About PK3

PK3 is one of the most advanced mastering peak limiters available today on the market with a variable look-ahead time window providing an unmatched flexibility in its class.

The state-of-the-art algorithm behind the processor is the result of several researches and years of experience, which offers a clean peak limiting without audible distortion.
Thanks to its design PK3 also offers an "analog" feel similar to a warm studio compressor with all the accuracy of a 64-bit precision of digital limiter. No compromises between the sound quality and the CPU usage have been made, except for some clever forms of optimizations that are necessary to get this kind of limiters to work in real-time. No matter how loud is the input signal, NUSofting PK3 will always keep the peaks on the limiting threshold.

Maximizing the loudness of a mix

Increasing the perceived level of a mix sometimes can be a very difficult task. Audio mixes often show strong and short peaks (e.g. spikes that are two or three times greater than the rest of the audio). By attenuating these peaks it is possible to safely raise the overall volume.

PK3 performs this task in a clean manner. It decreases the volume of the mix just before the peaks (the attack time) and increases the volume after the peaks (the release time).

Conventional analog limiters allow only to decrease the volume once the peak reached a certain threshold set by the user, either by instantaneously lowering the volume causing audible distortion (especially on bass frequencies) or with a longer attack time, letting some of the peak pass through the limiting threshold causing, once again, distortion. In the analog world the distortion side effects were negligible and sometimes a choice of the sound engineer, but in the digital world this kind of distortion simply sounds bad! To avoid distortion a compromise must be found between the limiting threshold and the attack time, at the expense of a lot of work and probably not reaching the maximum possible average volume.

Using PK3 it is possible to achieve the best results simply boosting the input volume using the Gain control. The Ceil (threshold) control lets you adjust the maximum output level (generally 0dB, but for CD-Mastering you may want to choose -0.3dB, because some Digital to Analog converters of older and poorly designed CD players may increase slightly the peak levels)

For mastering the attack and release time should be kept around 2.5/7 ms. (5ms attack/7ms release is a safe setting).

In general, the shorter the attack/release times the higher the level perceived of the signal. However short times may introduce a slight distortion on bass frequencies. If this distortion is not acceptable try increasing the attack and/or the release times.

For creative limiting (especially when working with drum tracks) try increasing the gain and the release time.

Limiting the output
Sometimes working on mix you may need only a good limiter to prevent clipping distortion or audible artifacts. By setting the PK3 with "relaxed settings" (gain to 0dB, ceil to 0dB, attack time around 10ms and release time around 30ms) the limiter should perform well in any situation.

Look-ahead latency
Because PK3 needs to know in advance the audio input to process it has to delay the audio output. The latency of PK3 is fixed to 2048 samples.
VST hosts that offer support for plug-ins with latency have no problem dealing with the latency of PK3 , but when editing wave files with certain hosts you may need to add 2048 samples of silence at the end of the audio files before processing and delete the first 2048 samples after processing the signal with PK3 .

Known issues
Moving the attack control could cause noises in the sound. This is because the complex algorithm used in PK3 needs to initialize itself each time you move the knob. We will try to minimize this effect in future releases of PK3 .

Advices
To achieve the maximum levels from a mix you should consider compressing individually each track and work out a frequency space for each track that doesn't sound "loud enough" using a set of equalizers. That's not easy, but your mix will for sure sound louder and better. Only at a later stage use PK3 as a "level maximizer" to attenuate peaks.

Obtaining technical support
For technical support contacts, advices and information please visit our forum at kvraudio.com:

Happy mastering!