LASTAR : a batch audio processor for loudness adjustment and file splitting


Logiciel Automatisé Simple de Traitement Audio Rapide

LASTAR is a batch (non-interactive) audio processor for loudness adjustment and file splitting of a batch of audio recordings, using audio transparent maximizer.

At the opposite of usual available softwares, loudness normalization is done on signal power, which leads to a louder and more homogeneous result than a usual "peak" normalization, in particular on live recordings.

Its purposes are :

  • to split, equalize and normalize digitized analog tapes or vinyls,

  • to split, equalize and normalize live recordings from microphones (ex ZOOM H2 recordings),

  • fast and homogeneous normalization of a group of files (compilation for instance),

  • loudness and dynamic reduction for listening in a noisy environment (car...)

  • and so on...

This software aims to be very fast and easy to use : the most efficient computing techniques have been implemented, and there are very few parameters to set (most of them are automatically adjusted by analyzing the file).

It embeds :

  • an automatic RMS normalizer,
  • an Automatic Gain Controller (compressor)
  • a 10 bands automatic equalizer
  • a 3 bands semi-parametric equalizer
  • a file splitter
  • a noise gate
  • preset management
  • a preview function.

For interactive audio edition, please use instead an audio editor like Audacity.


If you need some help or request new feature, please use this forum.

Technical features

  • This software is a freeware available under gpl licence.
  • Available on Windows XP 32 bits and above, should be easily portable to Linux
  • wav or mp3 input,
  • wav or mp3 output
  • support of id3 tags V1 & V2
  • Design to process large files (several Go) and full directory trees
  • Automatic file analysis to set up the best parameters
  • RMS Amplifier with fast lookahead limiter to prevent clipping
  • Left/right channel automated balancing
  • 10 bands automatic equalizer
  • 3 bands semi-parametric equalizer
  • real time pre-listening function
  • Transparent and fast 3 bands processing (using FIR implemented by multi-threaded FFT convolution)
  • Automated amplifier gain adjustment and noise estimation for file splitting
  • Smooth automatic gain control (AGC) to compress dynamic without "pumping" effect
  • Output noise gate
  • English or French GUI
  • Comes with a simple user guide
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