This document is an operation manual for Miller & Kreisel (M&K) powered subwoofers, covering models MX-700, MX-200, MX-125 Mk II, MX-105 Mk II, MX-70B, VX-100, V-125, V-75 Mk II, and VX-7 Mk II. It provides comprehensive instructions for setup, operation, and maintenance of these deep bass powered subwoofers, designed to enhance audio and multichannel audio/video systems.
Function Description:
M&K powered subwoofers are designed to reproduce deep and powerful bass frequencies, complementing satellite or main speakers in an audio system. They are non-directional below approximately 100-150 Hz, meaning their placement does not affect the perceived direction of bass sounds, which are instead localized by higher frequency overtones from the satellite speakers. All M&K powered subwoofers feature exceptionally sharp (36 dB/octave) low-pass filters to remove unwanted midbass and midrange frequencies, ensuring that the subwoofer only reproduces the intended low-frequency content.
Important Technical Specifications:
- Models Covered: MX-700, MX-200, MX-125 Mk II, MX-105 Mk II, MX-70B, VX-100, V-125, V-75 Mk II, VX-7 Mk II.
- Low-Pass Filter: 36 dB/octave slope, adjustable up to 125 Hz. The "LOW PASS FILTER" control provides a rolloff of 12 dB/octave up to 125 Hz, where it shifts to 36 dB/octave. A setting of 85 Hz is generally recommended for optimal blend with M&K Satellites.
- Inputs: RCA-type jacks for preamp-level connections (preferred for MX-700, MX-200, MX-125 Mk II, VX-100) and speaker wire connections (for MX-70B, V-125, V-75 Mk II, VX-7 Mk II).
- Power Requirements (Switched Outlet Minimums):
- 200 watts: V-100, V-75 Mk II, VX-7 Mk II
- 300 watts: MX-105 Mk II, MX-125 Mk II, MX-70B, V-125
- MX-700 and MX-200 should not be used with switched outlets.
- Fuse Values (U.S. Standard, 3AG-250 VAC SLO-BLO 1 1/4" x 1/4"):
- MX-2000: 110v 6 amp, 220v 3 amp
- MX-300: 110v 6 amp, 220v 3 amp
- MX-200: 110v 4 amp, 220v 2 amp
- MX-700: 110v 5 amp, 220v 2.5 amp
- MX-145: 110v 2.5 amp, 220v 1.25 amp
- MX-125 Mk II: 110v 4 amp, 220v 2 amp
- MX-100: 110v 4 amp, 220v 2 amp
- MX-105/Mk II: 110v 2.5 amp, 220v 1.25 amp
- MX-90: 110v 2 amp, 220v 1 amp
- MX-80: 110v 1.25 amp, 220v .75 amp
- MX-70/MX-70B: 110v 2 amp, 220v 1 amp
- V-100: 110v 4 amp, 220v 2 amp
- V-125: 110v 2 amp, 220v 1 amp
- V-90: 110v 1.25 amp, 220v .75 amp
- V-75/V-75 Mk II: 110v 1.25 amp, 220v .75 amp
- V-3B: 110v 1.25 amp, 220v .75 amp
- VX-4: 110v 1 amp, 220v .75 amp
- VX-7B/VX-7 Mk II: 110v 1 amp, 220v .75 amp
- VX-100: 110v 2 amp, 220v 1 amp
- Fuse Values (IEC 127-2/III Standard, 5 X 20 mm timelag "T" fuse):
- MX-2000: 220v 2.5 A
- MX-300: 220v 2.5 A
- MX-200: 220v 1.6 A
- MX-145: 220v 1 A
- MX-125: 220v 1.6 A
- MX-100: 220v 1.6 A
- MX-105/Mk II: 220v 1 A
- MX-90: 220v 800 ma
- MX-80: 220v 630 ma
- MX-70/70B: 220v 800 ma
- V-100: 220v 1.6 A
- V-125: 220v 800 ma
- V-90: 220v 630 ma
- V-75/V-75 Mk II: 220v 630 ma
- V-3B: 220v 630 ma
- VX-4: 220v 630 ma
- VX-7/7B/Mk II: 220v 630 ma
- VX-100: 220v 800ma
- Magnetic Shielding: MX-700, VX-100, and V-125 are magnetically shielded. Other models are not and require 2-3 feet clearance from televisions.
- Warranty: Three-year limited parts and labor warranty, transferable to subsequent owners. Covers subwoofer amplifiers but excludes abuse, misuse, unauthorized repairs, speakers without serial numbers, and shipping/accident damage.
Usage Features:
- Placement: M&K subwoofers perform well in most room locations. For best performance, placement against a wall, preferably in a corner, is recommended. Experimentation with orientation (e.g., aiming the front driver into the wall) is encouraged. Avoiding corners near doorways or openings is advised. For multiple subwoofers, placing them in the same location (stacking or side-by-side) is ideal, but different locations at equal distances from the listening position can be used to avoid phase cancellation.
- Connection Methods:
- RCA Jack Inputs: Preferred method, connecting directly to preamp-level components (surround sound processors, preamplifiers, integrated amps with preamp outputs, electronic high-pass filters, crossovers) using shielded RCA-RCA interconnect cables. A Y-connector can be used if only one preamp output is available or for feeding two subwoofers.
