MK Sound V-1250THX User's Manual
Contents
1. 4 FOLLOW INSTRUCTIONS All operating and use instructions should be followed 5 ATTACHMENTS Do not use attachments not recommended by the product manufacturer as they may cause hazards 6 WATER AND MOISTURE Do not use this product near water for example near a bath tub wash bowl kitchen sink or laundry tub in a wet basement or near a swimming pool and the like 7 ACCESSORIES Do not place this product on an unstable cart stand tripod bracket or table The product may fall causing serious injury to a child or adult and serious damage to the product Use only with accessories recommended by the manufacturer or sold with the product Any mounting of the product should follow the manufacturer s instructions and should use a mounting accessory recommended by the manufacturer 8 POWER SOURCE This product should be operated only from the type of power source indicated on the marking label If you are unsure of the type of power supply to your home consult your product dealer or local power company 9 OVERLOADING Do not overload wall outlets or extension cords as this can result in a risk of fire or electric shock 10 LIQUID ENTRY Never spill any liquid of any kind on the product 11 SERVICING Do not attempt to service this product yourself Opening or removing covers including any over bottom or side speaker drivers may expose you to dangerous voltage or other hazards Refer all service to qualified service person2. subwoofer page 16 9 IF YOU NEED SERVICE Contact your dealer or M amp 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 You can call M amp K between 8 30 AM and 5 00 PM Pacific Time Monday through Friday at 310 204 2854 If you call outside these hours leave a message and we will return your call DO NOT RETURN YOUR SPEAKERS TO THE FACTORY FOR SERVICE WITHOUT OBTAINING PRIOR AUTHORIZATION M amp K subwoofers have a five year limited parts and labor warranty This warranty is transferable to new owners upto five years from the date of original purchase It does not cover abuse misuse repairs by unauthorized service stations speakers without serial numbers and damage in shipping or by accident If you have questions about the warranty please contact M amp K or your dealer SAVE ALL OF YOUR SUBWOOFER PACKING MATERIAL YOU MUST USE IT ANY TIME YOU SHIP YOUR UNIT 10 SPECIFICATIONS V 1250THX POWER OUTPUT 125 watts RMS AMPLIFIER DISTORTION Less than 0 0396 from 20 to 125 Hz at full output into subwoofer driver INPUT IMPEDANCE 15 Kohms NOISE better than 90 dB relative to full output TYPICAL ROOM RESPONSE 20 125 Hz 3 dB DIMENSIONS H x W x D 18 x 15 1 4 x 23 WEIGHT 44 lbs 11 CABINET MAINTENANCE Treat this cabinet as you would any piece of fine furniture Regular dusting with a lin
3. make sure that any SUBWOOFER OFF ON switch found on the controller front or rear panel or remote control is set to ON Make sure that the SUBWOOFER OUTPUT level control on your THX controller is set above the MIN position d Check the red LED on the subwoofer s back panel If the LED is not lit check the AC fuse next to the LED Unplug the subwoofer before changing the fuse See instructions on Page 15 If the element inside the fuse is broken replace the fuse If it blows again contact your dealer or M amp K e Ifthe red LED is still lit set the BASS LEVEL switch to the VARIABLE position Turn the BASS LEVEL control to MIN Plug a standard RCA cable into the LEFT MONO FROM PREAMP jacks Lightly touch the plug at the free end of the cable Then turn the BASS LEVEL control clockwise If you hear a buzz or hum from the subwoofer when you touch the cable the subwoofer is working Look elsewhere in your system for the problem If you hear no output contact your dealer or M amp K for service f Make sure your cables are OK Re check all connections and replace any defective cables 2 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 13 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 f you hear a thump through the subwoofer ev
