Abbingdon Music Research Reference Class Proffessional Monitor LS-77 Owner's Manual

Reference class professional monitor loudspeakers

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LS-77 Reference Class

Professional Monitor Loudspeakers

Owner's Manual

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Summary of Contents for Abbingdon Music Research Reference Class Proffessional Monitor LS-77

Page 1 LS-77 Reference Class Professional Monitor Loudspeakers Owner’s Manual...
Page 3: Warnings
WARNINGS The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the literature accompanying this component. This component weighs over 30 kilograms. Do not place this component on an unstable cart, stand, tripod, bracket or table as the component may fall causing serious injury to a child or adult and serious damage to the unit.
Page 4 Precautions This component has been tested and found to comply with the limits set out in the EMC Directive using a connection cable shorter than 3 metres. Running-In AMR estimates that the LS-77 may take between 300-500 operating hoursat fairly high sound pressure levels for all of the internal components to be fully-broken in.
Page 5: Table Of Contents
WARNINGS Section 1 - Unpacking Section 2 - Component Overview Section 3 - Setup 3.1 Connecting the loudspeakers 3.2. Connecting the amplifier 3.3 Multi-channel set up 3.4 Choice of loudspeaker cable Section 4 - Positioning 4.1 Symmetry and room modes 4.2 Distance between the loudspeakers 4.3 Distance to the loudspeakers Contents...
Page 6 Appendix A - Adjusting tonal balance Appendix B - Abbingdon Acoustic Setup Regime Appendix C – Biamping the LS-77 Appendix D – The AMR Active System Appendix E – LS-77 in OptiArray configurations Appendix F - Acoustics Background Information G.1 Acoustics G.2 Good acoustics G.3 Reverberation time G.4 Diffusers...
Page 7: Section 1 - Unpacking
Section 1 - Unpacking Figure 1.1 - Front Panel of the LS-77 Figure 1.2 - Rear Panel of the LS-77 LS 77 Profes sional Monito Sensit ivity: 87dB Imped ance: Cont Power 8Ohm s Handi ng Peak Prog Handi 150W 600W Frequ ency Respo nse:...
Page 8 Thank you for purchasing this AMR reference class component. We hope you derive as much pleasure from using your new AMR LS-77 Reference Class Professional Monitors as we have enjoyed making them for you. This section refers to the unpacking of the LS-77 and its subsequent setup. Due to the weight the LS-77 Pair is Please check that shipped individually packaged.
Page 9: Section 2 - Component Overview
Section 2 - Component Overview Figure 2.1 - LS-77 Front Fascia F1. HIGH FREQUENCY driver: to repoduce the high frequencies. F2. LOW FREQUENCY driver: to reproduce the low frequencies.
Page 10 Figure 2.2 - LS-77 Rear Panel LS 77 Profes sional Monito Sensit ivity: 87dB Imped ance: Cont Power 8Ohm s Handi ng Peak Prog Handi 150W 600W Frequ ency Respo nse: 27Hz-4 0kHz High Frequ ency Leve l Adjus tmen Warning: ensure speaker con-...
Page 11: Section 3 - Setup
Section 3 - Setup 3.1 Connecting the loudspeakers The LS-77 is fitted with shrouded binding posts prepared for bi-wiring that are standard in high end audio. recommends the However, we do not normally recommended their use. They are provided to allow users to easily integrate our sonically superior speakers into an existing system already fitted with cables prepared for such connections.
Page 12 LS 77 LS 77 Speaker R LS 77 Professional Monitor Sensitivity: 87dB Impedance: 8Ohms Cont Power Handing 150W Peak Prog Handing: 600W Frequency Response: 27Hz-40kHz High Frequency 1000 10000 Level Adjustment Frequency Hz Frequency Hz Speaker Cable Interconnect Cable Analog Outputs Pre-amplifier Figure 3.1 - System connection using Speakon connector equipped speaker cables...
Page 13 3.1.2 Using Binding Posts When not using AMR's or another manufacturer’s Speakon® equipped loudspeaker cables, you need to use a conventional two or four pole speaker cable. Please consult your authorised AMR retailer for recommendations. Connect a suitable loudspeaker cable to the speaker binding posts, located at rear of the LS-77. When using two-pole speaker cables, the cable should be connected to the upper pair of binding posts and the included short Bi-Wire Jumper Cables must be connected between the upper and lower binding post of the same colour marking.
