主题：知道"打飞机"原理吗

那天听到给音箱打个飞机,我真没反应过来.终于有个女孩跟我说,就是把音箱躺在地上,测频响啦.还小声地说2m远.我问为什么,她说不知道.

我真不知我们的工程师们知道不?

测量的一种方法,没什么奇怪的.

呵呵，这种测试方法好想LMS的手册里有介绍哦，似乎还要将MIC摆在节点位置，节点是什么意思啊？

只知道是方法真不叫懂技术!这个问题可以看出是否懂声学的基本原理.

如不懂这原理来搞电声设计,真是农民造潜水艇!

db老师讲讲嘛！！现在已经有农民造飞机了，造潜艇好象还没有！

DB老师讲讲原理，也让偶们农民能糊糊喇叭，呵呵。。。。。

先谢过了！！

真实的,我还举一例,还有造飞碟,哈哈,愚公移山,无穷尽也.

你看电脑中国芯造出来了吗,多是吹的,出来的也是落后的.

要学得从头开始,先卖本书吧

问题是偶不知道头在哪里啊！db老师，您给指个方向，行吗？

让大家想一想再说.不忙下结果

看来今天的不到结果了，先下了，明天再来向老师请教！！

谢谢啊。。。。。。。。。

1米也可以的，呵呵，只不过计算灵敏度的时候-6

不过我感觉这种方法不是很准确的，中高频估计和其他方法有点不同

这个方法真的不知道，是自由场还是半场？但是只要地面是反射的，中低平应该去修正才是。

这种方法需要平整光滑的地面，要求在8米左右范围内无反射体，也就是说至少16米乘16米的范围内无反射体，好象不太容易满足吧！如果满足也只能测低频，测出的结果减6dB

Ground Plane Measurements

Ground plane measurements are very nearly identical to anechoic measurements. Because the measurement includes both the direct sound from the enclosure, plus the mirrored image from the ground plane, the SPL for the same microphone placement distance will be 6dB higher than the anechoic SPL level.

The only requirement for a ground-plane measurement is a large reflective surface, such as a parking lot or drive-way, with no obstructions for a radius of 20-30 feet or more. The procedure is to place the loudspeaker on its side on the ground, and then place the microphone on the ground in front of the speaker.

Ground plane measurements, like anechoic measurements, will have a rising character in the response caused by diffraction off the loudspeaker baffle board. This occurs in the mid range region. The increase in SPL is about 6dB, the frequency being determined by the total area of the baffle.

If you are measuring a multi-way enclosure with low, mid, and high frequency drivers, the enclosure should be positioned on its side with the high frequency driver nearest the ground. The microphone should be aligned on axis with the high frequency driver as well. The off-axis angle relative to the wavelengths of the mid and low frequency drivers will typically not be significant.

Many times it is a good idea to slightly tilt the enclosure downward toward the microphone. The important goal here is to try to keep the microphone on-axis with the high frequency driver.

The ground plane method is a very good choice and does not require any expensive or elaborate set up. All that is required is a flat surface with some open area around it. See the figure below.

上面是LMS上介绍的。

可能新手的缘故，图片发不上来。

图呢?100K以下的JPG GIF BMP文件均可,需按上传栏中的浏览_上传,再发表!不能直接粘贴.

半自由场测标准1m和打飞机2m比较spl-f曲线形态一致.

此主题相关图片如下：

此主题相关图片如下：

下图距离增倍－６dB,镜像原理+3dB，总效果-3dB．

满足何种声场条件，由专家去说吧．

此法为何会出现，背后有何目的呢？

ＤＢ大师开了个好头，希望各位专家发表高论啊．

不要让众信徒们等的太辛苦了．

我先打个地铺，不信没人来，哼！