過去大三弦的琴碼擺放位置，約在琴鼓下方三分之一的地方；目前因音域增加和指距縮小的需求，另有「五度音」的擺法。本論文引用林昱廷研究二胡千金位置時，所運用的頻譜與協和度分析方法，對於大三弦琴碼位置進行研究。結果顯示，五度音擺法不失為一可取的方式。
另外，在研究過程中，發覺某些大三弦的專業老師，因著音色和力度感的堅持，對於琴碼位置的改變，持有較多保留意見。但多數學生對於指距縮小，以及會有演奏技巧較易之優點，則有較高的接受度。

The bridge of Dasansian (lit. big sansian) is usually placed at the one-third of the resonant body, above the bottom of the instrument. However, there is another alternative to place the bridge, called ‘fifth interval’ on account of the increase of octave and the decrease of note-fingering distance.
This study aims to find out the ‘fifth interval’ place may be a good choice for performers, because this newly bridge place is easier for fingering, and at the same time, it will not damage its tone quality. In order to demonstrate this, the study, therefore, adopts the approach of Lin, Yu-ting, which examines the suitable place of erhu bridge through the analysis of its sound spectrum, to analyze the spectrum of each string, and also provide the reference of its acoustic data to the performers.