Page 14 LS 77 LS 77 Speaker R LS 77 Professional Monitor Sensitivity: 87dB Impedance: 8Ohms Cont Power Handing 150W Peak Prog Handing: 600W Frequency Response: 27Hz-40kHz High Frequency Frequency Hz Frequency Hz 1000 10000 Level Adjustment Speaker Cable Interconnect Cable Pre-amplifier Figure 3.2 - System connection using banana plug/spade connector equipped speaker cables Connect the respective bi-wire jumper cables as shown.
Page 15: Connecting The Amplifier
3.2. Connecting the amplifier Connect the other cable ends to the loudspeaker outputs of your switched-off power amplifier. When using Always switch your amplifier off Speakon® equipped speaker cables you only need to identify the correct channel and connect the cable. If using when making or two or four pole speaker cables of conventional design, please make sure that the red marked posts of the b r e a k i n g...
Page 16: Section 4 - Positioning
The LS-77 Reference Class Professional Monitor is a Transmissionline port loaded loudspeaker design with no unusual or extraordinary positioning demands, neither in stereo nor in multichannel applications. Despite this, every room will typically have its own particular sound characteristics as shaped by its own acoustic properties. Rooms are also shaped, decorated and furnished uniquely, and therefore remain quite independent regarding options for positioning loudspeakers.
Page 17: Distance To The Loudspeakers
If the speakers are positioned too close to each other, the stereo image will not seem realistic; if that distance is too wide, the image may leave an acoustic hole in the middle. Paying attention to the image during listening tests and using the adjustment/diagnostic tracks on AMR's test CD will help dictate optimum placement during experimentation and set-up.
Page 18: Levelling/Speaker Support
4.5 Levelling/Speaker Support The best surface for any compact speaker is a dedicated stand construction, providing a solid foundation and allowing the proper listening height (high frequency driver at ear height). Dedicated high quality stands are available at your AMR retailer. As an alternative, the LS-77 may also be placed on shelves, bases or furniture.
Page 19: Loudspeaker Toe-In
4.6 Loudspeaker Toe-in Depending on your personal listening environment and room dimensions, the LS-77 Reference Class Professional Monitors may be angled in towards the listening area to help focus the sound radiation. This positioning will Toe-in of the typically improve imaging, and is recommended by AMR. The ultimate positioning, however, is also a matter of speakers often personal taste and room acoustics.
Page 20: Section 5 - Care & Maintainance
5.1 Care and maintenance To maintain the aesthetic quality of the LS-77 Reference Class Professional Monitors for the long term, placing them into a very warm, very cold, or very humid environment should be avoided. Direct sunlight or excessive brightness can affect the drivers but will have no effect on the Aluminum Enclosure.. The cabinet and other plain parts should be cleaned with a soft dry or slightly damp cloth.
Page 21: Power Rating
5.3 Power rating Due to the construction and the driver technology, the LS-77 Reference Class Professional Monitors can be driven with very high power levels. With a high quality amplifier, delivering undistorted signals, the LS-77 can achieve high volumes without any compromise in sound quality. Also, as the LS-77 Reference Class Professional Monitors have a reasonably high sensitivity, even high quality amps with a medium power rating can drive the speaker to yield excellent results.
Page 22: Section 6 - Ls- 77 Technical Features
Section 6 - LS- 77 Technical Features The following section provides a brief explanation of the most salient technical features of the LS-77. 10” High Performance Low Frequency Driver - a unique design provides unparalleled low frequency extension in a compact speaker, combined with the midrange performance only available from large dome midrange drivers while minimising distortion and thermal compression.
Page 23: Section 7 - Troubleshooting
Section 7 - Troubleshooting Figure 7.1 Troubleshooting Guide Symptom Possible cause No sound • incorrect audio cable connections • incorrect amplifier operation Sound with no bass • check speaker connectors are not and generally strange connected with wrong polarity Sound is too bright or •...
Page 24: Section 8 - Specifications
Figure 8.1 - Specifications Table Sensitivity (2.83V/1m in room): Long Term Power Handling (AES/RMS): Peak Program Power Handling : Impedance, nominal: Impedance, minimal: Frequency Response (in IEC Standard Room): Directivity Index (DI) 500-10KHz: Low Frequency Driver: High Frequency Driver: Bass Enclosure Principle: Weight: Dimensions (W x H x D) each: Crossover:...
Page 25: Appendix A - Adjusting Tonal Balance
Appendix A - Adjusting tonal balance If you feel that the tonal balance in the upper midrange and lower treble frequencies of the LS-77 is not correct for you, you may wish to change the resistor combination fitted under the cover labelled “High Frequency Level Adjustment”.
