Abbingdon Music Research Reference Class Proffessional Monitor LS-77 Скачать руководство пользователя | Manualshive

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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. Standing waves between parallel walls are called axial
modes. Other modes exist. For instance tangential and radial modes. Normally the axial modes are the strongest.

The standing waves are characterized by having a maximum sound pressure at the boundaries of the room.
Depending on the frequency there are one or more dips across the room. In a box shaped room the frequencies
can be calculated as follows:

Where:

f = frequency in Hz; c = speed of sound (approx. 340 m/s or 1130 ft/s); l = length of the room;

b = width of the room; h = height of the room; n = integer from 0 and up

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Содержание Reference Class Proffessional Monitor LS-77

Страница 1: ...LS 77 Reference Class Professional Monitor Loudspeakers Owner s Manual ...

Страница 2: ...2 ...

Страница 3: ... surfaces may cause the component and cart combination to overturn Any mounting of the device on a wall or ceiling should follow the manufacturer s instructions and should use a mounting accessory recommended by the manufacturer Read and follow all the safety and operating instructions before connecting or using this component All warnings on the component and in its operating instructions should ...

Страница 4: ...touching and connect normally to the Amplifier In conjunction with an out of phase mono signal this will cancel most noise A heavy blanket may be thrown over the speakers to cancel more noise Play the Pink Noise Out Of Phase track Track 4 fromAMR s System Test CD included with the speakers on repeat Raise the volume as high as sensible but quite high the out of phase nature will cancel a lot of no...

Страница 5: ...try and room modes 16 4 2 Distance between the loudspeakers 16 4 3 Distance to the loudspeakers 17 4 4 Distance to back and side walls 17 4 5 Levelling Speaker Support 18 4 6 Loudspeaker Toe In 19 4 7 Room and furniture influence 19 Section 5 Care Maintainance 20 5 1 Care and maintenance 20 5 2 Running in the loudspeakers 20 5 3 Power rating 21 Section 6 LS 77 Technical Features 22 Section 7 Troub...

Страница 6: ...LS 77 33 Appendix D The AMR Active System 36 Appendix E LS 77 in OptiArray configurations 42 Appendix F Acoustics Background Information 47 G 1Acoustics 47 G 2 Good acoustics 47 G 3 Reverberation time 47 G 4 Diffusers 49 G 4 1 Absorbtion or diffusion 49 G 4 2Absorbers 49 G 5 Standing Waves 50 G 6 Room modes 51 ...

Страница 7: ...gned and Engineered in Great Britain LS 77 Professional Monitor Sensitivity Frequency Response Peak Prog Handing Cont Power Handing Impedance 87dB 8Ohms 150W 600W 27Hz 40kHz IN OUT 100 100 1000 1000 10000 10000 Frequency Hz Frequency Hz 50 50 60 60 70 70 80 80 90 90 100 100 Output dB Output dB HF LF Level Adjustment High Frequency ...

Страница 8: ...individually packaged Upon unpacking please find in each package i LS 77 Reference Class Professional Monitor ii Set of two TO 220 Power Resistors 10R 22R iii Set of two Foam Port Plugs iv Set of two OptiLink Bi Wire Jumpers installed v Quick Start Card vi AMR Warranty Card vii Aluminium professional flightcase viii LS 77 Owner s Manual ix AMR Test Disk x 2mm Allen Key Please ensure that all items...

Страница 9: ...ure 2 1 LS 77 Front Fascia Section 2 Component Overview F1 HIGH FREQUENCY driver to repoduce the high frequencies F2 LOW FREQUENCY driver to reproduce the low frequencies LS 77 PROFESSIONAL MONITOR 15 F1 F2 ...

Страница 10: ...eaker cables R5 SPEAKON low high frequency outputs for connection of Speakon terminated speaker cables R6 SPEAKON low high frequency inputs for connection of Speakon terminated speaker cables Warning ensure no speaker con nector is in contact with the chassis HF LF Designed and Engineered in Great Britain LS 77 Professional Monitor Sensitivity Frequency Response Peak Prog Handing Cont Power Handin...

