Alesis M1 Computer Monitor User Manual
Contents
1. connector will cause the drivers to move outwards Unbotanced line Input Balonced Line h gnc Tip Het Tip Cad Ring Grand MM Hee Ground eave Tip Tip Iewe Ring Jesus Direct connection of unbalanced 10 dBV line level sources Most synthesizers drum machines effect devices cassette decks and CD players operate at this level Their average signal level is about 1 3 of a volt They have a 2 conductor output jack that is either a 1 4 phone or RCA phono type These may be plugged directly into the M1 Active s LINE IN jacks But do NOT plug the speaker output of an amplifier receiver or similar device into the LINE INPUT jack Use only line level sources Plugging too loud of a signal into the LINE INPUT jack may damage the electronics Balanced 4 dBu line level sources Professional recording and processing equipment typically provides a balanced 3 conductor signal output that is a higher voltage 1 24 volts nominal level than most synthesizers and stereo equipment The LINE INPUT jacks are designed to handle these balanced inputs Balanced sources often feature XLR outputs Connect them with an XLR to XLR cable Many consoles such as the Alesis Studio series feature balanced outputs on M1 ACTIVE REFERENCE MANUAL 23 Speaker Installation 1 4 jacks you may use a TRS to TRS balanced phone cable or an XLR to 1 4 inch phone TRS tip ring sleeve cable as s2. Limited Warranty applies only to products sold to users in the USA and Canada Customers outside of the USA and Canada are not covered by this Limited Warranty and may or may not be covered by an independent distributor warranty in the country of sale Do not return products to the factory unless you have been given specific instruc tions to do so SPECIFICATIONS Enclosure Materials and Construction Front baffle painted in metallic charcoal gray one inch 1 thick MDF with radiused edges to minimize diffraction Sides and rear baffle covered in metallic charcoal gray vinyl laminate over five eighths inch 0 625 thick MDF Multiple internal random spaced and length edge boundary cleats break up and elevate common frequency mode aberrations Dual ports with 45 inlet and flared front baffle outlet allow precise phase accurate woofer to port frequency transition Ports also aid in cooling internally mounted primary amplifier heat sink Flush mount rubber woofer trim ring allows consistent power response characteristic at wide off axis angles Flush mount tweeter plate and Alesis M1 Active logo pilot light plate also assure smooth off axis response UL approved fiberglass acoustical damping material damps internal mid frequency reflections from rear of woofer cone before entering port lessening IM distortion Transducers Low frequency driver 6 5 165mm diameter dynamic driver with proprietary non woven carbon fi
3. distances What you want to find is the maximum distance that you can separate the two speakers while still holding a solid center image If you get this placement correct and you ve done a good job in the mix you should be rewarded with a soundstage that accurately places the musicians in the width and depth perspective in which they were recorded The sound should be very similar to what you heard at your mixing board with possibly a little more ambience contributed by the listening room The other playback check mode sometimes considered of greater importance than the home environment is to listen to your mix over a car audio system Bear in mind that an expertly designed car audio system can approach the imaging and soundstaging capabilities of an optimally setup studio or living room but most times this is NOT the case The inherent limitations of an always off axis listening position and the variables of speaker placement bass coupling boost in the small interior and numerous other factors make the car environment highly suspect So understand the sonic capabilities and deficiencies of your or other car audio systems and evaluate your mix accordingly 20 M1 ACTIVE REFERENCE MANUAL Speaker Installation Plugging the ports to adjust for room acoustics The low frequency response of the M1 Actives can be custom tailored by plugging the ports If the speakers must be placed less than one foot from a front wall or if they
4. imaging The first path is the direct one and the second is via a reflection off the mixer main control panel ei i Direct Path Monitors placed on the console s meter bridge can directly radiate back onto the console control panel causing a strong delayed reflection at the listening position This kind of speaker placement also couples acoustic energy from the speaker s cabinet more readily into the console s chassis Both conditions should be reduced by placing the speakers on their own stands acoustically detached from and slightly behind the console as shown below In this location the reflective path off the console s control panel is now blocked by the meter bridge M1 ACTIVE REFERENCE MANUAL 15 Speaker Installation 16 Direct Path Random Reflections Moving the monitors to a position behind the meter bridge causes the bridge to block the offending reflective path Careful consideration should also be given to the physical spacing between the speakers Alesis recommends that the distance between the speakers for stereo applications equal the distance between the listener and either speaker In other words the listener and the two speakers are at the three corners of a triangle having equal length sides The illustration below shows this concept Note that both speakers are turned in somewhat so that the prime listening position is directly in front of each speaker Applications that require monitoring b
5. separate the frequencies before being sent to the amplifiers have fewer phase problems and less power loss than the traditional passive crossover used after the amplifier Eighth order filters are extremely steep 48 dB per octave which minimizes the interaction between woofer and tweeter near the crossover point Additionally the high pass tweeter section of this system employs an electronic time alignment circuit Thus the launch of frequencies from both the woofer and the tweeter will originate at exactly the same time There are several advantages to using built in amplifiers and active electronic crossovers versus a passive network system most of which have been previously enumerated in Vance Dickason s Loudspeaker Design Cookbook e Lower intermodulation distortion due to amplifier operation over a more narrow bandwidth Also clipping caused by low frequency overload is reduced being limited to only one driver within a two driver system e Increased dynamic range The M1 Active s 75W and 25W amplifiers in their bi amp setup will clip at about the same levels as one 200W amplifier operating into a passive crossover M1 ACTIVE REFERENCE MANUAL 11 About the M1 Active Improved transient response Better amplifier speaker coupling for woofers Better crossover performance working into a constant impedance load Better subjective sound quality than high level passive networks Easier control over driver sen
6. 7 wib Miz Ski Skiz NI re M1 ACTIVE REFERENCE MANUAL 21 Speaker Installation Connections The M1 Active has been designed to be as simple as possible to set up and use However please follow the instructions to ensure that you get the best possible performance from your monitors Before connecting the speakers make sure the power switches of the M1 Actives and any equipment they will be connected to are turned OFF AC power cable READ ALL SAFETY WARNINGS IN THE PREVIOUS SECTION OF THIS MANUAL TO ENSURE SAFE OPERATION OF THESE UNITS Connect the M1 Actives to the specified power using the AC cables supplied The AC cables are removable If the distance to your AC outlet is longer or shorter than the supplied cable you may substitute an approved standard NEMA to CEE power cable of the correct length available from most electronics stores Grounding CONNECT THE M1 ACTIVES TO A PROPERLY GROUNDED OUTLET ONLY DO NOT USE ADAPTERS WHICH REMOVE THE SAFETY GROUND PROTECTION OR CUT OFF THE GROUNDING PRONG ON THE POWER CORD Proper grounding is essential for user safety and low noise If you experience 60 cycle hum in your sound system as a result of different ground potentials between different units in your system plug all units into the same AC circuit if the total power load allows and make sure other devices in the system are properly grounded themselves The M1 Active features balanced inputs so if it is properly con
