JBL VT4887 User Manual
Page 5
NOTES REGARDING LIMITER SETTINGS
• The recommended limiter threshold settings provide 3 dB of headroom before the
component or bandpass peak voltage is reached.
• The component or bandpass peak voltage is 6 dB above the voltage used at
continuous maximum power.
• These settings assume the use of a Crown MA-5002 in stereo mode with input
sensitivity of 1.4V for a voltage gain of 37 dB. Amplifier limiter and Offset
Integration switches are set to the off position.
Integration switches are set to the off position.
• If a different amplifier is used or if the input sensitivity is changed, the limiter
threshold must be re-calculated.
• Not all DSP controllers behave the same way. Please study your unit accordingly.
• Users must take into consideration that the digital controller gain outputs are not
all “0” dB, i.e. for VT4889/4880, the VLF is at +6 dB, the LF is at 0 dB, the MF is
at -2.5 dB and the HF is at - 4 dB. Hence, the actual headroom before limiter
threshold is effectively greater than it may seem from the above charts.
at -2.5 dB and the HF is at - 4 dB. Hence, the actual headroom before limiter
threshold is effectively greater than it may seem from the above charts.
• Users should carefully test these settings, and lower or raise the thresholds for a
given type of program material as required.
VT4887 & VT4881 Transducer Complement:
Model
Speakon NL8
Terminals
Per
box
box
Nominal
Impedance
per
Transducer
Nominal
Impedance
per
Passband
AES Power
100 HR
Rating per
Transducer
Peak
Power
Rating per
Transducer
Recommended
Power per
Passband
HF
2407H
Pins 4±
1
x 2
8Ω
8Ω
25W 100W 450W
MF
2104H
Pins 4±
1
x 4
8
Ω
8
Ω 50W
200W
450W
LF
2168J
Pins 3±
2
x 2
16Ω
8Ω
350W 1400W 1000W
VLF
2256G
Pins 1± & 2±
3
x 1
2 x 8
Ω
8
Ω + 8Ω 600W 2400W 1200W
1
PASSIVELY CROSSED OVER MID/HIGH FREQUENCY SECTION.
2
LF SECTION HAS TWO 8” COMPONENTS WIRED IN PARALLEL.
3
SINGLE COMPONENT WITH TWO VOICE COILS INDEPENDENTLY WIRED.