Страница 11: ...s gold contacts gastight construction and special locking high pressure contact arrangement AMR s own speaker cables are equipped with Speakon connectors as are AMR s amplifiers thus guaranteeing the highest performance and most reliable method of speaker connection available 3 1 1 Using AMR s OptiLink Speakon Cable When usingAMR s Speakon equipped OptiLink loudspeaker cables you simply plug the S...

Страница 12: ...ut dB Output dB HF LF Level Adjustment High Frequency HF LF Designed and Engineered in Great Britain LS 77 Professional Monitor Sensitivity Frequency Response Peak Prog Handing Cont Power Handing Impedance 87dB 8Ohms 150W 600W 27Hz 40kHz IN OUT 100 1000 10000 Frequency Hz Frequency Hz 50 60 70 80 90 100 Output dB Output dB HF LF Level Adjustment High Frequency Stereo Amplifier Figure 3 1 System co...

Страница 13: ...the binding posts The LS 77 high quality binding posts can accommodate different connection systems 6 mm pins The pins can be placed directly into the binding post without any screwing necessary Cable spades Un tighten the binding posts insert the spades into the openings and secure the spades into the posts by tightening the posts Tighten the posts and check the contacts after a few days to make ...

Страница 14: ...requency HF LF Designed and Engineered in Great Britain LS 77 Professional Monitor Sensitivity Frequency Response Peak Prog Handing Cont Power Handing Impedance 87dB 8Ohms 150W 600W 27Hz 40kHz IN OUT 100 1000 10000 Frequency Hz Frequency Hz 50 60 70 80 90 100 Output dB Output dB HF LF Level Adjustment High Frequency Stereo Amplifier Figure 3 2 System connection using banana plug spade connector eq...

Страница 15: ...d to offer the most advanced performance in both stereo and multi channel applications effectively enabling the maximum performance from either of these formats When connecting a loudspeaker to a multi channel system in general the same guidelines as previously mentioned in the text above will apply Because there are many different set up options from 5 1 to 10 2 channel applications and due to th...

Страница 16: ...less then additionally identical distance to the side walls should be maintained In all normal rooms certain low frequencies will be boosted or reduced by standing waves developing between parallel walls If the speakers are placed directly at walls or at half way or quarter way between walls these standing waves will influence the speakers performance to the largest extent hence such placement is ...

Страница 17: ... positioned with a wider distance between each other as well To maintain a balanced sound integration from the driver arrangement a 2 0 meter distance is a good starting point during experimentation The listening distance to each speaker from the listening position should be identical 4 4 Distance to back and side walls When loudspeakers are positioned too close to walls the sound quality can be r...

Страница 18: ...other obstructions in front of the speakers b Place the speakers so that the high frequency drivers are at ear height and oriented vertically c If necessary the speakers can be placed with the woofer above the tweeter to make this easier to achieve d If necessary the high frequency drivers can be rotated by 90 Degrees This will be carried by your authorised AMR retailer as it requires disassembly ...

Страница 19: ...the Controlled Dispersion design of the LS 77 a placement with as much toe in as is practical can reduce the reverb significantly By adjusting the high frequency tonal balance to produce less high frequency output the bright tonal balance may be ameliorated Nevertheless it may also be desirable to fit some acoustic treatment or at least some carpets and maybe some heavy wall hanging rugs or whatev...

Страница 20: ... cover or metal grille interferes significantly with sound reproduction no grill is included All materials used byAMR are integrated into the LS 77 Reference Class Professional Monitors with exceptional care By taking care of your LS 77 Reference Class Professional Monitors you will preserve the finish and build quality for a very long time 5 2 Running in the loudspeakers The moving parts of a new...