7. A DRY CLOTH ON THE BACK PANEL OF THE POWER AMPLIFIER Do not attempt to clean the cabinet with a brush which may damage the surface or a sponge which may leave small crumbs in the texture Do not attempt to clean either of the drivers The M1 Active Surround speakers require no periodic maintenance M1 ACTIVE REFERENCE MANUAL 3 Troubleshooting AN Refer All Servicing to Alesis We believe that the M1 Active is one of the most reliable powered monitors that can be made using current technology and should provide years of trouble free use However should problems occur DO NOT attempt to service the unit yourself Service on this product should be performed only by qualified technicians THERE ARE NO USER SERVICEABLE PARTS INSIDE Service Before sending the M1 Actives in for repair make sure they are faulty and that the problem isn t being caused by something else in the system Distortion or noise may be caused by a defective preamp cable equalizer etc or a loose connection in the system Connect the speakers to a system that is known to be working properly to check whether the monitors have malfunctioned Obtaining Repair Service Before contacting Alesis check all your connections and make sure you ve read the manual Customers in the USA and Canada If the problem persists call Alesis USA at 1 800 5 ALESIS and request the Technical Support department Talk the problem over with one of our technicians if necessa
8. Contents Safety Warnings Introduction Thank you for purchasing the Alesis M1 Active Biamplified Reference Monitor To take full advantage of the M1 Active s operation and to enjoy long and trouble free use please read this user s manual carefully We value any comments you may have about this monitor system this manual your Alesis dealer and about our factory service Please take a minute now to fill out your warranty card and tell us what you think How to use this manual This manual is divided into the following sections describing the various features of the M1 Active Though we recommend you take time to read through the entire manual once carefully those having general knowledge about monitors should use the table of contents to reference specific functions Chapter 1 About the M1 Active Engineering specifications and reasons why nearfield monitors have become so popular Chapter 2 Speaker Installation This chapter explains how to connect the M1 Actives to a mixer or other line level source and discusses proper speaker placement for stereo operation Chapter 3 Surround Sound If you are using the M1 Active speakers in a multichannel surround sound setup you ll find helpful setup and operation information here Chapter 4 Troubleshooting This chapter contains troubleshooting tips and service information should problems occur When something important appears in the manual an icon like the one on the left w
9. achen Betreiben Sie es nicht ber l ngere Zeit mit hoher Lautst rke oder einem Pegel der Ihnen unangenehm is Wenn Sie ein Nachlassen des Geh rs oder ein Klingeln in den Ohren feststellen sollten Sie einen Ohrenarzt aufsuchen M1 ACTIVE REFERENCE MANUAL Contents Safety Warnings Information to the User for Class A Digital Device FCC Part 15 Class A This equipment has been tested and found to comply with the limits for a class A digital device pursuant to Part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause interference to radio communications Operation of this equipment in a residential area is likely to cause interference in which case the user will be required to correct the interference at his own expense The user is cautioned that changes and modifications made to the equipment without the approval of manufacturer could void the user s authority to operate this equipment Use only shielded and grounded cables with this equipment to ensure compliance with FCC Rules Industry Canada Digital Apparatus Interference Causing Equipment Standard ICES 003 Issue 2 This Class A digital apparatus meets all requirements of the Canadian Interference Causing Equi
10. alized Speakers ear eer mine I RTE ER 31 Troubleshooting nuuuunnnunnnnn nun nn nun nun nun nn nn nn nun nun nun nnnnnn une 32 Troubleshooting Ind anheben 32 Maintenance zei nee ee Cen 33 Specifications a a a RE a a a a a a a aa a aa anna 35 nclosure nee ee e A asie osent tetes ni es etes opte 35 KEE 35 CrOSSOVET SEO a He dE edel 37 Am plitier sectiones dost ite rent EEN 37 Acoustic SECTION EE 37 General er EEE 37 Index ununnnunnnnnnnnnnn nun nun nun nun nun nun nun nun nun nun nun nun nun nun nun nun nun nun 38 Alesis Extended Warranty 39 2 M1 ACTIVE REFERENCE MANUAL Contents Safety Warnings IMPORTANT SAFETY INSTRUCTIONS Safety symbols used in this product N This symbol alerts the user that there are important operating and maintenance instructions in the literature accompanying this unit Please follow these precautions when using this product Read these instructions 2 Keep these instructions 3 Heed all warnings 4 Follow all instructions 5 Do not use this apparatus near water 6 Clean only with a damp cloth Do not spray any liquid cleaner onto the speakers or rear panel as this may damage the speakers controls or cause a dangerous condition 7 Install in accordance with the manufacturer s instructions 8 Do not install near any heat sources such as radiators heat registers stoves or other apparatus including ampl
11. and amplifiers in the same compact cabinet Powered monitors are growing in popularity over the traditional separate amplifier and speakers for a number of reasons convenience and ease of hookup being only one of them You can connect a powered speaker directly to any line level source normally the control room output of a mixer simply by connecting a patch cord Another benefit is improved sound quality With careful design the speaker amplifier and electronic crossover can be optimised for each other The M1 Actives are biamplified meaning that low frequencies and high frequencies are handled not only by separate speakers the tweeter and the woofer but by separate amplifiers A pair of M1 Actives contain a total of four power amplifiers Because of the increased efficiency of biamplification these are much louder than a single channel power amplifier of the same wattage feeding a passive crossover as in other designs New technology makes it possible to make these high wattage amplifiers small enough to fit inside the speaker cabinet with very little weight or size gain Since the M1 Actives are self powered DO NOT connect them to the speaker output of another amplifier such as a powered mixer or hi fi receiver Connect them only to the line level outputs of such devices 4 dBu nominal 24 dBu maximum Tone Tonally every effort has been made to emulate the accurate studio sound of Alesis Monitor One but with enhanced l
12. appareils dans le rack g n rant beaucoup de chaleur loignez les Ne pas intercaler cet appareil entre deux appareils produisant beaucoup de chaleur Ce produit utilis avec un amplificateur et un casque ou des enceintes est capable de produite des niveaux sonores pouvant engendrer une perte permanente de l ou e Ne l utilisez pas pendant longtemps un niveau sonore lev ou un niveau non confortable Si vous remarquez une perte de l ou e ou un bourdonnement dans les oreilles consultez un sp cialiste Beim Benutzen dieses Produktes beachten Sie bitte die folgenden Sicherheitshinweise 1 SP HL fer ba N 10 11 12 M1 ACTIVE REFERENCE MANUAL Lesen Sie die Hinweise Halten Sie sich an die Anleitung Beachten Sie alle Warnungen Beachten Sie alle Hinweise Bringen Sie das Ger t nie mit Wasser in Ber hrung Verwenden Sie zur Reinigung nur ein weiches Tuch Spr hen Sie keine fl ssiger Reiniger auf die Oberfl che dies k nnte zur Besch digung der Vorderseite f hren und auch weitere Sch den verursachen Halten Sie sich beim Aufbau des Ger tes an die Angaben des Herstellers Stellen Sie das Ger t nich in der N he von Heizk rpern Heizungsklappen oder anderen W rmequellen einschlie lich Verst rkern auf Verlegen Sie das Netzkabel des Ger tes niemals so daf man dar ber stolpern kann oder da es gequetscht wird Benutzen Sie nur das vom Hersteller empfohlene Zubeh r Verwenden Sie a
