Sampling frequency : Frequency with which the audio signal is divided into samples, that is into numerical values. The frequencies are expressed in Hertz, whose symbol is Hz. Audio CDs, for example, are sampled at 44100 Hz. The sampling frequency affects the quality of the audio signal, the higher the smapling frequency the better the quality. But the sampling frequency affects also the performance of PCs, the higher the sampling frequency, the higher the PC must make calculations.
MIDI Device : Software embeded in the operating system of the PC (ie Windows) to make the interface between application softwares like Canta and sound restitution of MIDI files with a sound card. On the same machine, with a single sound card, multiple MIDI devices can be installed. The selection of one or the other must be made by the user depending on the results obtained.
MIDI : Acronym meaning "Musical Instrument Digital Interface", it is a standard of music information transmission by network between machines (synthesizers, keyboards, computers, etc.) or by file.
Spectrum : It is the decomposition of a signal, in this case your voice, as does the human ear, into a sum of simple signals of different frequencies. You will notice that for the same note sung, this spectrum can take different forms with bumps of different heights depending on the vowel sung or the pronunciation. The spectral shape is closely linked to the timbre of the voice.
Octave : The human ear perceives two notes of double frequency of each other as similar. This double frequency interval is called an octave. The notes an octave apart have the same name. To differentiate them, they were assigned a number. For example, the correpsond A4 Hz to 440, A3 to 220 Hz, A2 to 110 Hz, A5 to 880 Hz, and so on. By convention the number octave changes with C notes, ie that all notes between a C and the C one octave above have the same octave number.
Fondamental : Musical sound and the voice are harmonic sounds, ie they are composed of a multitude of elementary sounds, sinusoids, whose frequency is a multiple of a common value called the fundamental ferquency. The human ear can recognize this fundamental and what gives us the opportunity to recognize the pitch of a sound, to identify the emotion in the voice spoken or sung, and to appreciate the music.