Use a demonstrative pronoun only if the connection to the intended antecedent of the pronoun is quite strong. Otherwise, your pronoun reference may be too broad, thus unclear.
The sophisticated computer sound system lets the user input pitch and duration
from the MIDI keyboard. This facilitates musical
transcription.
[Does this refer to the sophisticated computer
sound system, to letting the user, or to the inputting of pitch and
duration?]
Sophisticated computer sound systems let the user input pitch and duration
from the MIDI keyboard. This direct input facilitates musical
transcription.