• Oatmeal v37-6b - Two-oscillator subtractive synth. [VST]
• Obie Editor v1.1 - Patch editor for the Oberheim Matrix 1000
• ObjektSynth 2 - A real-time, multi-timbral, modular synthesizer - like a traditional analog synthesizer.
• Ocarina Composer 1.6 - Create tablature music for your ocarina.
• Ocean Waves v1.4 - Generate the sound of ocean waves.
• Octav8r v1.0 - 7-node pitch-shifter that generates 6 differently pitched stereo versions of the audio input. [VST]
• Octave Shifter v2.0 - Real-time pitch shifter. [AU]
• OctoDel - Simple delay/echo [VST]
• OctoEcho v1.0 - Array of eight delay units. [VST]
• Octopus v1.2.1 - Dual-Matrix synthesizer. [VST]
• Octopus v1.2.2 - Dual-Matrix synthesizer. [AU/VST]
• Oddity - The Oddity is modeled on the classic ARP Odyssey.
• Oddity - The Oddity is modeled on the classic ARP Odyssey.
• Oddity - Modeled on the classic ARP Odyssey. Go to the full commercial version of Oddity
• Oddity AU - The Oddity is modeled on the classic ARP Odyssey.
• offZET v1.2 - Offset sample streamer for live acts and improvisation. [VST]
• Ogg Drop v1.0b5 - AIFF, AIFC, CDA, QuickTime and System Sound files to OGG
• OGG Encoder Decoder 1.2.8b - Encode WAV and MP3 to Ogg Vorbis, decode to WAV
• OGG Encoder/Decoder Control v1.3 - Encodes audio to OGG files and decodes OGG.
• Ogg Vorbis Encoder 1.0b4 - Encoder for the latest compressed audio format
• Ogg Vorbis Encoder 1.0b4 - Encoder for the latest compressed audio format
• Ogg Vorbis Win32 SDK 1.0rc2 - Source Code / Development Tools for Ogg Vorbis
• Ohmicide : Melohman v1.0.1 - Effects Suite. [VST/AU/RTAS]
• Ohmicide : Melohman v1.0.1 - Effects Suite. [VST]
• OhmzBoyZ VST - VST Predelay with resonat filter, distortion and high shelf
• Okoker All To Mp3 Converter v2.6 - Convert all kinds of Video and Audio files to MP3, WAV and WMA.
• Okoker Audio Factory v3 - Record, edit, mix, convert, cut, and join audio files and create special effects.
• Okoker CD to Mp3 v1.5 - Rips a CD to MP3.
• Okoker Mp3 Splitter v2.6 - Splits MP3 files.
• Okoker Mp3 to CD Burner v1.7 - Burn your mp3 files into an audio CD.
• Olga v1.0 - Virtual analog synthesizer. [VST]
• omb 1.2 - Real-time autoaccompaniment system
• OMeR 1.6 - Optical Music easy Reader for Windows
• OMeR 2.0.1 - Optical Music easy Reader for Macintosh.
• Omnisone v1.05 - Spatial image processor. [VST]
• Omniverb v2.0.1 - Reverberation plugin. [VST]
• OnAirRecorder v1.7 - Digital timer, provides ability to control audio/video recording.
• One Click Ringtones v1.01 - Turn MP3's into ringtones.
• One Man Band v10.0 - Arranger with real time chord recognition.
• One-2-Five music theory e-tutor - Complete music theory covering 5 grades
• One-click Audio Converter v3.13 - Converts multiple audio files (MP3, WMA, WAV, OGG) right from Windows Explorer
• One-click CD Converter v1.5 - Converts CD audio to WAV, MP3, WMA, OGG, APE, FLAC files with one click of mouse.
• One-click CD/DVD Writer v1.3 - Burn data/audio CD and DVD with one-click.
• One-click Multimedia Jukebox v1.3 - Multimedia Jukebox.
• One-click Ringtone Converter v1.10 - Transforms music files of all popular formats to polyphonic ringtones.
• One-click Tag Editor v1.2 - Edit MP3,WMA,OGG tags from Windows Explorer.
• OnePingOnly beta 1 - A VST virtual synth
• OnePingOnly beta 1 - A VST virtual synth
• OneShot Recorder v1.1 - Record/sample, normalize, reorder, detect MIDI note and save/export your audio stream automatically. [VST]
• OneShot Recorder v1.1 - Record/sample, normalize, reorder, detect MIDI note and save/export your audio stream automatically. [VST]
• OneshotRecorder 1.41 - A simple Macintosh audio recording application
• OnLineLive - Lets you watch 850+ free Internet TV and listen to 1500+ free online radios stations.
• OnStage Performer - Live Playback Software For Music
• Onyx Arranger v2.1 build 202 - Advanced arranger/ sequencer with flexible real-time control for pro and amateur musicians
• Onyx Arranger v2.1 LE (Lite Edition) - Arranger/sequencer with real-time control.
• OOBOX iTuner v2.02 - Guitar Tuner.
• Open Sound World v1.2.7 - Graphical programming environment for real-time music and audio applications.
• Open Sound World v1.2.7 - Graphical programming environment for real-time music and audio applications.
• Open Tuning v1.5.1 - Virtual tunings for all MIDI or MIDI-fied instruments.
• Open Video Converter v3.0.1 - It is an easy-to-use tool for video conversion, splitting and editing.
