Quickly and easily subtract interfering  music, television or speech from an audio recording if you have a reference  song, TV show, or speech recording that you want to remove from the recording.

Two tracks automatically synchronised audio in SMARTSubtract

Two tracks automatically synchronised audio in SMARTSubtract

SMARTSubtract  uses  MADCAT (TM) audio fingerprinting technology to to align the two  files and perform reference cancellation. The high quality ‘reference cancellation’ is provided by two powerful VST plugins from two leading audio processing software companies namely Salient Sciences (previously Digital Audio Corporation) and Acon Digital (creators of Acoustica).

Example Use Case:  
Consider a  recording of people talking in a room with a radio playing over the top of their speech. This may mean their voices are inaudible in the recording due to being drowned out by the radio broadcast. Reference cancellation of the synced audio can help by taking the reference audio (i.e. the song that is playing on the radio) and subtract this audio from the original audio recording.

In order for this process to be as successful, the two audio clips need to be very precisely time-aligned so that the reference audio is playing at the same time as it is in the original track. SMARTSubtract will do this for you with a click of a button.


  • Precise time synchronisation of two audio signals
  • High quality time and frequency domain plugins to perform cancellation
  • Crisp spectrogram and waveform views of the signal
  • Automatic amplitude normalisation
  • Playback and preview enhancement in real-time
  • Highly configurable VST plugins from the leading audio software manufacturers
  • Easily export results to WAV format

Reference cancelled audio saved inline with primary audio

Easily choose between two powerful VST plug-ins

(Information on each VST taken directly from their respective manuals – please see the manufacturer website or contact them for more in-depth information)

Cardinal Minilab


Acon Digital

SMARTSubtract Minilab Plugin
SMARTSubtract Acon Plugin

The Cardinal Minilab Reference Canceller Filter comes equipped with the following features:

  • Filter sizes up to 8192 taps
  • Delay line up to 32768 samples
  • Auto-Normalizing adapt rate
  • Conditional Adaptation
  • Reference Gain
  • Selectable Filter Output
  • Coefficient Display (with max peak indicator)
  • Dual-trace spectral analysis (with max peak indicator and averaging

For more information on Cardinal Minilab:

The Acon Digital Reference Canceller comes with the following settings:

  • Analysis Mode –  estimates the transformation of the reference signal 
  • Emphasis Filter – applies frequency weighting to the cross-talk estimate.
  • Difference Monitoring -monitor the signal removed by the reference cancelling algorithm
  • Reduction level (%) – Sets amount of reference cancelling in percent.
  • Ambience level (%) – For reverberant rooms , use ambient reduction
  • Reverb time (sec) – For ambience reduction and specifies the reverb time of the room where the recording was made.
  • Time align (ms) -fine tune the alignment using the time-align setting.

For more information on Acon Digital:

Workflow Walkthrough
Load a reference and primary audio file by simply dragging and dropping
Files will be automatically aligned on load. Auto-normalise the tracks by dragging a selection and clicking "Edit > Auto-Normalise"
Select the track you wish to subtract using the '+' and '-' buttons
The track set to '-' will be reference cancelled from the track set to '+'
Make a selection in the audio, select your VST, and click the open VST button
You will be able to listen to the reference cancellation in real time, and modify the parameters to get the best results.
Cancellation results can be saved inline with original recording, or to a new tab in SMARTSubtract
Results can also be set to auto-normalise on save
Results can then be exported to WAVE (.wav) files
Use "File > Save Current Tab..." to save the selected tab audio to a wav file

Why not drop us a line for more info: