Pro tools | hdx (aax dsp) version only, Dac simulation mode, 1 pro tools | hdx (aax dsp) version only – Sonnox Oxford Limiter User Manual

Page 15: 1 dac simulation mode

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8.1 Pro Tools | HDX (AAX DSP) version only

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 Pro Tools | HDX (AAX DSP) version only

The AAX version of Oxford Limiter has

two Reconstruction Meter modes – DAC

Simulation that was present in the RTAS/TDM version, and a new True Peak mode.

8.1.1 DAC Simulation Mode

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

corrects for illegal sequences of legal sample values, not corrects illegal sample

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

Recon Meter option allows you to correct for inter-sample peaks manually if you

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