MK Sound LFE-4 User Manual
LFE-4
Miller & Kreisel Sound, Inc.
9351 Deering Avenue
Chatsworth, CA 91311-5858 USA
(818) 701-7010 fax (818) 701-0369
www.mkprofessional.com
©2003 Miller & Kreisel Sound, Inc.
bass management
operation manual
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Bass Management Controller
TABLE OF CONTENTS
1. SAFETY PRECAUTIONS..........................................................................................................3
2. M&K’S DESIGN PHILOSOPHY...................................................................................................4
THE LOGIC OF BASS MANAGEMENT, OBSERVATIONS BY KEN KREISEL..........................4
4. INTRODUCTION.........................................................................................................................5
INPUT AND OUTPUT CONNECTOR WIRING...............................................................7
GENERAL CONNECTION GUIDELINES........................................................................7
5. GROUNDING......................................................................................................................7
6. CONNECTING FOR STEREO......................................................................................................8
7. CONNECTING FOR DOLBY DIGITAL.........................................................................................9
8. CONNECTING FOR DTS...........................................................................................................10
9. CALIBRATING YOUR M&K PROFESSIONAL SYSTEM...........................................................11
THE M&K PROFESSIONAL TEST DISC......................................................................11
10. SPEAKER PLACEMENT.....................................................................................................12
ITU-R BS.775.1 RECOMMENDATION...........................................................................12
11. GENERAL GUIDELINES FOR SPEAKER PLACEMENT..........................................................12
12. SUBWOOFER PLACEMENT.....................................................................................................13
13. SPEAKER CALIBRATION....................................................................................................14
14. SUBWOOFER CALIBRATION...................................................................................................14
15. SPECIFICATIONS.....................................................................................................................15
DIAGRAMS
FIGURE 1 FRONT PANEL............................................................................................................ .....6
FIGURE 2 REAR PANEL...................................................................................................................6
FIGURE 3 GROUNDING..................................................................................................................7
FIGURE 4 STEREO CONNECTIONS................................................................................................8
FIGURE 5 DOLBY DIGITAL 5.1 CONNECTIONS.............................................................................9
FIGURE 6 DTS 5.1 CONNECTIONS...............................................................................................10
FIGURE 7 ITU-R BS.775-1 SPEAKER PLACEMENT......................................................................12
FIGURE 8 SPEAKER CABINET ORIENTATION.............................................................................13
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1. SAFETY INSTRUCTIONS
1. READ INSTRUCTIONS - All safety and operating instructions should be read before this product is operated.
2. RETAIN INSTRUCTIONS - The safety and operating instructions should be retained for future reference.
3. HEED W ARNINGS - All warnings on this product and in the operating instructions should be adhered to.
4. FOLLOW INSTRUCTIONS - All operating and use instructions should be followed.
5. ATTACHMENTS - Do not use attachments not recommended by the product manufacturer as they may cause hazards.
6. WATER AND MOISTURE - Do not use this product near water - for example, near a bathtub, washbowl, kitchen sink,
or laundry tub; in a wet basement; or near a swimming pool; and the like.
7. ACCESSORIES - Do not place this product on an unstable cart, stand, tr ipod, bracket, or table.The product may fall,
causing serious injury to a child or adult, and serious damage to the product. Use only with accessor ies recommended
by the manufacturer, or sold with the product. Any mounting of the product should follow the manufacturer's instructions
and should use a mounting accessory recommended by the manufacturer.
8. POWER SOURCE - This product should be operated only from the type of power source indicated on the marking label. If
you are unsure of the type of power supply to your home, consult your product dealer or local power company.
9. OVERLOADING - Do not overload wall outlets or extension cords as this can result in a risk of fire or electric shock.
10. LIQUID ENTRY - Never spill any liquid of any kind on the product.
11. SERVICING - Do not attempt to service this product yourself. Opening or removing covers, including any over bottom or
side speaker drivers, may expose you to dangerous voltage or other hazards. Refer all service to qualified service
personnel.
