本帖最后由 nfsking2 于 2009-4-11 17:07 编辑
无意间看到这篇ixbtlabs的英文评测。看样子这篇评测出来已经有一段时间了，不过考虑到里面的扇子基本上都是市面上很容易买到的，也是大家经常用的，评测涵盖了双滚珠和油封两种轴承，再加上ixbtlabs的评测向来非常公正客观，所以就转过来了，希望对大家选择风扇有所帮助。
原文当中有同一品牌8cm和12cm两种风扇的评测，这里只转载12cm的，8cm也可以作为参考
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Arctic Fan 12cm
The shootout starts with models from Arctic Cooling — "inverted" Arctic Fan 8 (80x80x38 mm, 2000 rpm) and Arctic Fan 12 (120x120x38 mm, 1500 rpm).
首先是Arctic Fan 12cm，转速1500rpm
A distinctive (practically unique) feature of Arctic Fan 8 and Arctic Fan 12 is their crafty case design — there is no case as such, a stator with an impeller are mounted on a frame with a special rubber suspension system to dampen vibrations. We should also mention the inverted stator-impeller block. Owing to this design, the impeller rotates clockwise (the other standard fans rotate counterclockwise), which may be a considerable advantage for unusual usage of Arctic Fan 12 (it will be described later).
AC的这两款风扇拥有与众不同的框架设计：没有普通常见风扇的外框，马达与叶轮安装在顶部，配合橡胶的悬架系统抑制转动所产生的振动。另外需要注意的是叶轮的固定方式。通过这种设计，扇叶按顺时针方向转动（其他普通风扇都是逆时针），这样一来，AC的这两款风扇就有了更多特殊用处（后文会提到）。
While Arctic Fan 8 and Arctic Fan 12 look very well in aerodynamic terms, the technical image of these fans fades a little in mechanical terms — although they are equipped with improved sleeve bearing (this one consists of two sleeves — inner surface of the first sleeve is polished and mated with the shaft, the second has a larger inner diameter and rough surface covered with soft lubricant that holds oil), this is hardly "fluid dynamic bearing " (according to Arctic Cooling specs).
AC的这两个风扇看起来有很不错的空气动力学设计，同时也有着很不错的机械构造--使用了改进的油封轴承，包含两层构造：第一层是被光滑套筒包裹的扇叶轴，第二层是粗糙的表面，用于存储润滑油。看来这两个风扇都没有使用AC的“液压轴承”
We also have some gripes with the electric binding of the engine — the inductor is controlled by a simple Anpec APX9140 chip, which only advantage is its ability to work with low voltages — starting from 3 V. There are no additional smoothing capacitors, which are usually used in such circuits to clip reverse voltage surges and protract the front-decay of switching impulses in the inductor coil. It leads to a noticeable component in fan noise - co-called engine popping (noises in the stator-impeller block caused by switching inductor coils). And perhaps the biggest gripe — performance of Arctic Fan 8 and Arctic Fan 12. Despite the advanced impeller, these fans demonstrate weak performance in our testbed. They are outperformed by practically all contenders. The situation with noise characteristics is ambiguous as well (especially what concerns Arctic Fan 12). To all appearances, it's the fault of the open frameless design of Arctic Fan 8 and Arctic Fan 12 — the impeller actually works in the propeller mode here - with intensive vortex formation and significant pressure loss. As a result, fan performance slumps in a section with high impedance (our reference test heatsink), they generate minimum airflow. When in slow mode (1500 rpm for Arctic Fan 8 and 700 rpm for Arctic Fan 12), there is practically no effect from them. What concerns the other two Arctic Fans — Arctic Fan 8L and Arctic Fan 12L, they are complete aerodynamical copies of Arctic Fan 8 and Arctic Fan 12 and differ in lower speed (1500 rpm in Arctic Fan 8L and 1000 rpm in Arctic Fan 12L).
