P60/K300 MONITORING SYSTEM INSTALLATION MANUAL
Contents
1. P60 K300 MONITORING SVSTEM INSTALLATION MANUAL E H KEF ELECTRONICS LIMITED TOVIL MAIDSTONE KENT ENGLAND 1 H CONTENTS LIST 1 0 2 0 2 2 2 3 0 4 0 4 1 4 2 5 0 5 1 5 2 6 0 6 1 6 2 7 0 7 1 7 2 7 3 General Description Features P60 Loudspeaker K300 Amplifier Unpacking Installation Room placement Mounting Connections Input connections Output connections Operation Setting Input sensitivity Bass shelving Technical Data P60 Loudspeaker K300 Amplifier Performance fesso 1 0 GENERAL DESCRIPTION The P60 monitoring system consists of two P60 loudspeakers and one K300 equaliser amplifier It can be used for any audio monitoring situation where modest size high quality and high output are required This includes radio and television control room monitoring outside broadcasting editing suites nearfield pop monitoring programme quality control cutting rooms and classical music monitoring The P60 system takes full advantage of the hybrid crossover a newly developed technique combining the best attributes of active and passive crossovers A high level passive crossover combines the drive units with best possible phase overlay It also prevents out of band energy due to amplifier overload from reaching the drive units Low level active filtering equalises the system flat without wasting drive unit sensitivity an2. 10 Conductor Area mm O MONO 0 82 1 31 2 08 3 31 5 26 Ohms metre 0 034 0 023 0 017 0 011 0 021 0 013 0 0083 0 0052 0 0033 Maximum Run metres 7 5 11 0 15 0 22 0 12 0 19 0 30 0 48 0 76 0 2 6 0 OPERATION 6 1 SETTING INPUT SENSITIVITV The input sensitivitv control is continuousiv variable over a wide range with calibration marks over the 14 to 6dBm range By using this calibrated control the K300 amplifier sensitivity can be set optimally between the noise floor and clipping level of the control desk The calibration markings correspond to an input required to give a nominal loud level 105dB at 1m but not the maximum level the system is capable This will be 6 to 10dB more depending on frequency This sensitivity control will be set to the nominal control desk output 4dBm for 0 as example with the understanding that peaks above the nominal desk output will routinely occur driving the system towards full output In this manner peak levels above nominal of the control desk and monitoring system will be well matched and system noise will be minimised If more gain in hand is required the amplifier sensitivity can be increased with clockwise rotation of the control If the gain in hand is too great and the desk monitor output is found to be set too low then the system sensitivity can be decreased by counter clockwi
3. 2 AMPLIFIER K300 SP2072 Dimensions Max Power Output Max Voltage Output Signal to noise Ratio Input Impedance Input Sensitivity Mains Voltage Weight 470 h x 250 w x 312 d mm 24 litres B200 SP1216 200mm dia diecast chassis polypropylene diaphragm T33 SP1210 25mm dia soft dome Ferrofluid cooled 3kHz 4 ohms 15 kg 19inch rack mounting x 2U high 150 watts per channel into 4 ohms 24 5 volts rms 100dB A weighted rel to 24 5 rms output 22 kilohms active balanced input 11 kilohms unbalanced OdBM 0 775 volt for full output Sensitivity is adjustable by a front panel contro continuously variable and calibrated over the range 14 to 6dBM 110 120V or 220 240V 50 60Hz 15kg an optional transformer is available to provide a fully floating input and high DC offset tolerance 11 2 4 7 3 PERFORMANCE Frequencv Range Low Frequency Extension Directional Characteristics Maximum Acoustic Output Issue 4 19 5 86 60 to 22 000Hz 2dB 3dB at 60Hz 6dB at 40Hz Horizontally within 3dB of reference axis response up to 25 degrees at 10kHz Vertically within 3dB of reference axis response up to 5 degrees at 10kHz 113dB spl each system at 1m
4. and thereby improves its power handling As the general operating temperature is reduced the compression due to thermal effects reduce and response becomes less a function of input level DUIS RES SN are ese a 2 2 K300 AMPLIFIER 2x150 Watt Amplifier The externally rack mounted 2U high amplifier is capable of 150 watts per channel into a 4 ohm load 24 5V rms into a P60 loudspeaker Active Equalisation Shaping of the loudspeaker s response is done by active equalisation within the amplifier rather than through power wastage within the loudspeaker Equalisation is first optimised by computer and then further refined after exhaustive listening tests The P60 system sets new standards for response smoothness and balance Active Bass Extension Active bass extension allows the P60 s LF response to be equalised with a complementary response which precisely extends and reshapes it to a new lower limit This frees the designer of the LF drive unit from the normal tradeoffs of sensitivity versus LF extension Low Frequency Shelving A 288 per step five position bass shelf is provided for the minor equalisation required by room effects and placement effects The two channels may be independently set but cannot be set without internal access to the amplifier thereby preventing indiscriminate changes by unauthorised personnel Calibrated Input Sensitivity Control A continuously variable active
