Q2 Audio Compex F760X-RS, Руководство пользователя

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OPERATION PROCEDURE
Establishing the unit in the channel
a). Check Expander section switched ‘out’; Compressor Ratio switched to 1:1 (i.e. non-operative); the Peak Limit switched
‘In’; and the output attenuator turned down (in a stereo unit the individual channel potentiometers would be fully open on
each channel with control effected on the ganged device) would be adjusted as required.
b). With the channel by-pass switch to ‘out’ (i.e. by-passing the F760 Compressor amp section) the channel levels should
be established in the usual way as though the F760 were not in circuit. The channel level should be peaking to at least
-10dBm, but preferably to 0dBm in order to obtain maximum compression possibilities.
c). Having established the normal level, switch the F760 ‘In’ and adjust the Input pot until the overall amount of gain reduc -
tion likely to be required, is indicating on the meter (e.g. 10dB). At this stage the Peak Limit section is working and red
indicator will be flashing.
d). Open the Output attenuator and adjust so that the level is peaking to the same level as the direct signal. This is best
done under dynamic signal conditions rather than on tone if monitoring with VU meters (see LIMITING & COMPRESSION
– Considerations). A relevant direct comparison is now available between direct and compressed signal at the flick of the
‘In/Out’ switch at closely approximating peak levels.
e). With the compressor Ratio control select the Slope required (e.g. 2:1) and adjust the Compressor Threshold control
until the Peak Limit only indicates on peaks above the amount of compression required (i.e. move the threshold down
from ‘0’ towards the -20 point until the Limit light goes out, then come back one position). The limit section will then oper -
ate on any further unexpected increase in level. The amount of compression may be changed by increasing/decreasing
the Input pot and adjusting the Compressor Threshold adjust the relationship between compression and peak limiting.
Once set-up it will not be necessary to alter the Output level (as per step ‘d’).
f). The Release time in the compressor section will be adjusted for effect and the Attack time. Note when long Attack time
is selected more peak limiting will occur.
g). In adjusting the compressor section always reference it to the Peak Limiter even if the Pk.Limit is then switched out
during operation. This maintains the optimum signal-noise level in the system. When using the tighter slopes in the com -
pressor the Threshold will lie just under the Pk.Limit in position -2 to -8 (20:1 to 3:1 ratios).
h). The Compression Slopes are calculated on a 15dB range of gain reduction. (i.e. the 2:1 ratio is established in the
set-up procedure as 30:15). It will be found in practice that the initial slope in that position is more akin to 1:1.5 becoming
slightly tighter as gain reduction increases. Thus if only 6dB of compression were required this will be softer than the ratio
indicated and the next position higher could be selected. In practice this will not be found of great importance but it is use -
ful to know of.