以 DSP 頻譜觀點看樂器的分類，可將之概分為和諧式(Harmonic)樂器與非和諧式 (Non-harmonic)樂器。樂器中的吉他、鋼琴、豎琴和提琴等的絃樂器，以及管樂器皆屬 於和諧式樂器，因它們演奏音符聲音的頻譜，約為單頻信號的基頻與其整數倍率的諧 波頻率組合而成。基頻決定音高，諧波則組成所謂的泛音。不同樂器的泛音皆不一樣， 產生樂器的音色。 非和諧式樂器則多為打擊式樂器，包含鑼(gong)、銅鈴(Tingshaw Bell)、木(鐵)琴 (xylophone)、鐵弧(pelog)等。此種形態的樂器，其聲音的頻譜中，基頻與各主要泛音的 頻率，無所謂的諧波關係，成不規則的形態，故名之為非和諧式樂器。打擊樂器源起 比較早，因很多都是從自然界現成的素材發展出來，近代則廣泛流傳並發揚光大於印 尼，其種類繁多，統稱為 Gamelan(甘美藍)，為印尼語。中國古代的樂器亦有類似 gamelan 的樂器，只是很多都已絕跡失傳，僅能從博物館中一窺究竟。Gamelan 一般僅具有 5 到 7 個音階，不同材質的 gamelan，音階的個數與頻率皆不一樣，是經過幾千年的試煉 而來。許多 Gamelan 的特殊音階與音色，甚至具有引人遐思、冥想與慑魂的作用，使 得西方音樂的人士，趨之若鶩，爭相研究。 本次計畫在建立一能適用於以廣泛材料的廣義式 Gamelan 的分析、設計與製作模式， 用於裝置藝術與智慧性生活的應用。我們首先探討音階合成的原理，並引用 Plomp and Levelt 的不愉悅度(Dissonance) 曲線的數學模型的理論基礎，以 DSP 的方法來驗證傳 統 Gamelan 的經驗式設計值，我們用來比對的 gamelan 為從 ebay 買來的爪哇鍍鉻金屬 鐵管 Gamelan( Xylophone)，驗證與修正理論的模型。目前已初步完成以自創的玻璃管 Gamelan 的設計。計畫中將簡述我們初步研究的進展，以此為基準，未來推展至大型 玻璃管與 PVC 管 Gamelan 的設計與製作，用於廣泛的智慧型生活應用。此應用中我們 將完成一具展示表演的裝置藝術，包含人機互動的操作以及自動音樂演奏應用的系統， 其中將使用我們前幾期 NSC 計畫所發展的一些成果，以電腦中的虛擬境界配合 Max/Msp、 Processing 等互動式軟體以及微處理器 Arduino、感應器等所形成的互動式 系統於公園中表演發表。
Musical instruments can be dichotomized into harmonic and non-harmonic sounding structure. Instruments like guitar, piano, harpsichord and violin belong to the stringed type harmonic instrument because the spectra of their voice played are multiple harmonics of fundamental frequency. The fundamental frequency decides the pitch of the sound, whereas the adscititious harmonics or overtones constituent timbre of each particular instrument. Non-harmonic instruments covers percussion type instruments, like the hang, gongs, the xylophone, certain type of cymbals and metallophones. The spectra of the sound played by those instruments do not follow the integer multiple of harmonic pattern, and are irregularly arranged peaks over the entire frequency domain. A gamelan is a traditional musical ensemble from Indonesia, typically from the islands of Java and Bali, featuring a variety of non-harmonic instruments Its music scale does not follow the common 12-tet (12 tone equal tempered) scale but has only 5 to 7 scales. The selection of frequencies for each scale was evolved over thousands of years to make consonant sound when playing. For most Indonesians, gamelan music is an integral part of Indonesian culture; however it has drawn particular interest by Western musical society as it can create certain mysterious meditation effect. In this research proposal, we would like to build up a design and fabrication method for general gamelan. New Gamelans will be invented that extensively uses common materials from daily life for installation art consideration. The instrument can be placed in park or recreation ground for intelligent living application. The analysis and design frame work is as follows: We will first review the work by Promp and Levelt’s mathematical model that utilizes Dissonance curve of sound to find the proper music scale for each particular type of percussion instrument. Then model is adjusted by verifying a real xylophone bought from overseas. We then use this model to do a preliminary design of our newly invented glass tube Gamelans. Two sizes of equal height glass tubes filled with water with its heights adjusted to fit the calculated scale. Based on our experimental glass Gamelan result, we will then extend the similar idea to build a much larger glass and PVC pipe Gamelans with different sizes. Finally we will furnish an experimental Gamelan park to fulfill our idea where both the glass tubes and PVC pipes gamelan will be installed in park for demonstration. Amongst the installation art performing, self-made interactive music playing system which covers proper use of Max/Msp and Processing interactive software running on PCs as well as micro-controllers, Arduinos and sensors for controlling the Gamelan apparatus based on a interactive 3D graphic written in Processing . Some our design tools accomplished in previous NSC projects will be integrated into the current project.
