Theta Digital Casablanca II, Руководство пользователя

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your dealer or subwoofer manufacturer to determine if this is suitable for your particular subwoofer. If the subwoofer is
capable of handling this range, this is potentially the best sounding of Casablanca II's crossover types.
Phase Perfect Crossover Diagram
Butterworth
This is the most common type of crossover used in home theater, speakers and outboard electronic crossovers.
Separate high and low pass slopes and crossover frequencies may be set for speaker sets [Left/Right], [Center],
[Surround Left / Surround Right] and [Center Surround]. (The [Sides] are derived from the L/R Surround channels and
therefore the configuration and crossover parameters for the sides are set in the L/R Surround sub menu). As with
Phase Perfect and Linkwitz-Riley crossovers, it is possible to invert the phase of the low pass for each of these speaker
sets. This allows precise tailoring of the subwoofer response to the main speaker's response. A negative attribute of
this crossover type is that the high and low pass signals have different phase shifts from each other.
Butterworth Crossover Diagram
Linkwitz-Riley
This type of crossover, developed in 1976 by Siegfried Linkwitz and Russ Riley, eliminates some of the inherent
problems of Butterworth filters. Specifically, a Butterworth filter of 12, 18 or 24 dB/octave (or higher) slope exhibits
different phase shifts between the high and low pass outputs. A Linkwitz-Riley alignment solves this problem, as it
exhibits zero phase difference between outputs at all frequencies. Acoustically, this means that if the sound sources
are in proper time-alignment, a smoother frequency response will be realized at the listening position. The Linkwitz-
Riley crossover is only applicable to slopes of 12 and 24 dB/octave. A proper Linkwitz-Riley crossover with a 12dB
slope should have the low pass portion inverted. This is done internally in the Casablanca II.
Linkwitz-Riley Crossover Diagram
A note on crossovers
Casablanca II's complement of crossover options can at first appear daunting. Most surround sound processors offer a
simple selection to set their crossovers: Speaker Small or Speaker Large. When set to small, normally a 12dB/octave
Butterworth crossover is performed at 80Hz. Occasionally, it is a 24 dB/octave slope. This simple setting does not
take into account the huge variations in speaker design and room acoustics and more often than not results in non-
optimum performance. We have endeavored to offer this rich set of options with the aim of superior performance.
With this in mind, following are a few simple suggestions to make this process easier.
A note on home theater
There are a few common misconceptions about home theater and bass reproduction. Chief among them is that the
".1" or "LFE" channel normally contains most or all of the bass information. This is unequivocally false. The LFE
channel contains sound effects such as explosions, rumbling and the like. All other channels (left, center, right, left
surround, right surround) may contain an equal amount of bass, and often do. Their bass, however, tends to be more