13. are too close to a corner then the bass may become exaggerated and inaccurate The rules of thumb for these situations are as follows a less than 1 foot from a front wall but away from any corner plug one port b less than 1 foot from a front wall and a corner plug both ports The plug can be wad of cloth to completely block the port s or a more porous material like fiberfill which will give less bass attenuation The bass output of the M1 Active is thus easily variable depending on in room positioning and or personal preference If the M1 Actives are to be used in a system with a subwoofer the proper blend of the two systems is critical if low bass accuracy is to be maintained Here again your ear is your most important piece of test equipment If the subwoofer such as the Alesis Point One or preamplifier has 80Hz high pass filters built in for connection to the other amplifiers then no port plugging is necessary The proper match will have already been taken care of electronically In the absence of an 80Hz high pass filter feeding the M1 Actives you ll need to experiment with various degrees of port plugging to minimize the cancellations and nodes that can occur from bass sources placed several feet apart in a room In practice we ve found that a single port plugged with cloth is usually the best compromise See Figure 5 below It shows the approximate bass attenuation that can be expected with one port plugged Sul
14. ber NWCE cone and 1 5 diameter long wind voice coil Santoprene surround with moderate internal damping and constant linear displacement Nomex spider 5 mm X max excursion capability Dual magnet structure uses top magnet in opposed bucking configuration for magnetic shielding 10 gauss at outside edge of cabinet High frequency driver 1 Japanese silk dome tweeter M1 ACTIVE REFERENCE MANUAL 35 Specifications Medium viscosity ferrofluid cooling extends power handling while retaining impulse response capability Dual magnet structure uses top magnet in opposed bucking configuration for magnetic shielding Additional 16 gauge low carbon steel cup lowers leakage to 3 gauss at outside cabinet top or side 36 M1 ACTIVE REFERENCE MANUAL Crossover section Crossover type Input Impedance Low Frequency Filter Amplifier Section Specifications Eighth order 48dB octave Linkwitz Riley 1500Hz 20kQ balanced 10kQ unbalanced 2nd order optimal Q high pass filter at 50Hz with 1dB boost Low Frequency Amplifier Rated power output Distortion Slew rate Signal to Noise ratio 75 watts 6Q load lt 0 03 THD 30 watts 8Q 20Hz 20kHz 19V usec gt 110dB referenced to 60 watts 8Q A weighted 1kHz High Frequency Amplifier Rated Power Output Distortion Slew rate Signal to Noise ratio Acoustic Section Free Field Frequency Response Lower Cutoff Frequency U
15. d This method works well with most stereo only recordings which have no surround encoding But it s much better if the rear channels have true matrix mono surround like applause encoded in the mix The second method of using Dolby Pro Logic gets the center channel back into the mix Most of these same home audio receivers have an audio only surround mode which significantly attenuates the output of the center channel in relation to the left and right The audible benefit here is that the mix sounds like a stereo only recording but the center image like a vocalist becomes a hard center There is no image wander as the frequencies change for instance And the classic listening sweet spot expands dramatically allowing for accurate soundstage and instrument placement when listening far off axis This attenuating of the center channel for audio only is also employed by advanced professional matrixed decoders such as the Circle Surround Miles Technology and Lexicon units Placement of the center M1 Active speaker in the studio The left center and right speakers should all be placed in an arc so that the distance of all drivers to the listener is identical see page 29 The equilateral listening triangle as described earlier for stereo two channel playback should be retained with the center speaker placed vertically in the center exactly between the left and right vertical M1 Actives It does not matter what type of M1 Active
16. d all left channel signals are fed to the center In Dolby Pro Logic the center channel information is derived from sum and difference information encoded in the left and right channels The very attributes that make this matrix type system viable for video application make it less desirable for music only reproduction In practice there is a hard center dialog channel but there is also a sort of phantom mono channel developed between the left and center channel and the right and center channel This between channel phantom mono image exists because so much of the information contained in each channel left and 26 M1 ACTIVE REFERENCE MANUAL Surround Sound center or right and center is identical Hence mono In the few music only recordings encoded in Dolby Pro Logic the derived center channel could lead to some drastic changes in spatial perception In developing the M1 Actives for use as left center and right front channel sources we wanted them to be useable in both audio video and audio only matrix type applications We discovered two already available solutions to the large wall of mono effect produced by Dolby Pro Logic when playing audio only material The first is easy Most home audio Dolby Pro Logic receivers will let you take the center channel out completely by putting the receiver in the phantom no center channel mode It preserves the classic stereo effect of the front channels while adding rear surroun
17. dB SPL at one meter a level which may cause hearing loss after prolonged exposure While the biamplified design of the M1 Active avoids the common blown tweeter problem of conventional designs when a broadband amplifier clips on a bass note it sends unusually high energy to the tweeter which tries to reproduce the square wave it is not invulnerable If you need higher power levels you are not using the speaker in a near field application For extremely loud mid field and far field monitoring we recommend the Alesis Monitor Two speaker with a 300 watt per channel amplifier Many studios will check recordings on both systems alternating to avoid ear fatigue and to gain perspective on the mix M1 ACTIVE REFERENCE MANUAL 25 Speaker Installation CHAPTER 3 SURROUND SOUND About surround sound Surround sound is the term used for several different systems which use multiple channels of playback in the listening room to recreate a truly three dimensional sound experience The practice of recording music only in surround sound is a fairly recent innovation Surround sound for video however has been around for over ten years With modern encoding methods multichannel audio may be delivered to consumers on standard video tape video discs and even through broadcast with the proper encoders devices which take multiple channels of audio and combine them into two channels and decoders used at the receiving end to split the signal back
18. e normally or has been dropped This product may be capable of producing sound levels that could cause permanent hearing loss Do not operate for a long period of time at a high volume level or at a level that is uncomfortable If you experience any hearing loss or ringing in the ears you should consult an audiologist Instructions de Securite Importantes Symboles utilis es dans ce produit N Ce symbole al rte l utilisateur qu il existe des instructions de fonctionnement et de maintenance dans la documentation jointe avec ce produit AN Ce symbole avertit l utilisateur de la pr sence d une tension non isol e l int rieur de l appareil pouvant engendrer des chocs lectriques Veuillez suivre ces pr cautions lors de l utilisation de l appareil SOIR SUN a N Lisez ces instructions Gardez ces instructions Tenez compte de tous les avertissements Suivez toutes les instructions N utilisez pas cet allareil proximit de l eau Ne nettoyez qu avec un chiffon humide Ne pas vaporiser de liquide nettoyant sur l appareil cela pourrait abimer les contr les de la face avant ou engendrer des conditions dangeureuses Installez selon les recommandations du constructeur Ne pas installer proximil de sources de chaleur comme radiateurs cuisini re ou autre appareils don t les amplificateurs produisant de la chaleur Ne pas enlever la prise de terre du cordon secteur Une prise murale avec terre deux broches et u