Page 26 Below and overleaf are listed our recommendations for different listening distances and placements. However, there is not per se any specific value that is right or wrong. Please use your own preference, discernment and hearing as guide. It is right when it sounds right. To increase the upper midrange and lower treble frequencies compared to whatever you have currently installed use a combination marked with a greater dB value;...
Page 27 Listening Distance around 5m (farfield listening or monitoring) HF Level +3 dB 15 R 22 R +1.5dB 15 R 47 R 0 dB 15 R not fitted - 1.5dB not Fitted 22 R If you feel that the tonal balance in the low frequencies of the LS-77 is not correct for you or your room, you may need to change the positioning of the LS-77.
Page 28: Appendix B - Abbingdon Acoustic Setup Regime
Appendix B - AASR The Abbingdon Acoustic Setup Regime (AASR) is a process of optimising the Speaker/room/listener placement interactively, repeatable and is rooted in decades worth of practice. AASR takes account of the simple fact that no rigid mathematical principle, no simulation software and no measurement system currently available correlates reliably with subjectively perceived "good sound".
Page 29 With the person speaking and continuing to walk toward the listening position while talking at the same level, listen for the next change in the voice's tonal quality. This will be the first interaction of the opposite wall and should sound like a loss of focus that seems to resonate because of the side and rear wall reflections. Again, mark the position on the floor when the artifact first appeared with tape.
Page 30 ″/ ″/ 100 254cm 100 254cm ″/ ″/ 115 290cm 115 290cm ″/ ″/ 115 290cm 115 290cm Figure B.1 - AASR illustrated...
Page 31 If your floor is not carpeted (which is a bad idea acoustically) you may want to put something between the speaker stand and floor that will allow you to slide the speakers more easily, like a cloth or mat with a smooth underside.
Page 32 With the most important of the rough adjustment being the front-to-back distance, mark the speakers' positions on the floor where the front edge of the speaker would be with tape, so you can always return to this position. The tape should extend beyond the ends of the baffle, because you will be moving the speaker relative to the main rough position.
Page 33: Appendix C - Biamping The
Appendix C – Biamping the LS-77 AMR’s LS-77 speakers are designed from the inception with the option to be bi-ampliffied. This means that dedicated amplifiers are used to drive the low frequency driver and high frequency driver separately. This provides improved clarity and resolution, as the amplifier driving the high frequency driver does not have to deliver the large currents drawn by the woofer and hence will produce less distortion.
Page 34 LS 77 LS 77 Speake r R Speake r R LS 77 Professional Monitor Sensitivity: 87dB Impedance: 8Ohms Cont Power Handing 150W Peak Prog Handing: 600W Frequency Response: 27Hz-40kHz High Frequency 1000 10000 Frequency Hz Frequency Hz Level Adjustment Speaker Cable Mono BiAmplifier Interconnect Cable Figure C.1 - System connection using Speakon connector equipped speaker cables (AMR AM-77)
Page 35 LS 77 LS 77 Speake r R Speake r R Sensitivity: 87dB Impedance: 8Ohms Cont Power Handing 150W Level Adjustment Peak Prog Handing: 600W Resistor Frequency Response: see graph 1000 10000 Frequency Hz Frequency Hz LS 77 Professional Monitor Speaker Cable Speaker Cable Mono BiAmplifier Analog...
Page 36: Appendix D - The Amr Active System
Appendix D – The AMR Active System For maximum performance AMR's active system allows AMR's LS-77 speakers to be driven in active mode by AMR's amplifiers. Separating the frequency ranges before the amplifiers avoids the destructive intermodulation between the low and high frequency signals being passed through the same amplifier and increases the available power and SPL.
Page 37 D.2 - Setting up the AMR Active System Loosely place the speakers and connect the bi-amplification speaker cable supplied to each speaker, using the connector marked "LS-77". Speakon connectors are first inserted and then rotated clockwise until they lock in place. To remove Speakon connectors you need to pull the metal catch backwards and rotate the connector counter-clockwise to unlock the connector so it can be pulled out.
Page 38 Scenario 2: AM-77 CCE x 1 AM-77 x 2 (each AM-77 must be in Monoblock Power Amplifier Mode) (see page 46 of AM-77 Manual). Option cable Left channel RCA (Blue) Option cable Right channel RCA (Red) Attach the power cables to the amplifiers, however do not connect the power cables to the mains yet nor should the amplifiers be switched on.
Page 39 Scenario 2: AM-77 CCE x 2 (each AM-77 CCE must be in Monoblock mode) AM-77 x 2 (each AM-77 must be in Monoblock Mode) Left speaker cable connector marked "CCE" Right speaker cable connector marked "CCE" Left speaker cable connector marked “AM-77” Right speaker cable connector marked “AM-77”...
