Alesis ACTIVE M1 User manual

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Thankyou for purchasing theAlesisMl Active Biamplified ReferenceMonitor. To
takefull advantageof theMl Active's operation,and to enjoylong and trouble-free
use,pleasereadthis user'smanual carefully. We value any commentsyou nay have
aboutthis monitor system,
this manual,your Alesis dealerand aboutour factory
service. Pleasetakeaminute now to fill out your waranty cardand tell us what vou
think
How to use this manual
This manual is divided into the following sections describing the various features of
the M1 Active. Though we recomrnend you take time to read through the entire
manual once carefully, those having general lnowledge about monitors should use
the table of contents to reference specific functions.
Chapter 1: About the Ml Active. Engineering specifications and reasons why
nearfield monitors have become so popular.
Chapter 2: Speaker Installation. This chapter explains how to connect the Ml
Actives to a mixer or other line-level source and discusses proper speaker placement
for stereo operation.
Chapter 3: Suround Sound. If you are using the M1 Active speakers in a
multicharmel surround sound setup, you'll find helpful setup and operation
information here.
Chapter 4: Troubleshooting. This chapter contains troubleshooting tips and service
inforrration should problems occur.
When something important appearsin the manual,an icon (like
the oneonthe left)will appearinthe left margin, Thissymbol
indicates
that thisinformation
isvitalwhen operatingthe M1
Actives.
III ACIIUE REFEREilC- MAilUAL

ConbntsAtafety Warrrlng
ffiI ACITUE REFTEICE IUIANT'AL

Contents/SaileQrWarnlngs
lmpoRTArurSnTETY
Safety syrmbolsused in this product
This
symbolalertstheuserthatthereareimportantoperating
and
maintenance
instructionsintheliteratureaccompanying
thisunit.
Please follow these precautions when
using this product:
1. Read
theseinstructions,
Keep these instructions.
Heed all wamings.
Follow all instructions.
Do not use this apparatus near water.
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.
Install in accordance with the nanufacturer's instructions.
Do not install near any heat sources such as radiators, heat registers, stoves, or
other apparatus (including amplifiers) that produce heat.
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:ue provided for your safety. Whm the provided plug does not fit into
your outlet, consult an electrician for replacement of the obsolete outlet.
Protect the power cord from being walked on or pinched, particularly at plugs,
convenience receptacles, and the point where they exit from the apparatus.
Use only attachments or accessories specified by the manufacturer.
z
J.
4.
5.
6.
7.
8.
10.
11.
III ACTTE REFERETCE ilIATUAL

trFll
w
-=- 12. Useonly with acart,stand bracket,rack,or table designedfor usewith
professionalaudio or music equipmmt. In any installation, makesurethat
injury or damagewill not result from cables
pulling onthe apparatusand its
mounting. If acart is used,usecaution when moving the cart/apparatus
combinationto avoid injury from tip-over.
Conbntr/lSafcty Wenrlngs
13. Unplug this apparatusduring lightning stomrsor when unused for long periods
of time.
14.Referall servicingto qualified service
personnel. Sewicing isrequired when the
apparatushasbeendamaged
in any way, suchaswhen thepower,supply cord
or plug isdamaged [quid hasbeenspilled or objectshavefa]len into the
apparatus,the apparatushasbeenexposed
to rain or moisture, doesnot operate
normally, or hasbeendropped.
15. Thisproduct may becapable
of producing sormdlevelsthat could cause
pernanent hearing loss. Do not operatefor along period of time at ahigh
volume level or at alevelthat is r:ncomfortable. If you experience
anyhearing
lossor ringing in theears,you should consult anaudiologist.
A
A
lnstructions de S6cufit6 Importantes
Symboles utllis5s dans ce produit
CesymbolealErteLutilisateur qu'il existedesinstructions defonctionnement et de
maintenancedansla docurrrentation
jointe avecceproduit,
CesymboleaaertitI'utilisateurdelapresmce
il'une tension
nonisol6edl'intEieur ilel'appareil
pouoant
enganibudes
chocsAlatriques.
Veuille. suiune ces pr€cauffons lorc de
l'utilisatlon de I'appareil:
1. Lisezcesinstructions.
2 Gardezcesinstructions.
3. Tenezcomptede touslesavertissements.
4 Suiveztouteslesinskuctions.
5. N'utilisez pascetallareil i proximit6 de l'eau.
6. Ne nettoyezqu'avec un chiffon humide. Ne pasvaporiser deliquide nettoyant
sur I'appareif celapourrait abimer lescontr6lesdela faceavant ou engendrer
desconditionsdangeureuses.
7. lnstallez selonlesrecomrrrandationsdu constructeur.
8. Ne pasinstaller i proximil6 desources
dechaleurcommeradiateurs,cuisiniEre
ou autreappareils(don't lesamplificateurs) produisant dela chaleur.
9. Ne pasenleverla prisedeterre du cordon secteur.Une prisemurale avecterre
deuxbrochesetune troisiErmereli6ei la terre. CettedemiEreestpr6sente
pour
4TNACTTUE Rffi TAM|IL