同时，我们对AC这两个风扇的电子设计方面也有所不满：电路板上有一颗APX9140 IC，作用仅仅是让风扇的启动电压更低（3V），但这影响了风扇的顺滑度，所以在使用当中造成了比较明显的轴承噪音（磁极切换声）。
另一个比较大的问题就是风扇的性能。由于扇叶的特殊设计，无边框构造导致风压的损失，并且就像是一个螺旋桨，造成了一定的气流不均匀。噪音情况也不是很理想。
Cooler Master SAF-B83-E1-GP and OAF-L12-E1
第二个出场的是酷冷的OAF-L12-E1
Another representative of the budget family of Cooler Master (OAF-L12-E1) does not pretend to be an outstanding fan — being an ordinary 120x120x25 mm model, it offers a slimmed-down case and 7-blade impeller (nominal 1600 rpm). 与8cm型号同一家族的12cm风扇OAF-L12-E1并不算是一个出色的产品。默认转速1600rpm，7片扇叶，超薄框架设计。 As in case with the SAF-B83-E1-GP, aerodynamic configuration of the OAF-L12-E1 impeller is designed for reduced noise: sweep and lean blades, the chord is 20 mm at the hub and 35 mm at the tip, chord-pitch ratio - 1 at the hub and 0.7 at the tip, angles of attack - 35° at the hub and 20° at the tip, 0.38 hub-tip ratio, 1.5 mm tip clearance. 与8cm型号不同，这款12cm风扇的设计目的是为了降低噪音：叶片角度等细节都作了比较大的调整。 But the electrical situation still leaves much to be desired — the inductor (which coil is not very tidy) is controlled by the ATS276 chip. Besides, the circuits should have incorporated smoothing capacitors. But there aren't any with all natural consequences — popping of the OAF-L12-E1 engine is audible. In practice, the OAF-L12-E1 demonstrates acceptable efficiency in our testbed, both in the standard mode and at 1000 rpm. But performance drops significantly in a slower mode (700 rpm). It looks like the sparing aerodynamics of the impeller is not efficient at low speed and cannot generate a steady airflow with acceptable static pressure
不过风扇的电路方面还是有需要斟酌的地方：线圈排列不整齐，使用了ATS276 IC来控制电感。本来轴承应该使用更平滑的capacitors（电容？），但CM没这么做，所以这个风扇的马达声还是比较明显。
在测试中，标准转速和降速到1000rpm的OAF-12L-E1性能还是不错的，不过在700rpm时，风压和风量就不合格了。
GT12025-EDLA1
GlacialTech的12cm风扇
Parametric layout of the GT12025-HDLA1 is also interesting. Its impeller is notable for the reinforced aerodynamic profile on the front edge of blades (8% of the chord). It demonstrates low-noise design with a good performance potential — sweep and lean blades, the chord is 24 mm at the hub and 37 mm at the tip, chord-pitch ratio - 1.33 at the hub and 0.74 at the tip, angles of attack - 45° and 30°, 0.35 hub-tip ratio, 1.8 mm tip clearance.
GT12025的设计也相当有意思。叶片作了增加气动性能方面的强化。目的是在低噪音的前提下获得足够好的性能。
GT12025-HDLA1 look neat in electric terms as well: although the engine binding is based on the simple S211 chip (however, it's better in some parameters than the ATS276/277 chips popular in the budget segment). A neat inductor and smoothing capacitors at the output of coil drivers improve the situation — the electric popping in the fan noise is still noticeable, but it's quieter than in Arctic Cooling Arctic Fan 8L or Cooler Master SAF-S12-E1-GP
GT12025在电路板做工方面还是相当不错的：虽然使用了最简单的S211 IC，不过看起来甚至比某些使用ATS276/277的风扇的情况还好点。由于电容和线圈设计不错，因此，虽然有少量噪音，不过比AC和CM的扇子要好多了。
Scythe Minebea 12cm Mid and Minebea 12cm High
忍者扇子。不过这个其实就是NMB的B19和B29。
The 9-blade impeller has a very interesting aerodynamic configuration, which is designed for maximum performance with acceptable noise ergonomics — sweep and lean blades, chord - 20 mm at the hub and 30 mm at the tip, chord-pitch ratio is 1.25 at the hub and 0.79 at the tip, aggressive angles of attack - 50° and 35°, 0.41 hub-tip ratio, 1.5 mm tip clearance. Minebea's impeller also has three aerodynamic benefactors that reduce the noise and raise its efficiency — a screen on the front edge of the blade, dihedral blade, and smoothed rear edge of the blade.
