Open your preferred digital audio workstation and import the song you will use to host the sound effects as well as the sound clip itself. If you do not own a digital audio workstation, programs such as Cubase, Record, and ProTools utilize audio multi-tracking tools that allow users to manipulate and choreograph any number of individual audio tracks.
Download the free sound effect as a .WAV or .AIFF file and copy it to a disc or flash drive for use with a hardware multi-track device if you do not wish to use a digital audio workstation for your editing tasks. Check the specifications of your hardware device to determine which method of storage (i.e. CD or flash media) is most conducive for transferring audio. Open both files on your recording device.
Determine where exactly you would like to place your sound effect. If your sound effect is acting as a substitute for audio in the song, cut out the precise duration from the original song file in the exact location you will place the sound effect using the cutting tool within your software or hardware. Move the sound effect into place with your selection device.
Adjust the strength of your sound effect using the audio mixer volume tools within your workstation. If your sound effect is replacing a section of audio in the original song, match the volume of the effect to the music surrounding it. If you plan on playing the sound effect concurrently with the song, balance the strength of the sound effect with the music, ensuring that the material you consider to be of primary importance is loudest in the mix.
Change the position of the sound effect within the stereo field using the "pan" tools with your software or hardware workstation. When listening carefully to commercial recordings, you will notice that certain elements of the music or song play primarily in the left or right speaker. This geographical assignment of audio helps establish priority and dominance with the mix. If you turn the physical or virtual "pan" knob to the left, any audio assigned to that control parameter will mostly play through the left speaker, When turning the "pan" knob to the right, a similar, matching effect occurs. Placing the pan "knob" in the center setting allows the audio clip to play through both speakers at equal strength.