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Audioworks Sound 2MIDI

Audio-to-MIDI Conversion Software
Published January 1997

The first software release from AudioWorks offers hope to MIDI musicians with limited keyboard skills. Sound2MIDI lets PC users record note‑perfect sequences, using only a soundcard and a microphone. Dominic Hawken sings for his supper...

Phil Collins had a dream. Three years ago, blessed with a love of the recording studio, an in‑depth knowledge of computer systems, and a complete lack of keyboard skills, he decided to turn his dream into reality. Driven by a desire to record compositions without having to develop the necessary playing skills, he recruited a programming team capable of developing a system that could record his singing voice and automatically convert the audio signals into MIDI note data.

Three years on, the first AudioWorks product has finally hit the streets. Philip Collins — at pains to distance himself from his multi‑million album‑selling namesake — is now a company director, and the future is looking groovy. Two major projects are currently underway — a noise removal system to rival Sonic Solutions and the other pro‑based alternatives, as well as the Sound2MIDI system currently on offer. Both were originally intended as hardware systems, but during their extended development time, as off‑the‑shelf computing power increased, it soon became apparent that they could be released as software products that could run on a stand‑alone PC.


Sound2MIDI is designed to work with any PC running Windows, including the latest Windows 95 update. A comprehensive setup routine automatically backs up any previously installed files, and generally takes care of most of the common problems associated with bad installation software. Once run, the program adds a new MIDI input driver that can then be selected by a Windows‑based sequencer as the instrument source. It also installs the Sound2MIDI Control Panel, which can then be optimised to suit your current hardware configuration and operating environment.

The software interfaces directly with a sequencer or scoring package — the review copy was tested with Cakewalk Pro Audio v4.01. Two operational modes are provided, 'synchronous' and 'asynchronous', in an attempt to interface with as many systems as possible. Products that support asynchronous mode (where the time‑stamp of the incoming MIDI is recorded, rather than re‑generated internally) generally work best, although Sound2MIDI automatically buffers and delays incoming signals to compensate for any timing deficiencies that might occur with synchronous products. Sequencers currently recommended by AudioWorks include the latest versions of Cakewalk, MidiSoft, Musicator, Encore and WinJammer.

The software works by analysing the audio sent to the input of the PC's soundcard. The programming algorithms quickly detect the waveform of the signal, determine the current pitch and note lengths of the incoming sound, and then convert this information into MIDI data. Selecting Sound2MIDI as the current MIDI input device allows your sequencer to record the resulting MIDI information as if it were sent from a master controller — no keyboard skills required! It is also possible to import WAV files, and process these as though they were live audio. In this way, you can load up a previously‑recorded take, and automatically replay the part with a new MIDI‑based sound as if the sequencer had performed the original.

Setting Up

Sound2MIDI installs with a basic default configuration designed to work with most PCs without alteration. The Control Panel automatically links with your current soundcard mixer utility, and to get the system up and running, all that is usually required is careful setting of the microphone input level, which is done by checking a level meter on the left of the screen. Power users can optimise the system by adjusting three main sliders that alter the sensitivity, detection threshold and sustain settings — see the parameter box for a detailed description. As well as detecting pitch and note durations, Sound2MIDI can also be used in 'rhythm' mode to create complex percussion tracks. Under these settings, the software ignores pitch information, but tracks volume, dynamics and timing, and sends out the MIDI data on a single note that can be defined in the setup menu. This is great for generating programmed versions of drum loops — with any subtle timing nuances remaining intact — or for triggering a MIDI gate in time with a previously‑recorded audio track.

In Use

The software installed without a hitch and actually worked first time. It is a very strange feeling to sing a phrase into a basic microphone (in this case connected to a Creative Labs AWE32 soundcard), and then hear the same phrase immediately played back, note‑perfect, with a piano sound! After more experimentation, and careful adjustment of the sensitivity control to remove any spurious notes generated by the high level of background noise in my room (hard drives clanking and the like), it was possible to record complete multitracked performances with very little editing and correction. Admittedly, some odd notes did creep in along the way, but it has to be said that these were more likely down to my lack of singing prowess rather than any particular fault of the software! The program identified incoming audio signals very quickly, and time‑stamped them accurately, so that the synchronisation between different tracks remained consistent.


All in all, a very pleasant surprise. Sound2MIDI actually does detect pitch information, and converts audio into MIDI note data. Admittedly, it is only capable of working accurately with a monophonic source — a voice or wind instrument is ideal — but some interesting effects can be obtained by feeding a wide variety of audio files into the system and recording the results. The concept of using Sound2MIDI to single‑handedly record an entire multitrack composition, though not impossible, remains a daunting one, but the software excels as a tool to record phrases and lines as they are heard by the user, without the need for any playing ability or a master keyboard. I look forward to the next release from AudioWorks with much anticipation.

SOUND2MIDI Parameters


This control sets the threshold below which low volume signals, such as background noise, will be ignored. The higher the value, the greater the signal required to register a MIDI note.


This controls the software's ability to detect the start and end of a note. Generally, the faster the music, the lower the figure required to accurately detect all of the notes.


When using a MIDI voice with a different attack and decay to that of the source sound, altering this parameter will sustain the edges of the note to make them sound more natural. The higher the value, the longer the sustain.

System Requirements

  • IBM or compatible PC with 486 66MHz or greater processor.
  • Windows 3.x or Windows 95.
  • Windows‑compatible 16‑bit soundcard with MIDI capability or MIDI out port.
  • PC sequencer or notation software supporting external MIDI input.
  • Minimum of 8Mb of RAM.


  • Works with any Windows‑based soundcard.
  • Easy to install and operate.
  • Good results with even the most basic microphone.


  • Only available for the PC!


Great utility for the Windows‑based musician.