Techniques are described of efficiently identifying sets of audio parameters to be applied during a time frame. For example, a list of indicators may be generated. Each of the indicators in the list may indicate a Musical Instrument Digital Interface (MIDI) voice present in a MIDI frame. Furthermore, in generating the list, the indicators in the list may be restricted to those indicators that indicate the most acoustically significant MIDI voices in the MIDI frame. After the list is generated, a digital waveform may be generated for each of MIDI voices indicated by an indicator in the list. A combination of the waveforms of each MIDI voice may constitute an overall waveform for the MIDI frame.