Norman Labs Model 331 Loudspeaker

In the mid-1970s, Norman Labs, based in Norman, Oklahoma, developed a reputation for building high-fidelity loudspeakers that delivered natural sound reproduction and rugged reliability. The Model 331, introduced as part of their acclaimed line, embodies the company’s philosophy: quality components, solid cabinetry, and performance that outpaces its modest footprint.

Acoustic Design

The Model 331 is a three-way acoustic suspension system, carefully engineered for smooth frequency response and low distortion. Its driver complement includes:

• 10-inch woofer with a treated paper cone for deep, controlled bass.

• 4-inch midrange driver in a sealed sub-enclosure for clarity and presence in vocals and instruments.

• 1-inch dome tweeter, designed to extend high frequencies with precision and sparkle, without harshness.

Together, these elements produce a balanced soundstage, suitable for both critical listening and dynamic rock playback.

Cabinet Construction

Crafted from dense, furniture-grade particleboard and wrapped in hand-finished walnut veneer, the 331’s cabinet is as much a piece of décor as it is a performance instrument. The enclosure minimizes resonance, while the removable sculpted grille cloth provides protection without compromising sound.

Performance Highlights

• Frequency Response: 35 Hz – 20 kHz (±3 dB)

• Power Handling: Recommended amplifier power up to 100 watts RMS

• Impedance: 8 ohms nominal

• Efficiency: High sensitivity allows use with moderate-power receivers and amplifiers common in the ’70s.

The result is full-range sound with tight, musical bass, natural midrange, and open highs—ideal for reproducing everything from orchestral works to electric guitar riffs.

Placement Versatility

Designed with the living room in mind, the Model 331 performs equally well on the floor with short risers or elevated on sturdy stands. Its acoustic suspension design allows for placement closer to walls without muddying the bass response.

A Commitment to Sound

Every Norman Labs loudspeaker, including the Model 331, was hand-built and tested in Oklahoma. The company’s direct-to-dealer sales model meant audiophiles could own a speaker that rivaled far more expensive brands, while supporting American craftsmanship.

The Norman Labs Model 331 brought the warmth, accuracy, and durability that made the brand a favorite among discerning listeners of the 1970s hi-fi era.