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LEI75.LE85 And 376 Compression Drivers

 A compression driver 

musi be bolted to the appropriate high frequency horn, which in turn, will 

be mounted to the baffle panel or freestanding on top of the enclosure. 

Bolts (%-20.

 'Aè'

 hex head) supplied with the driver should be tightened 

evenly, and just enough to achieve a snug fit without overtightening. The 

perforated center section o( the fiber gasket on the mating surface of the 

driver must be removed before installation. It is good practice to cover the 

exposed throat opening with plastic electrical tape whenever the driver is 

not actually installed on a horn to prevent foreign matter from entering 

the driver, particularly iron filings or chips which can be attracted by the 

strong magnetic field which exists in the driver throat 

Horns And Acoustic Lenses 

A horn/lens assembly couples the output of a compression driver to the 

air in the listening environment and spreads the sound outward throughout 

the room in a predetermined pattern.The smaller horn/lens assemblies 

are usually mounted to the enclosure baffle panel; the larger horn/lens 

assemblies will be freestanding on top of the enclosure. 

Caution:

 When a horn is mounted to a sturdy baffle panel of the recom-

mended thickness, it will not be necessary to support the driver However, 

the driver must be separately braced or removed from the enclosure 

whenever the loudspeaker system is transported, since under such circum-

stances it is possible lor the weight of the driver to pull the horn from 

the baffle panel. 

HL87 Perforated-Plate Horn/Lens

 The HL87 mounts from the front of 

the enclosure in a 134 mm (5%? in) diameter baffle cutout. It is secured 

by four machine screws and T-nuts. After making the baffle cutout, place 

the HL87 in position and use it as a pattern to mark the location of the 

holes for the mounting screws. The drill bit size required for the T-nuts 

is 8 mm

 (Me

 in). 

HL88 Perforated-Plate, HL89 Serpentine And HL90 Slant-Piate 

Horn/Lens Assemblies

 These large horn/lens assemblies mount on top 

of the enclosure. The mounting brackets must bo assembled to the 

horn/lens per the accompanying illustrations. The HL89 is shown with the 

MA25 installation kit, consisting of mounting brackets and a baffle which 

is required for optimum performance. It is also possible to mount an HL89 

on the enclosure baffle panel using the cutout illustrated. 

HL91, HL92 And HL93 Slant-Plate Horn/Lens Assemblies

 The HL91. 

HL92 and HL93 mount on the enclosure baffle panel, as illustrated- The 

baffle cutout is 108 mm

 (4%

 in) in diameter. Countersink the four 7 mm 

0& in) holes for the flathead mounting screws The white vinyl ring gasket 

should be placed on the horn mounting flange to insure an airtight seal. 

(Continued on page 12.) 

Summary of Contents for 124H

Page 1: ......

Page 2: ...ontinually engages in research related to product improvement New materials production methods and design relinements are introduced into existing products without notice as a routine expression ol th...

Page 3: ...essential for optimum bass performance An enclosure having the proper internal volume and tuning for the loud speaker increases low frequency dynamic range and improves tonal quality it also reduces...

Page 4: ...ent is properly adjusted and the overall volume level of the sound system should be reduced In almost all cases the acoustic level generated by a JBL loudspeaker will become noticeably discomforting t...

Page 5: ...peaker system is complete Mounting In An Enclosure Widest sound distribution will be realized and response through the midrange region will be just a little more natural and transparent when a loudspe...

Page 6: ...ize 1 ront Mount Rear Mounl Boll Circle Diymoior Frame Mourning Hoie Drill Size Front Mount Rear Mount D208H 179 mm 7X m 179 mm 7Vi in 194 mm 7 in 5 4 mm in 5 8 mm m b 8 mm 1 LE8T H t 7 9 m m 7M m Noi...

Page 7: ...s are attached to the center of the PR15C The fiberboard disc in fronl of them is integral to the passive radiator and must not be removed Each of the metal discs weighs 100 grams Six fiberboard discs...

Page 8: ...D130H 380 mm 15 in extended rango 45 Hz 130H 380 mm 15 in lowfrequency D208H 200 mm 6 in extended range 55 Hz I system tuning is higner than recomn eindcd for the loudspeake covai a portun pi the non...

Page 9: ...o moderate density with fiberglass acoustic damping material A sub chamber can be fabricated of a tube having an internal diameter of 114 mm 4ftin and a length of 130 mm 5 in flush mounted on the baff...

Page 10: ...I 105 mm Diameter 075 077 Mounting Dimensions 075 Or 077 Installation Install the 077 as shown lor widest sound distribution in the horizontal plane LE21H Mounting Dimensions...

Page 11: ...support the driver However the driver must be separately braced or removed from the enclosure whenever the loudspeaker system is transported since under such circum stances it is possible lor the wei...

Page 12: ...10...

Page 13: ......

Page 14: ...with staples or small carpet tacks As the lens is removed from the tape a ripping sound will be heard indicating normal disengagement A clearance of 67 mm 2 in between the baffle panel and the grille...

Page 15: ...Adjustment of the level control should be made on the basis of evaluation of normal program material played monaurally with amplifier tone controls at the middle generally referred to as flat position...

Page 16: ...the control assembly of the larger LX30 LX50A and LX80A Wood screws as well as machine screws and T nuls are pro vided to secure the assembly to the enclosure Be certain that the white vinyl flange ga...

Page 17: ...s well as the horn lens assembly utilized The wiring illustrations are correct when an HI 87 HL91 HL92 or HL93 is mounted on the enclosure baffle panel and when an HL88 HL89 or I1L90 is positioned so...

Page 18: ...strations Noie The color codes illustrated represent the latest configuration Earlier units were supplied with Iwo black wires instead ot green black and yellow black wires and a red wire instead of I...

Page 19: ...The color codes illustrated represent the latest configuration Earlier units were supplied with two black wires instead ol green black and yeilow Wack wires and a red wire instead ol Ine yellow wire...

Page 20: ...The color codes illustrated represent the latest configuration Earlier units wore supplied with two black wires instead ot green black and yellow black wires and a red wire instead of the yellow wire...

Page 21: ...tie Black Input Terminal Ol The N7000 Network YELLOW BLACK Note The color codes illustrated represent the latest configuration Earlier units were supplied with two black wires instead of green black a...

Page 22: ...mi nal of the primary net work would have lieen connected to the red torrrvna of the com YELLOW BLACK pression driver connect it to the red input of this network YELLOW Note The color codes illustrate...

Page 23: ......

Page 24: ...will be energized and the compression driver will be phased as if it were still connected 10 Ihe network When Ihe swilch is thrown tho phase of the driver will be reversed II is recommended thai Ihe...

Page 25: ...er trom whom It was purchased If it is not possible to contact a dealer write directly to the JBL Service Department describing the difficulty as fully as possible Products returned to the factory mus...

Page 26: ...James B Lansing Sound Inc 8500 Balboa Boulevard Northridge California 91329 50711 IMLCS 7 S0 Printed n U S A...

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