THE MclNTOSH MQ101 ENVIRONMENTAL EQUALIZER

Price $1.25

Your MQ101 EnvironmentalEqualizer will give you many yearsof pleasant and satisfactoryperformance. If you have anyquestions concerning the operationor maintenance of this instrument,please contact:

CUSTOMER SERVICEMclntosh Laboratory Inc.2 Chambers StreetBinghamton, New York 13903Phone: 607-723-3512

Take Advantage of 3 yearsof FREE Factory Service ...Fill In the Application NOW.

Mclntosh Laboratory Incorporated guarantees thisinstrument to be capable of performance as adver-tised. We also guarantee the mechanical and elec-trical workmanship and components to be free ofdefects for a period of 90 days from date of pur-chase. If such defects occur, Mclntosh Laboratory

or one of its authorized agencies will repair thedefect at no cost to the purchaser. This guaranteedoes not extend to components damaged by im-proper use nor does it extend to transportation to andfrom the factory or service agency. This guaranteecovers the MQ 101 only, and not its cabinet.

THREE YEAR FACTORY SERVICE CONTRACT

An application for a FREE THREE YEAR FACTORYSERVICE CONTRACT is included with this manual.The terms of the contract are:

For Three Years from date of purchase —1. Mclntosh wil l provide all parts, materials and

labor needed to return the measured performanceof the instrument to the original performancelimits free of any charge. The SERVICE CON-TRACT does not cover any shipping costs to andfrom the authorized service agency or the factory.

2. Any Mclntosh authorized service agency will re-pair all Mclntosh instruments at normal servicerates. To receive the free service under the termsof the SERVICE CONTRACT, the SERVICE CON-TRACT CERTIFICATE must accompany the instru-ment when taken to the service agency.

3. Always have service done by a Mclntosh author-ized service agency. If the instrument is modifiedor damaged, as a result of unauthorized repair theSERVICE CONTRACT will be cancelled. Damageby improper use or mishandling is not covered bythe SERVICE CONTRACT.

4. The SERVICE CONTRACT is issued to you as theoriginal purchaser. To protect you from misrepre-sentation this contract cannot be transferred to asecond owner.

5. The SERVICE CONTRACT is given to purchaserswho live in the 50 United States or Canada only.

6. For your protection Mclntosh selects Its dealerscarefully. Only one dealer in ten qualifies for aMclntosh franchise. To receive the SERVICECONTRACT your purchase must be made from aMclntosh franchised dealer.

7. Your completely filled In application for a SERV-ICE CONTRACT must be postmarked within 30days of the date of purchase of the instrument.

8. To receive the SERVICE CONTRACT all informa-tion on the application must be filled in. TheSERVICE CONTRACT will be issued when thecompletely filled in application Is received atMclntosh Laboratory Incorporated In Binghamton,New York. If the application is not received atMclntosh Laboratory, only the service offeredunder the 90-day guarantee will apply.

Copyright © 1970 by Mclntosh Laboratory, Inc.

CONTENTSGUARANTEE 1

INSTALLATION 2

HOW TO CONNECT 3, 4

USING THE FRONT PANEL CONTROLS 5

PERFORMANCE LIMITS 6

PERFORMANCE CHARTS 6

TECHNICAL DESCRIPTION 7,8

BLOCK DIAGRAM 8

1

GUARANTEE

InstallationAdequate ventilation extends the trouble-free life

of electronic instruments. It is generally found thateach 10° centigrade (18° F) rise in temperature re-duces the life of electrical insulation by one half.Adequate ventilation is an inexpensive and effectivemeans of preventing insulation breakdown that re-sults from unnecessarily high operating tempera-tures. The direct benefit of adequate ventilation islonger, trouble-free life. Allow at least 15 inchesdeep x 16½ inches wide x 3½ inches high for mount-ing the MQ 101.

To prepare the MQ 101 for installation remove theplastic protective covering. Turn it upside down sothat it rests on its top on the shipping pallet. Removethe two screws that fasten the chassis to the cabinet.After the screws have been removed slide the chassisout of the cabinet. Next, place the mounting brackets,the parts bag and the mounting template at hand.

The PANLOC professional mounting design elimi-nates the need for any shelf or bracket. The MQ 101is supported by its own mounting brackets.

The design of the mounting template allows you toposition or locate the cutout from the front or rear ofthe panel to which the instrument is to be mounted.Position the plastic mounting template over the areaof the mounting panel to be cut out for installation.

If the cutout is to be located from the front of thepanel, begin at Step 2. If the cutout is to be locatedfrom the rear of the panel, begin here.

1. On the back of the mounting panel, scribe a ver-tical centerline through the exact center of thearea in which the cutout is to be made.