4. Congratulations Your new M amp K THX Select 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 If you have any questions about your subwoofer please contact your M amp K Home THX Audio dealer or call the M amp K factory directly at 310 204 2854 from 8 30 AM to 5 00 PM Pacific Time We will be more than happy to help you with any question no matter how simple or complex it may be For more details on the installation and calibration of your Home THX Audio system please refer to the THX Installation amp Operation Manual THIS OWNER S MANUAL HAS TWO SETS OF SET UP INSTRUCTIONS ONE SET IS FOR USING THE SUBWOOFER WITH A THX CONTROLLER THE OTHER SET IS FOR USE WITH NON THX PROCESSORS To operate it with a THX controller see Section 4 on Page 5 To use it with a non THX controller see Section 6 Page 8 3 WHERE TOPLACE YOUR SUBWOOFER M amp K Subwoofers perform well in most room locations Unless your ear is a foot or two away from the Subwoofer you will hear the deep bass coming exclusively from your Satellite or main speakers There is no need to place your Subwoofer in between the Satellite speakers For the best performance we recommend that your subwoofe
5. WITH A NON THX PROCESSOR OPERATION OF THE LOW PASS FILTER SWITCH With a non THX controller preamp etc this switch should be set to the 80 Hz 24 dB OCTAVE position Do not operate this switch unless the BASS LEVEL control is set to MIN For non THX systems your subwoofer has been optimized for an 80 Hz crossover with a 24 dB octave slope This low pass filter makes a rapid transition to 36 dB octave above 125 Hz which provides the extremely sharp attenuation needed to make the subwoofer s sound non directional For optimal performance we strongly recommend that you use an M amp K HP 80 High Pass Filter Your subwoofer with this filter and M amp K Satellites forms a 4th order Linkwitz Riley crossover between satellite and subwoofer The linear phase of this crossover means uncompromised performance with great flexibility in system setup without elaborate calibrations or adjustments sv 1250THX subwoofer page 9 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 THX on page 7 WIRING WITH A NON THX PROCESSOR OR PREAMP The FROM PREAMP RCA terminals on the subwoofer allow you to connect the su
6. controller has only one subwoofer output jack LOW PASS LOW PASS LerTiy6no RIGHT FILTER FILTER T 80 Hz 398 T 80 Hz 24 dB OCTAVE i 24 dB OCTAVE INPUT PHASE THE THX CAUTION CAUTION RISK OF ELECTRIC SHOCK RISK OF ELECTRIC SHOCK DO NOT OPEN DO NOT OPEN AVIS RISQUE AVIS risque DE ELECTRIQUE NE PAS OUVRIR ELECTRIQUE NE PAS OUVRIR EE Made in U S A novac soso T a amp 12vac 5060 a amp AG SLOWBLOW sr iin AS v0 subwoofer page 7 If you have two subwoofers do not use a Y connector to feed both inputs on each subwoofer Connect the interconnect cable to the LEFT MONO INPUT only Run the Left interconnect cable to the Left subwoofer and the Right cable to the Right subwoofer See Figure 2 on 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 Setthe 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 SUB WOOFER OFF ON switch on its front panel rear panel or remote control set it to ON See the controller s manual for details Plug the subwoofer s AC cord in The red LED on the back panel should illuminate Play some program material that has good bass content through your system Carefully advance th
7. ER 6 FIGURE ONE SUBWOOFER TO A SURROUND CONTROLLER NON THX 9 FIGURE 4 TWO SUBWOOFERS TO A SURROUND CONTROLLER 10 FIGURE 5 ONE SUBWOOFER AN AMP OR PREAMP NON THX 10 FIGURE 6 TWO SUBWOOFERS TO AN AMP OR PREAMP NON THX 11 25 subwoofer page 3 CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN The lightning flash with arrowhead CAUTION The exclamation point within an equi within an equilateral triangle is in TO PREVENT THE RISK OF ELECTRIC lateral triangle is intended to alert the tended to alert the user of the pres user of the presence of important op ence of uninsulated dangerous volt SHOCK DO NOT REMOVE COVER OR erating and maintenance servicing age within the product s enclosure BACK NO USER SERVICEABLE instructions in the literature accom that may be of sufficient magnitude to PARTS INSIDE REFER SERVICING TO panying the appliance constitute a risk of electric shock to persons QUALIFIED SERVICE PERSONNEL 1 SAFETY INSTRUCTIONS 1 READ INSTRUCTIONS All safety and operating instructions should be read before this product is operated 2 RETAIN INSTRUCTIONS The safety and operating instructions should be retained for future reference 3 HEED WARNINGS All warnings on this product and in the operating instructions should be adhered to