Cont*r/Sailcty Warnlngs
votre s6curit6. Sile cordon secteurnermtre Pas
dansla prise decourant,
demandezirun €lectricienqualifid deremplacerla prise.
10. Evitez demarchersur le cordon secteurou delepincer, enparticulier auniveau
dela prise,et auxendroits oir il sordel'appareil.
N'utilisez quedesaccessoiressp€cifi6s
par Ieconstructeur.
N'utilisez qu'avecun stand,rack ou tableconguspour l'utilisation d'audio
professionnelou instmments demusique. Danstoute installation, veillez dene
rien endommageri causedecAbles
qui tirmt sur desappareilset leur support.
13. D€branchez
l'appareil lors d'un orageou lorsqu'il ntst pasutilis€ pendant
longtemps.
14. Faites
r€parerpar un personnelqualifi6. Une rdparationestn€cessairelorsque
l'appareil a6t6endommag€dequelquesortequecesoit,par exemplelosrquele
cordon secteurou la prise sontendommagds,si du liquide acoul6ou desobjets
sesontintroduits dansl'appareil, sicelui-ci a6t6expo# i la pluie ou i
Itrurriditd, nefonctiormepasnomralement ou esttomb6.
15. Cet appareilproduit dela chaleur enfonctionnementnorrral. Sicetappareil est
utilis6 dansun rack,veillez i sa
bonneventilation lors de sonutilisation. Ne pas
faire fonctionner dansun rack ferm€. S'il y ad'autres appareilsdansle rack
g6n€rant
beaucoupdechaleur,6loignezles. Ne pasintercaler cetappareil entre
deuxappareilsproduisant beaucoupdedraleur.
16. Ceproduif utilis€ avecun amplificateur etun casqueou desenceintes,est
capabledeproduite desniveaux sonores pouvant engendrerune perte
permanentedel'ouie. Ne I'urilisez paspendant longtemps i un niveau sonore
6lev6ou i un niveau non confortable. Sivous remarquezune pertedel'ouie ou
un bourdonnementdanslesoreilles,consultezun sp6cialiste.
Beim Benutzen dieses Produlrtes beachten
11.
72.
8.
9.
10.
11.
Sie bilte die folgenden
Sicherheitshinweise:
1. ksen Sie die Hinweise.
2 Halten Sie sich an die Anleitung.
3. Beachtm Sie alle Wamungen.
4 Beachtm Sie alle Hinweise.
5. Bringen Sie das Gerdt nie mit Wasser in Bertihrung.
Verwenden Sie zur Reinigung nur ein weiches Tuch. Spriihen Sie keine fliissiger
Reiniger auf die Oberfliiche, dies k<innte zur Beschiidigung der Vorderseite
fiihren und auch weitere Schiiden verursachen.
Halten Sie sich beim Aufbau des Geriites an die Angaben des Herstellers.
Stellen Sie das Geriit nich in der Niihe von Heizkrirpem, Heizungsklappen odbr
anderen Wirmequellen (einschlie8lich Verstirkem) auf.
Verlegm Sie das Netzkabel des Geriites niemals so, da8 man dariiber stolpem
kann oder da8 es gequetscht wird.
Bmutzen Sie nur das vom Hersteller empfohlene Zubehiir.
Verwenden Sie ausschlie8lich Wageq Stiinder, Racks oder Trsdre, die speziell ftir
professionelle Audio.und Musikinstrumente geeignet sind. Achten Sie immer
darauf, da8 die jeweiligen Geriite sicher installiert sind, um SchAden und
Verletzungen zu vermeiden. Wenn Sie einen Rollwagenbenutzen, achten Sie
darad das dieser nicht umkippt, um Verletzungen auszusdrlieBen.
12. Ziehen Sie wdhrend eines Gewitters oder wenn Sie das Gerit iiber einen
liingeren Zeitraum nicht benutzen den Netzstecher aus der Steckdose.
SIACIII,E Rffi NAil'AL

