本帖最后由 yamuling 于 2016-5-27 12:54 编辑
Q：Am I right to assume your theoretical end-game DAC uses half band (full band?) filters with +1M taps? Or will your WTA filter still be a better approximation/reproduction of the analog wave due to the taps not being infinite? If I understand you well, this is where we walk into the ceiling of what is possible with 16bit coefficients - so more (or infinite) taps stop making a difference due to this limitation. Do these 16bits refer to the recording (so for 24bit high-rez recordings these numbers would be higher) or to the filter / processor architecture?
I'm looking forward to your +1M taps DAC somewhere in the future :-) As computational power keeps rising, we might actually be able to pull it off. Or am I dreaming your dream too loudly now?
A：The 16 bits refer to the accuracy of the coefficients against the ideal sinc function - so if we want to get an impulse response that has 16 bit accurate coefficients (that is the truncation of the coefficients occurs when the coefficient is below 16 bit in level), then you need about 1M taps. But what level is audible? Hugo is about 12 bits accurate against the ideal, Dave is about 14 bits - and there is a substantial difference in SQ between the two. But at what point does increasing tap length make no difference? Nobody knows the answer to that, but I will find out! There is also the issue of oversampling level, but that's another story...
Q：Dear Mr Watts,what does 12 bits accurate against the ideal mean?
A：The ideal impulse response, the sinc function gradually converges to zero, so the future and past samples no longer have a significant effect. With the 12 bits accuracy, then one can say that the WTA impulse response is roughly the same as the ideal sinc function to a 12 bit accuracy, as the coefficients are now smaller than 12 bits. There will come a point when the coefficients are so small they no longer have an audible effect, and I certainly have not hit that point yet.
找到了，不过完全没说要升级呀，这还是在发布半年之前的讨论...只是在讨论一些极限理想值 :lol
更新隔壁yeziwong的解释：
这个精度说的是数字滤波器和理想滤波器（理想的滤波器的时域波形是一个sinc函数，因为频域是一个方波，是一个非因果系统，不可能完全实现，是能无限逼近）之间的接近程度，tap越多，数字滤波器越接近理想值，当然硬件开销会越大，并且tap数越多，后面的系数越接近于0，所以精度的提高和硬件开销最终是一个指数关系
这个和DAC的精度是两码事
Zickson 发表于 2016-4-17 12:36
几天前注册的原因就是因为查dave的评论和感想时看到了这里有两个dave用家，本意就是希望能交流一下经验（再 ...
说的很对！别TM的像一些人写个测评都有铜臭味！
yamuling 发表于 2016-4-17 13:00
我觉得白版这次的评价还是略有偏颇。之前评价鲁迪耳放、ad功放等品牌的高端产品，我看到的更多是美文而 ...
说的很对！为了买dave，我把帖子翻到这里，每篇有关于dave的帖子我都一字一字的仔细观看，包括评论。但总是会有人写测评或评论时总带着点铜臭味与私心！我想说钱是为人服务的，别像一些人唯利是图的去挣昧良心钱！产品的好与坏留给市场去评判，这类产品每人都有每人的听感与判断！我想一首歌在同样的设备中，但在你心情好时与坏时听都会有不同的感受吧！所以劝大家不要盲目的崇拜大神，他的听感只是他的，自己去听了自己的感受才是最重要的！任何事适合自己就好！别被一些人打着测评的名义给把自己绑架了！什么事自己喜欢，钱花了，自己开心就好！
GRADO，无论价格，做工，素质，风格都有比CHORD更多的黑点，但白版在评测grado的耳机时是基本不会写缺点的，紫坛也看不到黑grado的 ...
PS.grado是我最喜欢的耳机品牌。
defleppard 发表于 2017-2-23 00:16
GRADO，无论价格，做工，素质，风格都有比CHORD更多的黑点，但白版在评测grado的耳机时是基本不会写缺点的 ...
白版肯定会说grado最贵也只卖一万块上下，要是卖六万块肯定就黑了。ps：我最喜欢的也是grado耳机......
AnalogDevices 发表于 2016-4-14 20:45
Dave employs a 28nm Xilinx FPGA that gives RW 166 DSP cores with which to do interpolation, filteri ...
评价下RME ADI2-PRO上的FPGA呢？2.17GIGAFLOPS的运算能力
AnalogDevices 发表于 2016-4-18 08:08
其实还有一款声音和Dave一样，那就是mola-mola，因为这两个结构几乎一毛一样
点评下RME ADI2-PRO呢
fpga硬件的能力是一方面，但是用来做效果器，还是用作升频滤波之类，每家的需求和算法都完全不同，所以只能同类产品去对比。
zhzh0000 发表于 2016-4-17 22:50
Rob的宣传的确很有问题，很夸张，而且风格一直如此，从Hugo开始就是这样，说得他的设计刀枪不入似的
rob营销确实做的好
yamuling 发表于 2016-4-18 10:33
Chord DAVE Review – Project EvaD (Evaluation DAVE)
https://audiobacon.net/2016/04/1 ... ad-evalu ...
这文章简而言之，dave默秒全，对usb线不敏感。看这种枪文还不如俱乐部看看各家之言来的真实。别的领域不清楚，hifi圈子game changer=枪。
就如同博主自己说的“他还见过有人觉得ref比dcs和msb旗舰stack还好听呢”，至于他自己又说dave比ref好那不是啪啪响吗？
Berkeley这种价格很实的厂，固执到不做内置usb不做dsd去迎合市场的厂，都不用提人家的专业背景，dac单功能旗舰被越级k了，还是被自己二手价比人全新价还高的多功能神机给k了…有人信，我是不信的…
九段总他们组织的那种x万级横评这种高质量活动真是应该多一些，不一定符合每个人的听感，但参考性是绝对强的。老外的软文软起来真比国内大神还夸张
