IIIx Operation IIIx Technical Description
Musical Tastes
An added benefit of the contour controls on the IIIx CROSSOVER, is the ability to adjust your speaker's personality to your style of listening.
It is well known that an “audiophile” listening priority is different from that of “rock” or “classic European” listening orientation. By setting your frequency control to 30 Hz and the boost/cut control to 0dB, you will have what is known as the "Audiophile setting". This setting allows the deepest bass extension and most linear theoretic performance. Experimenting slightly with the boost/cut control will give you either a drier or deeper and more extended performance. However, if a “rock” orientation is your preference, set the frequency control between 40 to 50 Hz with a slight boost, and you will get more of the emphasized percussive effect of rock music. The last priority, “classic European”, consists of a dry, clean, very tight bass structure. It can be accomplished by resetting the frequency control to 30 Hz and turning down the boost/cut control. At this point, you will still have deep and extended bass, but it will be slightly rolled off to give you a very tight, defined performance level.
In the final evaluation, your ears will determine where these controls should be positioned. They have been established for your flexibility and use and can be used much like an accurate bass/room equalizer. So don't be afraid to experiment and have fun!
Theory of Operation
The audio signal coming from the pre- amplifier of your audio system is typically representitive of a low imped- ance voltage source. There are a few preamplifiers, such as older tube designs, which may not conform to this, as they have a much higher output impedance. In addition many cables can change the preamplifiers output characteristics.
In order to assure a high level of performance with all types of preamps and cables, the MONOLITH IIIx CROSS- OVER has a high input impedance, low output impedance buffer for its first stage. Futhermore, since there is no substitute for isolation to prevent various filter sections from interacting with each other (normally the high pass and low pass filters), the MONO- LITH IIIx CROSSOVER has a separate buffer for the
These buffers are designed using two complimentary
In being a dedicated electronic crossover/equalizer, it is vital to tailor the system to the needs of the speaker. Planar speakers have two main areas of concern: 1) Rear wave cancellation, which causes a decrease in the speaker’s output below 500 Hz, and 2) Primary resonance, which is the frequency the speaker is tuned to.
Rear wave cancellation requires corrective equalization beginning at
500 Hz and increasing to roughly 12dB at 100 Hz. Primary resonance affects this response as well, because the speaker is effectively out of control at primary resonance. A notch filter works well to negate the effects of this typically 12dB resonance. The decision of resonance tuning and rear wave cancellation compensation, combined in balance with the high frequency roll- off point, is a system decision based on the sonic properties of the speaker itself.
The MONOLITH IIIx CROSSOVER's high- pass pathway utilizes three separate filter sections; one for raising energy between 100 Hz and 500 Hz, empha- sizing 100 Hz (referred to as a shelving filter), another for decreasing energy at the speaker resonance (notch filter) and a third
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