5. d amplifier power in the passive network Active bass extension prevents further reductions in system sensitivity by allowing the designer freedom to choose any low frequency extension and shape By designing the loudspeaker and amplifier as an integrated system major engineering compromises are sidestepped Traditional trade offs between mid band sensitivity and output low frequency extension and low frequency cut off shape no longer apply Hybrid crossover results in a system with smoother more balanced performance and greater dynamic range These performance parameters combine for a closer approach to the classic monitor requirement a faithful replica of the input signal independent of music type and level and consistent from system to system Note the response shape of the P60 is mirror imaged by the equaliser shape within the K300 For this reason the P60 must not be used with other amplifiers or the K300 with other loudspeakers 2 _______________________ _____ _______ _ _ Bens 2 0 FEATURES P60 LOUDSPEAKER 2 1 P60 LOUDSPEAKER Passive Butterworth Squared Crossover Network In the P60 the job of the crossover is limited to the smooth blending of the drive units no response shaping is done passively preventing the typical power wastage of conventional crossovers and preserving the maximum system dynamic range The P60 s passive crossover when combined with the drive un
6. d for custom bracketry A sturdy mounting with provision for aiming will give best results Ej 9 0 CONNECTIONS 5 1 INPUT LEADS The actively balanced input of the K300 has high rejection to external noise and hum when properly driven Both balanced and unbalanced sources may be used for hum free connections The K300 has its case mains earthed In general if the source is also mains earthed the cable shield should be connected at the source only If the shield must be connected at both ends it should be through pin 1 of the input XLR rather than the connector body An earthing resistor between pin 1 and case serves to reduce circulating currents a Balanced source Use twin screened cable as shown in Figure 1A Signal and return connections are made to pins 2 and 3 respectively at both the source and the K300 The cable screen should be connected to case at the source end For unearthed sources also connect cable screen to K300 at pin 1 This presents a 20K ohm input impedance to the source b Unbalanced source screened twin cable When using screened twin cable with an unbalanced source connect as shown in Figure 1B At the K300 connect signal and return to pins 2 and 3 respectively For unearthed sources also connect cable screen to pin 1 At the source link both return and screen to case This presents a 10K ohm input impedance to the Source c Unbalanced source sing
7. input sensitivity control calibrated over the useful range of 6 to 14dBm allows the input sensitivity to be preset to the nominal mixing console output level ensuring proper signal levels and optimum signal to noise Active Balanced Input Active balanced input circuitry features high common mode noise rejection An optional input transformer converts the input to fully floating allowing up to 100V DOC offset above ground The novel virtual earth transformer termination greatly reduces typical transformer distortion All connections are through XLR connectors to IEC specification 3 0 UNPACKING The P60 and K300 are shipped in sturdv cardboard cartons with moulded polvstvrene inner packing to ensure against shipping damage To unpack carefully slit the upper carton tape and remove the upper polystyrene tray The P60 System can then be drawn out by its polythene bag Alternatively slit the carton tape and fold the four top flaps back Roll the system slowly over until fully inverted The carton may then be removed along with the polystyrene inner packing Save all packing for future shipment or storage Systems returned for service must be properly packed in their original cartons to ensure arrival without damage 7 4 5 _____ __ __ ___________________ _ 4 0 MOUNTING 4 1 Much of the final performance of the 60 monitoring svstem
