Sound Recovery

Sound Recovery free audio-restoration by Bitsonic

Sound Recovery is a free audio restoration Stand Alone, VST plugin developed by Bitsonic. Compatible OS(s): Windows, macOS.

The objective of Sound Recovery is to repair hard to understand and low quality soundtracks to a decent level. The software helps in cases when the mid-high frequency is completely missing. This can be audio recorded through a wall, or a conversation from the microphone’s dead space. In these cases simply using EQ can’t help. The software fixes the mid frequency by creating harmonics from the low frequency sign using distortion overdrive. The created harmonics help a lot to make the sounds more understandable. This function is most useful to forensic expert and audio restaurators.

The other function of the software is Multiband Denoiser, that erases the unwanted noise from (low-mid) and (mid-high) frequencies. This function has a more broad use. It for situations when using Equalizer negatively affects the noisy audio overall.


  • Input Volume: Simple volume control, the maximum value uses the original value of the amplitude.
  • Split Freq: Selects the frequency range where the user would like to have the biggest difference during the change of the audio.
  • Recovery: Connected to Split Freq, this function works in the frequency range set in Split Freq. Recovery sends the sign into overdrive. Use only when significant repair is necessary, or when only higher frequency ranges need to be strengthened. (See: Low quality MP3, with no high frequency range.).
  • Enhancer: This function is similar to Recovery’s mechanism, but the user can set a narrow frequency range, to get more harmonics from. The other difference is that overdrive is made by a more specific algorithm.
  • Low pass: This simple low pass filter can be used when the high frequency noise is deemed too much.
  • Denoiser Low/High: Filters the noise from the low/high frequency range set by Split Freq.

Denoiser Low needs specific settings to function properly. For example, when the user would like to handle the low frequency range while Recovery is at maximum and Split Freq modifies too high of a range.

If the software is used only for noise filtering don’t use Recovery and Enhancer. The blue led knobs can be used to turn these functions on and off.

Using the Standalone version the user can load audio using the Load WAV function. For playing, looping, and audio exporting 3 function knobs can be used. The part of the audio to loop is shown by the bottom graphic display, marked by two vertical markerlines.

After the editing is done, the preset can be saved used the File knob.

The VST version works only with 32-bit DAW software, but with Bridges it can be used on a 64-bit system as well. Standalone can be used on 64-bit systems too, and with the help of Wine works on OS X systems as well.

3 WAV files are included as well, to show the way the 3 presets work.

{See video at top of page}

Noise Reduction

Noise Reduction free audio-restoration by Christian Budde

Noise Reduction is a free audio restoration VST plugin developed by Christian Budde. Compatible OS(s): Windows.

Noise Reduction is a plug-in containing a spectral noise gate optimized to remove unwanted noise.


  • Highly customisable spectral noise gate.
  • Continuous and consistent characteristic.
  • Fully adjustable soft knee in dB (as margin below the threshold).
  • Several exotic window functions available.
  • Low CPU usage.
  • Different FFT sizes.
  • Manual included.
  • Open Source (as part of the Delphi ASIO & VST Project).