Opera Callas Bookshelf Speakers; pair

The Opera Callas bookshelf speakers are compact in size but anything but small in performance. Designed to deliver a rich, immersive listening experience, Callas was created with the goal of recreating a three-dimensional soundstage that’s stable, focused, and tonally correct. Through exhaustive listening tests and highly selective design choices, every element of the Callas speaker is intended to eliminate fatigue and maximize engagement, whether you're relaxing to jazz or dissecting the finer points of a string quartet.

Key Features

• Two-Way Reflex Design: Compact 14-liter enclosure with rear porting for extended low-frequency response
• Seas Woofer: Custom 7" long-throw polypropylene woofer with annealed diaphragm and copper rings above and below the T-shaped pole piece
• Scanspeak 9700 Tweeter: Renowned 1" soft dome tweeter known for low distortion, wide dispersion, and exceptional reliability
• Switchable Midrange Output: Adjustable +2 dB boost between 300–3000 Hz to fine-tune voice presentation to suit room acoustics and taste
• Acoustic Trap Cabinet: Non-parallel side walls with layered polyurethane foam to suppress internal reflections and cabinet resonance
• High-End Crossover: 2nd-order network built with Mundorf capacitors, MOX resistors, and OFC inductors; bi-amp ready

Cabinet Design

The Callas cabinet isn’t just rigid, it’s a carefully engineered acoustic chamber. With 14 liters of internal volume dedicated to the woofer, the enclosure uses a combination of MDF and curved plywood veneer. The panel thickness varies from 25mm on the sides to 50mm on the front, with milled inner edges to minimize turbulence near the driver membranes. Non-parallel walls combat standing waves, and two layers of absorbent foam (20 cm thick total) act as an acoustic trap. This open-cell foam features a pyramidal profile (7x7 cm base, 3–7 cm height), delivering up to 100% absorption at 500 Hz. By killing reflections rather than coating the entire interior, Opera achieves a midrange with exceptional transparency and articulation.

Drivers

The woofer is a 7" custom Seas unit with an annealed polypropylene diaphragm, optimized for a balance of internal damping and rigidity. The copper rings positioned above and below the T-shaped pole piece help suppress distortion, and its 12mm pk-pk displacement ensures clean, extended bass. Capable of maintaining accuracy well past its 2000 Hz crossover point, it allows for seamless integration with the tweeter across multiple octaves. The Scanspeak 9700 tweeter, a staple in high-end designs, is known for its low distortion, wide bandwidth, and smooth integration. Used across Opera’s flagship models, it brings an unmistakable clarity and balance to the top end.

Crossover Network

The Callas crossover employs a 2nd-order low-pass for the woofer and a 2nd-order high-pass for the tweeter, with electrical phase transitions carefully controlled across the bandwidth. Because the tweeter must perform linearly across a wide frequency range, the 9700 was chosen for its broad response and ample excursion. Component selection is similarly uncompromising: high-quality Mundorf capacitors, MOX resistors, and OFC inductors are laid out to minimize mutual inductance and preserve clarity. Bi-amping is supported via completely separated crossover paths.

Tuning & Placement

Positioning flexibility is baked into the Callas design. A rear switch allows you to adjust midrange output, lifting the 300–3000 Hz range by +2 dB if needed. This makes them adaptable to a wide range of rooms, from cozy listening dens to more lively living spaces. Ideal spacing between speakers ranges from 1.5 to 3 meters, and placement should be at least 5 cm from the rear wall. Toe-in can be adjusted based on taste—crossed in front of the listener, aimed directly, or slightly behind—to fine-tune soundstage depth.

The Listening Room Difference

The Listening Room is a third-generation, family-owned hi-fi store where service is personal, not transactional. Owner Michael Hoatson is directly involved in every sale, and most customers speak to Mike himself by phone or email. From curated system design to delivery and setup support, we’re proud to offer real-world advice, fast answers, and a level of care you simply won’t find at larger retailers.

Specifications