® THX powered subwoofers operation manual MX-SERIES: MX-150THX V-SERIES: V-125THX Miller & Kreisel Sound Corporation 10391 Jefferson Boulevard Culver City, CA 90232 USA (310) 204-2854 FAX (310) 202-8782 © 1995 MILLER & KREISEL SOUND CORP. Manufactured under license from Lucasfilm Ltd. Lucasfilm and THX are registered trademarks of Lucasfilm Ltd.
THX subwoofers page 2 TABLE OF CONTENTS 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. SAFETY INSTRUCTIONS ................................................................................................ 3 INTRODUCTION .............................................................................................................. 4 WHERE TO PLACE YOUR SUBWOOFER ..................................................................... 4 OPERATION WITH THX COMPONENTS...............................................
THX subwoofers page 3 CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN The lightning flash with arrowhead, within an equilateral triangle, is intended to alert the user of the presence of uninsulated "dangerous voltage" within the product's enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. CAUTION: TO PREVENT THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE COVER (OR BACK). NO USER-SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
THX subwoofers page 4 2. INTRODUCTION Congratulations! Your new M&K THX® subwoofer truly represents the state-of-the-art in subwoofer performance. The new dimension of deep and powerful bass it provides will both thrill and excite you. We strongly encourage you to read this owner's manual, as there is a great deal of information provided here to help you get the best possible performance.
THX subwoofers page 5 OUTPUT jack on your THX controller to the "LEFT/MONO" "INPUT" jack on the subwoofer's backplate. See Figure 1 below. Some THX controllers have a pair of stereo subwoofer outputs, while others have a single mono output. Your subwoofer is compatible with both types. If your THX controller has stereo subwoofer outputs, use a stereo shielded cable, connecting it to the LEFT and RIGHT "INPUT" terminals on the subwoofer.
THX subwoofers page 6 TESTING THE SUBWOOFER (THX MODE) Once all of the interconnect cables are in place, you are just about ready to plug in the subwoofer. Set the "LOW PASS FILTER" toggle switch to the "THX" position and the "BASS LEVEL" toggle switch to the "THX" position. Set the "SUBWOOFER PHASE" switch to the "+" position. If your THX controller has a SUBWOOFER (OFF/ON) switch on its front panel, rear panel, or remote control, set it to ON. (See the controller's manual for details).
THX subwoofers page 7 For the V-125 THX, the "CALIBRATED" level is 4 dB lower than the "THX" level (switch set to "THX"). Set the control to this mark if you have only one subwoofer in the system (such as in a very small room). On both the MX-150 THX and V-125THX, the +2 and +4 marks indicate the points where your subwoofer is producing 2 dB and 4 dB more output than the "CALIBRATED" level.
THX subwoofers page 8 OPERATION OF THE "BASS LEVEL" SWITCH When using the subwoofer with a non-THX processor, preamp, etc., this switch should be set to the "VARIABLE" position. The subwoofer level can then be set independently to match your speakers. The "CALIBRATED" mark is a reference relative to THX levels. For a discussion of this "CALIBRATED" mark, please see "Operation of the Bass Level Switch" on page 7.
THX subwoofers page 9 FIGURE 5 - WIRING ONE SUBWOOFER TO AN AMP OR PREAMP WITH ONE SET OF PREAMP OUTPUTS POWER AMP MAIN IN LEFT BASS LEVEL RIGHT REFERENCE +3 dB VARIABLE LEFT/MONO RIGHT LOW PASS FILTER + 80 Hz 24 dB/OCTAVE +6 dB INPUT THX LEFT PREAMP PHASE THX RIGHT CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN AVIS: RISQUE DE CHOC ELECTRIQUE. NE PAS OUVRIR. use one Y-connector for each channel to split the output of the preamp Manufactured under license from Lucasfilm Ltd.
THX subwoofers page 10 To connect the subwoofer, run shielded RCA - RCA interconnect cables from the outputs on your component to the "INPUT" jacks found on the subwoofer's backplate. See Figure 5 on page 9. If your processor has a single subwoofer output, do not use a Y-connector to connect it to both the Left and Right input terminals of the subwoofer. The subwoofer combines both channels to mono in its amplifier input stage.
THX subwoofers page 11 DO NOT PLUG THE SUBWOOFER INTO A SWITCHED OUTLET ON ANOTHER COMPONENT. THE SUBWOOFER CAN DRAW UP TO 400 WATTS FROM THE AC LINE. IT MUST BE PLUGGED INTO A SOLID AC LINE. Now, play some music through your system to make sure that the Satellite speakers are working properly. If they are, carefully advance the "BASS LEVEL" control. The subwoofer should begin to play. Set the "BASS LEVEL" control where the subwoofer sounds in balance with the Satellite speakers.
THX subwoofers page 12 Here are two methods of setting the correct phase with your subwoofer. PHASING TEST METHOD ONE Set the switch labelled "SUBWOOFER PHASE" to the "+" position. Then, play a familiar CD, LP, laserdisc or tape with steady, consistent bass content. Listen carefully to the "mid-bass" region of 70 - 125 Hz. This is the part of the spectrum where electric or string basses and drums predominate. Then, reverse the position of the "SUBWOOFER PHASE" switch.
THX subwoofers page 13 The amount and quality of bass you hear is dependent on the room itself. Low frequencies are affected by a room's size and type of construction. Rooms differ when it comes to reproducing bass, and in every room, bass quality changes when the subwoofer is moved from one location to another. A simple rule to remember is that you get more bass when you move the subwoofer towards any wall or corner. Moving it away from a wall or corner gives you less bass.
THX subwoofers page 14 9. USE OF SPIKED FEET WITH "MX" SUBWOOFERS If your M&K THX subwoofer is an "MX" push-pull dual driver subwoofer, we have enclosed a hardware kit consisting of four black metal spikes, threaded at one end and tapering to a sharp point at the other. Depending on their orientation, they can be used either as carpet spikes or rubber feet. To avoid damage to the floor, do not use the spiked end on hardwood or tile floors.
THX subwoofers 2. page 15 If the midbass range (the area of transition between Subwoofer and Satellite or L/C/R speakers) sounds weak: See Section 7, PHASING TEST, on page 11. Reverse the position of the "SUBWOOFER PHASE" switch on the back panel of the subwoofer. The switch position that gives the most bass is correct. 3.
THX subwoofers page 16 REPLACEMENT FUSE VALUES 110 VOLT MX-150THX V-125 THX 220 VOLT 220 VOLT (3 AG 1/4" x 1 1/4" slow blow) (5 X 20 mm IEC-127/III) 4 amp 2 amp T 1.6 A (time-lag) T 800 mA (time-lag) 2 amp 1 amp 11. IF YOU NEED SERVICE Contact your dealer or M&K with a complete description of the problem. Please have the unit's model and serial numbers (found on the back of the cabinet), date of purchase, and your dealer's name.
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