Place the template against the back of the paneland match the template centerline with the center-line on the mounting panel.

Make sure that there is at least ¼ inch clearancebetween the bottom of the dashed line of the cut-out area on the template and any shelf or bracebelow the proposed cutout.

Mark the locating holes ("C" holes on themounting template).

Drill the two locating holes. Be certain the drillis perpendicular to the panel.

Now position the template on the front of thepanel by aligning the "C" locating holes on thetemplate with the drill holes.

2. If the cutout is to be located from the front of themounting panel:

With the template in place against the front ofthe mounting panel, mark the "A" and "B" drillholes and the four small holes that identify thecorners of the cutout. Join the corner marks witha line. The edge of the template can be used as astraight edge.

Accurately drill the holes on each side of thecutout area with a 3/16 inch drill.

IMPORTANT: DRILL THE 6 HOLES BEFOREMAKING THE CUTOUT

Carefully cut out the rectangular opening. Be cer-tain to saw on the INSIDE of the lines.

Secure the mounting strips to the rear of themounting panel using two screws from the hardwarepackage. Insert the screws in the center holes of thecabinet panel ("B" holes on the template) andtighten. The screw head should pull into the woodslightly. (Use two ¾ inch long screws for mountingpanels up to ½ inch thick, or two 1¼ inch long screwsfor panels ½ inch thick and over.)

Attach the mounting brackets to the mountingpanel using four screws.

Place the template over the mounting screws. Themounting screws should be centered in the "A" and"B" holes on the template. The sides of the mount-ing brackets should match the vertical dash lines onthe template. If necessary, loosen the screws andpush the brackets into alignment and retighten.

Insert the power cord through the mounting panelopening. Carefully slide the MQ 101 into the openingso the rails on the bottom of the equipment slide inthe track of the mounting brackets. Slide the instru-ment in until its front panel is against the mountingpanel. At the bottom front corners are the PANLOCbuttons. Depressing the PANLOC buttons will lockthe instrument firmly in the installation. Depressingthe PANLOC buttons a second time (as with a ball-point pen) will release the instrument. You can thenslide the instrument forward for easy removal.

2

CONNECTING TO A PREAMPLIFIER/POWERAMPLIFIER SYSTEM

The MQ 101 is added to the circuit between thepreamplifier and power amplifier. Connect shieldedcables between the MAIN outputs of the preamplifierand the MAIN inputs on the MQ 101. Connectshielded cables from the MAIN outputs of the MQ 101to the inputs of the power amplifier. The length of aconnecting cable is limited by its electrical capacit-ance. The total capacity of each cable must not be

more than 1000 pF. For instance: Cables with 25 pFper foot may be 40 feet long. The input impedance ofthe power amplifier should be 47,000 ohms or more.

For best signal to noise ratio when using the MQ101 between a preamplifier and power amplifier theinput attenuator switch on the back panel of theMQ101 should be in the 0 dB position. When usedwith preamplifiers that have bass trim controls it isrecommended that the bass trim controls be set inthe flat position.

3

CONNECTING TO A RECEIVER USINGTAPE MONITOR JACKS

Connect shielded cables between the tape outputson the receiver and the MAIN inputs on the MQ101.Connect shielded cables from the MAIN outputs ofthe MQ101 to the tape monitor inputs on the re-ceiver. The tape recorder can be connected to thetape monitor facilities on the MQ 101 in conventionalfashion. The length of a connecting cable is limitedby its electrical capacitance. The total capacity ofeach cable must not be more than 1000 pF. For in-stance: Cables with 25 pF per foot may be 40 feetlong. The input impedance of the power amplifiershould be 47,000 ohms or more.

The input attenuation switch on the back panel ofthe MQ101 should be in the —12 dB position to pre-vent the phono cartridge output from overloading theMQ101 at low frequencies.

PLEASE NOTE —TO USE THE MQ 101 THE TAPEMONITOR SWITCH ON THE RECEIVER MUST BELEFT IN THE "IN" POSITION.

CONNECTING TO A RECEIVER WITH "PREAMPOUT/POWER AMP IN" FACILITIES

Connect shielded cables between the preamplifieroutput jacks and the MAIN inputs on the MQ 101.Connect shielded cables between the MAIN outputson the MQ 101 and the power amplifier inputs on thereceiver. When connected in this fashion make cer-tain the input attenuation switch on the back panel ofthe MQ 101 is in the 0 dB position.

AC POWER OUTLET

The auxiliary AC power outlet can be used to sup-ply power to other equipment in the system. The out-let is not switched nor is it fused in the MQ 101.

AC POWER

The MQ 101 operates on 117 to 130 volts, 50/60Hz. It will be turned on and off when its power cord isplugged in one of the switched auxiliary AC poweroutlets in the program source.