8. If it was set to the position set it to the position The best way is to have a partner work the switch while you sit in the main listening position and listen Now listen to the same music concentrating on the mid bass If you hear less bass set the SUBWOOFER PHASE switch to the opposite position If you hear more bass leave the switch where itis the new position is correct PHASING TEST METHOD TWO First set the toggle switch labelled SUBWOOFER PHASE to the position Then feed wideband pink noise found on test CDs the Wow disc or a pink noise generator through your front channel speakers and your subwoofer You can do this test by listening butitis bestto use a spectrum analyzer and look at its display in the mid bass region of 70 125 Hz Then reverse the position of the SUBWOOFER PHASE switch If it is set to the position set it to the position If it was set to the position set it to the position The best way is to have a partner work the switch while you sit in the main listening position and listen Now listen to the same wideband pink noise or look atthe spectrum analyzer output in the mid bass region If you hear measure less bass set the SUBWOOFER PHASE switch to the opposite position If you hear measure more bass leave the switch alone the new position is correct This test is necessary because the different distances from each speaker to your ears mean that it is possible tha
9. OOFERS TO AN AMP OR PROCESSOR WITH A SUBWOOFER OUTPUT JACK NON THX SUBWOOFER or MONO OUT SURROUND PROCESSOR use a Y connector to connect to two subwoofers LOW PASS FILTER CAUTION RISK OF ELECTRIC SHOCK 80 Hz 24 dB OCTAVE AVIS RISQUE ELECTRIQUE NE PAS OUVRIR CAUTION See THX AVIS RISQUE DE ELECTRIQUE NE PAS OUVRIR Made in U S A ME MILER REISE SOUND CORPORATION 10391 Jefferson Bh Culver Ciy CA 90232 310 2042054 MOVACSOSDMS T 4 AMP ANG SLOWBLOW Made in U S A ME E KRESET SOUND CORPORATION 10391 Jefferson Bid Culver Cy CA 90232 310 2042854 FIGURE 5 WIRING ONE SUBWOOFER TO AN AMP OR PREAMP WITH ONE SET OF PREAMP OUTPUTS POWER AMP MAININ LOW PASS OO PREAMP id CAUTION use one Y connector for each channel to split the output of the preamp EE Made in U S A ME LER E KRESE SOUND CORPORATION 10391 jefterson Bhd Culver Gy CA 90332 310 2042554 VRVACSOSHE T aAMP ID O0 SLOV BLOW 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 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 v 1250THx
10. SWITCH essere nennen enne nnne 8 OPERATION OF THE BASS LEVEL SWITCH sess nne nnnt ener eren 9 WIRING WITH A NON THX PROCESSOR sssssssessssseseene nennen nnne erinnern innen ree innen nnne r inneren nis 9 USING THE SUBWOOFER WITH THE M amp K HP 80 OR VF 80 HIGH PASS FILTERS 11 TESTING THE SUBWOOFER NON C THX eei terna to ipn intu nain nta ana 12 SETTING SUBWOOFER LEVEL recedens ianiai neeaae ankaka 12 USING TWO SUBWOOFERS INON HX iesu ccce eue RREN ESETERE EEEE ARROAN 12 7 SATELLITE SUBWOOFER PHASING TEST 13 B TROUBLESHOOTING 14 IF YOU NEED TO REPLACE THE EXTERNAL 15 9 IFYOUNEED SEBVIGE eiraniucsssdsepcsad GududeudceS Ua yx Y asap SECO dE dup rcc E RPa ra Rd 16 10 t 16 11 CABINET MAINTENANCE csiascvasescosssicecientexsiensececnasatndnsuscewedsuasenceendincueniiaveiexcsseosseemiens 16 WIRING DIAGRAMS FIGURE 1 ONE SUBWOOFER TO A THX CONTROLLER 6 FIGURE 2 TWO SUBWOOFERS TO A THX CONTROLL
11. THX Select powered subwoofer operation manual V 1250THX Miller Kreisel Sound Corporation 10391 Jefferson Boulevard Culver City CA 90232 USA 310 204 2854 310 202 8782 www mksound com 1999 MILLER 2 KREISEL SOUND CORP LUCASFILM Manufactured under license from Lucasfilm Ltd Lucasfilm and THX are registered trademarks of Lucasfilm Ltd V 1250THX subwoofer page 2 TABLE OF CONTENTS 1 SAFETYINSTHUCTIONG tree enean P cea o Uu penu o OR pa ua cee 3 2 INTRODUCTION m 4 4 WHERE TO PLACE YOUR SUBWOOFER cun rac 4 4 OPERATION WITH THX COMPONENTS ceeeeeeeeeeeeeeee nennen nnn nnn nnn nnn nn nnn nnn 5 CONNECTING THE SUBWOOFER TO A THX CONTROLLER b TESTING THE SUBWOOFER THX sss enne nnne RRNK KEERA sinensis ener KERRAEN EN 7 5 CALIBRATING THE SUBWOOFER THX nennen nennen nnn nnn 7 OPERATION OF THE LOW PASS FILTER AND BASS LEVEL SWITCHES 7 SETTING SUBWOOFER LEVEL THEIX 8 USING TWO SUBWOOFERS THX 8 6 OPERATION WITH A NON THX CONTROLLER nennen 8 OPERATION OF THE LOW PASS FILTER
12. abinet To connect the subwoofer run a shielded RCA RCA interconnect cable from the SUBWOOFER OUTPUT jack on your THX controller to the LEFT MONO INPUT jack on the subwoofer s backplate See Figure 1 on Page 6 V 1250THX subwoofer page 6 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 f your THX controller has only a single mono subwoofer output use mono cable and connect it to the subwoofer s LEFT MONO INPUT jack See Figure 1 below Do not use a Y connector to connect the signal to both the LEFT and RIGHT inputs of the subwoofer These inputs are summed to mono in the amplifier input stage and if they are combined the result will be too much gain and bass level FIGURE 1 WIRING ONE SUBWOOFER WITH A THX CONTROLLER LOW PASS RIGHT FILTER 80Hz 24 dB OCTAVE SUBWOOFER OUT THX CONTROLLER CAUTION AVIS RISQUE CHOC ELECTRIQUE NE PAS OUVRIR E Made in U S A ME MILER amp KREISEL SOUND CORPORATION 10391 Jefferson Blvd Culver Cily CA 90232 310 2042854 SLOW BLOW 120 VAC 5060 v FIGURE 2 WIRING TWO SUBWOOFERS WITH A THX CONTROLLER THX CONTROLLER use a Y connector if SUBWOOFER OUT your
