JBL VerTec VT4889, VerTec VT4888, VerTec VT4881, VerTec VT4887, VerTec VT4880 System Configuration Manual
System Configuration Manual
Using crown I-Tech series
For models VT4889, VT4888, VT4887, VT4881, VT4880
TABLE OF CONTENTS
PAGE
GENERAL AMPLIFICATION NOTES & REQUIREMENTS…………………. 3
SUBWOOFER WIRING NOTES………………………………………………… 4
STANDARD AMPLIFICATION RACK
NOTES REGARDING LIMITER SETTINGS……………………………..…….. 5
VT4887 & VT4881
TRANSDUCER COMPLEMENT.………………………………….…….. 6
AMPLIFIER CONFIGURATION OPTIONS
VT4887 & VT4881 ARRAY WIRING……………………………………………. 7
VT4888
TRANSDUCER COMPLEMENT………………………………………… 8
AMPLIFIER CONFIGURATION OPTIONS
VT4888 ARRAY WIRING………………………………………………………... 10
VT4889
TRANSDUCER COMPLEMENT………………………………………… 12
AMPLIFIER CONFIGURATION OPTIONS
VT4889 ARRAY WIRING……………… ……………………………………….. 14
VT4880 TRANSDUCER COMPLEMENT & AMPLIFIER CONFIGURATION.. 17
VT4880 ARRAY WIRING……………… ……………………………………….. 18
VERTEC SUPPORT TEAM AND WEBLINKS…………………………….……. . 19
Page 2
GENERAL AMPLIFICATION NOTES & REQUIREMENTS
o For the purpose of this discussion: Crown I_TECH series amplifiers are used below. HF
indicates High Frequency drivers, MF indicates Mid Frequency drivers, LF indicates Low
Frequency drivers and VLF stands for Very Low Frequency drivers (subwoofers).
o Equivalent amplifiers can be used as substitutions.
o Users should observe differences in input sensitivity and maximum available power at a given
impedance load.
o Users may choose to use the same size amplifier to power all components / passbands.
o DSP crossover presets provided by JBL assume that the same amplifier models with equal
voltage gain, are used for each bandpass.
o If different gain settings or amplifiers models are used, users may need to adjust the output
gains of the digital controller(s).
VT4489
VT4888
VT 4887
VT4880
VT4881
o 4 VT4889 can be powered with (4) I-T4000.
Two boxes are wired in parallel per NL8 circuit.
(HF: CH1 & CH2, MF: CH1 & CH2, LO1: CH1 & CH2, LO2: CH1 & CH2)
o Using (4) I-T6000 would provide enough power to drive up to 6 VT4889.
Three boxes are wired in parallel per NL8 circuit.
o I-T4000 can be used for the HF section to power 2 or 3 boxes.
o 4 VT4888 can be powered with 4 I-T4000.
Two boxes are wired in parallel per NL8 circuit.
(HF: CH1 & CH2, MF: CH1 & CH2, LO1: CH1 & CH2, LO2: CH1 & CH2)
o Using 4 I-T6000 would provide enough power to drive up to 6 VT4888.
Three boxes are wired in parallel.
o I-T4000 can be used for the HF or MF section to power 2 or 3 boxes.
o 4 VT4887 can be powered with (1) I-T4000.
If four boxes are wired in parallel per NL8 circuit then
CH1: LF @ 2 ohms & CH2: MH/HF @ 2 ohms.
o 2 VT4880 can be powered with (1) I-T4000.
If two boxes are wired in parallel using NL4 cables then each amp channel powers (4) 2258
for a 4 ohms load.
o 3 VT4880 can be powered with (1) I-T6000.
If three boxes are wired in parallel using NL4 cables then each amp channel powers (3)
2258 for a 2.7 ohms load.
o 4 VT4880 can be powered with (1) I-T8000.
If four boxes are wired in parallel using NL4 cables then each amp channel powers (4) 2258
for a 2.0 ohms load.
Separate NL4 cable runs are recommended with parallel wiring at the amp.
o 4 VT4881 can be powered with (1) I-T4000.
