求助！！！用什么方法使小房（４Ｍ＊３Ｍ）　音响效果产生出大厅（３０Ｍ＊２０Ｍ）的效果来？？？？　

注：１：ＫＡＬＡＯＫ用，

　　２：成本不计．

是不是可以用量化数据来提要求呢??

房间简正的问题!!从这着手吧!!

吸声多一点，如何？

楼上的前辈说的有道理！！不顶不行啊！！

Small Recording Studio Room Acoustics and Helmholtz Resonators

Also unfortunate is the mistaken belief that the use of materials such as foam acoustical tiles and fiberglass can solve these coloration problems. The worst coloration problems are caused by frequencies around 300 Hz and below. In smaller rooms the most noticeable build up often occurs between about 100 and 300 Hz. While foam tiles and fiberglass are excellent absorbers at higher frequencies they become increasingly less effective below about 1000 Hz. Often times trying to use foam tiles or fiberglass to cure a bad sounding room actually aggravates the problem and results in a very dead sounding room with a lose of the natural clarity and sparkle of voice and instruments. A very dead room is not a very pleasant recording or listening environment and often seems to require excessive amounts of EQ with the resulting recordings still lacking in clarity and presence.

So how to control coloration without making the room too dead? Bass traps or low frequency absorbers are commonly used in professional recording and broadcast studios and can be constructed for use in small studios. A very effective and easy to build bass trap is the slat-type Helmholtz resonator. These can be designed to absorb the offending frequencies causing coloration problems while at the same time reflecting and diffusing the higher frequencies contributing to a very natural sounding acoustical environment for recording and mixing.

A simple example of a Helmholtz resonator is blowing across a pop bottle to produce a tone. Changing the volume of the airspace within the bottle changes the pitch of the tone. Likewise changing the enclosed volume of the airspace inside the Helmholtz resonator bass trap changes its working frequency.

A slat-type Helmholtz absorber is simply a six sided box with openings or slots on its front side to couple the enclosed volume of the airspace in the box to the air in the room. The depth of the enclosed airspace in the box behind the slots and the width and depth of the slots control the resonant frequency of the bass trap.

Slat-type Helmholtz absorbers are very easy to design. The formula for calculating the absorber\'s resonant frequency is:

f = 2160 * sqrt ( r / (( d * D ) + ( r + w )))

Where:

f = resonant frequency of the absorber in Hertz (Hz)

r = slot width in inches

w = slat width in inches

d = effective depth of slot in inches (1.2 x the actual thickness of the slat)

D = airspace depth (depth of box behind the slots) in inches

You can use a spread sheet such as Microsoft Excel to model various dimensions and tunings for slat-type Helmholtz absorbers. This can be very useful as you can easily see how changing any dimension changes the tuning of the absorber.

The formula for determining the fundamental frequency of a standing wave for a particular room dimension is:

fo = V / 2d

Where:

fo = Fundamental frequency of the standing wave

V = Velocity of sound (1130 feet per second)

d = Room dimension being considered in feet (length, width, or height)

Other standing waves occur at harmonics of the fundamental frequency - that is 2, 3, and 4 times the fundamental. Thus a room with an 8 foot ceiling has standing waves forming at 70 Hz (the fundamental frequency or first harmonic), 140 Hz (the second harmonic), 210 Hz (the third harmonic) and 280 Hz (the fourth harmonic).

As mentioned earlier, rooms with smaller dimensions often have standing waves or resonance build ups that are very noticeable causing coloration at around 200 Hz or so.

For example, building a box with an airspace depth of 4 inches using wood slats 1/2 inch thick and 2-1/2 wide results in a box tuning of about 240 Hz. In practice it is not usually necessary to be extremely exact with the tuning frequency. Being in the ballpark will often work very well. In fact many slat-type bass traps are designed with slots of varying widths (perhaps plus or minus 1/16 to 1/8 inch of the design center frequency) to cover a wider band of frequencies. Also loosely lining the inside of the box with materials such as fiberglass widens the bandwidth (lowers the Q) of the absorber. Building and mounting multiple units perhaps with slight variations in tuning can also improve the control of coloration. Mounting multiple units throughout a room improves absorption effectiveness and promotes diffusion of higher frequencies.

A more complete explanation of the principles of acoustics mentioned here can be found in Jeff Cooper\'s book entitled Building A Recording Studio. It is a fairly basic and easy to understand book on acoustics, and it is also very practical and very useful for someone interested in building a small recording studio.

楼主的题目有点漏风,什么样的大厅呢??

说句实话,3*4的房间产生30*20的声学效果太难,那位有现成的解决方案可以提上来学习一下

对房间的外观有要求么？

要求变动不大就用效果器，

没要求就参考11，12楼找木工整几个赫姆霍兹共振器吧，简单又省钱

跟这个有关，那位再深人分析一下。

3. 空间感

传统的观点认为空间感仅对后期混响声有关。自从Marshall(1968)等人发现早期侧向反射声对音乐厅音质起着重要作用后，仍有许多方面不甚明确。是森本政之等人首先把空间感认定由声源视在展宽度ASW和听者环绕感LEV 两方面组成。ASW主要由早期侧向反射声级决定， LEV则取决于后期侧向反射声。如今还认识到：LEV可由非侧向声产生；当早期和后期侧向声均出现时，对ASW和LEV有相反的效果。因此研究如何处理好两者的结合，具有实用意义。空间感只与侧向反射声的低频(125-1k Hz)成份有关，更高频率的则会造成声源位置有分离了的错觉，它不仅无助于环绕感，而且会搞乱声源定位感。当直达声和早期声之后加入了后期声，ASW会有所下降。所以明晰度(早后期声能比)C₈₀愈大，ASW也就愈高。对于LEV则有些情况正好相反。即出现较强早期声时，不论是否来自侧向，均会使环绕感LEV下降。另外，当总声级高时，LEV也增大。轻声时，整个空间感会消失。至于来自听者后方和上方的反射声对LEV有意外的效果，对ASW则无关。所以大厅后墙如作强吸处理，将会降低LEV。