扇叶为9片，设计比较有意思：其目的是为了获得最大性能的同时降低噪音。
Another feature of Minebea fans is their advanced electric binding of the engine called Silent IC. The integrated controller is based on Sanyo LB1868M (a counterpart of LB1668M). Interestingly, the outputs of inductor's drivers use integrating circuits (a couple of resistors, a key bipolar transistor, and an integrating capacitor between the base and collector) instead of capacitors. Integrators efficiently protract the front-decay of switching impulses in the inductor coil. As a result, this IC stands up to its title — Minebea 4710KL-04W-B19 and 4710KL-04W-B29 are the only fans today without electric popping in their noise. Minebea fans look great from the practical point of view as well. They achieve excellent results with acceptable noise ergonomics. They demonstrate the highest performance at nominal speed (1900 rpm for the 4710KL-04W-B29 and 1600 rpm for Minebea 4710KL-04W-B19). But the noise level grows rather high in this mode, which makes them less attractive in the standard mode. Their real potential is revealed at moderate speed — they demonstrate good universality of the impeller, spiced up with ergonomic noise characteristics. So they provide the best efficiency/noise ratio. Minebea 12cm Mid and Minebea 12cm High are very interesting products with excellent technical properties. Our only gripe is their prices: their average retail price is $18, which makes them the most expensive fans in the market. This price is too high in our opinion, even for High-End. But it cannot be helped — High-End requires sacrifices. :)
NMB风扇的另外一个特性就是拥有特殊的IC，用于消除磁极切换声。因此，B19以及B29是这次评测当中，唯一没有磁极切换噪音的风扇。
从客观角度看，NMB的风扇相当令人满意。它们在各自的转速当中都表现出了最高的性能（B19 1600rmp，B29 1900rmp）。不过噪音在高转速的情况下也相当明显。因此这两个风扇的价值就在于改转速之后：在低转速下，能够在噪音与性能之间取得一个比较完美的平衡点。
评测者唯一不满意的就是这两把扇子的价格（国外平均价格是18美刀，国内最近倒是便宜~~）
Scythe S-Flex SFF21E and SFF21F
忍者的SFF21E和21F（貌似也是ADDA的马甲）
The main peculiarity of the SFF21E and SFF21F fans is advanced mechanics, based on the unique hydrodynamic S-FDB bearing (designed by Sony). S-FDB uses three technical tricks — soft porous structure of the inner surface of the sleeve, hydrodynamic profile of the inner surface (V-shaped grooves) and fully hermetic bearing (polymer coating) to ensure active recirculation and grease confinement inside the sleeve. A special ring magnet is a good addition to S-FDB - it's mounted in the upper part of the bearing unit together with a metal ring pressed into a hub. Its purpose is to improve dynamic balance of the impeller.
这两个风扇的特点是使用了索尼的液压轴承。这个系列的风扇有三个技术特点：轴承内部柔软，液压轴承，以及轴承完全密封。这样就保证了轴承的稳定运行以及耐用度。
特殊的环形磁铁实际效果也相当不错：最大程度解决了扇叶的平衡性问题。
The SFF21E and SFF21F also have an interesting electric binding of the engine: along with a neat inductor, the fans are equipped with an unusual IC based on Sanyo LA6583. This chip has an interesting feature - the load (inductor) is connected as a bridge between driver outputs (that is it's a single-coil inductor), so coil switching (switching a single coil between drivers) is smoothed a priori. It looks like a magic recipe to eliminate engine popping once and for all. But it's not that simple in practice — the voice of the SFF21E and SFF21F has a noticeable electric noise, which volume compares to usual fans with noise filters based on capacitors. What concerns their results, these fans perform well in the standard mode (1600 rpm for the SFF21F and 1200 rpm). They demonstrate good performance and an acceptable efficiency/noise ratio. They also fare well at 1000 rpm, actively competing with Minebea models and SilentBlade II fans from GlacialTech. But efficiency of the SFF21E and SFF21F at low speed (700 rpm) slumps — which actually moves them towards outsiders in our today's shootout. The image of our fans suffers from another not-quite-positive issue in the standard mode as well — the noise generated by the SFF21E and SFF21F includes tonal coloring in this mode that subjectively makes it louder. The problem seems to be in the nonoptimal disposition of stator's holders, which results in acoustic mismatch of the impeller and fan case.
21E和21F的电路设计比较特殊：线圈整齐，使用了比较特殊的三洋LA6583 IC。这个IC有个比较有意思的特性：电感相当于一个桥梁，连接驱动电路（就相当于是单线圈结构），这样一来，风扇就会表现得非常平稳。这个方法看起来相当不错，不过实际上，比起带有噪音过滤电容的普通风扇，这两个风扇仍然有明显噪音。
这两个风扇在默认转速下（21F是1600rpm，21E是1200rpm），性能不错，不过噪音也明显。风扇转速降到700rpm时，它们成为了本次评测的亮点：此转速下的21F和21E仍然具有相当好的性能。
不过风扇在默认转速下的噪音似乎不止是磁极切换声，所以主观上感觉其噪音比其他风扇更大。问题似乎是出在风扇叶片和框架的搭配上。
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下面是比较直观的噪音数据测试图：
这是AC 12cm风扇的测试结果
噪音集中在125~200Hz这个频率上，因此主观的感觉就是低频的噪音比其他风扇更明显。
前面说到AC的扇子因为特殊的构造，因此也有特殊的用途，不过评测原文在后来就没提这事了.......大家发散一下思维，看看到底还能怎么用
AC 12cm扇子在降速后的表现
降速后的AC风扇有了比较好的表现，无奈其设计导致扇子在低转速下的效能并不好，并且噪音仍然集中在低频，另外，500Hz频率的噪音又凸显出来。看来这与它特殊的框架有关：风噪比较明显
酷冷的12cm风扇测试结果
低频噪音本来表现还算正常，不过200Hz处突然噪音陡增（大约8~10 dB），然后是400Hz处的明显噪音。接下来令人感到奇怪的是630Hz的噪音，一直持续到800Hz，并且与风扇自身的震动产生了共振（1.25KHz处）。另外，2KHz处凸显出来的噪音并不让我们感到意外：磁极切换声
GT12025的结果
看来这个扇子的噪音非常符合“人体工程学”，因为噪音突出的频率都是人耳不易察觉的频率.......
