https://manual-audacityteam-org.translate.goog/man/faq_recording_troubleshooting.html?_x_tr_sl=en&_x_tr_tl=es&_x_tr_hl=en&_x_tr_pto=wapp#Why_do_I_get_only_a_flat_line_and_no_sound_when_I_try_to_record.3F