13. ality of bass you get in your room are dependent on the room itself Low frequency bass sounds are affected most by the size of the room and the method of construction used to build it All rooms are different when it comes to reproducing bass and in any given room bass quantity and 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 Remember that the floor also loads the Subwoofer and that maximum bass is found with the woofer on the floor in a corner In some rooms a corner location may excite resonance modes resulting in a muddy or boomy sound In these rooms a more central location along a wall away from the corner may give better results If you experiment try to find a spot where no bass notes seem to overpower others and the overall sound is powerful and clean The goalis to achieve a smooth sound quality with the entire bass spectrum equally prominent In most rooms this is directly in a corner not the center of the room Because the Subwoofer generates a great deal of energy its output may vibrate objects close to it If you hear such vibration you may need to damp the vibration of nearby objects One Subwoofer is sufficient in a stereo system because of the nature of human hearing The ear brain hearing system is unable to locate the direction o
14. and pink noise signal into the full system both the satellites and the subwoofer Then set up the analyzer at the main listening position Adjust the BASS LEVEL control until the analyzer display shows the flattest response through the 70 125 Hz midbass region If you don t have access to an analyzer the best way to match the level of the subwoofer to your system is to do it by ear listening over several hours to familiar recordings Make adjustments to the level in small increments depending on whether the bass level sounds too high or too low There is a possibility that your surround sound processor has a built in test generator for the subwoofer level but the virtually all non THX processors do not If you do have such a surround sound processor see SETTING SUBWOOFER LEVEL THX on page 8 In any case remember that you can always deliberately set the level higher if you want more bass or lower if you don t want to disturb your neighbors USING TWO SUBWOOFERS NON THX Using two subwoofers in your audio video system will give you the ultimate in bass performance It will give you improved impact and definition as well as greater output and dynamic range If you locate the subwoofers in different parts of the room you will hear a better overall frequency 25 subwoofer 13 response as the room modes excited by one woofer are complemented by the presence of the other Alternately if you stack two subwoo
15. bwoofer to preamp level components other than THX controllers such as preamplifiers integrated amps and receivers with preamp outputs high pass filters crossovers standard surround sound processors etc All of the input connections and controls for the subwoofer are located on its large metal backplate which can be found on the back panel of the subwoofer cabinet FIGURE 3 WIRING ONE SUBWOOFER TO AN AMP OR PROCESSOR WITH A SUBWOOFER OUTPUT JACK NON THX BASS LEVEL LOW PASS REFERENCE LEFT MONO FILTER VARIABLE iz 24 dBIOCTAVE SUBWOOFER or MONO OUT THX SURROUND PROCESSOR CAUTION DISCONI ORD BEFORI ISE REPLA Y WITH SAME TYPE Made in U S A Mz MILLER amp KREISEL SOUND CORPORATION 10391 Jefferson Blvd Culver City CA 90232 310 204 2854 If your surround processor has only one PREAMP OUTPUT and no SUBWOOFER OUT and you do not have an M amp K High Pass Filter or crossover you must use a Y connector to feed the amplifier and subwoofer See Figure 5 above If you have a surround sound processor with a SUBWOOFER OUTPUT jack use it to feed the subwoofer See Figure 5 on page 10 Some surround processors receivers amps have very low output levels from their SUBWOOFER OUTPUT jacks If you do not get enough bass when using the SUBWOOFER OUTPUT jacks on a non THX processor use that processor s PREAMP OUTPUT jacks instead See Figure 5 V 1250THX subwoofer page 10 FIGURE 4 WIRING TWO SUBW