If four boxes are wired in parallel using NL4 cables then each amp channel powers (4)
distinct coils of dual-coil 2256Gs for a 2.0 ohms load. Each 2256G has (2) coils.
Separate NL4 cable runs are recommended with parallel wiring at the amp.
Page 3
NOTES ON SUBWOOFER WIRING
o VT4880: users may choose to wire both 2258 (18”) components in parallel to one (1) channel of
a an I-T amp for (4) ohms load. In this case each amplifier channel drives one VT4880. If two
VT4880 are wired in parallel, the load is two ohms. Three 4880s can not wired in parallel in this
situation.
o VT4881: users may choose to wire both coils
channel of an I-T amp for (4) ohms load. In this case each amplifier channel drives one
VT4881. If two VT4881 are wired in parallel, the load is two ohms. Three 4881s can not wired
in parallel in this situation.
USERS MUST NOT WIRE THE VOICE COILS ON A 2256G (VT4881) OUT OF POLARITY TO
EACH OTHER.
NL8: PIN 1 +
NL8: PIN 2 +
= RED CONNECTOR A & BLACK CONNECTOR A
= RED CONNECTOR B & BLACK CONNECTOR B
in a single 2256G component in parallel to one (1)
STANDARD AMPLIFICATION RACK
For those users looking to minimize amplifier rack configurations, one amplifier rack with
(1) I-T4000 and (3) I-T6000 and 2 NL8 output circuits can power up to:
o 4 to 6 VT4889 (2 or 3 boxes per circuits AMPS: HF, MF, LF1, LF2)
OR
o 4 to 6 VT4888 (2 or 3 boxes per circuits AMPS: HF, MF, LF1, LF2)
OR
o 8 VT4887 & 4 VT4881
(4 VT4887 & 2 VT4881 per circuit AMPS: MF/HF, LF, VLF1, VLF2)
This rack would use the same input signal path from the digital controller of choice. Users would only
need to recall the appropriate DSP file on the unit.
o VT4889 or VT4888
DSP outputs: LO, MID, HIGH (stereo)
o VT4887 & VT4881
DSP outputs: SUB, LO, MID/HIGH (stereo)
Page 4
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 I-T amplifier in stereo mode with input sensitivity of
1.3V for a voltage gain of 36 dB.
• 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.
• Users should carefully test these settings, and lower or raise the thresholds for a given
type of program material as required.
Page 5
VT4887 & VT4881 Transducer Complement:
Nominal
Model
HF
2407H
MF
2104H
LF
2168J
VL
F
2256G
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
Speakon NL8
Terminals
Pins 4±
Pins 4± 1 x 4 8Ω 8Ω 50W 200W 450W
Pins 3±
Pins 1± & 2±
Per box
1
x 2
2
3
x 2
x 1 2 x 8Ω 8Ω + 8Ω 600W 2400W 1200W
Impedance
per
transducer
8Ω 8Ω
16Ω 8Ω
Nominal
Impedance
per
Passband
AES Power
100 HR
Rating per
Transducer
25W 100W 450W
350W 1400W 1000W
Peak Power
Rating per
Transducer
Recommended
Power
per Passband
Amplifier Configurations:
Amplifier
I-T6000
I-T6000
Four VT4887 & Two VT4881 / Two I-T6000
Amplifier
Channel
Ch 1 Pins 4+/-
Ch 2 Pins 3+/-
Ch 1 Pins 2+/-
Ch 2 Pins 1+/-
Speakon
NL8
Terminals
Driving
8 x
2407H
& 16 x
2104H
8 x
2168J
2 x
2256G
2 x
2256G
Amplifier
Nominal
Impedance
at Pins
2ohms 2500W 625W 54V -3
2 ohms 2500W 625W 134V 2
4ohms 3000W 1500W 86V 0*
4ohms 3000W 1500W 86V 0*
Power
Rating at
Nominal
Impedance
Power
Available
to Each
Bandpass
Bandpass
Peak
Voltage
VAC
Limiter
Threshold
dBu
Page 6
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