ContentstSaiety Wanlngs
13. Die wartung solltenur durch qualifrziertesFachpersonal
erfolgen. Die wartung
wird notwendig, werm dasGerit beschedigt
wuide oder aberlas stromkabel
oder der Stecker,
Gegenstdnde
oder Fliissigkeit in dasGeriit gelangtsind,das
Geriit dem Regen
oderFeuchtigkeit ausgesetzt
war und deshhb nrchtmehr
normal arbeitetoderheruntergefallenist.
14' Beinormalem BetriebdesGerdtes
kommt eszu wiirmeentwicklungen. wenn sie
dasGerdtin einemRackeingebauthaben,
sollte wdhrend desBehiebes
die
Zufuhr von KtiNluft stets
gewiihrleitstet sein. Arbeiten Sienie bei
geschlossenem
Rack. BeimehrerenRa&geriten sollten diesemit einemgeringen
abstandvoneinandereingebautwerden. stapeln sie dieses
Gerdtnicht "wische"
Gerdten
mit hoherWiirmeentwicklung.
1.5.
DiesesProdukt kann in Verbindung mit einemVerstiirker und Kopfh<iremoder
LautsprechemLautstiirkepegelerzeugen,die anhaltendeGehdrschaden
verursachen. Betreiben
sieesnicht nber liingere Zeit mit hoher Lautstiirke oder
einen Pegel,
der Ihnen rmangenehm
is. WerurSieein NacHassm desGehiirs
oderein Klingeln in denohren feststellen,
sollten sie einenohrenarzt aufsuchen.
IUII ACTTUE RETEilCE ISATUAL

Contents6afafil Warnlngs
lnformation to the User for Class A D-gital
Deuice(FCC
Part'15, Class
A)
Thisequipment hasbeentestedand found to comply with the limits for aclassA
digital devicepursuant to Part 15of the FCCRules. Theselimits aredesignedto
provide reasonableprotection againstharmful interferencewhen the equipment is
operatedin acommercialenvironment. This equipment generates,
usesand can
radiate radio frequencyenergyand,if not installed and usedin accordancewith the
instructions,may causeinterferenceto radio communications. Operation of this
equipment in aresidential areais likely to causeinterference
in which casethe user
will be requiredto correctthe interferenceathis own expense.
Theuseriscautionedthat changesandmodifications madeto theequipment without
theapproval of manufacturer could void theuser'sauthority to operatethis
equipmmt.
Useonly shieldedand grounded cableswith this equipment to ensurecompliance
with FCCRules.
Industry Canada (Digital Apparatus)
lnterferGrGe-Causing Equipment Standard
ICES-OO3lssue 2
ThisClassA digitalapparatusmeetsallrequirementsof the Canadian
Interference-CausingEquipmentRegulations.
]UII ACflT'E REEREilCE MATTUAL

Conbrtr/Safety Warrrlnga
DECLARATIOIT OF COIUFORTIITY
Approwalspending. seeenclosed
sheetif product wasauthorized for shipment to
theEU.
ffiI ACITUE Rffi TATI'AL

About lfie Ml ActlYc
CIIAPTER .l
Aeour rHEMl AcrrvE
Unpacking and Inspection
Your M1 Active Biamplified ReferenceMonitors were packedcarefully atthefactory,
and theshipping cartonwasdesigp.edto protect the speakers
during shipping.
Pleaseretainthis containerin the higNy unlikely eventthat you needto retum the
speakersfor servicing.
Theshipping cartonshould containthe following items:
. Thisinstruction manual
o M1 Activeswith the sameserialnumbers asshown on theshipping cartons
. Two AC power cords(NEMA to CEEtype)
o Alesiswarranty card
. Twopiecesofadhesive-backed
non-skidfoam
It isimportant to register your purchase;
if you have not already
filled out your warranty cardand mailed it backto Alesis,
please
take the time to do sonow.
The Ml 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.
ilN AGTTUE REENEil(E ilIAilUAL