16. ch should be set to the 80 Hz 24 dB OCTAVE position The THX mode bypasses the internal crossover of the subwoofer and fixes its gain to a standard setting The THX controller contains the crossover and sets the rolloff point of the signal fed to the subwoofer to 80 Hz with a Linkwitz Riley characteristic OPERATION OF THE BASS LEVEL SWITCH THX When using the subwoofer with a THX controller this switch should be set to the THX position The controller sets the output level of the subwoofer so this switch disables the subwoofer s level control The CALIBRATED level control mark is referenced to the level set by the THX switch If you set the switch to VARIABLE and the level control to CALIBRATED its output level is the same as when you set the switch to THX V 1250THX subwoofer page 8 The 2 and 4 marks indicate the points where your subwoofer is producing 2 dB and 4 dB respectively more output than the CALIBRATED level SETTING SUBWOOFER LEVEL THX The proper method of setting the level of the subwoofer in THX mode is to use the low frequency pink noise test signal generator built into the THX controller and a sound level meter available from Radio Shack First set the master volume of the THX controller to the 0 or REF position Then set the Subwoofer Output control on the THX controller so that the output of the subwoofer causes the sound level meter to read 75 dB C scale slow mode when that test
17. e LOW PASS FILTER switch is set to the 24 dB OCTAVE position and the BASS LEVEL control to set to VARIABLE Make sure the SUBWOOFER PHASE switch is set to the position Then plug the AC cord in You should see the red LED on the back panel of the subwoofer illuminate When your system wiring is complete and the subwoofer is plugged into the wall leave it plugged in even when the system is turned off The normal mode of operation for the subwoofer is to remain plugged in 24 hours a day Among other things this means that you don t have to walk over to the subwoofer to turn it on every time you want to use the system 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 If the system is not working properly unplug the subwoofer and check all of your connections Call your dealer or the factory if you cannot solve any problem SETTING THE SUBWOOFER LEVEL NON THX Here are two ways to set the subwoofer level First if you can obtain a spectrum analyzer you can accurately match the subwoofer to the main speakers First feed a wideb
18. e system volume control You should hear the subwoofer operate If you think the subwoofer isn t working walk up to the speaker and listen to it from a distance of a foot or less If you confirm that it is not working unplug the subwoofer and check all of your connections before trying it again If you have a problem that you cannot solve contact your dealer or the M amp K factory When your system wiring is complete and the subwoofer is plugged into the wall leave it plugged in even when the system is turned off The normal mode of operation for the subwoofer is to remain plugged in 24 hours a day Among other things this means that you don t have to walk over to the subwoofer to turn it on every time you want to use the system DO NOT PLUG THE SUBWOOFER INTO A SWITCHED OUTLET ON ANOTHER COMPONENT IT CAN DRAW UP TO 400 WATTS FROM THE AC LINE IT MUST BE PLUGGED INTO A SOLID AC LINE 5 CALIBRATING THE SUBWOOFER THX On the back panel of the subwoofer three toggle switches allow you to select various modes of operation Two are described here A description of the function of the third toggle switch can be found in section 7 SATELLITE amp SUBWOOFER PHASING TEST page 13 OPERATION OF THE LOW PASS FILTER SWITCH THX When using the subwoofer with a THX controller this switch should be set to the THX position When using the subwoofer with a standard stereo system or a surround sound processor that is not THX certified this swit
