Separation In Mix – Top Priority
Separation in our recordings is one of the measures we use when we evaluate a recording’s quality level. With good separation in our recordings, we can hear every vocal and instrument in the recording. There is a distinct beginning and end to every vocal and instrument and even if both are recorded together, we can hear them as separate. This is what we refer to in the recording business as a clean recording.
Dynamics, Frequency Content, Pan Position
There are three factors that make up separation: dynamics, frequency content, and pan position. Dynamics refers to the attack and decay rate and level of the vocal or instrument. This dynamic ratio must be kept in balance by the engineer through mike placement and controlling room sound. A vocal must operate in its own dynamic range and the engineer must be able to apply this dynamic range in a consistent and predictable manner through the recording. One solution is to control these dynamics using compression.
The frequency range of the instrument can have a impact on separation. If you have an instrument that produces high frequencies, you can make the instrument “move” around from front to rear in the mix. If you trim some frequencies off the top end, you can reduce the immediacy of the instrument in the mix. Every signal or wave form has its place in the mix and assigning that place is critical especially when it comes to frequency response. Finding that one place where the interplay of the instrument or vocal needs to be in balance to all other sounds around them is both a blend of art and science.
Pan position is image movement across our sound stage with the turn of a button. In a mono recording of our overhead miked drum set, we have the snare,tom, and bass drum all in a bunch in the middle of our sound stage. Panning can move instruments and vocals from left to right electronically. This ability can provide immediate separation to the signal. Match the frequency responses of the instruments and lace them together, each with their own separation in place.
Separation In Room Acoustics
Separation in our recordings has the same meaning in room acoustics. It also has dynamics, frequency content, and even pan position. Room dynamics are defined by a room’s ability to produce dynamics. Room size and volume is critical to a good start. Resonance control is a must for all low and middle frequencies if any dynamics are to be able to be produced. Dynamics require head room and we must lower the noise floor of our room in order to make room for these dynamics. We must control and manage all low frequency issues.
Real Low Frequency Absorbers Needed
To do this, we must use low frequency absorbers that have the necessary rates and levels of absorption to really control low frequency resonances within the room. We must use powerful absorbers to deal with +20 Db. energy bumps within the room. Resonances are like thick maple syrup in our mixes and they can blurr or smear, sometimes both, sound energy in the vocal range. Room resonances can destroy low and middle mids with room coloration and no amount of EQ will take those resonances out.
Room Reflection Control
Reflection control is also necessary within the room coupled with lower reverberation times if we are going to have dynamics. Lower reverberation times and reflection control will add to the room’s dynamic range. Reflection control will allow for a more direct sound from the source to dominate, and thus allow for greater dynamic clarity and “room”. Lower reverberation times will allow for all the harmonics within the dynamic range to be heard.
Room Frequency Response
The frequency response or content of our room is critical to anything that goes on in the room from recording to playback. First, we must focus on the low frequency frequency response ability of our room. Will the room reproduce 30 Hz. energy without over powering everything else. Structurally, we need a single room dimension to be at least 30′ to be flat down through 30Hz. Since most rooms do not occupy that much real estate, we can achieve low frequency separation in our rooms using powerful diaphragmatic absorption.
Pan position is something we can have a little fun with. Panning is done in the digital domain in our recordings but it can be done in the analog domain of our rooms. using sound absorbing and sound diffusion technologies, one can actually move the image around the sound stage in front of the listening position. If you treat the left side primary wall reflection surface area with absorption technology such as acoustical foam, and the right channel side wall reflection with diffusion technology, you can move the image across the sound stage.
One can make the room seem larger by using sound diffusion on the front and rear wall. Just as in the digital domain with panning, we can move the image front or back in the “mix” by moving sound diffusion around on the front and rear walls. We can add depth and length to our sound stage presentation within our room by using the correct balance of vertical and horizontal diffusors on our front and rear walls. Our ceiling can be made to acoustically disappear by using the correct blend of vertical and horizontal quadratic diffusion laced with a balance of sound absorbing acoustical foam.
Separation in our mixes is the chief component one uses initially to tell a good mix from a bad mix. Without good separation in your mixes, no one will consider them for any further evaluation. Separation includes dynamics, frequency response, and pan control and all of this is done in the digital domain. We can achieve separation in our rooms just like we do in our mixes by controlling resonances, so dynamics can come into play. A room with a good frequency response will allow for all sounds to be heard without spreading any room stink on any frequency group within that frequency response. We can even “pan” vocals and instruments across left to right on our sound stage by using and moving sound absorption and diffusion technologies around on different room wall surfaces.