8 Conclusions
Preference results for the Multi Microphone Array vs. the Soundfield ITU definitively favour the Multi Microphone Array. However, it is not reasonable to expect that the recording and mix engineers will not adjust the output settings of the B-format decoding. Soundfield ITU vs. Soundfield Adjusted comparisons, although showing mainly parity, show indications that the adjusted specification gives a better sense of envelopment which promotes the assumption that the recording engineer would adjust default values in search for a better sounding production.
Therefore, the results of the Multi Microphone Array vs. Soundfield Adjusted are more important to consider. For quieter and less energetic pieces, their preference results achieved parity. This suggests that the engineer can focus on what type of sound characteristic they wish to achieve rather than picking an overall preferred array. However, these results could be based out of the spaced vs. coincident Multi Microphone Array considerations whereby the engineer could simply employ a coincident Multi Microphone Array technique to achieve a similar set of image characteristics that the Soundfield gives.
For more energetic pieces, preference was shown to be in favour of the Multi Microphone Array. The Soundfield Adjusted did perform better in the clarity attribute; however, the use of accent microphones or the use of a coincident front Multi Microphone Array can provide reinforcement for the Multi Microphone Array in this aspect. Additionally, an array being clearer is not indicative of positive preference so considerations should be made by the engineer on whether a production which is too clear could irrecoverably damage the perception of the audience.
An approach where clarity is supplemented into the production rather than taken away, which cannot be guaranteed, may be more prudent. Any deficiencies in the Multi Microphone Array used with respect to clarity can be addressed with the variable use of accent microphones or with the use of a coincident Multi Microphone Array for the capture of the front image.
Although a larger sample size would have been beneficial,results of this project show that the Soundfield does not perform significantly better in preference to mean that it should be considered the most competent recording array for classical quartets.
Similarly, any deficiencies in spaciousness or envelopment with the Soundfield system can be addressed with accent microphones; however, this would effectively make redundant the use of the rear pickup of the Soundfield which would not make financial sense. The use of discrete microphones in a Multi Microphone Array also means there is an added versatility with respect to the deployment of microphones across different areas of the performance space as well as in different styles of project.
9 Further Work
Attribute results in this project have shown that preferential results relate to spaciousness, envelopment and clarity. Some questions had results that were close to significance and would have benefitted from a larger sample size. However, enough indications were established to show an avenue for further work in this area. In this case, the borderline parity questions would be asked again if appropriate.
This project compared recording arrays for a classical quartet. This means that results are not directly applicable to a larger ensemble as the need accent microphones would make the assessment of the main array problematic. Additionally, care should be taken when applying these results to other musical sources such as a choir. With these warnings established, further work could explore a similar project question for configurations of other acoustic musical groups in difference spaces.
As outlined in Section 8, the performance of the Soundfield system in terms of clarity may be influenced in the coincident nature of the sound pickup rather than the specific use of the system. Further work in this area can investigate how a surround sound array with a coincident front and spaced rear pickup compares with the Soundfield system or how a coincident stereo array compares with the Soundfield in a stereo configuration.
This project compared arrays in a very favourable performance and recording environment. Queen’s University Belfast provides extremely high quality facilities in these respects. Another avenue for further work would be to recording in substandard or problematic performance spaces to investigate whether the Soundfield system’s post recording versatility translates into advantageous problem solving abilities.
