I have included a number of basic spectral editors, as well as applications which include spectral editing capabilities, in the TOOLS listings of this website since they are a good starting point for familiarizing oneself with the spectral content of one's source material and can be useful for experimenting with spectral editing. In some cases they are even available for free! Depending upon the source material, one might be surprised by what is possible using only basic spectral editing!
Those intending to upmix mono source material to stereo with professional level results should consider more sophisticated applications which help considerably with achieving higher quality separations as well as help cut down on the time and effort required to produce higher quality results.
SpectraLayers Pro 6, now from Steinberg, includes a harmonic selection tool and has been used on many of the best mono to stereo upmixes created and released commercially to date. SpectraLayers Pro 6 includes a number of tools to help select the desired sounds and has the advantage of being available for both macOS and Windows. SpectraLayers Pro 6 now includes an ARA 2 plug-in which allows it to be used directly from within a compatible DAW.
sonicWORX Isolate, previously available from Prosoniq, is a superb spectral editor specifically designed for extracting, suppressing, and processing instruments and voices present within a mono or stereo mix. The program, available only for macOS, includes not only a harmonic selection tool, but also intelligent pattern tracking for signal separation, and uses a proprietary transform that uses statistical properties of the signal to differentiate between noisy signals and harmonic content. The combination of an intuitive color coded display and powerful easy to use tools make sonicWORX Isolate an excellent application for those interested in upmixing mono source material to stereo. Zynaptiq recently acquired Prosoniq's product line and technologies but has yet to add sonicWORX Isolate into their current product line. Check with Zynaptiq about current availability of sonicWORX Isolate.
Audionamix, which has been providing sound source separation services to the industry for a number of years, introduced ADX TRAX, "the world's first non-destructive, automated melodic audio source separation software". Please check with Audionamix for their product availability since they recently discontinued offering most of their applications and plugins. ADX TRAX 3, the latest version, is available currently only for macOS and uses cloud-based computing to offload the heavy number crunching to Audionamix's computers. ADX TRAX 3 is designed for separating the lead vocal, and some solo instruments, from the backing content, even with mono source material. ADX TRAX 3 performs an initial separation automatically which can cut down considerably on your time and effort. A number of tools are provided to help optimize the results.
More recently, Audionamix introduced ADX TRAX Pro 3, which builds upon ADX TRAX 3 and includes built-in spectral editing capabilities, including a harmonic selection tool, to help optimize your separations even further for producing professional quality results. ADX TRAX Pro 3 is also currently available only for macOS. A number of powerful spectral editing tools are included with ADX TRAX Pro 3. I should point out that ADX TRAX 3 and ADX TRAX Pro 3 are both excellent at separating the lead vocal from harmony vocals and both now allow you to import MIDI as a pitch guide!
Audionamix had added two new products to their ADX TRAX family, ADX TRAX 3 SP and ADX TRAX Pro 3 SP. ADX TRAX 3 SP adds speech separation capabilities with Automatic Speech Targeting, Automatic Consonants Detection, New Automatic Extraction Options, and a Speech-Optimized Pitchogram. ADX TRAX Pro 3 SP adds all of these new features and also includes the spectral editing tools found in ADX TRAX Pro 3, making it the most comprehensive set of tools for separating your content.
Audionamix introduced their Vocal Volume Control (VVC) plugin, now up to version 3, which is available for macOS and Windows with support for VST, Audio Units and AAX 32-bit formats. Like other ADX products, the ADX VVC 3 plugin uses Audionamix's cloud-based computing to do the heavy lifting.
Audionamix has also introduced their Speech Volume Control (SVC) plugin, which is optimized for separating speech. This can be useful with source material that contains a mixture of spoken dialog and other background content.
Audionamix recently updated their XTRAX STEMS application to XTRAX STEMS 2. XTRAX STEMS 2 is a cloud-based application, available for both macOS and Windows, which takes a mono or stereo source and separates it into three stems: drums, vocals, and the remaining music. Although XTRAX STEMS 2 provides three algorithms for you to use for the best results, there are no other provisions for refining the separations. For that, you can easily export the separated stems and refine them in one of the ADX TRAX family of applications, or other spectral editors. XTRAX STEMS 2 produces the separated stems in an astonishingly short amount of time... literally minutes! It is very affordable and makes an excellent addition to your audio toolbox!