Страница 21: ...ese situations may result in the system trying soon to overreach the amplifier s performance limits and may send distorted output signals to the speakers Any damage caused under such circumstances is not covered by the AMR warranty and is easily avoided in the first place by consulting your authorised AMR retailer for advice regarding the choice of amplifier If you find that your system continuous...

Страница 22: ...TransmissionLine Port Low Frequency Loading AMR s acoustic load combines the ability of transmissionline speakers to play very low notes loud and cleanly with the more compact dimension of traditional box designs by synthesising a new enclosure type from the best features of both OptiSlope 10th Order Crossover AMR s unique crossover minimises any interference between low and high frequency drivers...

Страница 23: ...lly strange connected with wrong polarity required Sound is too bright or Incorrect placement of speaker Place speaker with high frequency driver upright and at dull ear hight pointing at the listening position Incorrect adjustment of HF Level Adjust HF level as perAppendixA Bass is too full or lean Incorrect placement of speaker Place speaker correctly as per Section 2 Incorrect use of port inser...

Страница 24: ...vity Index DI 500 10KHz 6dB 3dB Low Frequency Driver 243mm 10 Diameter 100mm 4 Voice Coil High Frequency Driver 125mm 5 long isoplanar ribbon Bass Enclosure Principle Transmission Line Reflex Port Weight Speaker each 35 Kg 77 lbs Shipped pair 116 Kg 255 lbs Dimensions W x H x D each 250 x 490 x 300mm 10 x 19 x 12 Crossover AMR OptiSlope design 60 dB octave Information and specifications subject to...

Страница 25: ...ent replacement if lost Under the cover you will in stock condition find two resistors one marked 15Ù and one marked 47R You will also find a pair of optional resistors included per speaker one marked 100 and the other marked 220 Respectively the resistor marked 100 will be referred to below as 10R the 15Ù as 15R and the one marked 220 as 22R Using different combinations allows an adjustment of th...

Страница 26: ...stment range insufficient please contact us for further options Listening Distance around 1m nearfield listening and nearfield monitoring HF Level R1 R2 Placement Suggestions 1 5dB 15 R 10 R Placement of speaker on a bookshelf or very close to walls 0 dB 15 R 22 R Placement within around 1m of rear wall 1 5dB 15 R 47 R Placement of speaker 2m or more from rear wall factory fitted 3 dB 15 R notfitt...

Страница 27: ...the LS 77 is not correct for you or your room you may need to change the positioning of the LS 77 Some of the required adjustment may be due to the differences in placement or the room s low frequency behaviour while others may be a result of differences in taste and furnishings If the low frequencies are percieved as too prominent you may wish to fit the large cell foam inserts to either reduce t...

Страница 28: ...a basic starting point With the aid of a friend who does not mind feeling a little foolish place yourself in the target listening position while your assistant speaks in a moderately loud voice at constant level projecting into the room Alternatively use your own voice and walk in similar patterns listen to how your voice interacts with the room Give it a few tries and listening very hard you will...

Страница 29: ...rders with tape Now if you do this alone you may find that the borders are marked fairly different for the various walls Simply using these borders would result in an asymmetrical arrangement of the speakers So take some measurements and average all the different borders you came up with Then re arrange the tape to reflect the symmetrical average of your various positions After performing these pr...

Страница 30: ...30 100 254cm 100 254cm 115 290cm 115 290cm 115 290cm 115 290cm 0 1 1 2 2 0 1 1 2 2 0 1 2 3 4 Figure B 1 AASR illustrated ...

Страница 31: ...elp you to gauge both left to right movements and to adjust the amount of toe in or toe out Again you should enlist the help of an assistant for be next phase of the AASR as it is difficult to do it alone Using a full range well balanced recording played at a moderate level first ensure the tonal balance of the speaker has been correctly adjusted This is easiest judged using a recording featuring ...

Страница 32: ... contains in phase and out of phase mono pink noise tracks that can be used to optimise both the Focus precisely defined instrument images and depth of the soundscape Toe in adjustments means only the rotating of the speaker on its centered position Change the toe in until the image focuses right in front of the speakers with a good sense of depth remaining You should cross check using an orchestr...

