The Art of Recording Chapter 5. Preliminary Stages: (under revision)

1 2 3 4 5 6 7 8 9 10 11

Bookshelf-type speakers are often used in the studio to provide a reference to this type of playback environment. They represent the typical, moderately priced speaker systems of most home listener's rooms. They tend to have a narrow frequency response, de-emphasizing high and low frequencies areas. These speakers are placed on the meter bridge of the console, about three to five feet apart. This is called near field monitoring. The sound is heard near the speakers, before the acoustics of the control room can act upon the sound.

Since the control room has very little influence on the sound quality of near field monitoring, this approach is often the exclusive monitoring system of control rooms that have poor room acoustics. Near field monitoring can be more accurate than many home systems. Certain studio monitor speakers have been specifically designed for near field use. These speakers are preferred over the large studio monitors by some recordists, especially during long sessions when the more intense energy of (some) large speakers may fatigue the hearing.

Figure 5-3. Loudspeaker Relationships to the Listening Environment and the Listener in Near Field Monitoring. (click on image for full size)

The size of the effective listening zone for near field monitoring is very small. The listener must be precisely centered between the two loudspeakers, and the listener cannot be beyond the distance from the two loudspeakers as they are from one another, or the effects of the room will come into play. The listener should be located approximately the same distance from each loudspeaker, as the two loudspeakers are from each other.

It is not unusual for recordists to periodically switch back and forth between room and near field monitors. This allows the recordist to evaluate the sound qualities and relationships of the recording from different listening locations and with loudspeakers that have different sound qualities. The recordist will be attempting to create a consistency between the sounds of the two monitor systems, in as much as this is possible. The speakers should be switchable at the mixing position; with each pair having a dedicated amplifier(s), set to match monitoring level while switching speakers.

Control room monitors also tend to provide much more detail of sound quality than near field monitors. This added detail allows for greater accuracy in critical listening applications.

The sound pressure level (SPL) at which the recordist listens will influence the sound of the project. Humans do not hear frequency equally well at all amplitudes. A recording created at a monitor level of 100 dB (SPL) will sound considerably different when it is played back at the common, home listening, monitoring level of 75 dB; the bass line that was present during the mixdown session will not be as prominent during the listening at the lower level. Similarly, the tracks that were recorded at 105 dB during a tracking session (because someone wanted to "feel" the sound), will have quite different spectral content when they are heard the next day at 85 dB, during the mixdown session.

The recordist will need to develop consistency of listening levels. Ideally, monitoring levels should be reasonably consistent throughout a project.

85-90 dB is widely regarded as the most desirable range for monitoring. Recordings made while monitored in this range will exhibit minimal changes in frequency responses (&Mac178;5 dB at the extremes of the hearing range) when played back as low as 60 dB SPL. Monitoring at this level will also do much to minimize listening fatigue, during prolonged listening periods (recording and mixing sessions).

The possibility of hearing damage is a very real job hazard for recordists. If the recordist primarily listens in the 85-90 dB range, they will have accurate hearing much longer than if they consistently monitor at a level 10-15 dB higher.

The recordist may need to be sensitive to how the recording being produced will transfer to other environments, and playback formats. Aside from the varying quality of home playback systems described above, the recordist may need to be concerned about the playback of a recording over radio, and in a mono format.

The targeted audience for some recordings may necessitate that the recordist be concerned with the stereo/mono compatibility of the recording. The recordist will monitor for this format, using a single-driver mini-monitor speaker, in the near field. This type of speaker is intended to simulate the listening conditions of a radio or an automobile playback system. The recordist may determine the mono compatibility of the stereo program (being mixed on the studio monitors) by routing the monitor signal to the single loudspeaker, or by summing the two channels through the console's "mono" switch and using both of the studio's usual monitor speakers.

When the two channels are summed, conflicting phase information causes comb filtering and other signal-integrity problems. In addition, the balance of the sound sources can be radically altered; center-image sound sources may be raised as much as 3 dB, when the signals of the two channels are combined.
For these reasons, it is not uncommon for separate mixes of the same work to be made for different releases. Mixes made for radio broadcast will often have altered frequency information to somewhat compensate for the inadequacies of the single, small speaker, and will seek to maintain many of the dynamic level relationships achieved in the stereo mix.

Headphones are required for creating and listening to binaural recordings, and headphones may be the only feasible monitoring option for a remote recording. Otherwise, monitoring is most accurately accomplished over loudspeakers, except in the rarest of circumstances.

Headphones will distort spatial information, especially stereo imaging. The listener will perceive sound within their head, instead of as occurring in front of their location; this distorts depth of imaging. The interaural information of the recording is not accurately perceived during headphone monitoring, causing potentially pronounced image size and stereo location distortions.

Further, the frequency response of headphones will not match that of loudspeakers, and it is inconsistent. Frequency response of headphones will vary with the pressure of the headphones against the head, and the resulting nearness of the transducer to the ear.

Sound evaluations can only be accurately performed over quality loudspeakers, in a transparent (or complementary) listening environment.