8. it response yields an acoustic Butterworth squared shape of the Linkwitz Riley family This gives an exact phase overlay between the two drive units throughout the crossover region This exact phase overlay ensures optimum driver blend with no peaks in the off axis response or the power response Low Colourati n Box Construction High density particle board and MDF of generous thickness make up an enclosure of extremely stiff characteristics Panel resonances that remain are damped by an application of damping pads and special adhesive These steps ensure that cabinet resonances do not colour the sound Low Diffraction Grille A new grille of novel design continues the flare of the HF unit mounting plate and thereby reduces diffraction and reflection effects across the front of the baffle This greatly reduces the response differences between the grille off and grille on condition and also contributes to response smoothness reducing colourations in the HF unit s range KEF Mounts KEF Mounts a proprietary rubber suspension between the low frequency drive unit and the cabinet further reduce vibration transmitted to the cabinet The voice coil reaction forces work against the mass of the motor and chassis rather than the complex impedance of the box Ferrofluid Protected Unit The HF unit tweeter has its thermal capacitv increased bv a magnetic fluid surrounding the voice coil This carries awav power dissipated in the coil
9. le core or co axial cable as would typically be used for connecting a K300 to domestic equipment Input signal is connected through the centre conductor to pin 2 of the K300 with screen to pin 3 for earthed source and to pin 1 and 3 for unearthed sources as shown in Figure 1C This presents a 10K ohm input impedance to the source 5 2 OUTPUT LEADS The output of the K300 amplifier feeds to the P60 loudspeaker using the supplied XLR connectors and a cable of length as required for the installation Wire gauge should be appropriate for the length of run its total resistance being the dominant factor As a 4 ohm nominal system cable resistance of up to 0 5 ohms will keep power loss and response ripple to 1dB or less Double insulated mains cable with a round PVC outer sheath is durable flexible and easily available in a variety of conductor areas Table 1 shows the maximum length for 0 5 ohms resistance with a variety of conductor sizes Heavier gauge wire or shorter runs than maximum will reduce the total resistance and hence reduce power loss and response variation Note that the maximum run assumes two lengths of conductor 2 esso 1 a Balanced Source 1 b Unbalanced Source Screened Twin Cable 1 c Unbalanced Source Single Core Cable FIGURE 1 INPUT LEADS E UR TABLE 1 Current Rating SA 6A 10A 15A USA AWG 18 16 14 12
10. se rotation of the control It is worth noting that channel balance has been optimised for settings near 4dBm Once set the sensitivity control need not be touched again 6 2 BASS SHELVING A five position 2dB per position jumpered control can be found within the amplifier This can be adjusted to aid in optimising the performance within the listening room As the controls effect is broad but subtle it cannot cope with specific room faults that would require acoustic treatment However if after room treatment and optimal speaker siting as covered in the section on room placement the system is determined to be generally bass thin or bass dominant then the control can be adjusted to improve the overall balance To Adjust the Control Remove The Mains Input Lead To The K300 Amplifier With mains removed from the K300 the top and bottom cover may be removed for access to the bass shelving controls the five position jumper found on each of the auxiliary boards mounted on each amplifier board These jumpers may be re positioned in 2dB steps in directions indicated for an increase or decrease of level below 200Hz The amplifier cannot be operated without the jumpers in place Replace top and bottom covers before re applying mains 10 7 0 TECHNICAL DATA 7 1 LOUDSPEAKER 60 SP3071 Dimensions Internal Volume LF Driver HF Driver Dividing Frequency Nominal Impedance Net Weight 7
11. will be determined bv the acoustics of the listening room and the positioning of the svstem and the listener within this room The dimensions of the room the construction of the walls damping materials on the walls and furniture within the room determine the standing waves and resonances that have a major effect on the lowest octaves of sound Large reflecting surfaces have the effect of simulating extra sound sources that promote colourations and degrade stereo imaging best performance site both the loudspeakers and listener awav from walls and major reflecting surfaces Experiment with placement within the room Peaks and dips in the low frequencv response can be reduced with movement toward the nodes or antinodes of offending standing waves The directional characteristics of the 60 are quite smooth If there is to be a single listener or an optimum listening position then the system s tweeter axis should be aimed at that position If a range of positions must be provided for then aim the system towards the listening area remembering that it is better that the system axis cross in front of the listener than behind 4 2 MOUNTING Within the framework of the above siting recommendations many means of mounting are possible wall shelving custom stands or hanging brackets Tee nuts are inset into the back panel of the P60 to accept M6 bolts The bolt pattern is intended for the Omnimount 100 series of loudspeaker brackets or can be use
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