Operation And Use; Power Up; Level Adjustment; General Level Adjustment - Ecler QEM16-2 Notice D'emploi

4. OPERATION AND USE

4.1. Power up

Once the unit is connected in any of the ways described in 3.2, your QEM is ready to work.
Just push the mains POWER switch (11) and the associated green pilot will light up. Even
though the noise produced by powering up is minimum and it is practically cancelled by placing all
faders at 0dB, it is always advisable to follow the classical power up sequence: signal sources, mixing
unit, equalizers, active filters (crossovers) and, at the end, power amplifiers. The power down sequence
must follow exactly a reverse order. By closely following this sequences, all peaks or transitories
produced by switching on and off devices do not affect the next devices in the chain and, of course,
never reach the loudspeakers, which are extremely sensitive about this.
In order to be able to use the controls we must first verify that the switches marked as FLAT
(2,6,27) are not activated. Once this is checked, all controls can operate and we are able to perform any
adjustment.
If anytime you wish to perform a BYPASS of all equalizer's controls, just push the FLAT
switches. In models QEM16-2 and QEM30-1, if you unplug the mains power connector (turning the unit
off abruptly), the BYPASS will be performed automatically, through an inner relay.

4.2. Level Adjustment

The correct starting point for a proper equalization is having all band gain faders (9,10,21) at
0 position. From this point on, either with a spectrum analyser or by ear, depending on your own taste,
all adjustments can be made.
As a general rule of thumb, it is advisable to avoid abrupt jumps in the response. It is much
better to use two or more contiguous frequency bands in order to achieve a given result.

4.3. General Level Adjustment

Any modification performed over the signal spectrum also affects the overall output level. In
order to compensate for this level change, which could overload the next steps in the audio chain, there
is the possibility to separately adjust each channel's general level by a ±12dB margin through the GAIN
controls (1,5) (the QEM30-1 has only got one GAIN control (26) because it is a mono unit).
By using the FLAT switches, it is possible to verify if the modifications performed are the
desired or right ones; by using them you bypass the equalizer operation (see 4.1).
Taking the original, unequalized, signal as a reference, you can adjust the overall output level
and avoid the risk of saturation in other elements of your equipment.
The QEM30-1 has also got a high-pass and low-pass tunable filters section. In order for these
to work, the FILTERS switch (25) must be pushed on. At this point, the LED on the right side (24) will
light up, indicating that the filters are into operation.
The LO-CUT filter (or high-pass filter) allows to cut or bypass low frequencies of the signal.
With this control (23) it is possible to simulate a "rumble" filter.
The HI-CUT filter (or low-pass filter) performs the reverse effect; that is, it allows to cut high
frequencies of the signal. With this control (22), a "scratch" filter can be simulated. By placing both filters
at their maximum band cuts, we would obtain the sound effect of a telephone line.
4.4. Clipping Indicators
This indicator is physically placed just over the FLAT LED (4,8,29) and it is marked as CLIP
(3,7,28). It will light up when the output signal is 3dB below clipping (+17dBV/600Ω). If, during the usual
equalizer operation, this indicator remains lighting up for a long time, it means we are producing a
distortion on the output signal.
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