BW Broadcast DSPXtra-FM, Руководство по эксплуатации

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Getting The Sound You Want
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constant circuit.
WE SUGGEST ONLY SMALL MODIFICATIONS FROM FACTORY PRESET SETTINGS IF YOU ARE
MODIFYING LOTS OF THE PARAMETERS. IF YOU ARE ADJUSTING ONLY A COUPLE FROM THE
ABOVE SUGGESTIONS THEN YOU PROBABLY HAVE A BIT MORE LEE-WAY. IT IS VERY EASY TO
LOSE YOUR WAY ONCE YOU START 'TWEAKING' LOTS OF DIFFERENT SETTINGS.
More STEREO ENHANCEMENT
We can obtain more stereo enhancement by employing the Arianes matrix mode of operation. This mode splits
the audio into 4 bands of SUM and difference signal. In other words a mono signal and a signal containing the
stereo information. By enhancing this stereo signal (the difference channel) we are able to increase the spatial
effect. This must be done carefully to avoid problems such as multi-path when the DSPXtra-FM is processing
for FM broadcast. The sophisticated controls in the Ariane section of the DSPXtra-FM are more than capable of
handling this problem, if set correctly. To increase stereo (spatial) energy, make sure the Ariane is operating in
matrix mode.
Set the L-R IDR to lower numbers
Set the Gate to higher numbers
Set the RELEASE for each band to lower numbers.
These settings will primarily affect how the L-R (spatial) energy is processed but there are some other controls
that also have a part to play but are much more important when it comes to worrying about multi-path when the
DSPXtra-FM is processing for analogue FM. These controls are the L-R restriction and L-R injection.
The L-R restriction control sets how much extra gain can be applied to the L-R signal in relation to the gain
being applied to the L+R signal. This prevents low level L-R (spatial) energy from being ‘sucked up’ too much
causing strange stereo effects. This control restricts the amount to a ratio between the L+R and L-R which is dif-
ferent to how the normal GATE control works.
The L-R injection level affects how much of the processed L-R signal (after the 4 bands are recombined) is
fed to the demultiplexor which recreates the original left and right channels. If this control is set at 0dB then full
processed spatial energy is demultiplexed with the L+R mono signal. At the other end of the scale setting the
control to OFF will inject zero energy into the demultiplexor leaving only the original L+R mono signal which after
demultipexing leaves only a mono signal. Try it and see. You will notice that you can achieve quite a lot with this
control and it is quite important when we consider multi-path. Unlike other processors we can use this control to
control our maximum level of L-R energy in the stereo subcarrier. By processing the L-R to increase the stereo
effect and then reducing the maximum level with the injection control we can create a consistent amount of
stereo enhancement but with less level in the subcarrier which results in less multi-path.
We recommend the L-R restriction control being set somewhere between -6 and -12dB. With -12dB being for
more stereo effect as the L-R gain is able to increase -12db past the L+R gain. A setting of 0dB ties the L-R
gain to the L+R gain which effectively turns off stereo enhancement.
We recommend the L-R injection control being set to somewhere between -6 and -3dB. Having the setting at
less than unity (0dB) helps reduce multi-path, and the reduction in stereo effect can be more than made up for
with the proceeding controls. Setting this control too low will minimise the stereo effect to the point of creating a
mono signal.
You may think that lowering the settings of the injection and restriction controls has a similar effect. The differ-
ence between setting the L-R restriction to 0dB and L-R injection to OFF is that the former disables enhance-
ment but the latter actually creates mono even if the input to the Ariane is stereo.
Less STEREO ENHANCEMENT
Set the L-R processing controls to the same as that of the L+R controls (for consistency in the processing)
Set the L-R restriction control to a higher number to restrict too much gain being applied past the L+R’s process-
ing.
Set the overall level of the L-R with the injection control. Lower numbers are less stereo. Don’t go too heavy on
this setting as you could actually end up turning down any stereo content in the original program material when
you are only trying to restrict enhancement.