19. ery time you turn the rest of your audio system on and your subwoofer is plugged in all the time Either the preamp amp receiver or surround sound processor is generating the thump and the subwoofer is reproducing it Contact your dealer or the manufacturer of the other component 4 f you hear a persistent hum or buzz through the subwoofer 250 subwoofer 15 Because the subwoofer easily reproduces 60 Hz signals the frequency of hum it is often blamed for causing hum that originates elsewhere in the system Always avoid running all speaker wires and RCA interconnect cables near to AC cords and component power supplies Placing wires and cables close to AC lines often results in hum If necessary reroute your cables To identify the source of hum remove all input cables to the subwoofer but leave it plugged into the AC outlet Setthe BASS LEVEL switch to the VARIABLE position Carefully turn the BASS LEVEL control up towards the MAX position If you hear hum from the subwoofer it is the source of the hum If you hear no hum or much less hum the problem is in another component or a ground loop For ground loop problems when the subwoofer is plugged into a separate AC outlet try plugging it into the same outlet as your amplifier or receiver If that doesn t work reverse the polarity of its AC plug If you cannot solve the problem call M amp K or your dealer 5 f you hear an unusual sound from the sub
20. f bass sounds below approximately 100 150 Hz Thedirection of low frequency sounds drums basses etc is determined by the higher frequency overtones and harmonics that are reproduced by the Satellite speakers All M amp K Powered Subwoofers have exceptionally sharp 36 dB octave low pass filters to remove the midbass and midrange frequencies unwanted in a Subwoofer This makes your M amp K Subwoofer truly non directional M amp K THX Subwoofers are magnetically shielded This allows you great freedom and flexibility in locating the subwoofer Even if itis close to your television set it will not interfere with the picture No matter where you put the Subwoofer you must allow room for ventilation of its heatsink and backplate The Subwoofer s power amplifier is mounted on the backplate and it generates heat 1 Leave clearance around the Subwoofer s heatsink Do not cover it with drapes 2 Do not place the Subwoofer near baseboard heaters or forced air heating outlets 3 Do not use the Subwoofer outdoors or in a humid environment DO NOT PLUG THE SUBWOOFER INTO AN AC OUTLET UNTIL ALL SYSTEM WIRING IS COMPLETE 4 OPERATION WITH THX COMPONENTS CONNECTING THE SUBWOOFER TO A THX CONTROLLER The INPUT RCA terminals on the subwoofer connect it to the outputs of your THX controller All ofthe input connections and controls for the subwoofer are located on its large metal backplate which can be found on the back panel of the subwoofer c
21. fers one on top of the other their outputs will couple and give you an additional total of 6 dB of output Wiring with two subwoofers is simple Instead of running two interconnect cables to one subwoofer just run one interconnect to each subwoofer using the LEFT MONO input on each subwoofer You don t need to use a Y connector See Figure 4 page 10 7 SATELLITE SUBWOOFER PHASING TEST WITH BOTH THX AND NON THX COMPONENTS Before you can sit down to enjoy your new subwoofer you need to perform one simple Phasing Test This test insures optimum sound in the critical bass frequencies where your subwoofer and Satellite or L C R speakers overlap When using the subwoofer with a THX controller and THX L C R speakers the crossover slopes are linear phase When the subwoofer is placed along the same axis as the front speakers the system will tolerate a plus or minus 28 inch offset before significant losses at the crossover point are seen 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 If it is set to the position set it to the position
22. nel 12 DAMAGE REQUIRING SERVICE Unplug this product from the wall outlet and refer servicing to qualified personnel under the following conditions a When the power supply cord or plug is damaged b If liquid has been spilled or objects have fallen into this product If the product does not operate normally by following the operating instructions Adjust only controls that are covered by the operating instructions as an improper adjustment of other controls may result in damage and will often require extensive work by a qualified technician to restore the product to its normal operation d If the product has been dropped or damaged in any way e When the product exhibits a distinct change in performance this indicates a need for service 13 REPLACEMENT PARTS When replacement parts are required be sure the service technician has used replacement parts specified by the manufacturer or have the same characteristics as the original part Unauthorized substitutions may result in risk of fire electric shock or other hazard 14 SAFETY CHECK Upon completion of any service or repairs to this product ask the service technician to perform safety checks to determine that the product is in proper operating condition 15 HEAT This product should be situated away from heat sources such as radiators heat registers stoves or other products including amplifiers that produce heat ME V 1250THX subwoofer page 4 2 INTRODUCTION
