主题：HI---2 distortion

现在在做的一款喇叭有遇到HI----2失真的问题，请教各位DX对此可否有研究，请指点一二。一般跟什么有关，如何改善？

各位大侠，都没人指教吗？

问题提得不是很明白，是指2次谐波失真吗？

偷偷问一句：“HI----2失真”是什么意思啊？？？

又是一个出了问题，自己不闻不问的！！

经确认，不是指2次谐波失真，附相关图片如下，望各位参考指点。

此主题相关图片如下：

楼主把问题再说清楚些，如测试条件测试内容和测试的扬声器规格等。

只看AP的测试图，是说THD+N(总谐波失真+本底噪声）在低频（估计是20-120Hz) 超出框图，在10Vrms.

玩了那么多年AP,没听说过Hi-2 失真的, 只有二次谐波失真,无论喇叭和功放的都没这个指标.

从你那个图线上来看, 失真都比原信号大了? 可能吗? 也许你的测量方法都错了.

搞音响要注重实用有成效的东西, 不要搞出那么多噱头.你测这个东西有用吗?

基本概念要清楚！！！

不甚明白!

此"danny"非彼"darry"

测试方法有否问题?是测的喇叭或音箱还是功放?在消声室测试的吗?

若是测试的喇叭,低频本来就很难测试得准确,还要考核(计算)低频的总谐波失真(THD)?考核本底噪声(N)只对功放有意义.

晕,哪里出来那么多名字像的.

顺便提一句,AP一般不用来测喇叭频响, 虽然AP精度很高,但更适合用在电子,功放开发方面.AP如果要测喇叭需要有很好的消声室,
一般很少有企业满足这个条件.我知道的目前可能只有国光是用这种方法.

谢谢大家对这个话题的关注，现在对大家的问题作个回答：

1.测试方法原文如下：The measurement microphone is placed in the near field of the front of the loudspeaker cone(within 2cm of the dust cover or the driver cone if accessible)for distortion testing.

2.作此项测试(HI 2 distortion)不是要搞什么嚎头，而是开发一新项目时客人的明文要求；

3.测试对象是一低音喇叭單元；

4.说实话，我目前也没搞清这个概念(HI 2 distortion)的意思,所以提出来请大家指教(大家的经验/经历都远在我之上)；

5.没错,我们公司的AP也是多用在功放测试方面；

此主题相关图片如下：

再加一个HI 2 Measure测试OK的图，供比对参考。

Hi-2 distortion is the total harmonic distortion with the weighing of harmonics. An 8.0-volt sine sweep from 20 Hz to 1 kHz to the speaker (appropriate maximum output voltage of the intended amplifier). The speaker is mounted in 1/2 space baffle or an equivalent of in-use acoustic condition with the microphone centered above the speakers protective grille. The fundamental is notch filtered and the harmonics are amplified by a 12 dB per octave high-pass slope to simulate annoyance. Weighted harmonics are summed and compared to the mid-range output of the speaker.

Why do we measure HI-2 distortion ? The limited height of voice coil, magnetic field, excursion capability of the mechanical suspension, varying voice coil inductance and nonlinear radiation (Doppler) are the dominant nonlinearities in loudspeaker systems. For loudspeakers without additional defects the amplitude of the harmonic and intermodulation components generated by the dominant nonlinearities decrease rapidly with the order of the distortion. Although, the second and third-order components contribute mostly to the total distortion and these components are perceived as benign distortion. When the voice coil hits the back plate or the loudspeaker has defects such as an axial mis-alignment of coil and gap or buzzing leads this may cause extreme distortion that produce higher-order components. D. Clark defined an intermediate type of distortion (called blat distortion) between the benign and extreme type "Blat is a result of an intermediate stiffness change which produces amplitudes of fourth and tenth harmonic which are too high to be masked by the fundamental and the benign second and third harmonics. Blat results from a design characteristic rather than a rub, buzz or tick type of unit defect. "

此主题相关图片如下：

原来如此

感谢PGH兄的指点，大家如果有其它看法不妨提出来讨论。

这个概念有人解释了，那如何改善呢？请有研究的DX侠们赐教。