JBL Technical Note - Vol.1, No.13 电路原理图.pdf
Technical Notes Volume 1, Number 13 JBL Concert Series Complete Sound Systems Introduction The JBL Concert Series consists of loudspeaker systems and pre-packaged amplification and loudspeaker signal processing equipment. Although primarily designed for touring sound reinforcement applications, Concert Series components and systems are equally suited for permanent installations with features such as built-in hanging hardware and pre-wired connectors for ease and adaptability of installation. This note describes the equipment and performance characteristics of complete Concert Series systems, organized by main loudspeaker type. Each is a complete two channel loudspeaker, loudspeaker signal processing and amplification system, and is shipped pre-wired, tested and ready for use. Detailed information on each component may be found in individual product literature sheets. 4825 Systems The 4825 is the smallest of the Concert Series loudspeaker systems and serves a wide variety of applications, including live and motion picture theater sound, church sound reinforcement, nightclub entertainment, front fill in large arrays, foldback, and many others. The 4825 features extended frequency range and exceptionally smooth and uniform wide angle (100 by 100) coverage. Systems based upon the 4825 may be readily expanded in economic increments. 4925 Illustrated at left is the 4925 system, consisting of (2) 4825 loudspeaker systems, (1) 9922 electronics rack and (2) 3850 fifty-foot loudspeaker connecting cables. The 4925 is an ideal live reinforcement system for small clubs and as a starter system with future expansion in mind. The loudspeakers are shown mounted on optional tripod stands, JBL model MT4612. Optional (not shown), is the model 9916RC road case and dolly for the 9922 electronics rack. 4926 The 4926 is identical to the 4925, but with four 4825 loudspeakers, two 3850 and two 3805 loudspeaker cables. No changes are required to the 9922 electronics rack. The 4926 configuration is ideally suited for wide coverage angle reinforcement applications, with the recommended splay angles between two units shown at left. This arrangement provides more than 180 degrees of nearly seamless horizontal coverage throughout the 4825s wide frequency range. Narrowing the splay angle will result in increasing sound pressure level along the axis of the array, which is useful in environments that are deeper than they are wide. Options include the MT4612 tripod stands and the 9916RC road case and dolly for the 9922 electronics rack. 4927 The 4927 employs (8) 4825 loudspeaker systems and the 9942 electronics rack. The 4825 loudspeakers may be stacked and splayed in many different array configurations to adapt to a wide variety of applications, installation environments and audio production requirements. For reinforcement applications, four 4825s may be arrayed on either side of the stage stacked in groups of two for narrowed vertical coverage and splayed as above for wide horizontal coverage. The 4927 includes (4) fifty-foot model 3850 and (4) five-foot model 3805 loudspeaker cables. Options include the MT4612 tripod stands and the 9916RC road case and dolly for the electronics rack. 4945 The 4945 includes (2) 4825 loudspeaker systems, (2) 4845 VLF loudspeaker systems, the 9923 electronics rack (2) 3850 fifty-foot and (2) 3805 five-foot loudspeaker cables. The 4945 is ideal for reinforcement in small clubs with keyboard synthesizers and small to medium discos. The 4945 system is shown at left. The 4825 loudspeakers are mounted on the optional MT4612 tripod stands with the 4845 VLF loudspeakers grouped for best coupling at low frequencies. Other options incude the 9916RC road case and dolly for the electronics rack and the 4870DL dollies for transporting the 4845s. 2 4946 The 4946 combines (4) 4825 and (2) 4842 loudspeakers with the 9923 equipment rack to deliver a compact sound system of very high output capability and great versatility. The four 4825s may be arrayed as in the 4926 system for wide or narrow coverage, depending upon the application, with the 4842s either arrayed as shown for best coupling or split as required to suit the installation environment. The 4946 is shown above, along with the optional MT4612 accessory tripod stands and the optional 9916RC road case and dolly. Also shown are the (4) fifty-foot 3850 and (2) five-foot 3805 loudspeaker cables, which are included with the 4946. The 4870DL loudspeaker dolly for transporting the 4842s is available as an optional accessory. System Comparison Chart Nominal horizontal and vertical angular coverage between - 6 dB points for each 4825 is 100 degrees. Angular coverage and axial sensitivity for arrays of 4825s will depend upon the splay angles used. Consult individual specification sheets 1. Maximum SPL is for continuous program from available amplifier power and calculated to 1 m reference, f r additional 