Sonnox Oxford Limiter - Manual (Page 15)

8.1 ProTools|HDX (AAX DSP) versiononly 8 RECONSTRUCTION METERING SECTION
Since the vast majority of metering within workstation environments responds to sample
value only, the above example would show a level of around —3dB below clipping.
However any further increase in the level of the signal would result in a potentially illegal
output level from the system converter. As this error would not be reported on metering
within the workstation, in this particular case a possible 3dB overload can result if the
signal is increased to a maximum reading on the workstation meters. This phenomenon is
sometimes termed as ‘inter-sample peaking’.
Although the above example is somewhat extreme and specific, there is plenty of
potential for this to occur within the mixing environment. Combining a number of
processed contributing tracks, and limiting the result to the maximum possible
modulation level in order to satisfy current industry trends, when using only peak value
metering, is a recipe for such hidden errors.
Since the very purpose of a limiting application is most often to increase average
modulation levels, a reconstruction meter with both manual and automatic correction
processing has been included in the Oxford Limiter plug-in, in order to provide the user
with a method to avoid or repair such errors.
8.1 ProTools|HDX (AAX DSP) versiononly
The AAX version of Oxford Limiter has two Reconstruction Meter modes – DAC
Simulation that was present in the RTAS/TDM version, and a new TruePeak mode.
8.1.1 DAC SimulationMode
A signal that is already 2dB over unity when it reaches the Auto Compensation section will
remain 2dB over unity. It is only inter-sample-peaks that are corrected, not
sample-peaks.
Therefore the AUTO COMP feature (in this mode) should be understood as a feature that
correctsforillegalsequencesoflegalsamplevalues, notcorrectsillegalsample
values.
Before examining the Recon Meter, and using the AUTO COMP feature, you need to
ensure that you have already controlled transients in some other way to bring them below
unity (see The Limiter Section). This means using
SAFE MODE, having 16-bit or 24-bit
dither enabled or lowering the input or output fader.
The ReconMeter option allows you to correct for inter-sample peaks manually if you
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