Q6：請問網路小廠或DIY的超低音送測data-bass是否如takeone4345先生所述與知名大廠送THX認證的等級差太多了？(https://www.mobile01.com/topicdetail...0&p=1#67032920)
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A6：
(1) 從其述而揣，當未進行過THX認證超低音與近10年來一些美國知名ID超低音…等之間的一些相關電聲測量比較，若有從之且豐，便會知曉許多大廠的超低音性能並非比這些知名ID超低音性能佳。
(2) 竊揣，其應也不明THX於超低音的認證採何測試與標準。
(3) 就基本項CEA-2010測量而言，係明文之測量及宣告規範，THX係私營機構認證。

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Q7：請問，THX標準是否如takeone4345先生說的那般，盧卡斯影業（Lucasfilm）制定的就比維基百科找不到的CEA-2010還行？(https://www.mobile01.com/topicdetail...0&p=1#67038448)
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A7：非也。許多規範標準在維基百科都會找不到，其顯有對此不明。

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Q8：CEA-2010是如takeone4345先生所述，「測量距離很詭異」？是「一個測量距離都搞不定的測試標準..推廣者的比喻是不倫不類..」？
(https://www.mobile01.com/topicdetail...0&p=1#67034392)
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A8：
(1) 從歷史以觀，並未見著CEA-2010之推廣者將此比喻是不倫不類。
(2) takeone4345先生口中的推廣者當是他錯指的brent butterworth，依brent butterworth原文也未見其比喻是不倫不類。
(3) 就takeone4345先生文述，可知其自身對超低音的Outdoor Test及電聲的一些相關Test所知甚薄，亦未閱讀CEA-2010的規範內容，而且也未有過超低音正確的Outdoor Test實務經驗，只要有一定學理知識、技術及實務經驗者，對於那距離的修改是知悉的，但這樣的距離修改，並不會使擁有Outdoor Test實務經驗的工程師無從下手。

從brent butterworth寫那份手冊(主要應是要給廠商看並諮詢)，其所探論問題，係就其個人Outdoor Test經驗與想法，對於他感到一些問題處進行了他的理解與探討。

CEA-2010初起所定測距是至少須距幅射單元1米，由於CEA-2010所使用的測量方法相應於傳統測量習慣上一般喇叭常用之1米距時，其所需使用的測量距離是2米，此在規範內亦有書 (了解學理者皆知)。因此許多測量者多會選擇2米測量，因為這樣好將數據進行整合及比較。

在CEA-2010的修改版中對測距有所修改，這對擁有Outdoor Test實務經驗者或工程師們等或許有些會感到不是很佳，因為先前多依相應於傳統的測距測定，如此要若改測距，這樣出來的資料較不能有方便而一致性的整合與比較，對消費者並不是能與先前已測量過的超低音數據方便而一致性的進行整合與比較，因此許多測量者依然會維持相應於傳統的2米測距測定。
若在3米測，距離將更遠些，信噪比易有較多的影響性，與舊有測量data的整合與比較性為不一致化。
對於尺寸較小的低音(這不是很好且正確的區分法，但為使一般民眾有個簡易的概知，因而行之的暫時簡便區分法，坦言之，這一階幾多非屬”超低音”)，其於2米測距來說(相較於1米測距)，信噪比易有較多的影響性，因此有的測量者多會選擇以1米測之，如brent butterworth所書述。

My recommendations for test distances are as follows:
Powered subwoofers with drivers 8 inches or larger: 2 meters
Powered subwoofers with drivers 7 inches or smaller, wireless speakers, 2.0-channel soundbars: 1 meter

在市場上對於「極低頻」有一定重播能力的「超低音」，幾乎多是大於8吋以上，因此許多測量者就CEA-2010之測定時，多選用2米測距。


PS.
就在下個人而言，因在下做過超低音的Outdoor ground plane measurement，由於曾於網上見過brent butterworth的某些Outdoor ground plane measurement照片，讓在下感到其在環境的設置上有較不夠嚴謹處，故個人對其data存有較高一點的保留。

