Oct 26th, 2012, 23:50 | 只看该作者 #23 | |
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不过一个破usb线要卖到$120简直是抢钱。其实最简单的办法就是用粗铜导线完事了,减少传输错误其实很简单,而且即使ebay上买来的破usb先在isosynchronous模式下应该错包率也小于千分之一吧(猜得),所以这$120玩意就是人傻,钱多,速来。 我亲自听过故意传输错误路高的音乐,高音部分会出现奇怪的噪音,较低的音则基本不被影响,估计着是掉包部分对高频数字信号影响大,毕竟频率高掉一个包就变频了,呵呵。 其实上述这些都是废话,听音乐用hdmi传输声音最好了,错包自动重发,所以哪怕是ebay $1买来的hdmi线,也和futureshop砍人出血的$100的monster 线无区别。 |
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Oct 27th, 2012, 10:23 | 只看该作者 #24 | |
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数码的,都可以响出来很干净的音质。至于喜不喜欢,完全是个人听感。很多人都会说是bullshit ,但这种听感不同的情况是存在的。完全是个人选择。 如果完全不讲究,其实什么都可以听。没必要长篇大论。 Sent from my SGH-I747M using Tapatalk 2 |
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Oct 27th, 2012, 12:32 | 只看该作者 #25 |
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网上看来的。。‘’USB线听感不同的可能的技术原因。 -1- Waveform distortion: due to its physical properties, the cable can possibly affect the square waves, in interaction with the source and receiver (from that point of view they form an analog system). This in turns affect the accuracy of the recovered system clock fed to the DAC chip. This in turns affects the accuracy of the digital to analog conversion. -2- Interaction in between power supply lines and data lines: it has been measured that 1Khz spikes coming from the data lines can couple into the power supply lines and that the longer the cable, the stronger the effect. Such spikes could maybe be directly heard as noise depending on the dac's pcb layout. Such spikes could also affect the accuracy of the ICs inside the dac, resulting either in increased jitter (for the clock or the receiver chip) or directly in higher distortion (for the dac chip and the opamps of the analog section). -3- Rfi shielding: the usb cables are quite susceptible to high frequency noise pick-up (a reason among others why long runs cannot be used). Noise making its way into data line can perturbate the receiver chip, causing early/late triggers, resulting once again in a poorer system clock. If the noise couples into the power supply lines, see -2-. -4- HF noise attenuation: the source computer signal's quality can vary widely. HF noise can find its way on the various USB lines. A cable attenuating this HF noise could thus have an impact. It could however interacts with -1-. All these are sound engineering reasons and have been measured or could be, given time and the proper (read expensive) equipment. The fact that USB cables affect the analog output of the DAC seems to have been proven by measurements by Paul Miller for the january issue of Hifi News (if anyone has the article, I'd love to read more than hearsay). HOWEVER, the existence of a technical difference in between cables does NOT prove the existence of anaudible difference. It is even more so as the differences outlined above are fairly small and that cables manufacturers don't seem to bother measuring the actual differences their cables make. And you have to keep in mind before any generalization that USB audio uses 3 different protocols with various levels of weakness to those problems, that the USB receiver chips are very different and that DACs are coming from a bazillion different manufacturers who pay more or less attention to their designs. Sent from my GT-I9100M using Tapatalk 2 |
------------------------------- You Cannot Be Serious! |
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Oct 27th, 2012, 13:53 | 只看该作者 #27 | |
别当真
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我觉着‘’USB线听感不同的可能的原因。”,最大嫌疑是听感可以“thought”,而人类的听觉又不怎么样,但烧友又怕别人说自己木耳,就纷纷附和“神耳”的听感! 说一个现象,就可以说明,同样的HDMI 的视频数字传输,怎么没有那么大的争议? 说起来视频的数字传输比音频传输的频宽,抗干扰能力要求强许多,大家为什么都对3刀的HDMI 没有争议?反而对音频数字传输有争议? |
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Oct 27th, 2012, 14:19 | 只看该作者 #28 | |
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2米要卖110$。 http://www.shop.perfecthometheater.c...CABLE-HDMI.htm Sent from my GT-I9100M using Tapatalk 2 |
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Oct 28th, 2012, 00:42 | 只看该作者 #31 | |
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就像我说的,如果有crc校验+错包重新发送,那么错码率基本就可以认定为0了,比如hdmi就是。 |
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Oct 28th, 2012, 11:22 | 只看该作者 #35 | |
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这个USB audio streaming类似UDP。但我们用的USB线也就一两米吧。Error rate是多少?如果你换了那根GT2很可能可以听出区别。我自己是听出来了。但往往到了最后都是A线A声,B线B声。就这样而已。谁知道哪根是100%对?这些都是玩的,我自己可没耐性刨根究底。发烧度不够。玩过就算了。Whatever floats your boat。 奇怪为什么Discovery Channel的Mythbuster不做个audiophile的玩意。。。 |
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