Music tracks can be the equivalent of noise, or they can be something more, if an engineer has competently mixed or arranged the sound elements. While even the best mastering software is just a tool, and cannot replace the skill of a professional, much can be said for using a good mastering app to edit the tracks. This can vary from a base program to a number of plug-ins. Red mastering uses the best paid tools in each such category, rest assured. But for those who have acquired some skills, but may be lacking in the budget department, the below examples of free and affordable tools can get the job done.
Equalizers M/S. Among the top freeware apps in this category are BaxterEQ by Variety of Sound, MQ57 by J1000, and NCL Phase EQ by matt42 (all three programs are in Windows). For equalizers that are linear-phase, there’s Marvel GEQ by Voxengo (Mac, Windows), ReaFIR by Cockos (Linux, Windows), and SplineEQ by Photosounder (Windows). Apps for dynamic equalizers include DuckEQ by HeelAudio (Mac), IQ4gui by Platinumears (Windows), or Smash Pro by Jeroen Breebaart (Windows).
Compressors. The best mastering software for free in this area (clean) are TDR Feedback Compressor II by Tokyo Dawn Records (Mac, Windows) or ReaComp by Cockos (Linux, Windows). Compressors for coloring include DCAM FreeComp by FXpansion (Mac, Windows), Density mkIII by Variety of Sound (Windows) and Molot by VladG Sound (Mac, Windows). Among multi-band compressors are 5ORCERY by Platinumears (Windows), Broadcast by Jeroen Breebaart (Windows), C3 Multi Band Compressor by slim slow slider (Mac, Windows), and ReaXComp by Cockos (Linux, Windows).
Limiters et al. Effects tools of this type include Barricade Pro by Jeroen Breebaart (Windows), Limiter №6 by VladG Sound (Mac, Windows), along with LoudMax by Thomas Mundt (Mac, Windows). Two saturation programs controlling for that factor are IVGI by Klanghelm Audio (Mac, Windows) and TesslaPRO mkII by Variety of Sound (Windows). Exciter programs include Thrillseeker XTC by Variety of Sound (Windows) and You Wa Shock ! by Image Line (Windows).
Other programs provide help for miscellaneous effects like clippers, transient shapers, M/S, spectrum analyzers and mastering suites, among other functions. Use of these applications can help one ‘master’ their mastering and mixing skills and familiarity with such software, until they may move on to better paid programs. In the meantime, freeware like BaxterEQ, TDR Feedback, Density mkill , Limiter etc will more than get you by.