2. Amplifier power is continuous average sine wave power available into nominal system load impedances. p System Main Loudspeakers VLF Electronics Frequency Response (3dB) SPL (1) Amplifier Power (2) 4925 (2) 4825 _ 9922 70 Hz to 17.5 kHz 127dB 750 w 4926 (4) 4825 _ 9922 65 Hz to 17.5 kHz 132 dB 1,500w 4927 (8) 4825 _ 9942 60 Hz to 17.5 kHz 137 dB 3,000 w 4945 (2) 4825 (2) 4845 9923 30 Hz to 17.5 kHz 130 dB 1,350w 4946 (4) 4825 (2) 4842 9923 25 Hz to 17.5 kHz 135 dB 2,700 w 4850 Systems The 4850 family of modular high-power loudspeaker systems deliver exceptional performance for quality sound reinforcement and playback applications. Two-way models (4850, 4852) are designed for biamplification and consist of dual 12 inch LF loudspeakers and a 4 inch diaphragm HF compression driver mounted to a Bi-Radial Flat-Front horn in a vented enclosure. Three-way models (4851, 4853) employ triamplification and incorporate dual Bi-Radial Constant-Coverage compression VHF transducers in addition to the LF and HF devices. Both types are available in either 90 degree (4850, 4851) or 60 degree (4852, 4853) horizontal coverage versions. The enclosure tapers from front to back to enable tight cluster grouping for coherent wide angle coverage. 3 4921 The 4921 is a basic 2-way system, consisting of (2) 4850 (90 degree) or (2) 4852 (60 degree) main loudspeakers, (1) 9922 equipment rack and (2) 3850, fifty-foot loudspeaker cables. Applications for the 4921 include reinforcement and music playback in medium-sized clubs, halls, churches and auditoriums, front and side fill for large concert systems and as a beginning investment toward the development of a full-scale touring concert system for large venues. The 9922 equipment rack has room for 12-1/4 inches of additional electronics. Options for the 4921 include the 4850DL loudspeaker dolly and the 9916RC road case for the electronics (see below). 4921T The 4921T is identical to the 4921 except for the addition of (2) VHF transducers per loudspeaker system and the 9922T electronics rack, which includes the additional crossover system and VHF power amplifier. The 4921T may be ordered with either 90 degree nominal horizontal coverage loudspeaker systems (model 4851) or 60 degree horizontal coverage loudspeaker systems (model 4853). The components of the 4921T are shown above. One loudspeaker system is shown face down on the optional 4850DL loudspeaker dolly, and the 9922T equipment rack is pictured in the lower half of the optional 9916RC road case, with the upper pod assembly standing alongside. 4941 The 4941 expands upon the basic 4921 system to include four 4850 or 4852 two-way loudspeaker systems. The 4941 is powered by the 9942 electronics rack, which includes two channel signal processing and electronic crossover equipment and 2700 watts of available amplifier power. The 4941 comes equipped with (4) fifty-foot 3850 loudspeaker connecting cables. Optional equipment includes the 9916RC road case (shown above) for the 9942 electronics rack, and the 4850DL loudspeaker dollies. One dolly per loudspeaker cabinet is recommended for transportable applications. 4 4941T The 4941T is a three-way version of the 4941. Systems may be ordered with 4851 loudspeakers (90 degrees nominal horizontal coverage), or 4853 loudspeakers (60 degrees nominal horizontal coverage). The 9942T electronics rack includes two channels of three-way signal-processing crossovers and power amplification equipment. The 4941T includes (4) 3850 fifty-foot loud- speaker connecting cables. The 4941T is shown at right. Two of the loud- speaker systems are shown stacked on optional 4850DL transportation dollies, and the 9942T electronics rack is shown with the optional 9916RC road case. The upper pod of the road case is inverted and stacked on the 9942T for temporary storage. 4924 The 4924 adds a pair of 4845 VLF loudspeakers to the basic 4921 along with an additional crossover-processor and power amplifier contained in the 9923 electronics rack. The result is a three-way system capable of extended low frequency response at high output levels for medium-sized venues. The 4924 comes equipped with (4) 3850 and (2) 3805 loudspeaker cables. Options for the 4924 include: model 9916RC road case and dolly for the electronics, model 4850DL dollies for the main loudspeakers and 4870DLs for the 4845 VLF loudspeakers. The 4924T, shown below in optional road livery, is a complete four-way sound system. The 4924T is identical to the 4924 except for the addition of two JBL _ _ _ _ _ 2404H very high frequency transducers to each main loudspeaker cabinet and the additional two channel electronic crossover and power amplifier. Standard equipment includes (2) 3850 and (2) 3805 loudspeaker connecting cables. The 4924T may be ordered with model 4851 (90 degree horizontal coverage) or model 4853 (60 degree horizontal coverage) main loudspeaker systems. The 4850DL dollies (for the main loudspeakers), 4870DL dollies (for the subwoofers) and the 9916RC road case (for the 9923T electronics) shown at right are optional accessories for touring applications. 