评测原文给出的词是"不同寻常"，看来这个扇子确实很安静！！
接下来是大名鼎鼎的B19/B29
由于两个扇子只是转速不同，因此原为只给出了B29的测试结果图。
由于是双滚珠轴承，再加上很高的转速（1900rpm），因此B29的噪音分布显得很“平滑”：每个频段似乎都差不多。
考虑到这样的转速，噪音表现其实算是很不错的，最高处就是315Hz，而其他大部分地方的噪音其实只有一个来源：风噪~~
综合前面的评测来看，在转速降低之后，B19/B29在各方面的表现都能让人相当满意。
21F的结果
整体表现不错，但在200Hz处有明显噪音，甚至比相邻频段的噪音高出11~12 dB。然后噪音在400Hz和500Hz处又有明显提升，最后，在800Hz再次出现第三次较大噪音，并且与风扇本身的震动产生共振。
21E/21F的噪音也不仅仅限于风噪或者轴承噪音，而是各种噪音混合起来。这种声音显得非常不某种水产，甚至可以叫刺耳（原文是这么说的）
评测还给出了一个TT的风扇：A1225L12S的成绩作为对比
这个扇子与TT大台风散热器上标配的风扇是一个型号。不过这个风扇的单独型号是Turbofan TT-1225。估计两者之间就只是颜色差异。
评测没有过多评价这个扇子，只是说在160Hz和315Hz处存在明显的低频噪音。虽然从测试图上看，这个扇子应该是很安静的，但主观的感觉上，低频噪音还是比较明显。
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评测部分到此结束。
下面说说我的看法。
以上几把扇子，我几乎都用过，除了21E/21F。
AC的扇子用途比较局限，且在默认转速时，噪音非常大（主要是风噪），但是默认转速的风量也相当猛，所以不怕噪音的朋友可以上，只是价格不某种水产。
TT的这个扇子是某TT专卖店的朋友送的，因为之前我买过一个发光风扇，噪音明显，他说这个扇子噪音几乎没有。
不过从我的使用来看，噪音明显。即使在接5v、调速器和降速线等多种办法降速之后，噪音仍然不能接受，不推荐。
酷冷的风扇用得不多，唯一一个就是机箱上原配的蓝色发光风扇（可测速的那种），由于转速比较低，只有1000rpm左右，因此噪音几乎没有，用来做机箱前置风扇给硬盘降温还是比较合适的。因此我觉得酷冷的风扇如果便宜，可以收一个转速低的来用。
GT的风扇不错。我用的型号也正是评测当中提到的。确实非常非常安静，被我当作第二个机箱前置风扇，专门给CPU/内存送风。价格貌似也不贵（这个是买U120E的时候硬要商家送的）。
NMB的B19。其实在默认转速下，关上机箱，B19的噪音也变得可以接受，但风噪较大，特别是跟机箱冲网之间产生的切风声，看来跟风量大小有关系。而装在U120E上面，即使全速，声音也不大。所以我的办法跟大家一样：加调速器。目前为止，机箱里的两个B19我都相当满意。机器满载时一般都是在跑游戏的时候，因此风噪也完全被音箱的声音掩盖了，需要静音的时候就把转速调低，噪音比GT的那个扇子大不了多少。
21E和21F没用过，不过看评测结果，似乎问题出在风扇共振嗦产生的低频噪音上。
因此，风扇在使用的时候需要注意的一个重要问题就是安装方法。
有共振的风扇或者转速高的风扇，最好不要采用胶钉来固定，这样振得更厉害。我是使用螺丝+厚海绵。在风扇与机箱接触的地方垫上一层较厚的海绵，再用螺丝固定死，这样共振就基本可以消除了。
另外，这种方法也可以用在硬盘上。很多人都说硬盘共振厉害，要用橡皮筋吊起来。其实用硬盘盒里面送的那种海绵条粘在硬盘侧面或者导轨上面，也完全可以解决共振问题。
OK，帖子全部编辑完毕~~~ |
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发表于 2009-4-11 14:34
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