FUSE

The MQ 101 uses a 0.5 Amp fuse. The auxiliary ACpower outlet is not fused.

4

Using the Front Panel ControlsIn Mclntosh loudspeakers the characteristics of

the speaker enclosure and the characteristics of theloudspeaker mechanisms have been combined toproduce nearly perfect transient response. The de-sign for excellent transient response has to com-promise the system low frequency response. Themost effective means of recovering a flat low fre-quency characteristic is the use of an electricallyequalized speaker input signal. The Mclntosh En-vironmental Equalizer does this job. Conventionallydesigned loudspeakers should not be used with theMQ 101 since it will overdrive them, distorting thesound and decreasing their useful life expectancy.Mclntosh loudspeakers should not be used with otherequalizers since they are designed for other applica-tions and will not produce the low intermodulationcharacteristic and the proper frequency balancewhich is so important to Mclntosh sound.

When a Mclntosh Environmental Equalizer is prop-erly connected in the stereo system all program ma-terial at all outputs except the tape output will beequalized.

TAPE MONITOR

The TAPE MONITOR is used only when the MQ 101has been connected to the tape monitor facilities ofthe source equipment. The control is used in exactlythe same fash ion as the tape monitor control on thesource equipment.

LOW FREQUENCY

A five position concentric switch selects from fivedifferent low frequency equalization curves, inde-pendently, in each channel. The outer knob adjusts

the right channel response. The center knob adjuststhe left channel response. Use low frequency equali-zation to compensate for the placement of the loud-speaker in your room. Position 1 modifies low fre-quency response least and position 5 has the great-est effect on low frequencies.

MID FREQUENCY

A five position switch selects from five differentmid frequency equalization curves for both channels.Use mid frequency equalization to compensate for theeffects of room acoustics and furnishings on the midfrequencies. Positions one and two select curves thatdecrease the amount of mid range loudness andpositions four and five select curves that increase theamount of mid-range loudness. Position 3 is electri-cally flat.

HIGH FREQUENCY

A five position switch selects from five differenthigh frequency equalization curves for both chan-nels. Positions one and two select curves that de-crease the high frequency loudness and positionsfour and five select curves that increase the highfrequency loudness. Position 3 is electrically flat.

PANLOC

Mclntosh developed PANLOC mounting brings pro-fessional installation technique to stereo. When theMQ 101 has been installed on PANLOC brackets,pressing the PANLOC buttons locks the equalizerfirmly in. Depressing the buttons (as with a ballpointpen) releases the instrument. The equalizer can thenbe slid forward for easy removal.

5

Performance LimitsPERFORMANCE GUARANTEE—Performance Lim-

its are the maximum deviation from perfection per-mitted for a Mclntosh instrument. We promise youthat the MQ 101 you buy must be capable of perform-ance at or exceeding these limits or you get yourmoney back. Mclntosh is the only manufacturer thatmakes this guarantee.

FREQUENCY RESPONSE: 0.5 dB from 20 Hz to20,000 Hz

DISTORTION: 0.1% at rated output level, 20 Hz to20,000 Hz

HUM AND NOISE: 80 dB below rated output (250µV)

INPUT SENSITIVITY AND IMPEDANCE: Main andtape input 2.5 volts at 60,000 ohms for rated outputat 1000 Hz

INPUT ATTENUATOR: Switched 0 dB, -6 dB, or-12 dB

OUTPUT: Main: 2.5 volts into 47,000 ohms or more,20 to 20,000 HzTape: 2.5 volts with rated input

EQUALIZATION: Low frequency: 0 to +17 dB at 20Hz in 5 steps (0, +6, +9, +13, +17dB in positions1, 2, 3, 4, 5, respectively)Mid frequency: -5 to +5dB at 4000Hz in 5 equalstepsHigh frequency: -4 to +4dB at 20,000Hz in 5 equalsteps

POWER REQUIREMENT: 120 volts, 50/60 Hz, 20watts

MECHANICAL INFORMATION

SIZE: Front panel: 16 inches wide (40.64 cm) by2-15/16 inches high (7.46 cm)Chassis: 15 inches wide (38.1 cm) by 13 inchesdeep (33.02 cm) including PANLOC shelf and backpanel connectors; Knob Clearance: 1½ inches(3.81 cm) in front of mounting panel

FINISH: Front Panel Anodized gold and black withspecial gold teal panel nomenclature illumination.