About the Ml Actlye
Inside your new speaker
lfyou're
inahurry
to getstarted,
skip
ahead
to Chapter2,
"Speaker
Installation',
for connection
and
placement
tips,
About powered monitons
The M1 Actives combine a speaker and amplifiers in the same compact cabinet.
Powered-monitors are growing in popularity over the traditional siparate amplifier
and speakers for a number of reasons, convenience and ease of hookup beingbnly
one of them. You can cormect 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 carefirl design, $e speaker,
arnplifier and electronic crossover can be optimised for each otherl The ML Actives
arebiamplified,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 Ml Actives contain a total of four power arnplifiers. Because of the increased
efficiency of biampMication, these are much louder than a single-channel power
amplifier of the same wattage feeding a passive crossover, as in other designs. New
teclurology makes it possible to make these high-wattage amplifiers small enough to
fit inside the speaker cabinet, with very little weight or size gain.
Sincethe Ml Activesareself-powered, DONOT
connectthem to
the speaker
output of another amplifier (such
asa powered mixer
or hi-fi receiver). Connectthem only to the line-leveloutputs of
such
devices
(+4dBu nominal,+24dBu maximum).
Tone
Tonally, every effort has been made to emulate the accurate studio sound of Alesis,
Monitor One but with enhanced low bass and high frequency extension. The nominal
frequency response is 50Hz-20KHz X2dB. (SeeFigure 1) Additionally, the use of
eleckonic 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 driverc
TheM1 Active's 5.5"woofer coneismadeof proprietary non-woven carbonfiber.
This material is25%lighter than polypropylene with twice the stiffnessfor quicker
transientresponse
in thelow-to-midbass region and vastly improved midrange
inteligibility (overpolypropylene at 1500Hz). Thenon-woven carbonfiber cone,
alongwith theclosedcellsyntheticrubber surround, areboth nearly impervious to
lo IFI ACflUE REFERrc ilIAilUAL

Aboui {ic mt Actlve
ozone,direct sunlight, heatandhumidity. Therefore,after aninitial break-in period
(about20hours),the soundshould remain virtually unchangedfor the life of the
product.
Alesis'proprietary designtweeter feafuresapure Japanese
silk dome,anintemal
pole'piecemounted phasingplug and low viscosity ferrofluid formulated
specificallyto retain thebest
balanceof transientresponse
to power handling. The
shieldedtweeterutilizes aventedpole piecewith aseparaterearchamberto lower
thefreeair resonance.
Thevery low 1500H2crossoverpoint of this tweeterproduces
anextremelywide dispersion,low distortion signalwithin the critical midrange
frequmcies.It is thesefrequencies
which areoften themost problematic in termsof
getting "right" during amix. Thetweeter is designedfor anoptimal response
for
non-fatiguing, long ter:n,high level,nearfield mixdowns. This desigrr
resultsin aflat,
linear mix when played backonhome or carsystemsfrom appropriate distances.
Magnetic shlelding
Your Ml Actives ate 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 screm "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 Ml Actine bi.amplifiers & electronic
crDssouers
The M1 active uses a 75W woofer amp and a 25W tweeter amp along with 86 order
high and low pass electronic crossover filters cmtered at 1500H2. Electronic
crossovers, which 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 alignnent 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 usingbuilt-in amplifiers and active (elechonic)
crossovers versus a passive network system, most of which have bem previously
enumerated in Vance Dickason's "Loudspeaker Design Cookbook":
r Lower intermodulation distortion due to amplifier operation over a more narrow
bandwidth. AIso, clipping caused by low frequency overload is reduced, being
limited to only one driver within a two driver system.
e Increased dynamic range. The Ml Active's ZSW and 25W amplifiers in their bi-
amp setup will clip at about the same levels as one 200W amplifier operating into
a passive crossover.
r Improved transient response.
If,IACTN'E REEHG il|ATUAL