• Open Video Joiner v3.0.3.062 - It joins all kinds of video files into a large avi file with transition effects.
• OpenNap 0.44 - OpenNap extends the Napster protocol to allow sharing of any media type
• OpenSebJ Beta v0.41 - Real-time audio sample DJ Mixing.
• OPL4 - FM Synthesis OPL4 Midi Device Driver
• Orange Metronome - Digital audio/visual metronome and rhythm trainer/companion
• OrangeCD Catalog v6.2.1.12131 - Music database software for cataloging your music collection in all formats
• OrangeCD Player v6.2.1.12131 - Taskbar-based CD Player.
• OrangeVocoder 2.02 - Perhaps the fastest, most flexible and most transparent sounding simulation of an analog vocoder effect as a VST plug-in
• OrangeVocoder 2.0X - Standalone simulation of an analog vocoder effect
• Oratorio 1.5 - Music library and a presentation package for church services
• Oratorio 2.0 beta 1 - Music library and a presentation package for church services
• OrbEdit - Patch editor for the E-mu Orbit family of sound modules
• orDrumbox v0.7.05 - Audio sequencer and Software Drum Machine
• orDrumbox v0.7.05 - Audio sequencer and Software Drum Machine
• orDrumbox v0.7.05 - Audio sequencer and Software Drum Machine
• Organ One v2 - 16 voice virtual organ. [VST]
• Organ v3.0.2 - Organ emulation. [VST/AU/RTAS]
• Organ v3.0.2 - Organ emulation. [VST]
• ORGANized trio v3.1 - ToneWheel organ simulator. [VST]
• Organizer MP3 v4.51 - Create MP3/CDs in 15 minutes.
• Organux v1.0 - Virtual organ plug-in. [VST]
• Orion Platinum v7.1 - All-in-one music making suite - Multitrack recorder, VST/DX host and more.
• Orion Pro v7.0 - A virtual music studio suite.
• Oront Burning Kit 2 Premium v2.5 - Application for burning, managing and erasing major types of CD and DVD.
• Oront Burning Kit Basic v2.5 - Application for burning, managing and erasing major types of CD and DVD.
• Orz v0.3 alpha - Modular synthesizer. [VST]
• OS/2 sound sample - OS/2 sound sample player through speaker
• OSC321 rc03/08/11 - Free 3 oscillator VSTi.
• OscillaStation v2.08 - Complete music recording, composing, performing and production system. Supports VST.
• OscilloMeter v5.57 - Real-time oscilloScope & spectrum analyzer.
• Osiris XT v1.0 - Dual wave file player / synthesizer. [VST]
• OSS Audio CD Maker v3.0.0.1 - Burn MP3, WAV, WMA, OGG files to music CDs.
• OSS Audio Converter Pro v5.6.0.5 - Convert audio formats from one to another.
• OSS Audio Converter v6.0.0.4 - Convert audio formats and record them.
• OSS Audio Extractor v5.6.0.5 - Extract audio from video files.
• OSS CD Ripper N' ID3V2 Tag Editor 2.2.0.3 - Rip CD audio tracks to WAV,OGG,MP3 and WMA.
• OSS Media Converter Pro v5.6.0.2 - All-in-one Video & Audio Convert & Decompile.
• OSS MP3-WAV Converter - MP3 to WAVE Decoder & Converter.
• OSS Video Converter 5.5.0.4 - Powerful & Easy Video Files Converter.
• OSS Video Decompiler v5.5.0.4 - Powerful & Easy Video File Decompiler.
• OSS/3D for XMMS - Provides sound card drivers for most popular sound cards under Linux
• OSS/3D R7 for All Popular Players - Audio Enhancement plugin with tons of features, supports all popular sound players
• otodidoto v1.0 - Auto MP3 DJ.
• Ots CD Scratch 1200 1.00.014 - The Ultimate Virtual Turntable Experience.
• OtsDJ v1.75.008 - CD/MP3 Radio and DJ software.
• OtsTurntables Free v1.00.012 - OtsTurntables -- The hottest MP3 mixer on the planet.
• OttoPhilter v1.2 - Autofilter effect. [AU]
• OttoPhormant v1.1 - Wah effect [AU]
• OttoVibe v1.1 - Auto/touch effect with MIDI control. [AU]
• Ouroboros v0.5 - Sample player that hosts AudioUnits.
• Out Of Phase 1.3 - A software music synthesis package
• OUTI v2.0 - A real-time loops player. Supports VST plug-ins.
• OUTI v2.1 - A real-time loops player. Supports VST plug-ins.
• Overdub v1.0.26 - Record voiceovers or overdub tracks quickly and easily.
• OverDubber v1.7.4 - Two tap delay focused towards Dub creation and Live use. [VST]
• Overnet 0.51.2 for MacOSX - Share files with millions of other people across the globe.
• Overture v4.01 - Professional standard notation software.
• Oxe FM Synth 1.1.2 - FM software synthesizer.
• OxyWaveZ Bazzoid v2.25 - Electric bass synthesizer. [VST]
• OxyWaveZ Live 2.15 - ASIO real-time effects processor and recorder for guitarists and singers.
• OZAB 1.5 - View and search Olga Zipped Archive files
• Ozone 2 v1.0.1 - Distortion plugin based upon the original free Ozone. [VST]

Don't forget to check out the full range of Shareware music programs available here on Shareware Music Machine - the World's biggest music software site.