23. r be placed against a wall preferably in a corner The ideal place for the subwoofer is the corner with the best structural strength If the corners are roughly equal in construction use the corner nearest the listening position If the listening position is in the front half of the room place the subwoofer in a front corner If the listening position is in the back of the room place the subwoofer in a back corner Feel free to experiment with the orientation of the subwoofer cabinet Sometimes the best sound results from aiming the subwoofer s front driver directly into the wall 1 to 2 from the wall itself If possible avoid corners near doorways or openings Another option to find the best location for the subwoofer is to place the subwoofer at the listening position and walk around the room Stand in and near each corner The location where you hear the tightest bass with the most impact is probably the best location in the room for the subwoofer If you are using multiple subwoofers place them in the same location Stacking is best but you can also put them side by side Alternately you can put multiple subwoofers in different locations This is appropriate when you have limited choices in locating the subwoofer and none of the available locations work well Try to place multiple subwoofers at equal distances from the listening position to avoid phase cancellation 250 subwoofer page 5 Ultimately the amount and qu
24. signal is playing All channels of the THX system should be calibrated to this 75 dB level when using the unit s internal test signal Special Note When calibrating the subwoofer level and only the subwoofer level you will find that the needle on your sound level meter will bounce plus or minus a couple of decibels when measuring the test signal To set subwoofer level read the AVERAGE meter level not the peak level Move around the room as you measure levels so that your measurements account for the room reinforce ments and cancellations found at various room locations For details on setting levels with your THX controller see the instructions provided with that unit USING TWO SUBWOOFERS THX Using two subwoofers in your THX system will give you the ultimate in bass performance It will give you improved bass impact and definition as well as greater output and dynamic range If you locate the subwoofers in different parts of the room you will get a better overall frequency response because the room modes excited by one woofer are complemented by the presence of the other subwoofer Alternately if you stack two subwoofers one on top of the other their outputs will couple and give you an additional total of up to 6 dB of output Wiring with two subwoofers is simple Instead of running two interconnect cables to one subwoofer run one interconnect to each subwoofer using each LEFT MONO input jack See Figure 2 page 6 6 OPERATION
25. subwoofer page 11 FIGURE 6 WIRING TWO SUBWOOFERS TO AN AMP OR PREAMP WITH ONE SET OF PREAMP OUTPUTS POWER AMP MAIN IN MAIN OUT use one Y connector for each channel to split the output of the preamp PREAMP LOW PASS wm pude LOW PASS RIGHT E FILTER 80 Hz 24 dBIOCTAVE PHASE 24 dB OCTAVE INPUT PHASE If you have two subwoofers it is not necessary to use both inputs on each subwoofer Connect the interconnect cable to one FROM PREAMP jack only Run the Left channel interconnect cable to the Left subwoofer and the Right interconnect cable to the Right subwoofer See Figures 4 and 6 WIRING WITH THE M amp K HP 80 OR VF 80 HIGH PASS FILTERS NON THX The M amp K HP 80 and VF 80 High Pass Filters can improve any system that allows its preamp and power amp stages to be separated by filtering the bass fed to the main amp and Satellite speakers These filters will give your system greater dynamic range lower distortion and an increased maximum output To use these filters with an integrated amp or receiver the amp or receiver MUST have back panel RCA jacks labelled PREAMP MAIN OUTPUT and POWER AMP MAIN INPUT There may be a switch or jumper connections between them which you will have to remove If you have any questions about your components contact your dealer or M amp K For non THX systems your subwoofer is optimized for
