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Uninterrupted Protection
The "ControllerTM" only attenuates
the signal if the overload is unacceptably high.
Easy to Use
No calibration is required, the front panel drawer is calibrated at the outset
according to the loudspeaker model chosen.
Varied Uses
For wide band use, the draw indicates "left" and "right"
channels. With use of bi-amplification, the draw indicates "low" and
"high".
Front Panel Connections
The "ControllerTM" and amplifier
installed in the flight case do not require any access through the rear panel. The
"link" outputs enable several amplifications to be set up in parallel.
Cable Check
The control signal returns from the "ControllerTM"
through the same cable as the loudspeaker signal; in the case of a faulty connection, the
limiting display is permanently lit up.
Operates with wide Range of Power Supplies
The "ControllerTM" can operate
perfectly well with power supplies ranging from 160 to 260 V. If the power supply is too
low, the voltage LED does not light up indicating that the power supplied to the
loudspeaker is not controlled.
Security
In order to eliminate any risk of a feedback loop, the control input signal is
not connected electrically with the amplifier.
Why the need to control the power supplied ?
Music contains extremely high modulation peaks, i.e. in the region of + 10 dB compared to the average signal level. These modulation peaks represent ten times the average power required. In view of the fact that a loudspeaker can handle these power peaks, it is interesting to have an amplifier with sufficient headroom.
It is for this reason that the "ControllerTM" checks that the duration of the peak does not exceed what the loudspeaker can handle.
The concept of the "ControllerTM" involves placing detectors in the loudspeakers that supply a voltage proportional to the power supplied to each transducer.
| The control signal controls the compression circuit located in the "ControllerTM" which attenuates the signal only when the duration of the overload exceeds the acceptable power of each transducer. |
Why modify the bandwidth ?
A loudspeaker always behaves as a filter in the sense that it only lets through without alteration part of the spectrum supplied, for example, from 50 Hz to 500 Hz for a woofer or from 50 Hz to 15 000 for a multichannel loudspeaker.
At the limits of the bandwidth, the signal is usually attenuated but only slightly deformed. Appropriate equalization can therefore considerably extend the spectrum supplied by a loudspeaker. However, beyond the limits of the bandwidth, the signal supplied is always a hindrance to the smooth operation of the loudspeaker. What effectively happens is the lower frequencies create excessive excursions which induce a high amount of distortion by intermodulation in the audible frequency range, and furthermore, the power supplied outside the bandwidth is not transmitted but contributes to overheating, and because of this, it decreases the useful sound pressure.
A plug-in circuit that is accessible through the front panel of the "ControllerTM" contains filters, the frequencies and quality factors of which are adjusted according to the type of loudspeaker. The front panel of the drawer indicates the loudspeaker model and useful bandwidth.
| The reproduction quality will therefore be substantially improved with appropriate filtering. |
Manufacturing and distribution for Switzerland by RELEC SA
=> E-Mail: info@relec.com
©2003 RELEC SA
