RBH Sound SI-663


Type: Speaker
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For installations where a center channel is intentionally removed from a surround system to allow for design requirements or otherwise cannot be used, the SI-663 is the perfect high-performance solution.


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For installations where a center channel is intentionally removed from a surround system to allow for design requirements or otherwise cannot be used, the SI-663 is the perfect high-performance solution. A pair of these in-wall speakers can eliminate the need for a dedicated center channel when wired for dual channel operation. For situations where a third SI-663 can be used as a dedicated center channel, the trio can be wired in standard configuration, allowing each to discretely provide left, center or right channels for a seamless front sound stage.

RBH Sound SI-663 Review


RBH Sound has established itself as a reputable manufacturer of high-performance audio products, with over 45 years of experience in the industry. Their Reference Series represents the pinnacle of their speaker lineup, and the RBH Sound SI-663 is a standout product within this range. In this review, we will delve into the design, audio performance, installation options, and overall pros and cons of the SI-663.

Design and Build Quality

The RBH Sound SI-663 boasts a solid construction with its MDF enclosure, providing stability and optimizing sound reproduction. The use of dampening fill inside the enclosure further enhances the audio quality by minimizing unwanted resonance. Additionally, the SI-663 features thoughtful design elements that facilitate installation, such as a metal ring around the baffle, foam pieces for securing the enclosure, and a raised baffle for flush mounting with drywall.

Audio Performance

One of the standout features of the SI-663 is its configuration of two tweeters and three woofers. This arrangement contributes to the speaker's excellent audio performance, delivering natural and dynamic sound reproduction. The 6 ½-inch woofer with a rubber surround and black aluminum cone, along with a phase plug, ensures accurate and controlled bass response. The inclusion of an air motion tweeter (AMT) adds to the speaker's capabilities, providing higher dynamics and a rich, smooth sound.

The SI-663's crossover network is also worth noting, as it features high-quality internal components and gold-plated push connectors. This attention to detail in the crossover design ensures seamless integration between the tweeters and woofers, resulting in a cohesive and balanced soundstage.

Installation and Configuration Options

The RBH Sound SI-663 offers various installation options to suit different room sizes and needs. It can be used as a center channel speaker by pairing two SI-663R speakers, with the top woofer and tweeter of each serving as the center channel. This flexibility allows for versatile setup configurations and ensures optimal performance in home theater systems.

When it comes to installation, the SI-663 excels with its install-friendly design. The metal ring around the baffle adds rigidity and durability, while the foam pieces included with the speaker ensure a secure fit within the wall. The raised baffle allows for flush mounting with drywall, creating a seamless and aesthetically pleasing look.


The RBH Sound SI-663 offers a range of strengths that make it a compelling choice for audio enthusiasts. Its audio performance is exceptional, with natural and dynamic sound reproduction that brings music and movies to life. The speaker particularly excels in piano and music playback, providing a close-to-real experience that is sure to impress even discerning listeners. The SI-663 also surprises with its imaging and soundstage capabilities, exceeding expectations for in-wall speakers and creating an immersive listening experience.

In terms of installation, the SI-663's thoughtful design features make the process easier and more convenient. The inclusion of the metal ring, foam pieces, and the raised baffle demonstrates RBH Sound's attention to detail and commitment to user-friendly installation.

Furthermore, the RBH Sound SI-663 is proudly made in America, supporting local jobs and ensuring high-quality craftsmanship.


While the RBH Sound SI-663 has numerous strengths, it does have a few areas where it falls short. One notable drawback is the lack of tweeter attenuation and boundary compensation features. These features are commonly found in high-end speakers and can help optimize sound performance in different room environments. Their absence in the SI-663 may limit its adaptability and performance in certain setups.

Another minor concern is the use of a cloth grill instead of a magnetic metal grill. While this does not impact the audio quality, a magnetic grill offers easier removal and attachment, providing a more seamless aesthetic when the speaker is being used without the grill.

Lastly, availability may be a limitation for some potential buyers, as RBH Sound only sells their products through authorized dealers. This restricted distribution channel can make it more challenging to find and purchase the SI-663 compared to brands with wider retail availability.


The RBH Sound SI-663 from their Reference Series line is a top-of-the-line in-wall speaker that delivers excellent audio performance, thoughtful design features, and versatile installation options. With its natural and dynamic sound reproduction, impressive piano and music playback capabilities, and good imaging and soundstage performance, the SI-663 is a standout choice for home theater setups and audiophile needs.

While the lack of tweeter attenuation and boundary compensation features, the use of a cloth grill, and limited availability through authorized dealers can be considered minor drawbacks, they do not overshadow the overall strengths and performance of the SI-663. If you can find access to this remarkable speaker, it is sure to elevate your home theater experience and satisfy even the most discerning audio enthusiasts.


  • Frequency Response: 55Hz-20kHz (±3dB)
  • Sensitivity: 90dB Main, 88dB Center, and 92dB Combined (2.83V @ 1 Meter)
  • Recommended Power: 75-220 Watts Main, 75-150 Watts Center and 75-400 Watts Combined
  • Woofers: (3) 6-1/2" (165mm) Aluminum Cone Woofers
  • Tweeter: (2) 1" (25mm) Silk Dome Tweeters
  • Tweeter Protection: Yes
  • Swivel Tweeter(s): No
  • Crossover Frequency: 2,700 Hz
  • Crossover Slope: 12dB/Octave
  • Impedance: 8 Ohms Main, 6 Ohms Center and 4 Ohms Combined
  • Baffle and Grille: Baffle Black; Grille Black or White, Sold Separately. Enclosure Sold Separately.
  • Baffle Dimensions: 8" W x 32" H (203mm W x 812mm H)
  • Enclosure Dimensions: 14" W x 56" H x 3-1/2" D (356mm W x 1422mm H x 89mm D)
  • Weight: 59 lbs. (26.76 kg)
  • Warranty: 5 years

Additional Info

Speaker Combinations

Each RBH Sound speaker series can be mixed and combined within the like series, creating a vast selection of options to create a unique home theater experience.