轉(zhuǎn)一篇最近的新聞（12月1日），大家理性探討。

It's hard for me to believe it's been seven years since researchers from Harman International presented the landmark paper “The Relationship between Perception and Measurement of Headphone Sound Quality” at the 2012 Audio Engineering Society Convention in San Francisco -- the first paper in which the company presented what became known as the “Harman Curve,” the target frequency response that average listeners would like best. When I first read that paper, I assumed it would quickly revolutionize the headphone business. As a headphone reviewer, I knew that the various headphones and earphones then on the market often exhibited wildly different sounds -- even among different models in a company’s line -- which indicated that knowledge was lacking or simply being ignored.

Yet we didn’t see a surge in headphones claiming to use the Harman Curve -- not even from Harman companies AKG, JBL, and Harman Kardon, although other manufacturers had quietly confided to me that they were basing?theirdesigns on the Harman Curve. In fact, the first set of passive headphones I’ve received from a Harman company using the Harman Curve only came across my desk last month: the?AKG K371s-- and the only way I knew that they were voiced within 1dB of the Harman Curve was by reading a Facebook post from Harman senior fellow Sean Olive.

It looks, though, like the dam is finally bursting. In a presentation last month to the Los Angeles chapter of the AES, Olive highlighted several other headphones and earphones designed along the lines of the Harman Curve (although not, as best I can tell, marketed as such). The earphones include Samsung Galaxy Buds; JBL Live 200s, Live 500s, Live 650s, and Reflect Flows; and AKG N5005s. Headphones, for now, seem to include only the AKG N700 NCs, K371s and K361s, but we can expect more. As Olive told me later in an e-mail, “Basically all new AKG headphones are designed to Harman target and for the past year JBL has followed it but with 2dB extra bass below 125Hz.”

Olive’s presentation detailed Harman’s ambitious research into headphones, which has since 2012 resulted in 19 papers, one patent (and three more pending), and a?one-click routine for the SoundCheck audio measurement suite?that uses the Harman Curve to predict listener preference. The effort started with the realization that, as Olive put it, “There were standards for diffuse-field and free-field headphone response, but no one was following them so there must have been something wrong.

“At the time, our marketing department was telling us that we should duplicate the response of Beats headphones, because those were the best-sellers,” he continued. But Harman’s researchers had already evaluated those headphones in blind tests, and found them to be unpopular among their listeners. “So we told them they should duplicate Beats’ marketing instead,” he said.

The researchers’ idea was that if headphone designers knew what measured response best suited the largest number of listeners, the designers could then tailor their products’ frequency responses to that target. This would be more efficient than “shooting in the dark” by building headphones, putting them through listening tests (which, if you want them to be blind, are much more complicated with headphones than they are with speakers), then repeating the process until most of the listeners are pleased.

Harman’s first effort involved a blind test of six over-ear headphones, followed by measurements of those response curves to see what response pleased the most listeners. Subsequent projects solicited the judgment of hundreds of listeners around the world, and measurements of hundreds of different headphones.

The result of all that effort was Harman Curves for earphones and over-ear headphones. But as Olive suggested in his above comment about JBL headphones, it’s not a “one-size-fits-all” target. His presentation identified three potential groups to which manufacturers can target their headphones.

“Harman Curve Lovers”:?This group, which constitutes 64% of listeners, includes mostly a broad spectrum of people, although generally under age 50. They prefer headphones tuned close to the Harman Curve.

“More Bass Is Better”:?This next group, which makes up 15% of listeners, prefers headphones with 3 to 6dB more bass than Harman Curve below 300Hz, and 1dB more output above 1kHz. This group is predominantly male and younger -- the listeners JBL is targeting with its headphones.

“Less Bass Is Better”:?This group, 21% of listeners, prefers 2 to 3dB less bass than the Harman Curve and 1dB more output above 1kHz. This group is disproportionately female and older than 50.

According to Olive, his group still has some more research into headphones to do, but they’re starting to wrap it up and anticipate moving on to new projects. We don’t yet have enough information to know if the Harman Curve will result in greater sales, millions more happy listeners, and Better standardization of headphone evaluation. I’ve learned from listening to several headphones and earphones that come close to the Harman Curve that it is, at the very least, an excellent baseline for performance. Headphones and earphones may, for various reasons, deviate to some extent from the Harman Curve. But if their measured response is far from the Harman targets, listeners and reviewers should at least question why, and the manufacturer should be able to respond with a plausible rationale based on research and testing.

I expect we’ll encounter manufacturers and reviewers who simply claim, “I listened to some Harman Curve headphones and I don’t think they sound very good.” Audio enthusiasts will then have to decide if they trust the conclusion of a single person, determined through casual, sighted testing, or the conclusion of years’ worth of research conducted with hundreds of listeners in carefully controlled blind tests. I know which way I’ll go.