- Speaker Wire Connections: Used for MX-70B, V-125, V-75 Mk II, VX-7 Mk II when RCA outputs are unavailable. Connect amplifier's left and right channel output terminals to the subwoofer's "FROM AMPLIFIER" terminals. An optional RM-2 High Level to Low Level convertor is available for MX-700, MX-200, MX-125 Mk II, and MX-105 Mk II if only speaker-level outputs are present.
- Satellite Speaker Wiring Options (when using speaker wire connections):
- Connect satellite speakers and subwoofer directly to the amp/receiver with separate wires.
- Connect satellite speakers to the subwoofer's "FROM AMPLIFIER" terminals, sharing the same terminals as the amplifier's output.
- HP-80 or VF-80 Electronic High-Pass Filters: Optional filters to improve performance by filtering bass signals to main amplifier and satellite speakers. Require preamp/main output and power amp/main input jacks. Should be turned off if the component has its own filters or is THX-certified.
- "BASS LEVEL" Control: Adjusts the subwoofer's output level to balance with satellite speakers. Can be set higher for cinema/TV or lower to avoid disturbing neighbors.
- "PHASE" Switch (+/-): Used to optimize the transition between subwoofer and satellite speakers. A phasing test involves listening to mid-bass (70-100 Hz) and selecting the switch position that yields more bass. For VX-7 Mk II, phase is adjusted by reversing positive and negative speaker inputs on BOTH satellite speakers.
- "BYPASS" Switch (VARIABLE/BYPASS): For MX-700, MX-200, MX-125 Mk II, MX-105 Mk II, VX-100, V-125. Bypasses the internal low-pass filter when using a THX, Dolby Digital, DTS component with a built-in low-pass filter or a separate electronic crossover.
- Multiple Subwoofers: Using two or more subwoofers improves impact, definition, output, and dynamic range. Connect one speaker wire or interconnect to each subwoofer. The "BASS LEVEL" control may need to be set slightly higher.
- Home Theatre Usage: For multichannel Home Theatre systems, use the Subwoofer Output jack. A higher playback level may be preferred for video sources.
- MX-700 & VX-100 Specifics: Pressure-loaded design allows for maximum coupling to a room, suitable for horizontal or vertical orientation. 17" width allows for rack mounting (kit available from M&K).
- MX-70B Specifics: Compact cabinet, suitable for vertical or horizontal installations. Has two speaker grills; if a solid grille covers the inverted driver, leave it in place.
- Feet/Spikes: MX-700, MX-200, MX-125 Mk II, MX-105 Mk II, VX-100 models include a hardware kit with black metal spikes/rubber feet. Spikes can elevate the subwoofer for better coupling on carpet. For hardwood/tile/concrete, spikes should be inverted with rubber feet pressed over the flat end. Use provided washer and jamb nut for secure mounting.
Maintenance Features:
- Power On/Off: Once wired and plugged in, the subwoofer should remain plugged in 24 hours a day. A "thump" sound upon plugging/unplugging is normal.
- Troubleshooting Guide:
- No Output: Check AC plug, "BASS LEVEL" control (must be above "MIN"), and the red LED on the back panel. If the LED is off, check/replace the AC fuse.
- Intermittent Output (after high volume): Indicates activation of the protection circuit due to overheating. Unplug for at least 30 minutes to reset.
- Low Output (using "FROM AMPLIFIER" terminals): Check input cable phase by reversing (+) and (-) connections for ONE CHANNEL ONLY.
- Weak Midbass: Perform the Phasing Test (Section 5, page 10) by reversing satellite speaker connections or switching the "PHASE" switch.
- Thump on System Turn-On: Indicates the preamp, receiver, or processor is generating the thump. Switch to speaker wire "FROM AMPLIFIER" input terminals to eliminate.
- Persistent Hum/Buzz: Remove all input cables to the subwoofer. If hum persists, the subwoofer is the source. If hum disappears, it's from another component. Reroute cables away from AC cords. Try plugging the subwoofer into the same outlet as the amplifier/receiver or reversing its AC plug polarity.
- Fuse Replacement: Disconnect the supply cord. Remove the fuse cap (push and turn counterclockwise for arrowed caps, use flat head screwdriver for slotted caps). Replace only with an identical size and value fuse to avoid fire hazard and maintain warranty.
- Service: Contact M&K dealer or M&K directly for service. Do not return speakers to the factory without prior authorization. Provide model, serial numbers, purchase date, dealer name, and problem description.
- Safety Instructions: Emphasizes reading and retaining instructions, heeding warnings, following instructions, avoiding unrecommended attachments, keeping away from water/moisture, using recommended accessories, connecting to proper power source, avoiding overloading, preventing liquid entry, and referring all servicing to qualified personnel. Unplug for service if cord/plug is damaged, liquid spilled, object fallen in, abnormal operation, dropped/damaged, or distinct change in performance. Use specified replacement parts. Perform safety checks after repairs. Keep away from heat sources.
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