Important Considerations before setting out on the journey of Realtime Audio to MIDI
Continuous MIDI output must be routed from MIDI Merlin to a destination MIDI device that generates sound. The outgoing data must travel over a hardware MIDI connection or a virtual software MIDI driver. Knowing how to configure the destination synthesizer and how it interprets the MIDI data streams are equally as important as correctly configuring MIDI Merlin’s internal tracking settings.
MIDI Merlin 2 functions best when its input signal is clean, monophonic, free of high frequency noise, and free of any ground hum (60Hz or 50Hz cycle noise caused by a ground loop in the electrical system). The tracking algorithm is exceptionally fast, but the user must be completely aware of the quality of the signal they are using as the input. As of the initial release of MIDI Merlin there are no correction filters added to condition the input signal. If there are any pitch tracking errors, there are only two possible reasons: no clean signal, or input pitch is below the lowest stable pitch according to the algorithm settings.
When using microphones with MIDI Merlin, it is very important to be aware of audio feedback. If a speaker is being used to monitor the sound of a destination synthesizer that is being controlled by a mic’d source, there is a great likelihood that the microphone may pick up the sound from the speaker (and ambience) which introduces polyphonic complexity to the input sound stream, which thereby causes the tracking algorithm to produce unpredictable results.
An important consideration for power users:
Conversion of audio data to MIDI data has been implemented many times in many audio software applications, but rarely does it occur in real-time. There are a number of variables that make the task very problematic and prone to producing very poor results. The approach MIDI Merlin takes is one of power and flexibility. If the user is a) provided with enough control of the defining parameters, b) educated on the limitations and tradeoffs of the configuration, and c) provided an efficient method of storing/recalling settings, then there will be a greater chance for a user to get good results. While there is a lot of power in the tracking algorithm, it is the responsibility of the user to know how to fine-tune the settings to achieve the desired result. MIDI Merlin will grow more useful the with time as you learn it, and experiment with different source and destination instruments.