《晋书·志·第六章》
准器的音高明确顺畅易于通晓，其分寸刻画明显，但由于弦的张力松紧而造成音的高低偏差，没有律管来校定又难以标准。
准之声明暢易达，分寸又粗，然弦以缓急清浊，非管无以正也。
The pitch of the precision instrument is clear, smooth and easy to understand, and the interval is clearly marked, but the pitch deviation is caused by the tension and relaxation of the string, and it is difficult to standardize without the adjustment of the pipes.