10.1 Standing Waves

The parallel surfaces of most listening rooms can lead to a potential problem at any frequency. A sound wave can be repeatedly reflected from opposing surfaces, back and forth. If the distance between the surfaces is an integral multiple of one-half the sound wavelength, a standing wave will be set up. This means that the incident and reflected waves combine with each other so that a stationary pattern of high and low sound pressures is established in the room. This irregular distribution of sound level is caused by cancellation and reinforcement between the reflected and direct sound waves.

At high frequencies, this pattern of high and low sound pressure levels within the room becomes too finely spaced to be discerned. However, when the dimensions of the room are comparable to the wavelengths of the musical notes, there will be obvious changes in the intensity of certain bass notes in different locations within the room. Additionally, the existence of the standing wave implies a resonant condition where acoustic energy is stored in the room. This energy storage can result in "heavy", "muddy", or "slow" bass.

Since the presence of standing waves is caused by parallel reflective surfaces, practically every listening room suffers from this problem to some degree. However, several factors are working in our favor here. First, as the room size increases, the affected frequencies become lower and thereby less audibly apparent. Second, the presence of shelving or furniture against the walls will break up the large surfaces, reducing the magnitude of the problem. Third, upholstered furniture can absorb a significant amount of bass, diminishing the build-up of resonant energy. Fourth, typical wall construction is not completely reflective at low frequencies.

However, in some cases audibly objectionable standing waves will still be present in the listening room. This can be noted by large variations of the intensity of certain bass notes in different areas of the room. Another indicator is an unevenness of loudness of different bass notes. (This is sometimes what is actually on the recording, so be sure that this is consistently a problem on a variety of recordings, or use a variable warble-tone generator.)

If you wish to reduce or eliminate standing waves that may exist in your room, it will be necessary to reduce the low-frequency reflectiveness of at least one of the parallel surfaces of opposing surfaces. The most effective method is to use Tube-Traps, available from Acoustic Sciences Corporation. This is the only commercially available sound treatment that absorbs significant amounts of energy below 400 Hz. Experimentation will be needed to determine the optimal locations.

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Avalon Acoustics Sentinel manual Standing Waves
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Sentinel specifications

Avalon Acoustics Sentinel represents a pinnacle in high-fidelity loudspeakers, designed for audiophiles who demand exceptional sound quality and elegant design. Known for their commitment to meticulous craftsmanship and innovative technology, Avalon Acoustics continues to push the boundaries of acoustic performance with the Sentinel model.

One of the standout features of the Sentinel is its unique three-way design. This configuration allows for precise sound reproduction across the entire audio spectrum, delivering rich bass, articulate midrange, and sparkling highs. The speaker utilizes proprietary drivers that have been engineered to minimize distortion while maximizing dynamic range and sensitivity. This ensures that every note is rendered with clarity and precision, making it ideal for any listening environment.

The cabinet design of the Sentinel is another aspect that underscores Avalon's commitment to excellence. Constructed from carefully selected hardwoods and finished to perfection, the enclosure not only enhances aesthetic appeal but also plays a critical role in acoustic performance. Its solid build effectively reduces resonance and undesirable vibrations, allowing the drivers to perform at their best.

In terms of technology, the Sentinel incorporates advanced crossover networks. These networks are designed to ensure seamless transition between drivers, providing a cohesive soundstage. By using high-quality components, the crossover systems significantly improve the overall performance, ensuring that listeners enjoy a balanced and natural tonal quality.

Moreover, the Sentinel features adjustable bass ports, allowing users to tailor the speaker's performance to fit their specific room acoustics. This flexibility helps to optimize the listening experience, regardless of the environment. The speakers also include easy-to-use bi-wiring and bi-amping capabilities, enabling audiophiles to customize their setup for optimal sound quality.

Finally, the visual appeal of Avalon Acoustics Sentinel cannot be understated. With its sleek lines and contemporary design, it is a statement piece that complements any décor. Available in various finishes, the Sentinel seamlessly blends performance with style, catering to both auditory and aesthetic sensibilities.

In summary, Avalon Acoustics Sentinel stands out as an exceptional loudspeaker that combines advanced technology, exquisite craftsmanship, and customizable features. Its three-way design, high-quality drivers, and adjustable features make it a top contender for those seeking unparalleled sound quality in a luxurious package.
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