sonicWORX Isolate – extract sound without effort

Prosoniq sonicWORX Isolate is a sound editor with one goal: to isolate one type of sound, whether it be a voice or a music instrument. At first I thought sonicWORX Isolate would be much like Sony’s SpectraLayers Pro, but it isn’t so. sonicWORX Isolate is far more accurate and automated and specialised in sound extraction and suppression.

I tested sonicWORX Isolate on a mid-2011 iMac i5/3.2GHz with 16GB of RAM. This proved to be powerful enough for sonicWORX Isolate to work without huge delays or other frustrating bottlenecks. Although I’m not going to try compare this application with SpectraLayers Pro, which as I said, has a different target market, I was surprised to find sonicWORX Isolate to be much faster than Sony’s program.

Internally, the program uses 44.1 kHZ 32/64 bit floating point arithmetic for its processing, but your file can be any frequency/bitrate as long as it’s not compressed and a format understood by OS X. Some metadata is preserved when importing/exporting.

The sonicWORX isolate interface

The test files I used for sonicWORX Isolate were:

  • a recording of Kiri Te Kanawa singing the Brahms Requiem
  • a recording of a harp with a string orchestra in the back
  • a field recording of an interview with a very nasty high pitched noise pattern that made the recording useless
  • a recording of myself quietly talking outdoors while cars and other background noise makes my voice hard to hear.

Note that the two latter usage scenarios I tested are not the application’s real purpose. The developers don’t advertise it as such and they are worried if you buy it for that purpose you’ll get inconsistent results. So, my advice is that you shouldn’t. Instead, buy it to extract/suppress vocals or music instruments in a music clip.

When you start working with sonicWORX Isolate, the first thing you’ll do is let the app analyse the sound file. That may take a while, depending on the size of the file and the speed of your processor. When you click the analysis button, you’re asked what you want to do: extract, suppress, or modify the file.

In principle, you can start working while the program analyses the file in the background, but I had time on my hands, so I let it finish analysis first. When the analysis was over, I could switch to a Component Editor showing me a spectral display. This display has two colours: yellow for consistent harmonic patterns and blue for irregular noise-like sound.

The sonicWORX Isolate field recording test
The field recording voice has more defined voice areas, visible in the yellow pattern.

In my field recordings, the yellow clearly represented voice, while in the Brahms clip yellow also could include violins playing sostenuto. You extract, suppress or otherwise modify a file by first setting a selection area, and then using a bunch of tools that do resemble those of SpectraLayers Pro to select the sound you want to process. Each selection takes a short while to finish, as sonicWORX Isolate figures out what exactly is signal and what is rubbish (from the viewpoint of the operator, of course).

I was very surprised at the accuracy with which the app recognises the exact patterns you’re after. The “first harmonic” tool is the first tool you’ll use. The “second harmonic” tool may work when the fundamental tone isn’t really visible. Despite its accuracy, sonicWORX Isolate wasn’t able to tell the difference between Te Kanawa’s voice and fragments of orchestral music (mainly violins) — at least not from the first selection.

That is normal and to fix it there is also a Magic Box tool. That one resolves interference between overlapping sounds. I was in for a second surprise as this Magic Box tool was quite good in filtering out Te Kanawa’s voice from the violins. In the field recordings my extraction was perfect after this step. The Te Kanawa clip would have required some more fine-tuning, as some of the soprano’s voice now disappeared as well.

That’s entirely possible by using the modifier keys on the first three tools. Depending on your source and your objective, you can also use the transient editing tool, harmonic exclusion tool, de-noising tool (works only on selections, though), and the de-selection tool. If you think you can do better than the app’s built-in intelligence, you can also use a single harmonic selection tool.

Once you have extracted sound (or suppressed it), you end up with a file containing only that sound with ugly gaps in-between where in the original were the instruments, background noise, etc. You can have sonicWORX Isolate auto-fill those gaps. I didn’t try that out; I was too mesmerised hearing Te Kanawa’s clear voice all by itself…

After having tried out sonicWORX Isolate for a week, I can only say it’s a brilliant sound extraction tool that is essential to a sound engineer’s toolbox and that is useful to concert recorders and (video) shooters. Having said that, the app is easiest to work with when the differences between the sound you want to process and the surrounding soundscape are clear and not too interspersed.

Listen to Kiri Te Kanawa (little time spent, so far from perfect).

Te Kanawa original


Kiri Te Kanawa ed


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