19. hey are cut with a 45 angle and faced toward the amplifier s internal heat sink This arrangement aids in keeping the internal amps working at a more constant temperature At the same time this 45 angle increases the port s air entry efficiency M1 ACTIVE REFERENCE MANUAL 13 About the M1 Active About Nearfield monitoring In the early days of recording most recording studios used big monitor speakers almost exclusively Unfortunately they also required high powered amplifiers and expensive acoustic treatment often poorly done of the entire control room Still a well constructed big monitoring system really was impressive to listen to a fact not overlooked by the studio owners who wanted to impress the record company executives who paid for the big studio s time These big systems had big level control knobs and clients enjoyed cranking up the volume Fortunately recording engineers and producers eventually learned that this was not the best way to accurately mix music because it wasn t the way most people listened to their radios cassettes and CD players Also big monitor systems and the costs for the required control room acoustic treatments were going through the roof no pun intended particularly beyond the budget limits of smaller project and home studios which were growing in numbers A new way of accurate monitoring was needed nearfield monitoring Nearfield monitors by their definition are intended for mounting clo
20. hown below The advantage of using an XLR on the speaker side is that it is a locking connector and cannot be accidentally disconnected NOTE Use high quality input connectors which conform to industry standard sleeve dimensions Some off brand connectors particularly cheap 1 4 TRS plugs do not provide reliable connections because of slight dimensional differences Setting the Input Level control In most cases the INPUT LEVEL control should NOT be set at full rotation For best system dynamic range follow the instructions below The goal is to set the input level of the M1 Actives for the desired listening level when all the rest of the system is at its nominal operating level Nominal means its normal average level expecting peaks from 8 to 15 dB above that on occasion For the best signal to noise ratio everything before the M1 Active should be as loud as possible The M1A s INPUT LEVEL control being last in the signal chain is the worst place to make up gain lost earlier in the system To set the level with a mixer 1 Turn on all system components the M1 Actives last and turn the M1 Active s INPUT LEVEL control all the way down 2 Play program through the mixer and raise the mixer s fader levels until its meter averages around 0 VU 3 Raise the Control Room Output to its nominal position usually 2 o clock or 3 4 of the way up 4 On one speaker raise its INPUT LEVEL CONTROL for a comf
21. hus can be center mounted But as hi end audiophile speaker companies have found a high quality dome tweeter offset in the cabinet toward the stereo image center between the left and right speakers will have a flatter characteristic frequency and power response This flat power response more closely characterizes the way humans hear On a horizontal polar response curve of the M1 Active with the cabinet placed vertically the tweeter response at one meter stays essentially symmetrical on either side of the cabinet s centerline This is because the angle subtended between the cabinet centerline to tweeter centerline 5 and the nominal nearfield listening distance 1 meter or 39 375 is only 1 27 degrees Thus acoustically speaking the offset tweeter design has no negative effects only the positive of smoothing the frequency response in the 2KHz 4KHz range In the tradition of the Alesis Superport design which uses the energy from the back of the speaker to enhance bass performance the M1 Actives use dual front baffle mounted long folded ports The dual ports on the M1 Active are also non symmetrical with relation to their distances from the woofer In developing the M1 Active Alesis engineers determined that dual ports offset to the outside of the stereo image center gave the most coherent and extended low bass augmentation The ports are flared on the front baffle to provide smooth and quiet exit airflow while inside t
22. iece will sound like in a typical home listening environment It is in this configuration that the imaging specificity of your mix can best be evaluated Generally in the playback check mode you want to arrange the speakers in the same equilateral listening triangle that you do in a nearfield setup but instead of each side of the triangle being about 3 feet long the distances between stereo speakers and to your listening position should be between 7 and 12 feet When setting the left and right speakers vertically place the tweeters toward the center with the ports toward the outside In this vertical position the M1 Active becomes a line source speaker which is the most common home set up A 12 three way with woofer on bottom midrange in the center and tweeter at the top is a line source as are most forms of tower speakers When the M1 Active is set vertically in its column configuration the horizontal dispersion left and right of the speaker is widest and the vertical dispersion up and down is narrowest Unfortunately a vertical setup will also increase room effects so there are minimum recommended setup distances from side and back walls the speakers should be a minimum of 2 5 feet from the side walls and 3 feet from the rear walls See the illustration on page 26 After you ve got the requisite distances from the side and back walls it s often helpful to adjust the 7 to 12 foot equilateral listening triangle
23. ientation with a modern wide dispersion design like the M1 Active will increase the likelihood of hearing unwanted first reflections and a variety of phase anomalies in your mix Horizontal Placement Recommendation Traditionally proper horizontal placement of speaker systems slightly behind not on a meter bridge accomplished two purposes it allowed both woofer and tweeter to be at ear level and many times it permitted the recording engineer to see over the speakers and into the studio Horizontal placement is a recommended arrangement with the M1 Active because the left and right mirror imaged pair permits a symmetrical alignment of drivers and ports This will be conducive to a balanced mix See Figure 2 below M1 ACTIVE REFERENCE MANUAL 17 Speaker Installation Proper tweeter orientation is toward the stereo image center the middle as shown Ports are always faced toward the bottom side of the cabinet This set up will promote a strongly focused center image such as for the vocalist And because the vocal image width will be narrower than if the speakers are placed vertically it will be possible to place the vocalist with great precision at stage center In this orientation there will be much less chance of first reflections from either sidewalls or the console coloring your mix Correct korizrmtal lacement tweeters tawerd inside 18 M1 ACTIVE REFERENCE MANUAL Speaker Installation Vertical Placement Recommendatio
24. ifiers that produce heat Ki 9 Do not defeat the safety purpose of the polarized or grounding type plug A polarized plug has two blades with one wider than the other A grounding type plug has two blades and a third grounding prong The wide blade or the third prong are provided for your safety When the provided plug does not fit into your outlet consult an electrician for replacement of the obsolete outlet 10 Protect the power cord from being walked on or pinched particularly at plugs convenience receptacles and the point where they exit from the apparatus 11 Use only attachments or accessories specified by the manufacturer M1 ACTIVE REFERENCE MANUAL 3 Contents Safety Warnings 13 15 Use only with a cart stand bracket rack or table designed for use with professional audio or music equipment In any installation make sure that injury or damage will not result from cables pulling on the apparatus and its mounting If a cart is used use caution when moving the cart apparatus combination to avoid injury from tip over Unplug this apparatus during lightning storms or when unused for long periods of time Refer all servicing to qualified service personnel Servicing is required when the apparatus has been damaged in any way such as when the power supply cord or plug is damaged liquid has been spilled or objects have fallen into the apparatus the apparatus has been exposed to rain or moisture does not operat
25. ill appear in the left margin This symbol indicates that this information is vital when operating the M1 Actives M1 ACTIVE REFERENCE MANUAL 1 Contents Safety Warnings CONTENTS Important Safety Instructions EE EE EE EE EE EEN EE KEE EEN EEN Keen 3 Safety symbols used E ee ets en 3 Please follow these precautions when using this product 3 Instructions de S curit Importantes 4 Symboles utilis s dans ce produit 0c ccc cect cece cece eee aeeeeeeeeeenentenaes 4 Beim Benutzen dieses Produktes beachten Sie bitte die folgenden there tee AE RE TE eeh 5 Information to the User for Class A Digital Device FCC Part 15 Class A 7 About the M1 Bette EE E E e 8 Unpacking and Inspection sysh Siet rahis unie neun Ainsi 8 Inside your new speakerg ss 10 About Nearfield monitortng 14 Speaker Installation EE EE EEEEEEEEEE EE EEE EE nun nun nun EE EEE EE ER 14 Avoiding reflections in the SIG ete ee nt es 14 Stereo nearfield placement of the M1 Active 17 RR ssl i ee ne nt ner ta miennes one detre tien 22 Setting the Input Level Controls w nen 24 Surround Sound ununnunnunnnnnnn nun nun nun nun nun nun nun nun EE EE EE KEE Een 26 About surround sound laine ee geed ses 26 Center speakers in MUSIC mixen 26 Placement of the center M1 Active speaker in the studio 27 Placement of rear surrounds ss een 29 Mixing for discrete six channel reproduction matched vs speci
26. into multiple channels Systems are in use which use three left right and surround five left center right left surround right surround often supplemented by a sixth subwoofer channel and more speakers The original Dolby Surround of the mid eighties was a matrixed three channel only system It had left right and a mono surround rear track which was usually played through two surround speakers In 1987 Dolby Pro Logic a four channel matrix system was introduced Pro Logic added a dedicated center channel to which most dialog was assigned The rear surround channel was still in mono In 1996 Dolby Digital AC 3 and DTS fully discrete six channel audio delivery platforms with separate left rear and right rear channels first became available to consumers on laserdisc and more recently on DVD Digital Versatile Disc With so many listeners hearing music through their multimedia systems it is important for engineers to produce music on surround systems even if they re not working for film or video applications Powered monitors like the Alesis M1 Active Biamplified Reference Monitor have proven to be a simple cost effective way to add five channel surround to control rooms Center speakers in music mixes In video applications with left center and right channels all set to deliver equal output the ear tends to hear dialog as coming only from the center channel It s a psychoacoustic effect because all right an
27. is used for the center speaker tweeter in or tweeter out Since M1 Actives are sold as pairs a 5 channel system requires the purchase of a single speaker breaking up a pair Some dealers may request that you purchase in pairs only others may be able to arrange purchase of a single unit For the rear channels we recommend a mirror image pair although this is less critical than in the front As discussed above for music only recording the signal level to the center channel will be attenuated over the levels of the left and right speakers As a starting point we would recommend that you set the center channel level 6dB below the left and right channels To get these levels fairly accurate a white or pink noise source such as from a test CD is very helpful along with an inexpensive sound level meter such as the Radio Shack cat no 33 2050 If you are recording audio for video the center channel signal level should be the same as left and right channels The left center right speaker layout configuration can remain the same as for an audio only mix With all front speakers operating at M1 ACTIVE REFERENCE MANUAL 27 equal levels the sweet spot listening area will become very large but the wall of mono effect mentioned above in regards to music will be of little consequence since most of the dialogue will be mixed specifically into the center channel 28 M1 ACTIVE REFERENCE MANUAL Placement of rear surrounds The fo
28. ixing primary instruments and vocals into the surround channels So our basic recommendation for mixing an audio only six channel recording is to intentionally limit the frequency response of the rear speakers using a graphic equalizer or high pass 100 Hz rolloff low pass 12 kHz rolloff filter on your mixer This will help you get a rough idea of what a home system playback will sound like This arrangement will also allow your mix to sound best over a well set up car audio system This is because professional installers have learned that a mobile system performs best when they concentrate on producing a soundstage across the front of the vehicle They do this by placing high quality drivers in the front of the vehicle which produce frequencies from the mid bass about 80Hz on up In the rear go the subwoofers and sometimes small full range drivers which provide fill So in essence today s best car audio systems are designed to produce an enveloping environment very similar to that of a home theater M1 ACTIVE REFERENCE MANUAL 31 The use of M1 Actives or any monopolar speaker as full range surrounds would be useful in the following cases e Ifthe surround speakers are just as important as the fronts in achieving a specialized effect such as completely mixing the sax in the left rear only and a flute in the right rear e If you know that your mix will always be played back on a monopolar surround system e If the control r
29. llowing suggestions for optimal M1 Active placement are derived from several sources 1 Standard industry practice for home installations as recommended by the manufacturers of surround encoder decoder units 2 recommendations developed by Tom Holman for setting up THX surround theater sound systems and 3 Alesis engineers experience fine tuning the performance of the SMS Monitoring System in order to find the mounting configuration which results in the most natural and accurate surround placement With the many different playback systems in use there is room for interpretation of what the best placement is in a control room but the following represents a good starting point which you are free to change to your taste Vertically the M1 Actives should be placed on the side wall of the control room above your head with the woofers on top tweeters on the bottom The ideal location is to have the center of the speaker between the woofer and tweeter at 80 of the floor to ceiling height For a standard 8 foot ceiling height the center line would be at 96 x 80 76 8 from the floor Recommended positioning of surround speakers Horizontally place the M1 Actives slightly behind the 90 position at 110 on each side Make sure that at the position used there is still at least 3 feet to the back wall of your studio If you do not have at least 3 feet to the back of your studio then the speakers will work better if placed diagonal
30. ly in the rear corner as shown on the next page M1 ACTIVE REFERENCE MANUAL 29 KOSCH anly f Header distance is less chan Y Wall mounting Once your have located the general area for the horizontal and vertical position you need to find a wall stud Attach shelving brackets or other commercial speaker mounting device into the wall stud then attach the M1 Actives to the mount allowing room for the rear panel input and AC connections The M1 Actives weigh 19 5 Ibs so it is vitally important that any stand they re resting on be securely mounted through the wall material usually 3 4 sheetrock which by itself does not have the strength to support the speakers and into a wooden stud using hardened screws or other fastener rated to hold at least two times that weight 30 M1 ACTIVE REFERENCE MANUAL Surround Sound Mixing for discrete six channel reproduction matched vs specialized speakers While most speaker systems for monitoring music in surround use the same speaker cabinet in all positions both front and rear keep in mind that most consumer video surround installations use a different speaker in the rear channels These rear speakers typically do not have the same directionality or wide frequency response of the M1 Actives When mixing for film speakers with a broad ambient non directional response are used to mimic the multi speaker situation in most movie theatres Keep this in mind when making music mixe
