dm (h x w x d), which results in 62 liters. To determine the effective volume of the C^2 220-T6, we need to subtract the volume of the cabinet of the mid/tweeter section (1.5 x 2.9 x 1.95 = 8.5l), the volume of 2 internal braces (2 x 1 = 2l), the size of the inner plate of the bottom plate (2 liter), the inner size of the woofer (about 1l), and the lost space due to the edged corners (about 1.5l each). This results in an effective volume of about 62 - 19.5 = 42.5 liters. The moderate filling effectively increases the volume. So the total volume will be somewhere between 45 and 50 liters. For calculation purposes, we assume 47.5 liters.
Sealed enclosure
The C^2 79 has its own sealed enclosure. The effective volume (h x w x d) of this cabinet is 2.6 x 1.95 x 1.2 = 6.1l. With a fs of 96Hz, Vas of 3.1l, and Qts of 0.51, this results in a Qtc of 0.58 and a resonance fc of 110Hz. The filling will increase the effective volume, and hence in practive the resonance frequency fc and Qtc is a bit lower because of filling.The tweeter is shielded from the backside by a plastic cover.
next ->