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Q9：CEA-2010改版何以修改測距？



A9:
(1) 確準原因可能得請教CEA工作組成員。
(2) 依目前的學理、技術、操作方法、規範…等相關資料來看，可竊揣的原因當然非只一個，不過有一蠻可能的原因存在，係為了與ANSI/CEA-2034-A相應。以下為ANSI/CEA-2010-B的FOREWORD供參。

FOREWORD

The purpose of the tests described in this standard is to provide data that will help the consumer understand how loud in volume, and how low in frequency, the subwoofer is capable of operating. The reporting format of the test results should also help the consumer determine which subwoofers may work well with different full-range loudspeaker systems which carry ANSI/CEA-2034 ratings.

This standard describes how to measure and report the maximum usable sound pressure level of a subwoofer, and how to measure and report the input impedance of a passive subwoofer. It also describes how to calculate and report the required output power of the amplifier needed for the consumer to get the desired SPL from a passive subwoofer.

Finally, it includes a number of informational annexes to help readers gain a more thorough understanding of techniques for acquiring loudspeaker data in both anechoic and non-anechoic environments.
When used properly this standard should assist manufacturers in accurately measuring the capabilities of a subwoofer and specifying them to consumers. Using this in conjunction with ANSI/CEA-2034 Standard Method of Measurement for In-Home Loudspeakers for full-range loudspeaker systems, the ANSI/CEA-2010-B subwoofer ratings should make it easier for the consumer to select, purchase, and enjoy a subwoofer that will complement their main full-range loudspeaker system.

This standard was developed by the Consumer Electronics Association’s Audio Systems Committee (CEA R3 Committee).

(3) 在ANSI/CEA-2034-A的Scope Summary中也透出以下的訊息。

Scope Summary:

This standard describes an improved method for measuring and reporting the performance of a loudspeaker in a manner that should help consumers better understand the performance of the loudspeaker and convey a reasonably good representation of how it may sound in a room based on its off-axis response and how this response affects the consumers experience.

Finally, it includes a number of informational annexes to help readers gain a more thorough understanding of techniques for acquiring loudspeaker data in both anechoic and non-anechoic environments, as well as methods for using this acquired data to predict loudspeaker performance.

This standard applies only to loudspeaker systems, and not to raw transducers.
This standard is being revised to align it with CEA-2010-B Standard Method of Measurement for Powered Subwoofers.

(4) 一般燒友或音響愛好者可能對ANSI/CEA-2034-A較不知悉，在2016年S&V(有些燒友或音響愛好者較知此)的一篇專訪文中，Dr. Sean Olive (Harman) 就曾提及它。

At Harman we can characterize and predict the sound quality of loudspeakers with 86 percent accuracy based on a set of comprehensive anechoic measurements. Our measurements are now the basis for a new ANSI/CEA 2034-A Standard: Method of Measurement of In-Home Loudspeakers so there is hope that eventually these will be adopted as standards for the industry. We are doing similar research to develop specifications for headphones that indicate how good they sound. So some progress is being made but there is still more work to do.

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Q10：CEA-2010是如takeone4345先生所述在美國非主流？僅有一小部分人在吹捧？CEA-2010沒有參考價值？(https://www.mobile01.com/topicdetail...0&p=1#67038448)
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A10：
(1) 故意的胡亂吹捧或故意的惡意詆毀及扭曲CEA-2010，其心多為可議，猶似過往許多廠家、商家...等，再再詆毀DSP(EQ...)之狀，俟有商利之時，又拼命吹捧鼓售。客觀忠實的去了解與看待，方為正知智舉。
(2) CEA-2010當然非權威，其係測量規範之一，依其可得超低音一些基本性能的規範測試與宣告，並非無參考價值。無參考價值之述論，心可議焉。
(3) 不僅只美國的喇叭廠商，許多的「主流」往往是給出不清不楚的data，使消費者不清不楚，此可參究許多喇叭相關之測量PAPER、規範...等，此亦可參卓Dr. Floyd E. Toole 等之述及。
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