31. n Vertical placement of the M1 Active as shown in Figure 3 is highly recommended This position will simulate the soundfield that will be heard in most consumers homes and to a great extent their cars For this reason even if the M1 Actives are positioned horizontally for all of the mixing the vertical position should always be used in the final playback check mode See next section There are a couple of possible drawbacks to vertical placement of a nearfield monitor relating mostly to room interaction effects Vertical placement allows the M1 Actives to portray your mix with the widest and deepest soundstage possible so many people in the control room have an image of the sweet spot However this wide a dispersion pattern in a control room with walls in too close proximity to the speakers can add strong reflections to the sound you hear muddying your mix Figure 4 shows the control room placement distance recommendations which should help you determine if your available recording space would work well with the M1 Actives set up vertically Let vertical placement tweeters Sawer inside M1 ACTIVE REFERENCE MANUAL 19 Speaker Installation Playback check mode vertical mid field After vou ve got your mix just right it s always good practice to perform a playback check by standing the M1 Actives vertically and making the listening triangle larger The purpose of the playback check is to simulate what your masterp
32. ne troisi rme reli e la terre Cette derni re est pr sente pour M1 ACTIVE REFERENCE MANUAL 10 11 12 13 14 15 16 Contents Safety Warnings votre s curit Si le cordon secteur ne rentre pas dans la prise de courant demandez un lectricien qualifi de remplacer la prise Evitez de marcher sur le cordon secteur ou de le pincer en particulier au niveau de la prise et aux endroits o il sor de l appareil N utilisez que des accessoires sp cifi s par le constructeur N utilisez qu avec un stand rack ou table con us pour l utilisation d audio professionnel ou instruments de musique Dans toute installation veillez de ne rien endommager cause de c bles qui tirent sur des appareils et leur support D branchez l appareil lors d un orage ou lorsqu il n est pas utilis pendant longtemps Faites r parer par un personnel qualifi Une r paration est n cessaire lorsque l appareil a t endommag de quelque sorte que ce soit par exemple losrque le cordon secteur ou la prise sont endommag s si du liquide a coul ou des objets se sont introduits dans l appareil si celui ci a t expos la pluie ou l humidit ne fonctionne pas normalement ou est tomb Cet appareil produit de la chaleur en fonctionnement normal Si cet appareil est utilis dans un rack veillez sa bonne ventilation lors de son utilisation Ne pas faire fonctionner dans un rack ferm S il y a d autres
33. nected to other balanced units AC ground potentials will not affect the audio If you cannot get rid of ground loops consult a professional electrician familiar with sound system power designs Use clean power The M1 Active s internal power supply is designed to filter out most AC line noise However it is still good practice to plug your sound equipment into an AC circuit that is not shared with lighting dimmers refrigerators air conditioning units or other appliances that may induce noise into the power system Power switch The POWER switch is located on the back panel A blue power indicator lamp is on the front panel 22 M1 ACTIVE REFERENCE MANUAL Speaker Installation Input Connections Almost any conventional line level source may be plugged into the M1 Active s LINE INPUT jack The Line Input jack accepts both XLR and 1 4 input plugs wired either balanced or single ended unbalanced The best connection is to use a high quality XLR to XLR mic cable between the output of the source usually the CONTROL ROOM OUTPUT of the console and the speakers A conventional 1 4 patch cord TS type plug will also work for unbalanced sources which automatically ground the minus input Polarity Input connector wiring is printed to the left of the connector on the back panel and is as follows Pin 2 tip hot Pin 3 ring cold Shield Pin 1 sleeve ground A positive voltage on the hot
34. o get louder then softer then louder again as you move your head from side to side making it very confusing when trying to mix with precision Some people still believe that stereo separation is improved with tweeters to the outside but this is advice left over from the early days the sixties of stereo recordings when correct stereo often meant a complete hard right or hard left placement of an instrument or singer As stereo mixing techniques changed toward placing the vocalist for example in the center the old tweeters out orientation would indeed widen the image if one s head were kept in the exact center position But this set up proves to be very tiring very quickly for the recording engineer And to others who are listening to the mix from either side of the engineer the sound will seem to be coming primarily from the speaker closest to them Fortunately recording techniques have changed radically since the sixties Engineers have learned to how to place an instrument or singer within the mix so that an accurate re creation of the actual instrument and vocal positioning left to right and front to back is achieved In the M1 Active advances in crossover design technologies and improvements in the off axis response of tweeter domes and woofer cone materials and profile have made the requirement for tweeters to be placed to the outside of the cabinet obsolete In fact using a non toed in tweeters out or
35. o lower the free air resonance The very low 1500Hz crossover point of this tweeter produces an extremely wide dispersion low distortion signal within the critical midrange frequencies It is these frequencies which are often the most problematic in terms of getting right during a mix The tweeter is designed for an optimal response for non fatiguing long term high level nearfield mixdowns This design results in a flat linear mix when played back on home or car systems from appropriate distances Magnetic shielding Your M1 Actives are at home in recording environments wherein video is a major component They are magnetically shielded for use in fairly close proximity 3 minimum to a computer monitor or video screen Non shielded components can make the colors of a screen smear or appear out of focus if the speaker is too close Magnetic shielding was designed into both the woofer and the tweeter from the beginning so that the system exhibits about 10 gauss worst case leakage Shielding of both the woofer and the tweeter is accomplished by the use of a second opposing field oriented bucking magnet The tweeter has an additional sixteen gauge steel cup encasing the entire magnetic structure The M1 Active bi amplifiers amp electronic crossovers The M1 active uses a 75W woofer amp and a 25W tweeter amp along with 8 order high and low pass electronic crossover filters centered at 1500Hz Electronic crossovers which
36. of the surrounding room acoustics it is always prudent to optimize the listening environment whenever possible First the user should be aware of the effect that the size of the listening room can have on low frequency response In general the smaller the room the stronger the bottom end will be although placement within a larger room can also make a difference This has to do with the way low frequency waves travel in closed spaces If you find your M1 ACTIVE REFERENCE MANUAL Speaker Installation monitor system to be either light or heavy on the bottom try moving them around within your listening room You should avoid locating your M1 Actives near reflective surfaces such as glass tile large open walls or table tops Still many rooms used for recording have these surfaces so the best way to deal with them is to place the monitors out in the room away from reflective walls windows and sizable objects Even with these reflective surfaces separated from the monitoring position typical mixing situations usually still have the top surface of the mixing board to deal with Unfortunately the board itself can be a major source of reflections and the additional acoustic conduction into the board can affect your monitor s amplitude and phase response Speaker placement on the console s meter bridge allows two different acoustic paths between the speakers and the recording engineer which results in undesirable comb filtering effects and poor
