Open your preferred digital audio workstation, or DAW. For example Cubase, Pro Tools or Mixcraft. The last saved project opens automatically. If this isn't the correct project, click "File" and select "Open Recent." Select the relevant project from the drop-down menu.
Solo the tom-tom drum audio. Typically tom-tom drums are recorded one drum per channel, so the amount of channels you will work with depends on the amount of drums on the kit. To solo the channel, click the "S" logo on the left of the channel strip. Soloing mutes everything else, so you can hear the tom-tom drums in isolation.
Adjust the low frequency band on the equalization section of the channel strip. The size of the equalizer interface depends on which DAW you use. For example, in Mixcraft there are three dials: "Lo," "Mid" and "Hi." Turn the dial governing the low frequency to the left to increase the gain of the frequency. By increasing the gain of the low frequency band, you boost and enhance the low sounds present in the drum. Repeat this step for each tom-tom drum.
Click "Effects" and select "Compression." This opens a separate compression interface. Compression is a dynamic effect that boosts the low volumes and cuts the high volumes to temper peaks and dips in the audio. By cutting the peaks, you can afford to raise the overall volume of the tom-tom drums. Since equalizing them boosted the low end, by boosting the volume you enhance the overall low end in the mix.
Adjust the "Threshold" parameter. Threshold dictates the volume level at which the compression kicks in. The right level depends on the original volume that you recorded the tom-toms at. Adjust it by ear. If the drums become "fuzzy" the threshold is too high. Aim to set it as high as possible before the fuzziness kicks in.