Monitoring rooms or control rooms have one main objective at the monitoring position. The acoustic goal is to hear every vocal and instrument in the recorded mix without hearing any control room sound. They are continually striving for accuracy. If they can hear everything in the mix, they are better able to make parts do this or that which will hopefully add to the final sound quality in some form or fashion. Whatever ends up on the compact disc is a balance between the original vocals and instruments along with some engineered effects by the producer/engineer. Even the compact disc has a sound of its own.
Near Field Monitoring
To accomplish this critical level of listening, the engineer will sit in a near field position. He will sit in a small triangle with both left and right channel monitors and the monitoring position as the indices of the triangle. The triangle will be small and the left and right channel monitors will usually sit on the back edge of the mixing board or on freestanding stands set behind the board. The engineer by sitting near field will hear the direct sound from the monitors before he can hear any side wall reflections. The side, rear, and ceiling all produce reflections or to the engineer distortion. These room surface boundary reflections are termed “room sound”. The engineer does not want to fight through these distortions while mixing.
Comb Filtering From The Board
The engineer must also deal the comb filtering effect of the board itself. Energy from the monitors does strike the board and reflect back into the engineer’s ears and then is laced with the direct sound from the monitors. Since reflected sound energy is delayed because of longer traveling times, the engineer gets this board reflection or comb filter effect. This blending if you will of both direct and reflected energy, once again contributes to room sound or should we say board sound at the monitoring position.
Smaller Monitors Are More Accurate
Speakers or monitors do just that, they monitor each sound and try to duplicate as closely as possible the live or recorded music and vocals. Monitors usually have smaller diameter drivers, which contribute to better sound monitoring efforts. Smaller diameter loudspeakers are more accurate and produce a more detailed and distinct sound for every vocal and instrument source played back through them. This detail in presentation goes right along with the major mixing theme of hearing everything in the mix and being accurate.
Playback – Sit back
In playback of our recorded music, we try and achieve a different objective. We want to sit in a farther field than the near field set up of the professional. Our sonic goal is to hear everything in the recorded playback source provided we acoustically treat our playback rooms to accomplish this task, but we want to hear it with a much larger sound stage than a near field generated one.
We want our playback presentation to acoustically extend past our playback speakers both left/right, top/bottom, and back/forward. Our goal is to bring the stereo image in the recorded source and push air and space into it, so it sonically appears life like. Room sound is not necessarily a bad thing in playback mode as long as it is controlled through acoustic room treatment. We sit in a triangle, but it is a larger triangle and we may stray a little this way or that way from center positions depending on our room dimensions, listening position and our speaker sizes.
Most playback systems want to be able to project their sound stage into a larger area than near field space. If our sound stage is to portray real size instruments and vocals, we will need larger driver sizes in our speakers to produce the energy required for a realistic sound stage presentation. Hi – Fi speakers can have multiple arrays of speakers and come in floor standing versions. A monitor speaker in the professional world would be called a book shelf speaker in the hi-fi world.
Room Friendly In Playback Mode
The room in our playback presentation must have its acoustical negatives treated, so that we can hear every instrument and vocal on our new playback sound stage. We want to use the room to create our sound stage not eliminate it as in the control room mixing position. We want to control side wall reflections and reduce their impact at the listening position, so we achieve a nice balance between direct and reflected energy at the listening position. We want some controlled room sound in our presentation.
Properly controlled side wall reflections will enhance the width of our sound stage presentation The ceiling reflections must also be reduced and minimized at the listening position using a blend of diffusion and absorption. Proper diffusion and absorption treatment on our ceilings will make our ceilings acoustically disappear and extend the height of our playback sound stage. Rear and front wall acoustical diffusion and absorption will lend new depth to our sound stage presentation in the playback mode.
It is amazing that in the music/vocal source recorded creation, we are striving for recording accuracy. We need to hear everything, so we can add this or that artifact to make the recording sound better. Accuracy in data with no room sound is the goal. In playback presentation of this recorded source, we want to throw the source music into the room and try to achieve a more life like sound stage where every vocal and instrument is heard and “seen”. We want and need the room in our total sound presentation, if it will behave itself and take its acoustic treatment medicine.