Category
Aim
Technique
Requires
Effect
Performance Noises
Performance Noises
Sampled instrument or performance noises
Include performance noises such as fret buzz, string squeaks, breaths, etc. to give life to a virtual instrument piece.
Room Tone
Room tone recording
Adding a room tone sample can give the impression of a live recording
______________________________________________________________________________________________________
4. Imperfections & Artefacts - Summary
One area that, while more pertinent to the realms of visual art and CGI, is also worth addressing in regards to virtual mock-ups is that of the psychological phenomenon/hypothesis known as the 'uncanny valley'. This could largely be down to how people may express a disliking for overly 'perfect' performances created and how they may be able to tell what is real from what isn't. In effect, the premise of the uncanny valley phenomenon is that in regards to virtually rendered animations, images or scenes, the more realistic the rendition is, the harder the human brain works to try and identify discrepancies, inaccuracies or any other aspects which would signify that the image is not ‘real’.
Though human hearing may not be as complex and as difficult to ‘fool’ as our eyesight, the practice of attempting to replicate an artificial reality for one of the senses nonetheless contains similar difficulties. The complexity of human hearing; including the aural perception of space, time delay and positioning within the stereo field as well as intricate variations and discrepancies in human performances and instrument characteristics means that many different factors must be taken into account, and replicated where possible, to try to impart a sense of realism within a virtual recording.
One of the key weaknesses of MIDI has always been the rigidity, repetitiveness, or the exactness of its timing. To compensate for this, MIDI devices such as samplers or Digital Audio Workstations have long featured ‘Humanize’ options to apply to MIDI data; as a means of randomizing, by a user defined amount to introduce subtle varieties in the performance. As such this underpins the importance of imparting variations and subtle but noticeable imperfections to digital renditions of musical works. However looking beyond the musical performance itself, there are various other non-musical elements which are fundamental to live performances and which, when applied to virtual renditions, can help to improve how a listener can interpret the work.
Imperfections & Artefacts 4a)
As sample libraries consist of individual recordings which are then put together in sequence, sampled performances lack the characteristics of live players and instruments; namely in the sterility and ‘cleanliness’ of the recordings. The inclusion of performance noises, such as string squeaks, fret buzz, breaths for woodwind/brass/choirs etc, can make an otherwise sterile recording sound more realistic and lively. Many libraries often include separate performance noises specifically for this purpose, which have the added benefit of being from the same source as the sampled instrument. Where the library does not include these sounds, custom made noises can be used such as those recorded or sourced separately by the user. Used diligently and placed in the appropriate places, such as a choirs’ breath after a long phrase and before the start of another, can make a significant impact to the impression of the overall piece.
Imperfections & Artefacts 4b)
As Pejrolo and DeRosa make clear: “One of the biggest problems with a virtual MIDI orchestra is the fact that it is always perfectly in tune” (2007, p158). This issue of perfection is a factor that influences every aspect of the virtual ensemble and must be considered at each stage of emulation. Subtle detuning can be applied to parts to prevent the 'perfect orchestra' sound can be become prevalent in the middle of a phrase or performance for certain string instruments; particularly those without frets, as the player makes slight nuances moving from note to note. An additional note in relation to tuning is that many sampled ethnic instruments will be presented in the western standard tuning or equal temperament tuning, but will include options of using alternate tuning relative to the system used by the instruments country of origin or most commonly used style of playing.
Imperfections & Artefacts 4c)
The use of a room tone can be useful, particularly in works where there is silence before or after a part. Similar to instrument performance noises, including a few seconds before the music begins with a room tone applied and some additional subtle noises such as pages turning or boards creaking can 'fool' the listener into believing or anticipating that the following piece is real. This is a similar approach taken in the practice of sound design and dialogue recording for film, where the room featuring a scene with dialogue that will later be replaced has the ‘room tone’ captured and used in conjunction with the newly recorded dialogue. Some sample libraries such as Eastwest’s Symphonic Orchestra library provides a room tone, here referred to as ‘hall noise’, whilst Bela D Media’s Scoring Noise plugin provides room tone as well as incidental notices such as floors creaking and pages turning.
Figure 19. Northern Sounds free room tone plugin.
Imperfections & Artefacts 4d)
Again referring to the inconsistencies and deviations within musical performances, just as instruments should never always be exactly on the beat, they should never play and line up perfectly with other instruments either. Have some instruments slightly ahead or behind of others, and apply slight deviations across the entire piece.