12. DAMAGE REQUIRING SERVICE - Unplug this product from the wall outlet and refer servicing to qualified personnel under
the following conditions:
•When the power-supply cord or plug is damaged.
•If liquid has been spilled, or objects have fallen into this product.
•If the product does not operate normally by following the operating instructions.Adjust only controls that are covered by the
operating instructions as an improper adjustment of other controls may result in damage and will often require extensive
work by a qualified technician to restore the product to its normal operation.
•If the product has been dropped or damaged in any way.
•When the product exhibits a distinct change in performance - this indicates a need for service.
13. REPLACEMENT PARTS - When replacement parts are required be sure the service technician has used replacement part
specified by the manufacturer or have the same characteristics as the original par t. Unauthor ized substitutions may result in
risk of fire, electric shock, or other hazard.
14. SAFETY CHECK - Upon completion of any service or repairs to this product, ask the service technician to perform safety
checks to determine that the product is in proper operating condition.
15. HEAT - This product should be situated away from heat sources such as radiators, heat registers, stoves, or other products
(including amplifiers) that produce heat.
The exclamation point within an
equilateral triangle is intended to
alert the user of the presence of
important operating and maintenance (servicing) instructions in
the literature accompanying the
appliance.
CAUTION:
TO PREVENT THE RISK OF ELECTRIC SHOCK,
DO NOT REMOVE COVER (OR BACK).NO USER-
SERVICEABLE PARTS INSIDE. REFER SERVIC-
ING TO QUALIFIED SERVICE PERSONNEL.
The lightning flash with arrowhead,
within an equilateral triangle, is
intended to alert the user of the
presence of uninsulated “dangerous
voltage” within the product's enclosure that may be of sufficient magnitude to constitute a risk of electric
shock to persons.
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2. M&K’S DESIGN PHILOSOPHY
Our philosophy is that exciting and lifelike sound and music reproduction takes place when your ears , in effect,
become the recording microphones. Our speakers are designed to allow you to hear exactly what the microphones
heard, placing you as close or as far away from the music or sound source as the recording engineer placed the
microphones.
Too many so-called "music" loudspeakers are designed with a philosophy that all recordings should sound as
if the music comes from a stage 10 or 20 rows distant, ev en if a recording is closely mik ed with perf ormers as close
as a few inches from the microphones (as is often done on film soundtracks, especially for dialog).
This "homogenizing" effect may be pleasant for some music recordings, but it inaccurately reproduces both
close-miked recordings and those recordings that accurately capture the acoustic space of a recording site. This
is why many "music" speakers do so poorly when tr ying to reproduce both the intensity and intimacy of closely
miked sound effects and dialog on today's best soundtracks.
As an audiophile recording engineer and a high-end loudspeaker designer, my strong belief has always been
that a good loudspeaker should accurately and realistically reproduce whatever the microphone captured, whether
the source is a human voice, a musical instrument, an explosion, car cr ash, etc.;including the acoustical ambiance
of the environment in which the source was recorded.
Ken Kreisel
co-founder and CEO
M&K Sound Co.
3. THE LOGIC BEHIND BASS MANAGEMENT
OBSERVATIONS by Ken Kreisel
Engineers mixing multi-channel audio (Stereo, Dolby Surround, 5.1 Dolby Digital, DTS, and other surroundsound formats) are faced with numerous challenges when trying to accurately monitor complex and dynamic
material, and determine how this material will sound in its intended playback space. These issues include
reproducing 5, 7, or more channels of full range audio, plus an optional Low Frequency Effects channel (LFE), all
of which have a bandwidth to 10Hz or below, with very high dynamic range, and achieving consistent bass
response from all the channels throughout the control room monitoring area.
Any studio designer will tell you that for a stereo mix environment it is crucial that the left and right monitor
speakers, when in their selected studio location, have near identical bass response when measured at the mixer's
position. No less is true in multichannel mixing. Proper low frequency equalization and mixing decisions are
difficult, if not impossible, unless all 5.1 or more channels have the same bass frequency response at the mixers
listening position.
