Quick Guide for Beginners

CBT Quick Start Guide 21
How Far Each CBT Model “Throws” – Speaker “throw” has many possible definitions, some of which
require knowledge of venue-specific factors, such as acoustics, seating plane particulars, or SPL
differences between one listening location and another.
One speaker-specific definition of “throw” would be the distance at which the speaker can project a useful
sound level. Using that definition, following are the farthest distances at which each model (in each
combination of Vertical Coverage and Voicing settings) can produce a continuous level of 85 dB (peaks of
91 dB).
85 dB Distance Chart
(low-Z, full rated power, pink noise, 85 dB-SPL at 4 kHz octave band)
BROAD Setting NARROW Setting
Vert.°
Music Mode Speech Mode
Vert.°
Music Mode Speech Mode
CBT 50LA
20°
18 m (60 ft) 27 m (90 ft)
CBT 100LA
40°
30 m (100 ft) 46 m (150 ft)
15°
37 m (120 ft) 55 m (180 ft)
CBT 70J
45°
40 m (130 ft) 64 m (210 ft)
25°
52 m (170 ft) 67 m (220 ft)
CBT 70J+70JE
45°
40 m (130 ft) 64 m (210 ft)
25°
52 m (170 ft) 67 m (220 ft)
This stimulus signal for this chart is 1/3
rd
octave pink noise centered at 4 kHz at full rated power. This
frequency band is utilized in this chart because it is a challenging range to “throw” long distances yet is
important for articulation, speech intelligibility and musical clarity. 4 kHz also standardizes with the SPL
Maps throughout this Guide.
The distances listed take into consideration the natural attenuation of sound due to air (22°C/72°F, 50%
humidity) – otherwise the distances listed would be even farther.
It should be noted that it may not be advisable to throw these distances if there are also listeners at very
close distances, because levels for the near audience areas may be louder than a normal comfort level.
It may also be noted from the chart that while CBT 70J + 70JE produces greater low frequency SPL and
extended bass response, the mid-range throw is the same as the 70J by itself.
Applications Assistance -- More CBT applications assistance is available at JBL Professional’s website
www.jblpro.com
or by calling JBL Pro installed-sound technical assistance [phone].
CBT QSG 04/10
RK/DB/JF