About the Mt Actlye
o Betteramplifier/speaker coupling for woofers.
e Bettercrossover
performanceworking into aconstantimpedanceload.
r Bettersubjectivesound quality than high level (passive)
networks.
r Easier
conkol over driver sensitiviff differences.
r Easier
manipulation of phase,
time delay, resonance,
andvarious kinds of
shaping,contouring andequalization.
r sgeSificallyin thecase
of theMr Active, thewide, mid-frequency polar response
of thetweetercanbeutilized down to alow 1500H2
therebymutir,g *or" '
cohesivelywith the 6.5non-woven carbonfiber (NWCF)woofer. Tii" lo*
crossover
isonly possiblethrough theuseof avery steep,electroticeighth-order
(48
dBper octave
rolloff) high pass
filter.
The Ml Active power supply
P" M1 Active employsaregulatedswitching power supply. This type of supply
haspreviously only beenavailablein amplifiers sold atthe very high end of tire iro
Audio market.
Most power amp customers
arefamiliar with the largetransformer and output
capacitors
in high quality amplifiers. These
largecomponentsareusedto lieep the
amplifier's supply rails as
closeto DC aspossible. Fortraditional supplies,bigger is
better.
Brt by using Pulsewidth Modulation (PWM) and output voltage feedbackin theM1.
Active, we havetheequivalent of near-infinite transfonner and output capacitors,
but atafraction of thecost. PWM provides protection from line voitage surges
that
would otherwisedestroy theamplifier. No user-replaceable
fuseis required because
nuisance
tripping iseliminated. And finally, PWM practically eliminateshum
because
th9line frequency$0ru) transformer is replacedwith avery high
frequency(13Q000
Hz) transfomrer.
Theregulated-supply rails increase
the ampMier dynamic rangeand reduceclipping
distortion under heavy loading. Thecompactsizeof the supply doesnot
significantly reducethe intemal air volume of the speaker
cabinet. And lastly, fulI
power canbemaintained evenwith low or ',flat-topped,, line voltages.
Note, however, that this switching supply is NOT
a univercal
voltage type that may be usedwith any input voltage in any
country
simplybychanging
the cord. lf you wishto usethsMl
Activesin a country whose line voltage ii other than 120volts AC
they must be internally modified or uied with a stepdown
transformer.
72 IUTI
ACrTG RffiE ilIAIIUAL

About thc Mt ActiYe
The cabinet and port design
TheM1 Active cabinetconstructionemploysvinyl compositematerial laminated to a
.625"MDF (medium density fiberboard) corefor the four sidesandtherear. The
front panel is1" thick MDR to withstand the gteater demandsof the drivers
mounted on it. Theentire cabinetisbracedextensively in random fashion to
dissipateintramodal vibration.
Why the tureeters ane o'ftset
The Ml Active speakers have been developed as a rnirror-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 thus can be center mounted. But ashi-end audiophile
speaker companies have found, a high quality dome tweeter, offset in the cabinet
towardthe stereo"imagecenter" (betwemtheleftandightspeakers) willhaveaflatter
characteristic frequency and power response. This (flat power response) more closely
characterizes the way humans hear.
On a horizontal polar response curve of the ML 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-4I(Flz range.
In the tradition of the Alesis Superport design, which uses the energy from the back
of the speaker to enhance bass performance, the Ml 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 deterrrined that dual ports, offset to the outside of the stereo
image center gave the rrost coherent and extended low bass augmentation. The
ports are flared on the front baffle to provide smooth and quiet exit airflow while
inside they are cut with a45o angle and faced toward the amplifier's intemal heat
sink. This arangement aids in keeping the intemal amps working at a nore constant
temperature. At the same time, this 45o angle increases the port's air enky efficiency.
II]| ACTTUI REERENCI TIATUAL t3

About the l$l Actiue
About lllearlield monitoring
In theearly daysof recording, most recording studios usedbig monitor speakers
almostexclusively. unfortunately, they alsorequired high powered ampMiers and
expensive
acoustic
treaknent (oftenpoorly done)of theenlirecontrol room. still, a
well-constructed big monitoring systemreally wasimpressive to listen to, afactnot
overlookedby the studio ownerswho wanted to impressthe recordcompany
executirres
who paid for thebig studio's time. These
big systems
had big-level
control knobs,andclimts enjoyed"cranking-up" the volume. Fortunately, recording
mgineers andproducerseventually leamed that this wasnot thebestway to
accuratelymix rrusic becauseit wasn't theway most people listenedto their radios,
casset+esandCD players. Also, big monitor systems
and the costs
for therequired
control room acoustic
treahnentswere going through the roof (noprm intended),
particularly beyond thebudget limits of smallerproject and homeitudios which
were growing in numbers.A new way of accurate
monitoring wasneeded: nearfield
monitoring.
Nearfield monitors,by their definition, areintended for mounting closeto the
listener. Theideahereis to improve the direct acoustic
path betrareen
thespeaker
and the listenerby making it shorter, therebygiving lessopporhmity for thealways
presentindirect (reflected)somds to getback in and muddle things up. With
nearfield monitoring, the surrounding acousticmvironment becorresamuch less
significant factorin establishingthemonitor system's
sound character.
A good setof smallmonitors properly placedin areasonably
non-reverberantroom
and properly powered will yield surprisingly accurate
results atbudget prices.
Caried to anotherstudio, the same
monitor should alsoprovrde repeatable
r,esults.In
fact,somerecording engineerscarry their own speakersaround because
theylcrow
how theywill sound in almost any room. Now, eventhebig sfudios usesmaller
speakers
to augmenttheir big monitoring systems,andnearfield monitors have
becomeproven tools in the recording business.
,l/L ffiIACTIUE Rffi TIAilUAL