Страница 33: ...deliver the large currents drawn by the woofer and hence will produce less distortion YoumustusetwoIDENTICALstereo amplifiers to biamplify the LS 77 AMR sAM 77hasabuild in modedesignedforoptimumoperationtobiamplifyanyspeakers includingtheLS 77 Youmustalsouse two IDENTICAL pairs of conventional speaker cables or a special pair of dual headed Speakon connectorcablesavailablefromyourAMRretailer Pleas...

Страница 34: ... in Great Britain LS 77 Professional Monitor Sensitivity Frequency Response Peak Prog Handing Cont Power Handing Impedance 87dB 8Ohms 150W 600W 27Hz 40kHz IN OUT 100 1000 10000 Frequency Hz Frequency Hz 50 60 70 80 90 100 Output dB Output dB HF LF Level Adjustment High Frequency Mono BiAmplifier Mono BiAmplifier HF LF HF LF Figure C 1 System connection using Speakon connector equipped speaker cabl...

Страница 35: ...utputs R Analog Outputs L Pre amplifier Speaker R Speaker R Speaker L Speaker L LS 77 LS 77 LS 77 LS 77 HF LF Designed and Engineered in Great Britain LS 77 Professional Monitor Sensitivity Frequency Response Peak Prog Handing Cont Power Handing Impedance 87dB 8Ohms 150W 600W see graph IN OUT 100 1000 10000 Frequency Hz Frequency Hz 50 60 70 80 90 100 Output dB Output dB HF Level Adjustment Resist...

Страница 36: ... combines three separate devices into one without loss of performance but with the added benefit of eliminating several interconnects The amplifier boards are optimised for high frequency reproduction including the use of non magnetic Silver Foil Mica dielectric coupling capacitors which have been found most ideal for detailed resolved and non fatiguing high frequency reproduction Hence the high f...

Страница 37: ...e the amplifiers considering the amount of reach between the two separate Speakon connectors on the amplifier side of the bi amplification speaker cable Place the AM 77 CCE as you would normally place your preamplifier or AM 77 amplifier Confirm that the AM 77 CCE has been configured as Stereo Pre Main Amplifier see page 39 of AM 77 Manual Please refer to the connection diagrams overleaf for detai...

Страница 38: ...witched on Route the mains cables so that they run cleanly and without sharp bends towards the power extension strip and then attach the mains cables Speaker Connection Scenario 1 AM 77 CCE x 1 AM 77 x 1 the AM 77 must be in Stereo Power Amplifier Mode Left speaker cable connector marked HF CCE Æ AM 77 CCE s Left Channel Speakon socket Right speaker cable connector marked HF CCE Æ AM 77 CCE s Righ...

Страница 39: ... s Speakon socket Right speaker cable connector marked AM 77 Æ Right AM 77 s Speakon socket Now attach the input connections from your CD Source ONLY to the AM 77 CCE Connect the power cables of all amplifiers and the CD Player to the power extension strip ALL amplifiers and sources must be operated from the same power extension Failure to do so will lead to earth loops which may cause significant...

Страница 40: ... the power amplifier Please power down the all amplifier s before breaking and re making connections If the sound lacks severely in high or low frequencies and either high or low frequency driver remain silent please check all connections between speaker amplifiers and CCE again and compare to these notes and the included drawings Play some music with a large amount of high frequency and low frequ...

Страница 41: ... Level Adjustment High Frequency HF LF Designed and Engineered in Great Britain LS 77 Professional Monitor Sensitivity Frequency Response Peak Prog Handing Cont Power Handing Impedance 87dB 8Ohms 150W 600W 27Hz 40kHz IN OUT 100 1000 10000 Frequency Hz Frequency Hz 50 60 70 80 90 100 Output dB Output dB HF LF Level Adjustment High Frequency LF HF HF LF HiFi Pro Mode Int Amp Power Amp L R M M M HiFi...

