PNR Noise & Hum section Removes constant sounds, such as a 50/60 Hz hum.
For an example of what it can do, see this video:
When the Input gain is changed (stand alone version only), a new ANALYSIS STEP should be done. The same is true if the global processing settings (Quality (CPU load), Latency) are changed. This filter will automatically be switched off when the Quality (CPU load) or Latency setting does not match that when used during ANALYSIS STEP, but not when Input gain is changed. General panel Settings that control PNR Noise & Hum behavior.
If you play recordings in a studio that adds constant noises, you need to remove those constant noises before declipper. If however the constant noises are clipped as well, you need to declip first.
Minimum Multiplier Remove at least this much compared to the softest sound heard during ANALYSIS STEP.
This mainly affects the removal of constant sounds (tones). See ANALYSIS STEP.
AVG Multiplier Remove at least this much compared to the average level seen in ANALYSIS STEP.
This mainly affects the removal of (random) hiss sounds. See ANALYSIS STEP.
Sigma (variance multiplier) Controls how PNR responds to varying levels.
Setting this higher will cause less noise to be removed, at the cost of introducing very annoying artifacts. The default level (3, which corresponds to 3σ) is a tradeoff.
Sigma Steepness Controls how steeply the filtering changes around the measured average level.
These only have an effect during the analysis step. Afterwards they do nothing anymore, a new analysis needs to be done to effectuate changes.
Minimum Median Position Determines how much low level measurements are ignored when determining the minimum value.
See Minimum Multiplier. At 10%, this means that during analysis the 10% softest values are ignore when determining the minimum level.
Ignore lowest When calculating average level and variance, ignore the lowest samples.
This is useful to ignore for example a brief moment of silence in the measurement data.
Ignore highest When calculation average level and variance, ignore the loudest values.
This can be useful to ignore some sounds that might still be present during the Collect Data, which should only contain the disturbance but there might be occasional other sounds present.
Collect Data Lets Stereo Tool record some audio to be used to analyse the disturbance.
Only use this on moments of complete silence, so don't use this during a normal recording, otherwise PNR Noise & Hum will start removing "good" sounds as well.
Turning it on multiple times (without restarting Stereo Tool in between) is possible, the measurement data will be combined.