37. oom is completely damped with sound absorption on all surfaces This renders the reverberant field generating properties of a bipole dipole speaker ineffective Dolby Surround Dolby Pro Logic and Dolby Digital are trademarks of Dolby Laboratories Inc CHAPTER 4 TROUBLESHOOTING Troubleshooting Index If you experience problems while using the M1 Active Surround systems please use the following table to locate possible causes and solutions before contacting Alesis Technical Support for assistance No sound Speaker disconnected Check input cable connections INPUT LEVEL down Turn up input control on back panel AC power not on Blue LED on front should bd on Check switch and power input cable Unfocused sound bass Inputs out of phase Check and connections frequencies muddy or from mixer to input Verify missing pin 2 is hot Subwoofer being used Install port plugs when improperly using a subwoofer Poor mix Compare to commercial CD of similar style time to remix your track Distorted output Power amp overloading Turn down level speakers Damaged speaker Sw ap channel s to see if the components problem follows the speaker if so contact Technical Support 32 M1 ACTIVE REFERENCE MANUAL Troubleshooting Maintenance Cleaning The cabinet surfaces of the M1 Active are covered with a vinyl laminate Clean these surfaces when necessary with a lint free cloth dampened in warm soapy water USE ONLY
38. ortable level in the engineer s seat if you have a sound pressure meter 85 dB SPL is a common standard for listening 5 Match the level for the other speaker Note that the numbers on the back panel are only a rough guide for precise left right imaging use pink noise or test tones and a sound pressure meter The Input Level control has a 28 dB range with a center detent The detent has no particular meaning but helps in adding a mental reference position when attempting to set levels from in front of the speaker With the control at a maximum clockwise rotation 2 0 volt input will produce full amplifier output 102 dB SPL A weighted from two speakers at 1 meter 2A M1 ACTIVE REFERENCE MANUAL Speaker Installation For the technically minded here is an approximate chart of SPL levels for various settings of the INPUT LEVEL control measured at 1 meter from two speakers simultaneously all settings especially near the extremes of the range are subject to a plus or minus 2 dB error Es 10 MAX denotes recommended setting for control room use Avoiding damage The best protection against speaker failure is to mix at a reasonable listening level With a 4 dBu input and the input level control set to 6 the M1 Active speakers produce a sound pressure level SPL of 85 decibels at 1 meter which is a good working level for mixing At maximum output before clipping they can generate peak levels gt 118
39. ow bass and high frequency extension The nominal frequency response is 50Hz 20KHz 2dB See Figure 1 Additionally the use of electronic crossovers within the critical upper midrange frequencies has reduced phase and time delay anomalies often associated with passive crossovers By including discrete woofer and tweeter amplifiers and application specific electronic high and low pass crossover filters in the same enclosure the tonal accuracy of the M1 Active will always remain constant About the drivers The M1 Active s 6 5 woofer cone is made of proprietary non woven carbon fiber This material is 25 lighter than polypropylene with twice the stiffness for quicker transient response in the low to midbass region and vastly improved midrange intelligibility over polypropylene at 1500 Hz The non woven carbon fiber cone M1 ACTIVE REFERENCE MANUAL About the M1 Active along with the closed cell synthetic rubber surround are both nearly impervious to ozone direct sunlight heat and humidity Therefore after an initial break in period about 20 hours the sound should remain virtually unchanged for the life of the product Alesis proprietary design tweeter features a pure Japanese silk dome an internal pole piece mounted phasing plug and low viscosity ferrofluid formulated specifically to retain the best balance of transient response to power handling The shielded tweeter utilizes a vented pole piece with a separate rear chamber t
40. pment Regulations M1 ACTIVE REFERENCE MANUAL 7 Contents Safety Warnings CE DECLARATION OF CONFORMITY Approvals pending See enclosed sheet if product was authorized for shipment to the EU CHAPTER 1 ABouT THE MA Acr ve Unpacking and Inspection 8 M1 ACTIVE REFERENCE MANUAL About the M1 Active Your M1 Active Biamplified Reference Monitors were packed carefully at the factory and the shipping carton was designed to protect the speakers during shipping Please retain this container in the highly unlikely event that you need to return the speakers for servicing The shipping carton should contain the following items This instruction manual M1 Actives with the same serial numbers as shown on the shipping cartons Two AC power cords NEMA to CEE type Alesis warranty card Two pieces of adhesive backed non skid foam oO It is important to register your purchase if you have not already filled out your warranty card and mailed it back to Alesis please take the time to do so now The M1 Actives are designed as mirror imaged pairs If you have received a pair where the tweeters are both on the same side contact your dealer immediately M1 ACTIVE REFERENCE MANUAL 9 About the M1 Active Inside your new speakers 10 If you re in a hurry to get started skip ahead to Chapter 2 Speaker Installation for connection and placement tips About powered monitors The M1 Actives combine a speaker
41. pper Cutoff Frequency Maximum Peak SPL per pair Maximum short term SPL General Power Consumption AC Dropout Voltage Weight Dimensions H x W x D 25 watts 4Q load 0 06 THD rated power 9V usec gt 112dB rated output 2dB 50Hz to 20KHz 38Hz 10dB 23 5KHz 10dB gt 118dB SPL 1m 80Hz to 3 0KHz gt 105dB SPL Im 120 watts with musical program loud mix 12 watts quiescent idle 120V AC version 80V AC 240V AC versions 160V AC 19 5 Ibs 8 9 kg each 15 381mm x 8 5 216mm x 9 75 248mm INDEX AC power 12 22 37 amplifiers 10 11 37 balanced 23 M1 ACTIVE REFERENCE MANUAL biamplified 10 crossover 10 crossover 37 Specifications dispersion 19 frequency response 10 37 with ports plugged 21 fuse 12 grounding 22 INPUT LEVEL 24 detent 24 interference 7 LINE IN 23 Magnetic shielding 11 36 mounting 17 nearfield 14 noise 22 placement 15 horizontal 18 surround 28 vertical 19 Playback check mode 20 INSERT NOTICE HERE Polarity 23 ports 13 plugging 21 power supply 12 reflections 15 17 18 Safety 3 service 4 34 spacing 16 SPL 24 25 subwoofer 21 Surround sound 26 time alignment circuit 11 tweeter 11 36 mirror to inside 17 offset 13 warranty 9 woofer 10 36 XLR 23 ALESIS EXTENDED WARRANTY M1 ACTIVE REFERENCE MANUAL
42. rmer The regulated supply rails increase the amplifier dynamic range and reduce clipping distortion under heavy loading The compact size of the supply does not significantly reduce the internal air volume of the speaker cabinet And lastly full power can be maintained even with low or flat topped line voltages Note however that this switching supply is NOT a universal voltage type that may be used with any input voltage in any country simply by changing the cord If you wish to use the M1 Actives in a country whose line voltage is other than 120 volts AC they must be internally modified or used with a step down transformer 12 M1 ACTIVE REFERENCE MANUAL About the M1 Active The cabinet and port design The M1 Active cabinet construction employs vinyl composite material laminated to a 625 MDF medium density fiberboard core for the four sides and the rear The front panel is 1 thick MDF to withstand the greater demands of the drivers mounted on it The entire cabinet is braced extensively in random fashion to dissipate intramodal vibration Why the tweeters are offset The M1 Active speakers have been developed as a mirror imaged pair with dual front mounted ports and an offset tweeter In some applications an extremely wide dispersion tweeter such as used in the M1 Active will exhibit response dips if mounted exactly on center Wave guide style tweeters used in other products purposely limit dispersion and t
