Tonal Distinction 5 – Projection Quality to 6 metres.

The qualities of tone radiated to microphone 8 were measured to examine the projected volume and spectra of both pianos, to a distance of 6metres, in the direction of 90°. The amplitudes of soundboard vibrations of the same sounds were also examined to see if they corresponded to the projection levels at mic 8.

Microphone 8 was positioned at 90° and 6metres from the same measuring point on both pianos, in the MW performance space. Each piano was moved to identical positions in the MW space.

It was found that the Stuart piano projected significantly larger harmonic spectra with larger amplitudes of the Fnd., 2nd, 3rd & 4th partial frequencies, of the notes C2, C3,& C5. Both pianos sounded more similar levels and spectra of note C4 261. Hz. The magnitudes of the soundboard vibrations for each of the notes, corresponded with the contrasting radiated SPL of C2, C3,& C5 as well as the similarity of SPL levels for C4.

The boxgraph illustrates the generalised contrasts in SPL radiated to microphone 8, of the four notes, across the three velocity strikes. The SPL of the sounds of 12 notes on each piano, are represented in this graph. Each range, r1-4, partitions the SPL (dB) range of 12 sounds, into 4 segments, each of 3 notes, in their order of loudness. The loudest two ranges, r3 + r4, and the softest range, r1, are larger in the Steinway sound. A larger range is telling us that the difference in the softest and loudest note of that particular range is greater.

The three loudest notes of the Stuart sound, r4, struck at v81,are closer together in SPL than the 3 loudest notes produced by the Steinway, r4. The 3 quietest notes, r1, struck at v20 velocity strike were at an average 10dB louder in the Stuart sound, than Steinway. Continuing this test, using slower velocity strikes than v20, may produce data demonstrating that a wider SPL range is radiated by the Stuart piano to 6 metres.

This contrast can be more closely examined in the box graphs of specific notes, in the flowing pages. The telling result of the box graph above, is the extent of the difference in SPL which radiated to mic 8.In every range, the Stuart sound is significantly louder than Steinway.