Recording classical music presents a unique challenge to the engineer and producer. The tonal colors and dynamic range of a symphonic or operatic work, for example, are more extended compared to other styles of music and must be preserved in the recording without distortion. The acoustical environment surrounding the musicians - being part of the performance - needs to be captured in order to deliver a sense of hearing a concert instead of a recording per se.Therefore the entire signal/production chain - from microphones through recording media, editing and mastering phase to the final consumer format - the artist's vision of timbre and balance has to be attained and preserved. This postulate requires utilizing only the best available technology and finest equipment, an expensive proposition. It is not quantity (number of channels or numerous equipment), but rather quality (superb microphones, microphone preamplifiers, clean analog-to-digital conversion, etc.) that matters.
The production style is simple, yet demanding. Artists want to perform without interference or distraction by the engineer and equipment. In the case of a live performance, the engineer and his setup should be as unobtrusive as possible to avoid drawing attention to the recording and thereby spoiling the audience's enjoyment. In the case of a studio type recording session, the engineer and producer should provide a comfortable, relaxed environment for the musicians, as they have to imagine performing for an invisible listener. The producer's quality depends on his personal skill to guide the artist through the recording stage; and later, to edit the recordings in good taste and with the artist's vision in mind.
The audio industry has undergone transitions from mono to stereo to quadraphonic recordings between ca. 1930 to 1970. Now we see an even faster evolution, from the emergence of the 16-bit 44.1kHz consumer CD to the newest SACD and DVD Audio CD formats within the last 20 years. Currently, the recording engineer can choose between many digital audio formats: 16-bit 44.1kHz to 24-bit 192kHz (PCM format); DSD format; MP3 format; Surround Sound; on DAT, CD, tape, hard disk and computer recorders; flash memory and many more. In theory, we are able to record more faithfully to the original and to edit more precisely than ever before.Are we listening to better recordings now? The answer is yes and no! Depending on the producer, the results will vary because several parameters have a direct bearing on the sound quality and stereo image, and should be considered carefully: size and acoustical properties of the recording space, their reverberation time and quietness (no air conditioning or outside interference); surface of the stage or place where the musicians play; choice of instrument in the case of a piano, harpsichord or organ recording; and choice and proper placement of microphones. To some extent, the repertoire to be recorded will determine at least some of the parameters. For example, the B minor Mass by Bach has to be recorded in an open-sounding space, probably a church with some marble and hard surfaces to allow for a generous reverb time. On the other hand, a string duo would benefit from being recorded in an intimate space with wood paneling and perhaps just two seconds of reverb.
The experienced recording engineer knows the "good" venues and which halls are suitable for which music. Still, there is a certain amount of luck involved, as not everything can be controlled: musicians and their instruments; ensemble quality; and even humidity, which changes the reverb time and timbre as it rises. In keeping with a purist's approach, the use of equalizers, compressors, reverberation, gates, etc. as tools to "improve" a bad sounding hall should be avoided. Those "toy boxes" might be considered in the mastering process (final assembly and adjustment) and should be used with minimal settings.
