Insert a compressor onto the track containing the sound you want to bring to the front of a mix. Depending on your mixing setup, this can be done using a software compressor plug-in or a hardware compressor unit.
Set the threshold control of the compressor so that the level passes the threshold during loud portions of the audio, but stays below the threshold during soft portions of the audio. When the level of the sound passes the threshold, the compressor will turn on. When the threshold is set correctly, it will turn on during the loud passages and stay off during the soft passages.
Select the compression ratio depending on how much you wish to compress the sound in order to allow it to sit at the front of the mix. For instance, a ratio of 4:1 will only allow the sound to increase 1 decibel in volume for every 4 decibels it goes above the threshold. A low ratio will deliver more natural compression results while a high ratio will deliver more aggressive compression results.
Adjust the attack and release controls on your compressor to select how quickly the compressor turns off and on once the threshold has been crossed. A short attack time will allow the compressor to turn on more quickly, while a long attack time will allow the compressor to delay shortly before turning on. Similarly, a short release time will allow the compressor to turn off more quickly after falling below the threshold, while a long release time will allow the compressor to delay shortly before turning off.
Adjust the output gain of the compressor to make up for the gain lost through compression. For instance, if the compressor is reducing 6 decibels during the loudest sections, increase the output gain 6 decibels to make up for this loss. This will raise the volume of the quieter sections while keeping the louder sections at approximately the same volume they were before.