Страница 42: ...ely moisten the bottom this much is quite obvious so the need for more output from the speaker as rooms get larger is simple and intuitive However large listening spaces are invariably also less well damped in an acoustical sense than small ones This and the much longer dimensions with the thus increased delay between reflections lead to much longer reverb times in the room The room reverbrant fie...

Страница 43: ...ur and eight pairs of speakers finally up to sixteen pairs in a focused dual line array configuration used to cover cavernous listening spaces of up to 480m2 Due to the carefully considered directional properties of the single LS 77 and its seamless integration into larger arrays Each larger size array extends the tight 40o vertical and wide but controlled 120o horizontal radiation angle to lower ...

Страница 44: ...8dB 134dB 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 From thisAMR s OptiArray configurations extend to the awesome Omega system providing a configuration suited to any size dwelling and l...

Страница 45: ...0 80 90 90 100 100 Output dB Output dB HF LF Level Adjustment High Frequency HF LF Designed and Engineered in Great Britain LS 77 Professional Monitor Sensitivity Frequency Response Peak Prog Handing Cont Power Handing Impedance 87dB 8Ohms 150W 600W 27Hz 40kHz IN OUT 100 100 1000 1000 10000 10000 Frequency Hz Frequency Hz 50 50 60 60 70 70 80 80 90 90 100 100 Output dB Output dB HF LF Level Adjust...

Страница 46: ...y Hz Frequency Hz 50 50 60 60 70 70 80 80 90 90 100 100 Output dB Output dB HF LF Level Adjustment High Frequency HF LF Designed and Engineered in Great Britain LS 77 Professional Monitor Sensitivity Frequency Response Peak Prog Handing Cont Power Handing Impedance 87dB 8Ohms 150W 600W 27Hz 40kHz IN OUT 100 100 1000 1000 10000 10000 Frequency Hz Frequency Hz 50 50 60 60 70 70 80 80 90 90 100 100 O...

Страница 47: ...s that one must be aware of G 2 Good acoustics Here is a list of important parameters concerning good acoustics y Proper reverberation time yGood sound distribution y Adequate sound pressure level y Low background noise level y No echo flutter echo Now lets have a look on these headlines that will be adequate for the most purposes concerning sound production G 3 Reverberation time The reverberatio...

Страница 48: ... another but there is still no reverberation If the sound is generated in a room there are a whole lot of reflections Each of these travels different paths with different distances on the way to the receiver Each time the sound hits a surface it may loose some energy if the surface is absorbing One sound source and one listener in an open area Only sound coming direct from the source is heard One ...

Страница 49: ...ial technique developed by Manfred Schroeder is very capable in making a smooth and controlled diffusion These diffusers normally referred to as Schroeder Diffusers can be found as readily made modules G 4 2 Absorbers All materials in the room act acoustically even if they are not specially designed acoustical materials In domestic situations we have generally two types of absorbers G 4 2 1 Membra...

Страница 50: ...lk paintings to give good looking yet highly effective absorbers G 5 Standing Waves Standing waves exist in all kind of rooms The shape of the room the dimensions of the room and the relationship between the dimensions of the room allare important parameters that will determine the frequencies around which the phenomenon exists as well as the distribution of these standing waves But how do they oc...

Страница 51: ...tween parallel walls are called axial modes Other modes exist For instance tangential and radial modes Normally the axial modes are the strongest The standing waves are characterized by having a maximum sound pressure at the boundaries of the room Depending on the frequency there are one or more dips across the room In a box shaped room the frequencies can be calculated as follows Where f frequenc...

Страница 52: ...ding waves Parallel walls in the room should be prevented if possible Then the strongest modes are suppressed This obviously requires purpose built rooms When placing the speakers it is important that as few modes as possible are excited This is why the speakers should not be placed in a maximum of a standing wave nor should the listener be located in a maximum or minimum of a standing wave 2 8m 6...

Страница 53: ...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 ...

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