. . . Brent Butterworth
brentb@soundstagenetwork.com

我很難相信，自從哈曼國(guó)際的研究人員在2012年舊金山國(guó)際音頻工程協(xié)會(huì)會(huì)議上發(fā)表了具有里程碑意義的論文“耳機(jī)音質(zhì)的感知和測(cè)量之間的關(guān)系”以來(lái)，已經(jīng)有七年了，這是哈曼國(guó)際在第一篇論文中提出的所謂“哈曼曲線”，聽(tīng)眾平均最喜歡的目標(biāo)頻率響應(yīng)。當(dāng)我第一次讀到那篇論文時(shí)，我以為它會(huì)很快給耳機(jī)行業(yè)帶來(lái)革命性的變化。作為一名耳機(jī)評(píng)論員，我知道當(dāng)時(shí)市面上的各種不同型號(hào)的耳機(jī)經(jīng)常表現(xiàn)出迥然不同的聲音——即使是在一家公司生產(chǎn)的不同型號(hào)之間——這表明缺乏相關(guān)知識(shí)，或者只是被簡(jiǎn)單的忽視了。?

然而，我們并沒(méi)有看到聲稱使用哈曼曲線的耳機(jī)激增——甚至哈曼國(guó)際自己的AKG、JBL和Harman/Kardon也沒(méi)有，盡管其他制造商已經(jīng)悄悄地向我透露，他們正在設(shè)計(jì)基于哈曼曲線的耳機(jī)。事實(shí)上，上個(gè)月，第一批我從哈曼國(guó)際收到的使用哈曼曲線的被動(dòng)耳機(jī)才出現(xiàn)在我的辦公桌上：AKG K371——我知道它們?cè)诠€±1dB范圍內(nèi)的唯一方式就是閱讀哈曼國(guó)際高級(jí)研究員Sean Olive在Facebook的帖子。?

不過(guò)，看起來(lái)大壩終于要決堤了。在上個(gè)月向AES洛杉磯分部的一次演示中，Olive著重介紹了其他幾款按照哈曼曲線設(shè)計(jì)的耳機(jī)(盡管據(jù)我所知，它們并不是按照哈曼曲線設(shè)計(jì)的)。包括三星Galaxy Buds; JBL Live 200，Live 500，Live 650，Reflect Flow；和AKG N5005。目前，這些耳機(jī)似乎只包括AKG N700 NC, K371和K361，但我們可以期待更多。正如Olive后來(lái)在一封電子郵件中告訴我的，“基本上所有新設(shè)計(jì)的AKG耳機(jī)都是按照哈曼目標(biāo)曲線設(shè)計(jì)的，在過(guò)去的一年里JBL也遵循了這一標(biāo)準(zhǔn)，但額外在125Hz以下增加了2dB的低音。

這里我要更正一下，至少我測(cè)試過(guò)的，N5005和Galaxy Buds是哈曼曲線耳機(jī)，也許作者沒(méi)有搞清楚。。。

Olive的演講詳細(xì)介紹了哈曼對(duì)耳機(jī)的雄心勃勃的研究，自2012年以來(lái)，哈曼國(guó)際對(duì)耳機(jī)研究發(fā)表了19篇論文、1項(xiàng)專利（還有3項(xiàng)正在申請(qǐng)中）和SoundCheck audio measurement suite的一鍵式程序，該程序使用哈曼曲線來(lái)預(yù)測(cè)聽(tīng)眾的偏好。正如Olive所說(shuō)，這項(xiàng)工作的開(kāi)始是意識(shí)到“有擴(kuò)散場(chǎng)和自由場(chǎng)耳機(jī)響應(yīng)的標(biāo)準(zhǔn)，但沒(méi)有人遵循這些標(biāo)準(zhǔn)，所以肯定是哪里出錯(cuò)了。 ”

“當(dāng)時(shí)，我們的市場(chǎng)部告訴我們，我們應(yīng)該復(fù)制Beats耳機(jī)的頻響，因?yàn)樗鼈兪亲顣充N的，”他繼續(xù)說(shuō)。但哈曼的研究人員已經(jīng)在盲測(cè)中評(píng)估了這些耳機(jī)，發(fā)現(xiàn)它們?cè)诼?tīng)眾中不受歡迎。他說(shuō)：“所以我們告訴他們應(yīng)該復(fù)制Beats的營(yíng)銷模式。 ”

哈曼研究人員的想法是，如果耳機(jī)設(shè)計(jì)師知道什么樣的測(cè)量響應(yīng)最適合最大數(shù)量的聽(tīng)眾，那么設(shè)計(jì)師就可以根據(jù)這個(gè)目標(biāo)定制他們產(chǎn)品的頻率響應(yīng)。這將比“盲人摸象”的方法研發(fā)耳機(jī)更有效。讓他們通過(guò)聽(tīng)力測(cè)試（如果你想讓人們盲聽(tīng)，戴耳機(jī)要比聽(tīng)揚(yáng)聲器復(fù)雜得多），然后重復(fù)這個(gè)過(guò)程，直到大多數(shù)聽(tīng)眾滿意為止。?