26. t free cloth is all that is required Do not use any solvent based cleaners they may damage the cabinet surface 0199V1250THX PM65
27. t the Subwoofer s output may arrive at your ears out of phase with the Satellites output When this happens the midbass is cancelled Re do this test any time you move any of your speakers or the listening position ME V 1250THX subwoofer page 14 If you wantto experiment move the main speakers or subwoofer towards or away from your listening position in small increments When you hear the best combination of stereo image localization and focus with solid midbass impact and output you have the ideal location If you have two subwoofers perform one test for each subwoofer When you perform each test make sure the other subwoofer is not operating by either unplugging its input cable or its power cord 8 TROUBLESHOOTING Your subwoofer amplifier circuit provides high reliability and if necessary easy modular parts replacement This guide will help solve or diagnose most problems that may occur Remember if a fuse blows you mustreplace it with the correct value to avoid fire hazards and to maintain the warranty 1 If your subwoofer has no output a Make sure that the subwoofer is plugged into an AC outlet b Ifthe BASS LEVEL switch is set to VARIABLE make sure that the BASS LEVEL control is set above the MIN position Rotate it clockwise if it is set to the MIN position Make sure that the SUBWOOFER OUTPUT level control on your processor or amp is set above the MIN position Ifthe BASS LEVEL control is set to THX
28. use with the HP 80 High Pass Filter We strongly recommend that you use this filter with any component system that allows for its use When you use this subwoofer with an HP 80 and M amp K Satellites the combination forms a 4th order Linkwitz Riley crossover between satellite and subwoofer The linear phase of this crossover means uncompromised performance with great flexibility in system setup without requiring elaborate calibrations or adjustments Do not use either of these filters with a THX controller The THX controller has the appropriate filters in its built in crossover circuitry Also do not use a SUBWOOFER OUTPUT jack on your amp or processor to feed any of these filters To connect one of these filters run one set of shielded RCA RCA interconnect cables from the V 1250THX subwoofer page 12 receiver amp or preamp s MAIN OUTPUT to the input jacks on the HP VF 80 Run another set of interconnects from the high frequency output jacks on the filter to receiver or amp s POWER AMP inputs Last run interconnects from the subwoofer output jacks to the subwoofer s FROM PREAMP jacks See the instructions enclosed with your filter for wiring diagrams To use these filters make certain that the BASS LEVEL switch is set to VARIABLE and that the LOW PASS FILTER switch is set to 24 dB OCTAVE TESTING THE SUBWOOFER NON THX Once all of the interconnect cables are in place you are ready to plug in your subwoofer Make sure th
29. woofer when no signal or music is playing Try removing the input cables as described in Step 4 above If the noise disappears it is coming from another component If it does not go away contact your M amp K dealer or the factory 6 If the subwoofer will not play loud enough AND it is connected to the SUBWOOFER OUTPUT jack on a non THX surround sound processor Make sure that the BASS LEVEL toggle switch is set to VARIABLE Set the BASS LEVEL control to the MAX position If you get bass output but it is not enough then the processor s output level is too low A few processors receivers amps have very low output levels from their SUBWOOFER OUTPUT jacks If you do not have enough gain when using the SUBWOOFER OUTPUT jacks on a non THX processor use the processor s PREAMP OUTPUT jacks See Figures 5 and 6 pages 10 and 11 IF YOU NEED TO REPLACE THE EXTERNAL FUSE First unplug the subwoofer from the wall AC socket Remove the fuse cap Look carefully at the fuse s wire filament inside the glass If it is broken replace the fuse ONLY with one identical in size and value Using a larger fuse will void your warranty AND MAY CREATE A FIRE HAZARD Plug the subwoofer Ifitdoes not work unplug it immediately and contact M amp K or your dealer for service REPLACEMENT FUSE VALUES 110 VOLT 220 VOLT 220 VOLT 3 AG 1 4 x 1 1 4 slow blow 5 X 20 mm IEC 127 III V 1250THX 2 amp 1 amp T 800 mA time lag 250
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