PINNACLE^® Loudspeakers is a well-established U.S. speaker manufacturer--they've been in business since 1976. They make high value, stereo and home theatre speaker systems that utilize top quality components, and offer performance that equals or exceeds that of rivals costing far more. The current product line includes three powered subwoofers that share the same cabinet dimensions (a tiny cubical box about 15-inches on a side) and appearance. All three use 12-inch polycone drivers and efficient, powerful switching amplifiers. The Digital Sub^TM 150 and the Digital Sub^TM 250 are straight forward, air suspension designs with electronic equalization. The Digital Sub^TM 350 is a compound (Isobarik) design with two drivers, one behind the other. PINNACLE^® submitted the 150 and 350 models for this review.

The Digital Sub^TM 150 comes in a premium black vinyl cabinet just large enough to house its 12-inch driver. Its dimensions are 15 x 14.25 x 15 inches. The removable black, cloth-covered grille has a gold PINNACLE^® badge at the bottom center, and covers nearly the entire surface of the front of the cabinet. Solid brass, cone-shaped feet are furnished to improve bass definition by minimizing cabinet movement in reaction to cone movement. They work. The appearance is simple and not particularly striking, but this subwoofer is so small you will hardly notice it in the room anyway. The back panel has no protruding heat sinks as this product uses a switching power supply. There are blade-type (sometimes called push-to-connect) speaker-level inputs and outputs, line-level inputs, a phase switch, a volume control, and a control to vary the low-pass frequency from 75-180 Hz.

The Digital Sub^TM 150 uses a 12-inch polypropylene cone driver with a 1 1/2-inch dual-layer voice coil, a foam surround, and a 20-ounce magnet. This driver is mounted in a second-order, sealed enclosure and driven by a 150 watt amplifier with a switching power supply and discrete MOSFET output devices. A switching power supply is efficient, offering high power with low heat at minimum cost. An anti-clipping circuit, active second-order low-pass and passive first-order speaker-level high-pass filters are included. The low-pass filter is variable over the range of 75-180 Hz but there are no calibration markings between these minimum and maximum frequencies, so you have to measure as I did, or guess to achieve the desired crossover frequency.

The little PINNACLE^® 150 has surprisingly linear response, producing 100 dB at 50 Hz, a peak undistorted output of 103 dB at 40 Hz, and dropping only slightly to 101 dB at 35 Hz. Output at lower frequencies remained virtually flat giving 100 dB at 30 Hz and 99 dB at 25 Hz before rolling off sharply. This subwoofer will play louder than this but can be easily driven into doubling, a form of harmonic distortion usually caused by the voice coil leaving the gap. Is this a problem? Well, that depends. Doubling raises the intended frequency an octave and distorts the waveform, which is hardly noticeable on sound effects if the peak is brief. For music this type of distortion is objectionable, but 103 dB at 40 Hz is pretty loud for music and lower levels are reproduced cleanly. As long as the volume remains below the level where distortion becomes audible, bass is tight and well defined, pitch definition is very good, and rhythm and pace are easy to follow. This is excellent performance for the price when reproducing music. Punch and slam on sound effects is pretty good but can overload the subwoofer if level's are too high.

The PINNACLE^® Digital Sub^TM 150 costs only $595 and offers excellent performance for a product in this price category. It can be overdriven on loud effects, so using two would be advisable in larger rooms, but I think everybody should have at least two subwoofers anyway. One of these will be enough for smaller rooms (or lower levels), offering very good performance for music or film sound. At its modest asking price, this subwoofer is a real bargain.

The step-up product in the line is the Digital Sub^TM 250 (not reviewed). It utilizes a more robust 12-inch polycone driver with a 2-inch voice coil, rubber surround, and a 40-ounce magnet. The internal amplifier is a more powerful Class D switching device that produces 250 watts RMS continuous power. The cabinet looks the same as the 150 model, but the higher quality internal components should offer improved performance. The price of the Digital Sub^TM 250 is $850-still a very good deal.

Richard Hardesty / Widescreen Review Volume 6, Number 4, Issue 26