4924T 5 4944 For medium and larger venues, the 4944 consists of four main loudspeaker systems and two 4842 very low frequency loudspeakers. Like other 4850 Systems, the 4944 may be ordered with either 90 degree horizontal coverage main loudspeakers (4850s), or 60 degree horizontal coverage units (4852s). The 9943 electronics rack includes two channels of three-way signal processing and 3900 watts of amplifier power. The 4944 comes equipped with (4) fifty-foot 3850 and (2) five-foot 3805 loudspeaker connecting cables. System options include the 9920RC road case for the 9943 electronics rack, the 4850DL dollies for the main loudspeakers and the 4870DL dollies for the 4842 loudspeaker systems. One dolly per cabinet is recommended for touring applications. 4944T Shown above is the 4944T four-way concert system. The 4944T is an ideal system for reinforcement of wide-range programs including keyboard synthesizers, organs and drums, and is well-suited for a wide variety of venues, including large clubs, auditoriums, churches and medium-sized outdoor applications. The main loudspeaker units may be specified for either 90 degree nominal horizontal coverage (model 4851), or nominal 60 degree horizontal coverage (model 4853). The electronics rack, model 9943T includes two channels of 4-way crossover-processors and over 4,000 watts of amplifier power. The 4944T is supplied with (4) model 3850 50 foot and (2) model 3805 5 foot loud- speaker connecting cables. The 4944T is shown above. An optional model 4850DL loudspeaker dolly is shown attached to the face of one of the main loudspeakers, as it would be positioned for installation or removal. Next to the dolly is the optional 9920RC road case for the 9943T electronics rack. The 4870DL (not shown) is available as an option for transporting the 4842 subwoofers. One dolly per loudspeaker system is recommended. S System Comparison Chart System Main Loudspeakers l i l l l i l i i l l l i ; ; Electronics i ! Rack Assy, i Frequency Response (3 dB) Maximum SPL (1) Amplifier i ! Power (2) i 4921 (2) 4850 (4852) 9922 50 Hz to 16 kHz 133dB(135dB) 1,350 w 4921T (2) 4851 (4853) _ 9922T 50 Hz to 19 kHz 133 dB (135 dB) 1,450 w 4941 (4) 4850 (4852) _ 9942 45 Hz to 16 kHz 138dB(140dB) 2,700 w 4941T (4) 4851 (4853) _ 9942T 45Hzto19kHz 138 dB (140 dB) 2,800 w 4924 (2) 4850 (4852) (2) 4845 9923 30 Hz to 16 kHz 133dB(135dB) 1,950 w 4924T (2) 4851 (4853) (2) 4845 9923T 30 Hz to 19 kHz 133dB(135dB) 2,050 w 4944 (4) 4850 (4852) (2) 4842 9943 25 Hz to 16 kHz 138dB(140dB) 3,900 w 4944T (4) 4851 (4853) (2) 4842 9943T 25 Hz to 19 kHz 138dB(140dB) 4,000 w 1. Maximum SPL is for continuous program from available amplifier power and calculated to 1m reference. 2. Amplifier power is continuous average sine wave power available into nominal system load impedances. 4870 Systems The 4870 family of modular loudspeaker systems are designed for high-performance sound reinforcement and reproduction applications. Two way models (4870, 4872) consist of dual 15 inch direct radiator loudspeakers and a 4 inch diaphragm compression driver mounted to a Flat-Front Bi-Radial horn in a vented enclosure. Three-way models (4871, 4873) add dual Bi-Radial Constant-Coverage VHF devices. Both types are available in either 90 degree (4870, 4871) or 60 degree (4872, 4873) nominal horizontal coverage versions to suit a wide variety of applications and installation envoronments. 4922 The 4922 is the most basic of the 4870-based systems, consisting of (2) 4870 or 4872 loud- speaker systems, (1) 9922 electronics rack and (2) 3850 fifty-foot loudspeaker connecting cables. The 9922 electronics rack is a complete two channel, two-way amplification and signal processing system, incorporating balanced inputs and standardized input and output connectors. Each electronics rack is assembled, wired and fully tested before shipment. Loudspeaker systems are equipped with certified fittings for the attachment of hanging hardware. Options for the 4922 include the model 9916RC road case and dolly for the 9922 electronics rack and the 4870DL loudspeaker dollies. 7 4922T The 4922T is similar to the 4922 with the addition of (2) 2404H VHF transducers to each loudspeaker system, and the 9922T electronics rack, which includes a two-channel 7 kHz crossover processor and VHF power amplifier in addition to the 9922 complement. Loudspeaker systems are either 90 degree horizontal coverage (4871s), or 60 degree horizontal coverage (4873s). The 4922T is shown above, along with optional touring accessories, including the 9916RC road case and dolly for the 9922T and a pair of 4870DL loudspeaker dollies stacked at right. 4923 The 4923 adds a pair of 4845 very low frequency (VLF) loud- speaker systems to the basic 4922 system, extending the usable frequency range to 25 Hz. System components include: (2) 48
