Naturally the measured sound level depends on the strength of the sound source. It is therefore also of interest to determine a characterization of the sound source, which describes its strength independently of spatial considerations and the distance from the listener. This relates exclusively to the sound source itself. Such a quantity represents the sound energy radiated by a source in all directions during a unit of time. This quantity is designated as the sound power of the source. 221
A comparison of the amplitude output and directivity of both pianos is thoroughly illustrated in the data below, which illustrate the sound pressure levels that reached each microphone of the same sound. This data illustrates the Stuart piano’s highest signal of leqA was recorded by the microphone No 6, ata level of 66 dBA, and the Steinway’s highest leqA was recorded by microphone No 2 establishing distinctive radiation directivities, in opposite directions!The sound level volume of the instruments is recorded by mic7, and we see here that the Steinway is 4dB louder in Lp peak, and an average of 4dBA louder than the Stuart piano, averaged over the 50s duration of the note. The general sound pressure that was radiated into the space is higher in the Stuart piano sound.
| MWMicrophone Array C2 v81 | 13m180° (behind pianist) |
23m 45° | 33m 90° | 43m 120° | 53m 150° | 63m 180° (behind bass bridge ) |
7 SLM10cm over hammer | 8 6m90° cardioid |
| STE 58s Steinway Piano |
||||||||
| Lp | 88(.3) 86 | 88(.2) | 83.8 84 | 84(.3) | 85 | 86.9 87 | 95.9 96 | 71.6 72 |
| LeqA | 64.965 62 | 64.665 | 61.9 62 | 62 | 63 | 64(.3) 63 | 69.5 70 | 50.5 51 |
| M19 (STU) Stuart Piano |
||||||||
| Lp | 87(.2) 86 | 88(.4) | 86(.3) | 85.9 86 | 88 | 91.992 94 | 92.0 | 79(.4) |
| LeqA | 61.9 62 | 64 | 62.8 63 | 63.6 64 | 63 | 65(.4 )66 | 65.7 66 | 56.7 57 |
| Sound pressure level C2v81 Table 3.3 | ||||||||
| Stuart mix 90° mic 3 & 8 | Steinway mix 90° mic 3 & 8 |
| C2v81 M19 (STU) mic 3 & 8 | C2v81 STE mic 3 & 8 |
| Sound table 3.6 | |
The Lp and LeqA data collected for each of the 4 notes C2, C3, C4, & C5, is illustrated in Appendix 4.The characteristics of the sound of each note has been analysed at three velocities, v20,v54 ,v81, and at 8 various positions(mics 1-8), within the specific 3m and 6m sound field of the Music Workshop (MW) the atre space, at the Sydney Conservatorium of Music.
221 Meyer, 3.