CHAPTER2
SpemER lusrnlrATton
Like any speakersystem,
your Ml Active speakerswill workbest when properly
positioned in asuitableacousticenvironment. Achieving proper speaker placement
isusually shaightforward, but evenwith nearfield monitors, speakerplacementand
the acousticsof the listening room itself aretoo often overlooked and canbecome
significant contributors to aninaccurateanduninspiring monitoring environment.
Avoiding reflections in the studio
While nearfield monitors are more forgiving 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
monitor system to be either light or heavy on the bottom, try moving them around
within your listening rff)m.
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 frorr refl".1ivs r4'alls, 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 irnaging. The fust path is the direct one,
and the second is via a reflection off tJremixer main control panel:
Monitors
placed
ontheconsole's meterbridgecandirectlyradiate
backonto
theconsolecontrol
panel
causingastrongdelayed
reflectionatthelistening
position
t5

Speaker Insf,allatlon
This kind of speaker
placementalsocouplesacoustic
energyfrom the speaker's
cabinetmore readily into theconsole's
chassis.Bothcondidonsshould'be reducedbv
placing the speakers
ontheir own standsacousdcallydetached
from, and slightly
behind, theconsole
asshownbelow. In this location, thereflective path off tie '
console's
control panelisnow blocked by the meterbridge.
Random
Reflections
Moving tlremonitorsto apositionbehindthemeterbridgecauses
the
bridge
toblocktheoffendingreflectivepath-
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 Iistener and either speaker. In other
words, the listener and the two speakers are at the three comers of a triangle having
equal- length sides. The illustration below shows this concept. Note that both
speakers are tumed in somewhat, so that the prime listening position is directly in
front of each speaker. Applications that require monitoring by more than one
engineer are accommodated by a smaller rotation of the cabinets. This will widen the
prime listening position somewhat.
Thespeakers
and
listener
should
beat
thethreecomers
of
atriangle
having
equallength
sides
Prime
()
Listening
Position
t6 IUII ACITUE REFER!ilCE If,ATUAL

Spcakcr Installation
Stereo nearfield placement of the M{
Active
NOTE:We recommend
that the M1 Active speakersbe placed
with the
tweetersto the inside.
notthe outside,of the listeningtriangle.
The "classic" studio monitor layout used to be that the tweeters be placed to the
outside of ahot'tzontally-oriented speaker. In the past, this configuration was actually
beneficial in time aligning the tweeter with the woofer f 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 to 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 exarnple) in the center, the old "tweeters-out" orientation
would indeed widen the image f one's head were kept in the exact cmter 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 engheer, 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 leamed 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. ln 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 tobe
placed to the outside of the cabinet obsolete. In fact, using a non-toed-in, tweeters-
out orientation with a modern, wide diapersion design like the M1 Active will
inctease the likelihood of hearing unwanted first reflections and avariety of phase
anomalies in vour mix.
IT}I ACT]UE Rffi MAilUAL

Speaker Installdon
Horizontal Placement Recomnendation
Traditionally, proper horizontal placemmt of speaker
systems
slightly behind (not m)
ameterbridge accomplished
two purposes: it allowed both woofer and tweeterto be
at earlevel, and many times,it permitted the recording engineerto seeover the
speakers
and into thestudio.
Horizontal placementis arecommended
arrangementwith the M1 Active because
theleft and right mirror-imaged pair pemrits asymmetrical alignment of drivers and
ports. This will beconducive to abalancedmix. See
Figure 2below,
Propertweeter orimtation istoward the stereoimagecenter(themiddle) asshown.
Portsarealways facedtoward thebottom side of thecabinet.This set-upwill
promote astrongly focusedcenterinage suchasfor the vocalist.And becausethe
(vocal)imagewidth will benarrower than if the speakers
areplaced vertically, it will
bepossibleto placethevocalistwith greatprecision at stagecenter.ln this
orientation therewill bemudr less
dranceof first reflectionsfrom either sidewallsor
the
consolecolorhg your mix.
Correct horizontal placement
tweeters toward inside
IIIAC|TUE Rffi UATUAL