【空間處理探索系列】低頻陷阱

[chsiang]

沒什麼人要猜 ;(

那只好公佈答案了



答案是到65Hz都還有吸收系數都還有1, 很可怕吧!

所謂的Type 2產品厚度增加0.25英吋, 到達4.25英吋, 更是在極低頻有很大的效果!

請參考國外網友仿造這個設計概念自行打造的低頻陷阱的測量結果,

長寬高與RPG這個產品相近,

房間未加入低頻陷阱前



很亂的阿! 尤其是50Hz那附近......

用了之後,



真的是大幅改善, 也真的對極低頻的部分有很大的幫助

這個產品的原理我日後也會探討.......

[THXman]

請參考國外網友仿造這個設計概念自行打造的低頻陷阱的測量結果,

長寬高與RPG這個產品相近,

房間未加入低頻陷阱前



很亂的阿! 尤其是50Hz那附近......

用了之後,



真的是大幅改善, 也真的對極低頻的部分有很大的幫助

這個產品的原理我日後也會探討.......

版主,
國外這TEST與這產品DATA是兩回事.
版主是否沒弄清楚.

[chsiang]

THXman, 我不太懂你要表達什麼?

有話但請直說, 若有錯誤請直接點出, 拐彎抹角只是讓我迷糊而已,

若想正本清源我也歡迎你在版上另闢主題討論,

我並非沒有肚量之人, 請你安心分享.

以上!

[THXman]

版主,
在下的提問都是許許多多的徵節所在.

[chsiang]

THXman,

恕我駑鈍, 不知道你想表達的意思, 若你不提點, 我也不便勉強

我能做到的就只有今後不視你的意見, 等待其他能人異士來替我為你的問題開通

以上!

[THXman]

不視在下的意見沒關係,這些徵節點若未弄清礎,請小心,以免自誤誤人,而成日後需要被破除的誤論.

GOOD LUCK!!

[Mell]

THXman,

恕我駑鈍, 不知道你想表達的意思, 若你不提點, 我也不便勉強

我能做到的就只有今後不視你的意見, 等待其他能人異士來替我為你的問題開通

以上!

小小建議
請版主 慢慢論述您的觀點(或研究心得摘要)
其他疑問 待日後再一一回覆
我是初階班的學生 才要跟上進度時 不想被高階段的問題給打亂了學習進度
:)
Mell

[999369]

沒什麼人要猜 ;(

那只好公佈答案了



答案是到65Hz都還有吸收系數都還有1, 很可怕吧!

所謂的Type 2產品厚度增加0.25英吋, 到達4.25英吋, 更是在極低頻有很大的效果!

Type 1 Modex Plate shown above, for Type 2 click here.

Small rooms often exhibit poor low frequency response with significant emphasis at modal resonances. This is especially true when they are sonically well isolated, due to massive boundary construction. Porous or friction based surface absorption is ineffective at these modal frequencies because the air particle velocity near walls and corners is essentially zero, resulting in very low absorption efficiency. Many bass absorption products on the market today are in fact porous material based products that can not possibly meet the specifications that they claim. For these reasons, RPG developed its Modex™ product line and is extremely proud to introduce a new and unique addition to this line, called the Modex™ Plate. The Modex™ Plate technology was developed and patented by the Institute for Building Physics at the Fraunhofer Institute, and consists of a damped metal plate system. The Modex™ Plate offers broadband low frequency absorption effective down to 50Hz in a thickness of only 4 inches, and 35Hz in a thickness of only 4.25”. The Modex™ Plate has an attractive powder coated metal finish and can be surface mounted on walls or ceiling. Every now and then a new technology comes along that can change everything. You will be astounded at the transients and clarity of sound, once the Modex™ Plate removes all of the masking low frequency reverberation. Now you can absorb more bass in less space!
Technology
Sound (1) strikes the steel plate (2) which pistonically vibrates (3) against the porous absorption spring (4), mounted on a rigid backing (8). The porous absorption also damps plate bending modes (5) and absorbs higher frequencies which diffract around the plate (6) through a perforated (7) metal frame.
Surface or corner applied porous materials lose efficiency at low frequencies, because the particle velocity or air movement associated with these long wavelengths is low. In order to maintain efficiency at low frequencies, the Modex™ Plate consists of a damped metal plate system. While the velocity is low, the pressure is at a maximum near the boundary and it is this pressure that is exploited in a mass-spring manner offering absorption via three mechanisms. First, the metal plate provides pistonic absorption down to the lowest frequencies by vibrating against the “spring” of the porous backing. Second, the bending modes of the free-moving plate are heavily damped by the proprietary adhesive coupling with the porous backing which attenuates the lower mid-range frequencies. Lastly, mid-frequency sound waves diffract around the plate’s edges to be propagated and thus dissipated in the deep passive porous absorber layer. Together, these mechanisms offer the industry’s first truly efficient, broad bandwidth low frequency absorber with a shallow profile of only 4 inches.
Absorption
Many published low frequency absorption coefficients are misleading, because the accuracy of the absorption efficiency decreases frequencies below 100Hz in standard ISO 354 and ASTM 423 test chambers, due to inadequate diffusion and modal density. Therefore, additional testing has been carried out at the Fraunhofer Institute in large scale impedance tubes with a cross section of 1.6 x 1.2 m and a special approach monitoring the decay times of the lowest axial modes in a 5x4x3 m room, with and without the sample present on one of the opposing surfaces. You can trust these data to be reliable and accurate.

Installation
The Modex™ Plate is installed by attaching metal “L” brackets to the boundary surface and sliding the panel over and screwing to brackets. Panels should be installed at high pressure locations. In order of highest to lowest efficiency, this would be the intersection of three boundary surfaces, two boundary surfaces and on one boundary surface.
補上原网站全文~~~
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TYPE 1

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TYPE 2

[THXman]

999369兄,有用心.從原文處搬來.
版主應該將會熱心的翻譯給一般網友看看.
其實對於進過實驗室者的聲學設計者.工程師等,對於RPG的數據也以參考性而居.

此類技術坦言,全球聲學界早已使用,而RPG的產品開發是晚的,晚於德國好多年.
聲學設計者.工程師常為自己的CASE所需,設計自己當處當用的此類物品.

[將軍]

呵.給我足夠的資金與完備的實驗室,鄙人可以協助許多人看清許多事物.
猶如"流言終結者"或http://www.youtube.com/watch?v=NPx-sv8WCoA節目
事實是殘酷的,往往許多人與商家不願面對.

這樣的態度不好.
你有些文章是不錯,我都曾經給你個讚.
當然或許你認為不需要,但這是就事論事.
如果要提出你可以做到的具體反證,那必須要有實證.
提不出真正的實證,就只會淪入口水戰.
要證明自己比別人強不是不行,但要有真實力.
網路要用嘴巴說"真實力"誰都會.
但到了現實生活如果仍是這樣,那有何意義?

這裡的素質很優,我也認為你有獨到的一面.
但必須要有真正可顯示的實證(力)!!