43. ry you will be given a return order RO number and instructions on how to return the unit All units must be shipped prepaid and COD shipments will not be accepted For prompt service indicate the RO number on the shipping label Units without an RO will not be accepted If you do not have the original packing ship the M1 Active in a sturdy carton with shock absorbing materials such as styrofoam blocks or bubble pack surrounding the unit Make sure the drivers will not be pressed on by the packing in shipment Shipping damage caused by inadequate packing is not covered by the Alesis warranty Tape a note to the top of the unit describing the problem include your name and a phone number where Alesis can contact you if necessary as well as instructions on where you want the product returned Alesis will pay for standard one way shipping back to you on any repair covered under the terms of this warranty Next day service is available for a surcharge Field repairs are not normally authorized during the warranty period and repair attempts by unqualified personnel may invalidate the warranty Correspondence address for customers in the USA Alesis Product Support 1633 26th Street Santa Monica CA 90404 THIS IS NOT A SERVICE LOCATION DO NOT SHIP UNITS TO THIS ADDRESS M1 ACTIVE REFERENCE MANUAL Troubleshooting Customers outside the USA and Canada Contact your local Alesis distributor for any warranty assistance The Alesis
44. s with full range high power speakers like the M1 Actives as the surround speakers The difference between music surround and video surround playback has a long history e Dolby Pro Logic which works best with dipole De speakers splayed in different directions out of phase surround speakers has been the standard for surround sound in the home for 10 years e The most accepted home playback medium VHS videotape can only play back mono surround in Dolby Pro Logic VHS will not support Dolby Digital or DTS e There are only two playback mediums laser disc and DVD that support Dolby Digital discrete and DTS discrete After 20 years in existence laser disc has only a 2 market share Some digital satellite broadcasters have started broadcasting in Dolby Digital but these discrete broadcasts will be reserved for blockbuster movies initially e Discrete Dolby Digital DTS and Sony s SDDS are most commonly mixed for theatrical release using surround not monopolar direct monitors e Among the recording engineers who have recorded audio only the consensus seems to be that the role of the surround speaker is to give the listener a sense of immersion in the musical event This is done by reserving the rear channels for audience sounds in the case of a live recording or perhaps by reproducing the reverberant acoustics of the recording environment itself Other engineer producers prefer using five identical full range speakers and m
45. se to the listener The idea here is to improve the direct acoustic path between the speaker and the listener by making it shorter thereby giving less opportunity for the always present indirect reflected sounds to get back in and muddle things up With nearfield monitoring the surrounding acoustic environment becomes a much less significant factor in establishing the monitor system s sound character A good set of small monitors properly placed in a reasonably non reverberant room and properly powered will yield surprisingly accurate results at budget prices Carried to another studio the same monitor should also provide repeatable results In fact some recording engineers carry their own speakers around because they know how they will sound in almost any room Now even the big studios use smaller speakers to augment their big monitoring systems and nearfield monitors have become proven tools in the recording business CHAPTER 2 SPEAKER INSTALLATION Like any speaker system your M1 Active speakers will work best when properly positioned in a suitable acoustic environment Achieving proper speaker placement is usually straightforward but even with nearfield monitors speaker placement and the acoustics of the listening room itself are too often overlooked and can become significant contributors to an inaccurate and uninspiring monitoring environment Avoiding reflections in the studio 14 While nearfield monitors are more forgiving
46. sitivity differences Easier manipulation of phase time delay resonance and various kinds of shaping contouring and equalization e Specifically in the case of the M1 Active the wide mid frequency polar response of the tweeter can be utilized down to a low 1500Hz thereby mating more cohesively with the 6 5 non woven carbon fiber NWCF woofer This low crossover is only possible through the use of a very steep electronic eighth order 48 dB per octave rolloff high pass filter The M1 Active power supply The M1 Active employs a regulated switching power supply This type of supply has previously only been available in amplifiers sold at the very high end of the Pro Audio market Most power amp customers are familiar with the large transformer and output capacitors in high quality amplifiers These large components are used to keep the amplifier s supply rails as close to DC as possible For traditional supplies bigger is better But by using Pulse Width Modulation PWM and output voltage feedback in the M1 Active we have the equivalent of near infinite transformer and output capacitors but at a fraction of the cost PWM provides protection from line voltage surges that would otherwise destroy the amplifier No user replaceable fuse is required because nuisance tripping is eliminated And finally PWM practically eliminates hum because the line frequency 60 Hz transformer is replaced with a very high frequency 130 000 Hz transfo
47. usschlie lich Wagen St nder Racks oder Tische die speziell f r professionelle Audio und Musikinstrumente geeignet sind Achten Sie immer darauf da die jeweiligen Ger te sicher installiert sind um Sch den und Verletzungen zu vermeiden Wenn Sie einen Rollwagen benutzen achten Sie darauf das dieser nicht umkippt um Verletzungen auszuschlie en Ziehen Sie w hrend eines Gewitters oder wenn Sie das Ger t ber einen l ngeren Zeitraum nicht benutzen den Netzstecher aus der Steckdose Contents Safety Warnings 13 14 15 Die Wartung sollte nur durch qualifiziertes Fachpersonal erfolgen Die Wartung wird notwendig wenn das Ger t besch digt wurde oder aber das Stromkabel oder der Stecker Gegenst nde oder Fl ssigkeit in das Ger t gelangt sind das Ger t dem Regen oder Feuchtigkeit ausgesetzt war und deshalb nicht mehr normal arbeitet oder heruntergefallen ist Bei normalem Betrieb des Ger tes kommt es zu W rmeentwicklungen Wenn Sie das Ger t in einem Rack eingebaut haben sollte w hrend des Betriebes die Zufuhr von K hlluft stets gew hrleitstet sein Arbeiten Sie nie bei geschlossenem Rack Bei mehreren Rackger ten sollten diese mit einem geringen abstand voneinander eingebaut werden Stapeln Sie dieses Ger t nicht zwischen Ger ten mit hoher W rmeentwicklung Dieses Produkt kann in Verbindung mit einem Verst rker und Kopfh rern oder Lautsprechern Lautst rkepegel erzeugen die anhaltende Geh rsch den verurs
48. y more than one engineer are accommodated by a smaller rotation of the cabinets This will widen the prime listening position somewhat The speakers and listener should be at the three corners of a triangle having equal length sides Prime Listening Position NOTE On some mounting surfaces the vinyl finish of the M1 Active s cabinet may cause it to slip too easily Included with this reference manual packet are two pieces of adhesive backed non skid foam If necessary apply the pad to either the bottom for vertical placement or cabinet side nearest the ports for horizontal placement If you plan on using the M1 Actives in both modes simply cut the pad in half and apply to both the bottom and the side nearest the ports M1 ACTIVE REFERENCE MANUAL Speaker Installation Stereo nearfield placement of the M1 Active NOTE We recommend that the M1 Active speakers be placed with the tweeters to the inside not the outside of the listening triangle The classic studio monitor layout used to be that the tweeters be placed to the outside of a horizontally oriented speaker In the past this configuration was actually beneficial in time aligning the tweeter with the woofer if the cabinets were not toed in toward the listener However this configuration is highly prone to comb filtering effects if the listener s head is moved from side to side while mixing This comb filtering causes the mid to high frequency tones t
Download Pdf Manuals
Related Search