CHASSIS: Chrome and black

MOUNTING: Mclntosh developed professional PAN-LOC

WEIGHT: 15 pounds (6.80 kg) net, 19 pounds (8.62kg) in shipping carton

6

Technical Description

DESIGNING FOR NATURAL BASS

Research programs have one common advantagefor the alert scientist and engineer. The thousands ofhours of effort, analysis, conjecture, and synthesisuncover opportunities to make meaningful contribu-tions. Most of these opportunities are discovered justwhere lesser men saw only problems. One of thegreat opportunities that the Mclntosh acoustics re-search team uncovered was a design for naturalsound of bass instruments.

When a bass drum is struck, the motion of thediaphragm (drum head) pumps a large volume of air.The reproduction of such a sound image requiresthe motion of the same volume of air or, at least, asignificant portion of it. Because the design objec-tives of low distortion and widely dispersed radia-tion dictate a maximum effective cone diameter of10 inches the low frequency loudspeaker had to bedesigned with large excursion (back and forth move-ment) to achieve the air volume movement necessary.Our design objective was the development of a lowfrequency loudspeaker with a plus and minus onehalf inch cone excursion. Even with this large ex-cursion, a straight line relationship between drivingforce and movement had to be maintained.

To achieve this linear relationship our engineersemployed a long voice coil winding, a very light edgeand centering suspension and an air spring. The airspring is the natural result of mounting the speakerin a relatively small air tight extremely rigid box.When the cone moves inward, it reduces the volumeof air thereby increasing its pressure. The increasedair pressure returns the cone to the center of itstravel when the electrical signal returns to zero value.When the cone moves outward, the volume of air in-creases reducing the air pressure in the box. The airpressure in the room can now restore the cone to itscenter position when the electrical signal againreaches zero. One of the properties of an air springis an almost perfectly straight line relation betweenvolume and pressure for such small changes in vol-ume. This insures a low level of distortion at lowfrequencies and also a low level of intermodulationdistortion.

The linear air spring was combined with a stiffcone, a long voice coil winding and a very large andmassive magnet structure to achieve almost perfecttransient response for bass frequencies.

Design engineers, in the past, have not taken ad-vantage of this opportunity to obtain excellent tran-sient response because of the price that must bepaid. That price is a reduction in bass response.

There are two ways around this problem of loss ofbass. In the older technological approach to loud-speaker system design, flat frequency response wasobtained by compromising the transient responseusing mechanical resonances in the speaker and itsenclosure. This has been the traditional solution withits emphasis on cost reduction rather than reproduc-tion accuracy.

The other solution is the new approach. To restorethe system to a flat frequency response while pre-serving nearly perfect transient response, an elec-trical signal is supplied having an exactly oppositecurve to the curve of the reduction in bass response.

Supplying this electrical signal introduces anequalizer into this system. The combination of theloudspeaker system and the equalizer produces botha flat response and an excellent transient character-istic, free of ringing, down to 20 Hz.

As if this advantage were not enough, the equalizerbrings about another additional improvement to thesystem. The position of the loudspeaker in the roomcan substantially alter the loudspeaker's sound bal-ance. The equalizer can be designed to compensatefor different types of rooms and for different positionsof the loudspeakers in these rooms.

DESIGNING FOR DIFFERENT LISTENING ROOMS

The power out of a bass speaker at very low fre-quencies varies over an 8 to 1 range (9 decibels)depending on where the speaker is positioned in theroom.

For example if the loudspeaker enclosure is sus-pended in the center of a large, sound absorbingroom, a 20 hertz signal will radiate equally in all di-rections from the loudspeaker. It will be radiatinginto a sphere.

If the loudspeaker enclosure is then lowered to thefloor in the center of the room it would be radiatinginto a hemisphere. The signal striking the floor wouldbe reflected upward and the speaker power outputwill appear to double.

If the loudspeaker is then moved along the floor tothe center of the wall the power will double again.The loudspeaker is then radiating into one quarterof a sphere.

Then by moving the loudspeaker into a corner ofthe room the radiation is concentrated into oneeighth sphere with another apparent doubling inpower.

7

We have designed five curvature rates in the en-vironmental equalizer. They provide the electricalcorrection necessary to make a speaker sound as itwould in a corner when it's mounted on a wall or viceversa. For stereo, individual left and right controlsare provided to correct for different positions of thespeakers in the room.

The MQ 101 in addition to the bass correction alsoprovides correction for mid frequency and high fre-

quency differences in rooms. Some rooms are veryheavily draped and furnished. A room of this sortmay need mid frequency and treble boost to makethe music sound naturally alive. Other rooms arehighly reflective due to using glass areas, smoothhard walls and concrete or tile floors. The oppositecorrection may be required to restore the music tothe natural concert hall balance.

MclNTOSH LABORATORY INC.

2 CHAMBERS ST., BINGHAMTON, N. Y. 13903607-723-3512

Design subject to change without notice.

Printed in U.S.A.

038-669

BE052003