JBL HLA 4895, Руководство пользователя

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the OEM design, excluding the limiter settings. Files cannot be deleted and the default, or “blank slate” preset in
memory location 0 cannot be recalled. It is recommended that the password be changed to something unique
and meaningful that will easily be remembered by those responsible for the system.
When a knowledgeable technician is not present, it is recommended that the Owner lock be engaged,
as it still offers a generous amount of system control adjustment.
If the system will be left in the care of curious yet unqualified operators, it is recommended that only
presets for the current speakers and amplifiers be left in memory and the Owner lock be engaged. In this way
only valid presets can be recalled and operated. Presets can be deleted by disengaging the Owner lock, pressing
Recall and then Utility to get to the Delete File soft key.
Each output band has a mid-band limiter. Disastrous results can occur if the limits are set incorrectly,
either too high, too low, or not at all. Limiters should be carefully set for the gain and sensitivity of the specific
amplifier used in each band. (See Section #4, “Matching Transducers to Power Amplifiers).
HLA speakers can be used with a variety of professional power amplifiers and it is not possible to know
in advance which amplifiers may be chosen by a particular owner. The limiter engages when each bandpass
output’s signal reaches the set limit, either in millivolts or dBu (with 775 millivolts equal to 0 dBu). By first
choosing an output level for the limiter and then gauging the maximum amount of power this will allow the
amplifiers to feed to the transducers, the limiters can then be safely set for the rigorous demands of contemporary
live music.
Frequency System HLA System Maximum
Section on Bandpass Component Input Voltage
DSC280 Recommended
Band A Subwoofer 2242HPL 72 volts RMS, 144v Peak
Band B Low Frequency 2254J 98 volts RMS, 196v Peak
Band C Mid Frequency 2251J 80 volts RMS, 160v Peak
Band D High Frequency 2451SLJ 24.4 volts RMS,60v Peak
Careful calculations should be made prior to using the system, to correctly set the limiters. For
protection, this can only be done with the Owner lock released. After the limiters are set for use with the specific
amplifiers chosen for the system, their presets should be re-stored to preserve them. If the only files in the DSC are
HLA presets with the limits correctly set for the amplifiers, no other presets can be run with the Owner lock
engaged. With the Owner lock engaged, files cannot be deleted, the default program cannot be recalled and
limiters cannot be adjusted.