SOUND CHARACTERISTICS, TOP PLATE VIBRATION, AND SUBJECTIVE EVALUATION OF GUITARS MADE FROM SPRUCE, PINE AND PETUNG BAMBOO

TOBY ANINDYAJATI PURWANTO, Dr. Indraswari Kusumaningtyas, S.T., M.Sc.

2014 | Skripsi | S1 TEKNIK MESIN

Kualitas bunyi yang dihasilkan sebuah alat musik sangatlah tergantung pada bahannya. Kayu spruce diyakini sebagai salah satu jenis kayu unggulan dalam membuat alat musik. Penelitian terdahulu menunjukkan bahwa kayu pinus dan bambu petung mempunyai karakteristik yang mirip dengan kayu spruce. untuk lebih memahami kualitas bunyi yang dihasilkan ketiga jenis kayu ini, sebuah penelitian dilakukan untuk gitar dengan top plate yang terbuat dari kayu spruce, pinus, dan bambu petung. Penelitian ini dibagi menjadi dua bagian, pengukuran karakteristik bunyi dan getaran, dan sebuah evaluasi subyektif gitar melalui sebuah playing test. Karakteristik yang diukur adalah tuning characteristics, frequency response dari top plate gitar, serta faktor redaman dan spektrum bunyi gitar. Parameter yang dievaluasi dalam playing test adalah penampilan, tuning, keras bunyi, sustain, timbre, brightness, dan kualitas secara keseluruhan. Hasil pengukuran karakteristik ini kemudian dibandingkan dengan hasil playing test untuk memahami hubungan antara karakteristik terukur tiap gitar dengan persepsi bunyi yang ditangkap oleh telinga manusia. Hasil pengukuran menunjukkan bahwa gitar spruce mempunyai tuning, keras bunyi dan timbre yang lebih baik daripada kedua gitar lainnya. Gitar pinus memiliki brightness yang lebih baik. Gitar bambu petung mempunyai sustain yang lebih baik. Hasil penilaian subyektif menunjukkan bahwa gitar spruce lebih baik dibandingkan gitar lainnya dalam semua aspek. Akan tetapi, ada kemungkinan bias dalam penilaian seubyektif, yang disebabkan oleh pengetahuan dan pengalam peserta playing test itu sendiri.

The sound quality of a musical instrument is very much dependent on its material. Spruce is believed to be one of the best kinds of wood for making musical instruments. Previous studies have shown that pine and petung bamboo have similar characteristics to spruce. To understand better the quality of sound produced by the three types of wood, a study was conducted on three guitars with top plates made from spruce, pine, and petung bamboo. The study was divided into two main parts, i.e. the measurement of sound and vibration characteristics, and the subjective evaluation of the guitars through a playing test. The characteristics measured were the tuning characteristics, frequency response of the top plates, and the damping factor and frequency spectrum of the guitar sound. The parameters evaluated in the playing test were the appearance, tuning, loudness, sustain, timbre, brightness, and overall quality. The results of the sound and vibration measurements were then compared to the playing test evaluation, such that the correlation between the measured characteristics of each guitar and the perceived sound quality can be understood. The measurement results show that the spruce guitar has better tuning, loudness and timbre than the other two guitars. The pine guitar has better brightness than the other two guitars. The petung bamboo guitar has a better sustain than the other two guitars. The results of the subjective evaluation show that the spruce guitar is better in all aspects compared to the other guitars, which implies that they do not correlate with the results of the measurements in terms of brightness and sustain. However, there is a possibility of bias in judgment in the playing test, due to previous knowledge and experience of the respondents.

Kata Kunci : gitar, top plate, spruce, pinus, bambu petung, karakteristik bunyi dan getaran, evaluasi subyektif