Measurement and analysis of the acoustic properties of the padded tensing ring for wind instruments

1. COMPARATIVE TIMBRE ANALYSIS

In this section, we are going to study and compare the timbre of the alto saxophone, the tenor saxophone and the clarinet with a conventional ligature system and with a padded tensing ring over a low note from the instrument's corresponding range, a mid- and a high-pitched note, separated by an octave, in stationary position.

Each note was emitted five times and once the note was held, its spectrum was obtained from 0 Hz to 8000 Hz with 16 Hz resolution over a four-second period. In order to arrive at an average of the amplitude values for the five instances, the value of the harmonic with the greatest amplitude was set to 100 dB and the mathematical mean calculated for the values of each frequency. Typical deviation was also obtained and from there standard error of the mean corrected with Student t with a probability of error of p<0.05. The dispersion of the values obtained from the five instances was quantified as the mathematical mean of the standard errors of the mean.

ALTO SAXOPHONE

Spectrum comparison: high range, B flat

TENOR SAXOPHONE

Spectrum comparison: mid range, B flat

2.1. STACCATO ANALYSIS

The "Staccato" tests involved sound recordings of notes executed at great speed with the traditional ligature system and with the padded tensing ring on the three instruments (alto saxophone, tenor saxophone and clarinet) over a two-second period. Five two-second recordings were made for low-, mid- and high-pitched intonations, separated by an octave, from the three instruments with the two kinds of ligature.

Time analysis of the sound recordings means that the number of notes executed in each of these can be calculated without, for the moment, taking into account the quality and richness of the timbre. This type of analysis allows us to determine how many notes can be executed within the time unit or, equally, the average length of note execution. The results of this test are intended to be used in an assessment of any significant differences in terms of execution speed between the two ligature systems. The following set of figures compare these time values, including standard deviation of the mean, with a significance of both 95% and 68%.

ALTO SAXOPHONE B flat (Sm = 95%)

ALTO SAXOPHONE B flat (Sm = 68%)

3. PIANO

The "piano" tests were based on the execution of notes, from background noise to the clear establishment of the note at its minimum level of amplitude. The aim of these tests was to see if a note was easier (at a lower level) to establish in "piano" mode depending on the type of ligature system used. Obviously, the musician is the person that decides whether a note is clearly established and defined or not. Spectrum analysis can then quantify if the note is well defined at the pressure levels obtained via a comparative timbre analysis similar to that used in the first section.

The sound recordings consisted, therefore, of note execution from very low amplitude (practically background) up to minimum amplitude where the note became well defined. It is considered an advantage for maximum amplitudes to be achieved at lower levels. The registers took the form of Waterfall measurements with traces (1/3, 1/12 octaves) every 62.5 or 125 milliseconds. Sound recording time rounded the 10-second mark.

The following set of figures shows sound level progress over time in Wide Band (between 80 Hz and 12 kHz) for the tenor saxophone in high range B flat and clarinet in highest range E.

TENOR SAXOPHONE high range B flat

CLARINET highest range E

CONCLUSIONS

1. The influence exercised by the type of ligature system employed on the spectrum of notes produced by the three instruments under study (alto saxophone, tenor saxophone and clarinet) reveals different tendencies according to the case in hand: statistically significant differences (to probability of error = 0.05) were found to support enhanced timbre richness in the case of the padded tensing ring for the alto saxophone on the high note and the tenor saxophone on the mid-pitched note.

2. There was no significant difference between the two ligature systems when it came to the length of the note executed quickly (in staccato mode), at least not at 95% degree of reliability. Only in the case of the alto saxophone with padded tensing ring was there a somewhat clearer tendency towards faster note execution, albeit at 65% reliability. Regarding timbre analysis, note definition proved practically identical, revealing no statistically significant differences. The only exception to this occurred in the second harmonic of the tenor saxophone recording, which indicated significantly greater amplitude with the padded tensing ring.

3. As far as the maximum levels for the execution of "pianos" was concerned, the general tendency suggested that these were achieved at lower levels when using the padded tensing ring, as opposed to a conventional ligature, for all the ranges on the three instruments, except the alto saxophone in its high range.

Pamplona, 28th of July 2000

The staff at the Department of Physics at the University of Navarre who wrote up the Acoustics Laboratory report Inf. FfAC.Mus.00/1 have given FF Accesorios Musicales S.L. their authorisation for the publication of this report summary.