JBL Control 23 User Manual

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I •Incident/Reflected/Absorbed • JBL Control ® Contractor series speakers
-.l-- are designed as fixed installation loudspeaker systems for use in a variety of
environments. Performance may nevertheless vary from room to room
because of differences in the acoustical setting. Since an enclosed room
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presents acoustical boundaries (walls , floors & ceilings), sound indoors
exhibits quite complex behavior. Each time a sound wave strikes a boundary ,
· -· 7 part of the wave's energy is reflected and part is absorbed (see diag . 1 ).
Reflection & absorption are dependent on the frequency of the sound wave
··· -+ and the angle at which it strikes the boundary.
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' CONCR8E · ' . c '
• Absorption - When designing your system, note that
. people and furniture absorb sound, while glass and tile
reflect sound . The percentage of energy that a boundary
absorbs is often expressed by an absorption coefficient of
the boundary material, where an absorption coeffic i ent of
1 =complete absorption and O=perfect reflective surface (see
diag. 2) .
ON E L OUD SPEAK ER MULnPLE QU I ET SPEAK ERS
• Reverberation - Reverberation is the reflected sound
waves continuing to bounce between the boundaries , losing
energy with each reflection. When sound strikes the reflec-
tive boundaries of a room , after a time the room is filled with
random reflected sound waves . Music and speech become
unintelligible (see diag. 3A). To minimize reverberation in a
highly reverberant room, it is advisable to install more
speakers, and play them at lower levels (see diag . 38) .
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JBL Control 23 Specifications

General

Impedance	8 ohms
Color	Black or white
Power Capacity	50 W Continuous Program Power; 25 W Continuous Pink Noise
Sensitivity	86 dB SPL, 1W @ 1m
HF Driver	19 mm (.75 in) titanium-laminate
Connectors	Spring terminals
Enclosure Material	High-impact polystyrene
Mounting	Wall
LF Driver	polypropylene coated paper