為瞭解人耳對於音高的感知能力，早從1938 年西肖爾（Carl E. Seashore）出版的Psychology of Music（音樂心理學）一書以來，即不斷有人對於「最小可辨音差」（pitch discrimination）進行測試與研究。然因所用「基準音──比較音」的比較方法中，測試項的「音差值」為間斷變項（discrete variable），有精度不足之慮；某些實驗的測試聲音只播放一次，即要求受試者做出判斷，有判斷時間不足的問題。另外，要依何種律制觀點或標準設定音差值？在測定方法上，或容有商榷之餘地。本文引申二胡內、外弦「同音不同弦」的演奏經驗，為新測試方法之想法來源，試以「調整法」進行同音比較，並以測音所得的「誤差」進行閾值估算。結果發覺，因受測者主動調整「比較音」的音高變化，又與「基準音」能重複比較，所得「南藝大學生440 赫玆的最小可辨音差為1.7 至2.3 音分」之實驗結果，或許應可反映音樂專業人士，對於音高的分辨能力，未來可為音準研究的重點之一。

In order to understand the perceptibility of human ears to pitches, there have been studies on pitch discrimination since the publication of the Psychology of Music by Carl E. Seashore in 1938. Yet there have been concerns over the methodology that tests pitch discrimination by comparing a pitch with the benchmark pitch and using the value of pitch difference as the discrete variable. In some experiments, subjects may not have sufficient time to make judgment as the testing pitches are played only once. The methodology for test pitch difference, including the setting of the value of pitch difference and the tone system or standard to be applied, may warrant discussion. This study is developed upon the experiences in performing Erhu, in which "the same pitch produced on different strings." The study seeks to apply the "Adjustment
Method" to compare pitches, and assesses thresholds based the "differences" in pitch testing. The results show that, as the subjects can adjust the variation of pitches and can compare them with the benchmark pitch repeatedly, the outcome of the experiment that "for students of Tainan National University of the Arts, the minimum distinguishable pitch difference for 440 Hz tones is between 1.7 and 2.3 cents" should be able to better reflect the pitch difference perceptibility of music professionals. This may be an aspect for future studies on pitch perception.