Acoustica Premium Edition 7, from Acon Digital, is a reasonably priced application which includes spectral editing capabilities with harmonic tracking. The spectral editing capabilities, available only in the Premium Edition, include brush, freehand or magic wand selection tools. Acoustic Premium Edition 7 is available for both macOS and Windows.
Another inexpensive spectral editor worth considering is the newly updated iZotope RX 7 Elements. iZotope RX 7 Elements includes the important Harmonic Selection Tool as well as the revolutionary intelligent Repair Assistant which can detect noise, clipping, clicks, and more, and then offer different processing options to repair your content. It also offers Voice De-noise, De-clip, De-click, and De-hum tools.
The new iZotope RX 7 Standard and iZotope RX 7 Advanced applications offer very comprehensive suites of tools which are well designed... powerful, yet easy to use. They both offer sophisticated spectral editing capabilities including the important Harmonic Selection tool. Both also include the revolutionary new Music Rebalance module which uses machine learning to allow you adjust the levels of the vocals, bass, percussion, and the remainder, independently!
In addition to harmonic selection capabilities, the spectral editor in WaveLab Pro 9.5 includes a new Wavelet display for a more accurate visual representation of the musical content, as well as Patent-pending Audio Inpainting technology to recreate and/or replace corrupt audio material by logically using the spectral information of the surrounding area.
DeMIX Essentials, from AudioSourceRE, is an easy to use sound source application which allows you to quickly separate vocals, drums, and other instruments from mono or stereo source material. DeMIX Essentials includes a built-in mixer which allows you to hear your separated tracks in the context of a stereo mix. DeMIX Essentials is available for both macOS and Windows.
DeMIX Pro, also from AudioSourceRE, is a powerful application which includes advanced sound source separation capabilities as well as a built-in full-featured spectral editor. DeMIX Pro includes cutting edge automatic drum and vocal separation capabilities as well as a unique Melody Editor which allows for guided vocal and instrumental separations, even in the presence of harmony vocals and other instrumentation. DeMIX Pro includes a built-in mixer which allows you to hear your separated tracks in the context of a stereo mix. DeMIX Pro is available for both macOS and Windows.
ACID Pro Next, from MAGIX, is the world's first DAW with built-in zynaptiq® STEM MAKER audio source separation technology. According to MAGIX, "Algorithms based on deep learning, as well as patent pending DSP algorithms split your tracks into vocals, drums and music, so you can use these results in your own music and remixes." Denis Goekdag, CEO of Zynaptiq, indicates that "ease of use is maximized with this one: you just tell the thing to DO IT and that’s that, no parameters, no manual selection"!
Deezer Research recently introduced Spleeter, a free open-source Python library based on TensorFlow that makes use of deep learning to perform state-of-the-art source separation on your mono or stereo audio and provides 2, 4, or 5 stems in return. Spleeter is a command line tool with no GUI (graphical user interface). Those wishing to make use of Spleeter, but are wary of installing and using a command line tool, may wish to try Moises which provides a web-based service for Spleeter. Moises is currently available free of charge. Two other web-based services for Spleeter are Ezstems and Splitter.
I should point out that results with any of these applications are still highly dependent upon the source material used. Higher quality sources that are not highly compressed and contain fewer sound sources are easier to separate, and help produce higher quality, more pleasing stereo mixes. There are countless mono recordings that can benefit from being upmixed to stereo through the use of this technology. As the applications continue to improve and additional automation is added to the processing, the amount of time and effort needed to produce professional level results will decrease.
Please understand that I can't guarantee the quality of the results with any of these applications. It is important for the user to evaluate the applications themselves to insure that they will meet their needs. I highly recommend trying the product demos prior to purchasing any software.
I will update my recommendations as new applications and additional new features become available. Your questions and comments regarding this technology are always welcome. Please feel free to email me at firstname.lastname@example.org or use the contact form on the CONTACT page of this website.
Updated February 8, 2020