Spectra 33

About the Spectra 33

The Acoustat Spectra 33 (also known as Spectra 3300) is a full-range electrostatic speaker system designed with a unique three-panel configuration. It includes two panels for highs and mids and a third panel dedicated solely to bass, providing approximately 50% more radiating area for bass frequencies. This design results in improved bass extension and dynamic impact compared to the Spectra 22 model. The speaker has a frequency response of 30Hz to 20kHz ±3dB, nominal impedance of 4 ohms, and sensitivity of 88dB. It requires about 100 watts of amplifier power. The Spectra 33 features an internal 100Hz crossover accessible via a toggle switch, allowing it to operate full range or to integrate with an external subwoofer directly connected to the speaker. The speaker dimensions are approximately 66 inches high by 31.75 inches wide by 17 inches deep, with a panel array that can tilt back slightly for optimal positioning. Placement recommendations suggest at least 3 feet from the rear wall with slight toe-in for best sound. The speaker bases and original protective socks are noted for good condition in used examples. The sweet spot for listening is relatively narrow, typical for planar electrostatics, but the sound quality is highly regarded for a wide range of music genres. The Spectra 33 is considered a top-tier model in Acoustat's lineup, below only the 4400 and 6600 models. It was manufactured by Acoustat, a US company known for electrostatic loudspeakers since the 1970s. The product is no longer in production and is available only second-hand.