Due to unavoidable room modes, five or more correctly placed full range speakers, (in even the most
perfectly designed studio) will produce dramatically diff erent lo w frequency characteristics at the mix position. This
is especially true for the very crucial center channel speaker. Variations of 10 to 20dB may be measured at
frequencies below 80Hz.
When the bass from all the channels is redirected into a single, PROPERLY placed subwoofer, then each and
all of the multiple channels exhibits the identical bass response at the listening position, and gives surprisingly ev en
coverage in virtually every control room. Simply stated bass management is putting an electronic bass frequency
crossover (typically 80Hz) on all the channels, and redirecting the bass frequencies below 80Hz from each of the
channels to a common subwoofer.
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By combining a carefully designed low frequency acoustic rolloff of all the main speakers, including the
surrounds, and a matching 2nd order electronic filter in the M&K Bass Management Controller, M&K achieves all
the theoretical benefits of a 4th order Linkwitz-Riley filter. In addition, to further create a seamless bass managed
system, we use only non-ported sealed cabinet designs on all our speakers and subwoofers, eliminating ported
speaker phase anomalies which would prohibit smooth transitions at the bass managed crossover frequency.
Another good reason for using bass management in the control room is that even the least expensive Dolby
Digital consumer decoder, found in millions of homes, has bass management built in, allowing the bass from all
channels to be fed to a single subwoofer. Also, all Home THX systems utilize an 80Hz bass management system.
Monitoring with proper bass management in the professional control room insures proper playback translation into
the "home theater" environment and into larger spaces such as motion picture theaters.
It is important to understand that Bass Management is done as a function of the monitoring system and in no
way affects the actual mix. Full frequency musical content, is assigned or panned around the room via normal
console or software operations to the various desired subjective locations such as Left, Center, Right, Left
Surround, and so on. This full frequency musical data corresponding to each speaker location channel is stored
normally on tape, hard drive, etc.
Bass Management psychoacoustically works because the ear-brain mechanism cannot detect direction at low
frequencies, but takes its directional cues from the harmonics of the low frequency sound. In the monitoring
process, frequencies below 80Hz are redirected to the subwoof er . Frequencies above 80Hz are sent to the desired
speaker. During the hearing process, our hearing mechanism integrates the sound into the correct spatial
auditory image.
Bass management is equally suited to all formats from 2-channel stereo to 5.1 and beyond. Indeed, existing
control rooms that are doing stereo 2 channel mixes, especially with smaller nearfield monitors placed on the
console, can benefit immensely from the correct integration of Bass Management and a subwoofer; because the
engineer is now able to hear low frequency anomalies caused b y room rumble, microphone stand thumping, breath
pops, and other artifacts that cause undesirable actions later in the broadcast, film chain, or DVD Mastering
process.
When mixes are intended for theatrical presentation, it is sometimes necessary to use an additional channel
for extra low frequency effects or enhancement. This channel is called the LFE or Low Frequency
Effects/Enhancements channel. In the control room monitoring environment, the LFE channel, if or when it is used
in the mix, is monitored by the same subwoofer used for the regular [L,C,R,LS,RS] channels. M&K Bass
Management Controllers have both a 0dB (with unity gain) and +10dB (with 10dB gain) inputs to accommodate
any mixing / monitoring situation, as per Dolby specifications.
The M&K Professional Division supplies, at no additional charge, a special CD test disc to assist in the
proper setup and calibration of our Bass Management Systems. This disk has pre-filtered and calibrated tracks of
noise which allow quick, accurate, and error-free setup of the monitoring environment to the Dolby standard of
85dB SPL, or any other relative reference level, by using an SPL meter.
4. INTRODUCTION
The LFE-4 Bass Management Controller is a balanced, line-level studio bass management controller which is
intended for use with the M&K line of professional studio monitors. Although the LFE-4 was primarily designed for
monitoring 5.1 audio, its flexible architecture allows it to be used for monitoring mono, stereo, Dolby Surround,
Dolby Digital, DTS and other formats.
The LFE-4 combines several necessary functions in one 19” rack mount, 1RU package. Along with bass
management and LFE channel control, it also provides individual channel adjustment capability to properly
calibrate your entire monitor system.
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