Vintage - Rare - M&K MX-90 Deep Base Dual 12" Driver Powered Subwoofer - 125watts RMS

Vintage - Miller & Kreisel MX-90 Push-Pull Dual 12"Driver Powered Subwoofer. Conservatively rated at 125 watts RMS.
Frequence Response: 20-125 HZ +/- 2 dB
Low Pass Filter: 36 dB/octave low pass cutoff above 125 Hz. Set roll off between 50-125 Hz.
Serial Number: 477198
23" X 15 1/4" X 19 5/8"
70 Lbs.
Black Oak
Excellent condition. Ships in Original box.

Additional information from the manufacturer:

M&K MX-90 Powered Subwoofer
The MX-90 delivers a conservative 125 watts RMS. This honest M&K rating meets FTC power standards and the most stringent worldwide safety standards (UL, IEC-65, CSA) unlike the fantasy power ratings of so many other powered subwoofers.

Push-Pull Dual 12" Drivers &
Deep Bass Configuration
M&K's Push-Pull Dual Driver Configuration delivers a major improvement in bass detail and articulation by virtually eliminating even-order harmonic distortion and doubling the sound power per watt of amplifier power, allowing for a minimum of 6 dB in additional output!
The MX-90's Deep Bass design produces significant bass to frequencies as low as 10 Hz. Conventional subwoofers have extremely sharp rolloffs around 30 or 40 Hz (especially subs with passive radiators or vented cabinets, which have a minimum 24 dB/octave rolloff). The MX-90's deep bass to below 20 Hz frequencies that we feel but can't hear gives it a lifelike power and authority other subwoofers cannot match.
The MX-90 uses two each of the exceptional new advanced 12" speaker driver, for extremely tight, low distortion bass. The improvement in articulation is easily audible. This exceptional performance comes from many proprietary M&K design elements.
Adjustable Low-Pass Filter
The subwoofer also has M&K's standard Low-Pass Filter, which is continuously adjustable between 50 and 125 Hz. Above 125 Hz, a 36 dB/octave rolloff makes the subwoofer truly non-directional. In addition, a two-position switch matches subwoofer and main speaker phase without the muddy sound of variable phase controls (which introduce phase and group delay anomalies).
Low-Level RCA Input Only
Because virtually all of today's best preamps, controllers, and receivers have a low-level (RCA) subwoofer output, the MX-90 does not include costly and unneeded 5-way binding posts. Low-level inputs give the best sound, and are the only technically correct way to feed a subwoofer from multichannel components.
For amps and receivers with speaker outputs only (no preamp or subwoofer outputs), M&K has available an optional separate RM-2 High-Level to Low-Level Converter & Remote Volume Control. This interface component lets you drive the subwoofer with a high-level amplifier signal.
The MX-90 cabinet dimensions are 23" high by 15 1/4" wide by 19 5/8" deep. It weighs 70 lbs.