amplification directly connected to the high- and low-frequency sections of the crossover. There are two different methods for bi-amping with two stereo amplifiers. The first and most common is referred to as Horizontal Bi-amping. The second method is referred to as Vertical Bi-amping. With either meth- od you may use two stereo amplifiers or four mono amplifiers, or two mono amplifiers and one stereo amplifier. Get the idea? With either form of passive bi-amplification, your preamplifier must have dual outputs. If your preamplifier is not so equipped, you must either purchase or construct a “Y” adapter.

Horizontal Passive Bi-Amplification Horizontal bi-amping allows you to use two differ- ent types, models or brands of amplifiers (i.e. tubes on top, transistor on the bottom). However, we rec- ommend that you use two identical amplifiers (i.e. same brand and model). If you must use two differ- ent amplifiers, it is essential that they have the same gain or that one of the two have adjustable gain so that you can match their gain characteristics. If the amplifiers of choice do not have the same gain characteristics, then a sonic imbalance will occur. With horizontal bi-amping, one amplifier drives the high-frequency section of the speaker while the sec- ond amplifier drives the low-frequency section. To horizontally bi-amp your speakers you must loosen the binding posts and remove the jumper clips.

Connect the low-frequency amplifier to the lower set of binding posts of both speakers. Connect the high-frequency amplifier to the upper set of binding posts. Next, connect the left and right preamplifier outputs to the appropriate left and right inputs of both amplifiers (Fig. 3).

Vertical Passive Bi-Amplification

The very nature of vertical bi-amping dictates that both amplifiers be identical. With vertical bi-amp- ing, each of the stereo amplifiers is dedicated to one speaker. For instance, the left channel of each amplifier drives the low-frequency section while the right channel drives the high-frequency section. To vertically bi-amp your speakers you must loosen the binding posts and remove the jumper clips from both speakers. Starting with one speaker, connect the right channel to the lower binding posts and the left channel to the upper binding posts. Repeat the same procedure for the other speaker. Connect the left preamplifier outputs to both inputs of the left channel amplifier and the right preamplifier outputs to both inputs of the right channel amplifier (Fig. 4).

ACTIVE BI-AMPLIFICATION

We do not recommend active bi-amplification. The internal crossover can not be bypassed. This con- nection method seriously degrades performance.

Assembly and Placement

BREAK IN

Allow approximately 72 hours of break-in at 90 dB (moderate listening levels) before any critical listening.

PLACEMENT

Although your speakers are designed to deliver a superb sonic performance when placed close to a

wall, you may notice improved imaging and detail if you are able to place the speakers (measured from the tweeter and woofers) 2–3 feet from the front wall and 2 or more feet from the side walls (Fig. 5).

TOE-IN

To achieve superior stereo imaging we recom-

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MartinLogan 20, 40 user manual Active BI-AMPLIFICATION, Break, Placement, Toe-In
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40, 20 specifications

MartinLogan has long been recognized as a leader in the world of high-end audio, and their speakers, particularly the MartinLogan 20 and 40 models, embody the pinnacle of their innovative approach to sound reproduction. These speakers integrate cutting-edge technology with stunning design, ensuring that audio enthusiasts receive an unparalleled listening experience.

The MartinLogan 20 is a testament to the brand's commitment to electrostatic speaker technology. One of its standout features is the proprietary, high-performance, foldable electrostatic transducer. This design allows for an extremely fast response time and remarkable clarity in sound reproduction, capturing every nuance of the audio. The speaker also boasts a frequency response that extends from 34 Hz to 20 kHz, ensuring rich, deep bass and crystal-clear highs.

On the other hand, the MartinLogan 40 model enhances this experience with additional features geared toward an even wider sound stage. It incorporates a unique Active Bass Control system, which allows users to adjust low-frequency performance to match their room's acoustics. This adaptability is complemented by a dynamic woofer designed to deliver powerful bass without distortion, even at high volumes.

Both models utilize advanced materials, such as the lightweight and rigid aluminum frame construction, which contributes to a more focused and accurate soundstage. Additionally, they feature advanced crossover networks that seamlessly blend the electrostatic and dynamic drivers, ensuring a cohesive sound that immerses the listener.

The aesthetic appeal of MartinLogan speakers cannot be overlooked. The 20 and 40 models feature elegantly curved cabinets with a striking finish that complements any décor. Beyond their beauty, the speakers are engineered for optimal placement in various environments, including home theaters and dedicated listening spaces.

Moreover, the models are equipped with bi-wire capability, allowing audiophiles to use separate cables for the high and low frequencies. This feature enhances the overall performance and offers a level of customization for advanced users.

In conclusion, MartinLogan's 20 and 40 models represent a harmonious fusion of groundbreaking technology and artistic design. With their exceptional sound quality, innovative features, and elegant aesthetics, these speakers are well-suited for discerning audiophiles who demand the best from their audio equipment. Whether for a casual listening session or an immersive cinematic experience, these speakers elevate the auditory journey to new heights.
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