反正我又来发废文,因为确诊隔离太无聊了。
我是Chord DAC粉,应该是无庸置疑啦,虽然只有Hugo TT2和 Mojo 2 。
当初也是因为它用FPGA做DAC感到好奇才买的,因为以前做过一阵子FPGA设计。
Chord audio 设计师 Rob Watts 说过,
因为他开发的 WTA Filter 算法,
Chord DAC是以 tap 数决定 DAC 的素质,不包括放大电路等。
而 Chord DAC 一直以来都用 Xilinx FPGA,但中间换了好几次芯片。
以下这段大家可以看看
The WTA filter algorithm has taken twenty years of research to develop. It
solves the question as to why higher sampling rates sound better. It is well
known that 96 kHz (DVD Audio) recordings sound better than 44.1 kHz (CD)
recordings. Most people believe that this is due to the presence of
ultrasonic information being audible even though the best human hearing is
limited to 20kHz. What is not well known is that 768 kHz recordings sound
better than 384 kHz and that the sound quality limit for sampling lies in the
MHz region. 768 kHz recordings cannot sound better because of information
above 200 kHz being important – simply because musical instruments,
microphones, amplifiers and loudspeakers do not work at these frequencies nor
can we hear them. So if it is not the extra bandwidth that is important, why
do higher sampling rates sound better?
The answer is not being able to hear inaudible supersonic information, but
the ability to hear the timing of transients more clearly. It has long been
known that the human ear and brain can detect differences in the phase of
sound between the ears to the order of microseconds. This timing difference
between the ears is used for localising high frequency sound. Since
transients can be detected down to microseconds, the recording system needs
to be able to resolve timing of one microsecond. A sampling rate of 1 MHz is
needed to achieve this!
WTA 过滤算法经过二十年的研究开发。 它解决了为什么更高的采样率听起来更好的问题
。 众所周知,96 kHz(DVD 音频)录音的音质优于 44.1 kHz(CD)录音。 大多数人认
为这是由于超声波信息的存在是可听见的,即使人类的最佳听力被限制在 20kHz。 鲜为
人知的是 768 kHz 的录音听起来比 384 kHz 好,而且采样的音质限制在 MHz 区域。
768 kHz 的录音听起来再好不过了,因为 200 kHz 以上的信息很重要——仅仅是因为乐
器、麦克风、放大器和扬声器不能在这些频率下工作,我们也听不到它们。 因此,如果
重要的不是额外的带宽,为什么更高的采样率听起来更好?
答案不是能够听到听不见的超音速信息,而是能够更清楚地听到瞬变的时间。 人们早就
知道,人耳和大脑可以检测到耳朵之间声音相位的差异,达到微秒级。 耳朵之间的这种
时间差异用于定位高频声音。 由于可以检测到微秒级的瞬变,因此记录系统需要能够解
析一微秒的时间。 需要 1 MHz 的采样率才能实现这一目标!
Chord DAC基本上只开发了三个DAC,其他都是它的变形和改款。
旗舰 (reference DAC) (Choral)
DAC64(1024 taps) -> QBD76 HDSD (18,432 taps)-> Dave (164,000 taps)
然后就开发出以下一堆系列
Table Top (桌上型)
Hugo TT(26,368 taps) -> Hugo TT2 (98,304 taps)
Qutest (Chordette 升级) (纯解码)
QUTEST(49,152 taps)
Hugo (也是便携式,但是比较高阶的便携式)
Hugo (26,368 taps)(mobile) -> Hugo 2 (49,152 taps)(mobile)
Mobile (就标准便携式,也就 Mojo 系列)
Mojo (38,912 taps)(mobile) -> Mojo2 (40,960 taps)(mobile)
MX series (Chordette 同级改款)(这系列好像还有很多款,但我还没用心找到全部)
QX DAC(基于QBD76 HDSD架构开发)(18,432 taps)
Chordette (早期历史很长系列)
Chordette Gem(4096 taps) -> QuteHD (10,240 taps) -> Qute EX(找不到taps数) ->
2Qute (Qute EX+Hugo)(26,368 taps)
Ex. Chordette Gem 是基于DAC64的改款
Ex2. 为了怕让人误会,Chord 的设计分类清楚,不会让新款低阶上打到前代上一级,就
算taps数比较高,你可以想像放大电路和算法有小改,例如 Hugo TT 2 +M scaler 还
是打不过 Dave,明明 taps 数加起来超过。
Ex3. 有一篇文提到,Chord 产品最简单分级方式就是看大小,越大表示越高阶。
补上跟大佬的对话
https://i.imgur.com/t0ewD0X.jpg
以上,有问题再问我