Page 40 D.3 - Testing and Troubleshooting the AMR Active System Please use the AMR Test & Burn In CD's channel identification track to verify that your system’s channel assignment is correct. If the low frequency channels have been mixed up the channel identification sequence will have the high frequencies coming from one channel with the low frequencies from the other.
Page 41 D.4 - AMR Active System Configuration Diagram LS 77 LS 77 AM 77 AM 77 Control Editon Monoblock Amplifier Speake r R Speake r R LS 77 Professional Monitor Sensitivity: 87dB Impedance: 8Ohms Cont Power Handing 150W Peak Prog Handing: 600W Frequency Response: 27Hz-40kHz...
Page 42: Appendix E - Ls-77 In Optiarray Configurations
E.1 Introducing AMR's OptiArray® scalable acoustic system Above and beyond the role of an exceptional quality midfield monitor, the AMR LS-77 is designed to form the main element of the AMR OptiArray® scalable, modular loudspeaker system. The OptiArray® system takes account of several basic acoustic facts.
Page 43 While one can (and should) add acoustical treatment to large spaces, these are only effective to a certain degree and not at really low frequencies. To effectively damp the reflection of a 350Hz tone the layer of damping material applied to the wall would have to be at least 25cm thick! Instead of damping the reverbrations, using speakers that exhibit a significant increase in directivity at all frequencies over traditional systems attains an equal or greater improvement.
Page 44 AMR recommends the following OptiArray Setups: Room Size System Alpha (passive) AM-77 LS-77 (pairs) Power 360W SPL (3m) 109dB System Beta (active) AM-77 LS-77 (pairs) Power 560W SPL (3m) 113dB *: OptiArray configuration The Alpha system using a single pair of LS-77s with a total system power capacity of 360W, can sustain 109db SPL at 3m listening distance for the complete system and is thus appropriate for moderate city appartments and condominiums.
Page 45 AMR offers preconfigured wiring harnesses and where neccesary mounting and safety hardware for all larger OptiArray® systems. However, due to the complexity of setting up the larger OptiArray® systems we recommend to arrange the installation with your AMR retailer. The following pages show the wiring diagrams and setup options for some of the recommend speaker arrangements (the Epsilon/Zeta systems, the Iota/Kappa systems and finally the Omicron/Sigma systems).
Page 46 Output dB Output dB Epsilon/Zeta System wiring...
Page 47: Appendix F - Acoustics Background Information
Appendix G - Acoustics Background G.1 Acoustics When we talk about making a room "sound right", we are probably dealing with room acoustics. As a science acoustics has been around for about a hundred years. Until then good acoustics happened by experiment, by experience, or simply by accident.
Page 48 Why do we have reverberation? The speed of the propagating sound wave is very slow - at least compared to light: approx. 1130ft. or 340m per sec. If there are no reflecting surfaces between the sound source and our ears, only the direct sound is heard and there is no reverberation.
Page 49: Diffusers
G.4 Diffusers A diffuser provides diffuse reflection of the sound radiated against it. It can be a very useful solution in cases where reflections are disturbing the sound image and it is not advisory to add further absorption. So in order to reduce flutter echoes, comb filtering etc., special elements can be placed on the "disturbing"...
Page 50: Standing Waves
G.4.2.2 Porous absorbers These absorbers include mineral wool, foam, carpets, curtains, and so on. They can be very effective, but the thickness of the material has to be taken into account. Thin layers will only absorb the highest frequencies. To absorb a given frequency (and all frequencies above) the thickness of the absorber must be the quarter of the wavelength of that frequency.
Page 51: G 6 Room Modes
wave. Or one whole wavelength - or 1½, 2, 2½ and so on. This phenomenon is called standing waves. Actually the sound wave is not standing. But it is experienced like that because the sound pressure maxima and minima are positioned in fixed places in the room. G 6 Room modes These special frequencies are also called room modes.
Page 52 , , ( 1 0 0 25Hz , , ( , , ( 3 0 0 75Hz , , ( 4 0 0 100Hz , , ( 1 62 6 7m Undesirable Listening Positions How does the standing waves influence the sound field? - The curve expresses the area of the room where the actual frequency is audible.
Page 53 Abbingdon Music Research is a subsidiary of the Abbingdon Global Group 22 Notting Hill Gate; London; W11 3JE; United Kingdom; Tel: +44 (0) 870 420 5505; Fax: +44 (0) 700 596 1065...