哈曼國(guó)際的第一項(xiàng)研究是對(duì)六個(gè)入耳式耳機(jī)進(jìn)行盲聽(tīng)，然后測(cè)量這些耳機(jī)的響應(yīng)曲線，看看最讓聽(tīng)眾滿意的是什么。隨后征求了全世界數(shù)百名聽(tīng)眾的意見(jiàn)，并測(cè)量了數(shù)百種不同的耳機(jī)。?

所有這些努力的結(jié)果就是耳機(jī)的哈曼曲線。但正如Olive在上述關(guān)于JBL耳機(jī)的評(píng)論中所暗示的，這并不是一個(gè)“一刀切”的目標(biāo)曲線。他的演講中確定了三個(gè)潛在的群體，制造商可以瞄準(zhǔn)他們?cè)O(shè)計(jì)耳機(jī)。?

“哈曼曲線愛(ài)好者”：這一群體占聽(tīng)眾的64%，其中大部分人都是廣泛分布的，盡管一般都在50歲以下。他們更喜歡在哈曼曲線附近調(diào)音的耳機(jī)。?

“低音越多越好”：占聽(tīng)眾15%的下一組人更喜歡低音比300赫茲以下的哈曼曲線多3至6dB的耳機(jī)，耳機(jī)在1kHz以上也多1dB。這一群體主要是男性和年輕人——JBL耳機(jī)所瞄準(zhǔn)的這部分聽(tīng)眾。?

“低音越少越好”：21%的聽(tīng)眾喜歡比哈曼曲線少2到3分貝的低音，高于1kHz多1dB。這個(gè)群體中女性和年齡超過(guò)50歲的長(zhǎng)者比重較高。?

據(jù)Olive所說(shuō)，他的團(tuán)隊(duì)還需要對(duì)耳機(jī)做更多的研究，但他們已經(jīng)開(kāi)始總結(jié)，并預(yù)計(jì)將繼續(xù)進(jìn)行新的項(xiàng)目。我們還沒(méi)有足夠的信息來(lái)知道哈曼曲線是否會(huì)帶來(lái)更大的銷量，使數(shù)百萬(wàn)聽(tīng)眾快樂(lè)，以及更好的耳機(jī)評(píng)價(jià)標(biāo)準(zhǔn)化。我從聽(tīng)?zhēng)卓罱咏€的耳機(jī)中了解到，它至少是一個(gè)出色的基礎(chǔ)。由于各種原因，耳機(jī)和耳機(jī)可能會(huì)在一定程度上偏離哈曼曲線。但如果他們的測(cè)量結(jié)果與哈曼的目標(biāo)相距甚遠(yuǎn)，那么聽(tīng)眾和評(píng)論者至少應(yīng)該質(zhì)疑其原因，制造商應(yīng)該能夠根據(jù)研究和測(cè)試給出合理的解釋。?

我能預(yù)料到我們會(huì)遇到一些制造商和評(píng)測(cè)人員，他們只是聲稱，“我聽(tīng)了一些哈曼曲線耳機(jī)，我覺(jué)得它們聽(tīng)起來(lái)不太好?！比缓?，音頻發(fā)燒友將不得不決定他們是否相信一個(gè)人通過(guò)隨意的非盲聽(tīng)測(cè)試確定的結(jié)論，還是多年來(lái)對(duì)數(shù)百名聽(tīng)眾在精心控制的盲聽(tīng)實(shí)驗(yàn)中進(jìn)行的研究得出的結(jié)論。我知道我會(huì)走哪條路。?

基于哈曼曲線的耳機(jī)預(yù)測(cè)評(píng)分屬于心理聲學(xué)預(yù)測(cè)模型，而這種模型 是有一定的誤差和浮動(dòng)范圍的。我過(guò)去的測(cè)評(píng)基本上都是主客觀評(píng)價(jià)，算法評(píng)分通常都會(huì)標(biāo)準(zhǔn)僅供參考。主客觀評(píng)價(jià)是聲學(xué)行業(yè)內(nèi)最普遍的一種做法，但我感覺(jué)即便整整一年過(guò)去了，還是有很多人不太了解，所以近期會(huì)專門(mén)寫(xiě)一篇相關(guān)的介紹。