RMS and peak limiters, latency/look ahead


It seems that the RMS limiter does not introduce any signal delay. Is that correct?

What window length is used when the RMS value is calculated/how is the RMS value calculated?

When adding the limiter output and the inverted input signal, the signals cancel when the input signal is far below the limiter threshold. As the signal gets closer to the threshold, the signals do not fully cancel but the limiter still has its "active flag" to zero. I.e. the limiter degrades the signal unless far below the set threshold even though the limiter is not "active". Is it because the limiter does a gradual transition? 

Is it also true that the Peak limiter does not delay the signal? I.e. that it has no lookahead? I think I can implement look ahead by using a delay block.

I am using Sigma Studio 4.5 and ADAU1442. The RMS limiter has the parameters: RMS TC (dB/s), Decay (dB/s), and Threshold (dB).

Best regards,


[edited by: HifiDSP at 7:03 PM (GMT 0) on 19 Jul 2020]