Some partials that would normally be played are omitted from the synthesis. There are two ways to specify which partials to drop: by partial index number or by frequency. (Partial index numbers start at 0 and are expressed as integers; frequencies are in Hertz.)
| Message | Argument(s) | Type(s) | Description |
| min_index | Minimum partial index to be heard | Int | Default is 0. When this is higher than 0, the lowest-numbered partials will be silent. |
| max_index | Maximum partial index to be heard | Int | Like min_index only different. |
| min_freq | Minimum partial frequency to be heard (Hertz) | Float | Partials with frequencies lower than this number will be silenced. |
| max_freq | Maximum partial frequency to be heard (Hertz) | Float | Partials with frequencies higher than this number will be silenced. |
| normalize | 0 for "no", 1 for "yes" | Int | Whether to normalize overall energy when dropping partials. If yes, then when partials are dropped, the amplitudes of the remaining partials will be increased by an appropriate amount. |