NAS Streaming可以比CD靚聲嗎？CH Precision C1來告訴你

nickif

Ustortoise 發表於 2014-7-27 14:35
This is an interesting but contradicting answer.

If LPS at upstream will further improve sound q ...

My view is the limit of a system is always determined by the weakest link of the chain.

For example, if you have 100k budget for cables, would you buy a full set of cardas clear (or something else at same level) or a pair of siltech empress speaker cables as it is the last component off the chain?

diamondblack

Ustortoise 發表於 2014-7-27 14:35
This is an interesting but contradicting answer.

If LPS at upstream will further improve sound quality with the use of optical converter near DAC, I guess it deserves further examination what actually contributing to good sound. Are we missing something in the puzzle? I'm not trying to argue but wishing to find out what is happening in our chain of playback (I also have few LPS and optical converter in my setup).  If we can resolve this, maybe we can apply this good factor to other area?

Yes. I understand the contradiction, and I share your frustration.

This is my observation over the last 18 months during which I made countless changes to my network streaming setup from different router and switch configuration to vibration control for the NAS. I am not able to offer you a scientific explanation over the phenomenon. What I can share with you is, changes at the source end of the Optical-Ethernet conversion can be heard at the player end of the chain every time. That said, the Optical-Ethernet conversion is a highly effective mean, if not the most significant one, to lower the noise level of the signal path.

I think there's no universal solution but I believe the basic principles for producing good sound in analog playback are by large applicable, i.e. clean power and good vibration control. On top of these, reliability and speed of your disc system.

mahi

My experience is similar, after optical isolation is in place, I can still hear distinctively the difference in sound of two generic type cat cables, and that of two lps I use to feed a switch further upstream.

The closest analogy I can think of is like analogue cables, the sound you hear is a combination of its conductor and noise level. You can have vastly different sound from two pairs of cables if conductors are not the same, even though the rest of it like the structure, geometry, shielding, etc is the same.

mahi

When noises level are low enuf in the whole chain, then these miniscule differences are magnified to become relevant and bothersome.

I agree too the long supply chain of a cas system is prone to attack at multiple fronts and remains largely unresolved problem.

hitimfuk

看了大家對Rip file及數字檔案聽感的一些討論，真的感到很疑惑。因為當中有些說法真的很顛覆基本概念。我有一些想法讓大家思考，希望可以讓大家對有關問題能再擴闊考慮範圍。


1   同一個music file, 將它拷貝入其他folder. 你能聽出它們之間有分別嗎？
2   以不同ripping軟件rip同一張CD, 將整個檔案內容比較是否一樣？如果內容相同，你能聽得出它們有分別嗎？
3   如果1&2你能聽出分別，你試試聽同一個File幾次, 是否前後都有分別？

以上實驗有沒有聽感分別，我不會斷言無，雖然我是個電子工程師，徹頭徹尾的理性主義者，但我認同我們仍然不太懂超微弱的信息差異進入耳窩後，如何影響大腦對其解讀。

對以上問題我的看法是:

1   數字檔案是可靠的，即便僅僅以checksum來保護。
2   對同樣內容的檔案有聽感差異是源於系統的運作條件有差異，從而產生不同的noise。

差異1 - 文件處存的位置不同
差異2 - 播放的時間不同

差異1是電腦於不同的Disk location讀取文件可能產生不同的noise pattern.

差異2牽涉到系統穩定性，從外部供電，電腦系統內的電氣特性，甚至人耳及心理的穩定性。前後幾分鐘會否有可能產生這種感受上的差異？

科學的定義：能被推翻的理論就是科學

不能推翻的理論已經是真理，公理。

Jeffrey666

我建議大家可以試下呢個tool: https://iperf.fr/ 如果你有兩部電腦既話，佢可以試到中間如果用udp 既話，會有幾多 packet loss. 我試過一邊send 左200MB 去另一邊，但冇loss 只係有1kb data out of sequence.

因為 DLNA (Upnp) 係用 udp 黎stream, 咁你就可以睇下你個d 咩noise 咩interference 有幾大影響，so far 我全部用cheap 野／原裝野就有咁既結果。

------------------------------------------------------------
Server listening on UDP port 5001
Receiving 1470 byte datagrams
UDP buffer size:  192 KByte (default)
------------------------------------------------------------
[  3] local 192.168.1.3 port 5001 connected with 192.168.1.103 port 57914
[ ID] Interval       Transfer     Bandwidth        Jitter   Lost/Total Datagrams
[  3]  0.0- 1.0 sec  11.3 MBytes  94.9 Mbits/sec   0.242 ms    0/ 8070 (0%)
[  3]  1.0- 2.0 sec  11.4 MBytes  95.7 Mbits/sec   0.197 ms    0/ 8136 (0%)
[  3]  2.0- 3.0 sec  11.4 MBytes  95.7 Mbits/sec   0.230 ms    0/ 8138 (0%)
[  3]  3.0- 4.0 sec  11.4 MBytes  95.7 Mbits/sec   0.175 ms    0/ 8138 (0%)
[  3]  4.0- 5.0 sec  11.4 MBytes  95.7 Mbits/sec   0.188 ms    0/ 8137 (0%)
[  3]  5.0- 6.0 sec  11.4 MBytes  95.7 Mbits/sec   0.206 ms    0/ 8138 (0%)
[  3]  6.0- 7.0 sec  11.4 MBytes  95.7 Mbits/sec   0.191 ms    0/ 8138 (0%)
[  3]  7.0- 8.0 sec  11.4 MBytes  95.7 Mbits/sec   0.190 ms    0/ 8137 (0%)
[  3]  8.0- 9.0 sec  11.4 MBytes  95.7 Mbits/sec   0.241 ms    0/ 8139 (0%)
[  3]  9.0-10.0 sec  11.4 MBytes  95.7 Mbits/sec   0.189 ms    0/ 8137 (0%)
[  3]  0.0-10.0 sec   114 MBytes  95.6 Mbits/sec   0.239 ms    0/81358 (0%)
[  3]  0.0-10.0 sec  1 datagrams received out-of-order

Audiophilelp

Jeffrey666 發表於 2014-7-28 21:32
我建議大家可以試下呢個tool: https://iperf.fr/ 如果你有兩部電腦既話，佢可以試到中間如果用udp 既話，會 ...

重點呢1KB是否significant？當轉成analogue 時能否聽得出，可否解釋到不同LAN cable, optical-LAN etc唔同聲嘅原因？

hitimfuk

基本上我不認為cheap線傳輸數碼電訊會有錯誤或需要多次重發，通過認證的線都能勝任準確的傳輸。造成聽感影響是噪音電訊溜進需要精準時基的電路及模擬電路。

Jeffrey666

hitimfuk 發表於 2014-7-28 21:50
基本上我不認為cheap線傳輸數碼電訊會有錯誤或需要多次重發，通過認證的線都能勝任準確的傳輸。造成聽感影 ...

"噪音電訊溜進需要精準時基的電路及模擬電路"

呢個現像其實個原理係點?

petertang88

hitimfuk 發表於 2014-7-28 21:50
基本上我不認為cheap線傳輸數碼電訊會有錯誤或需要多次重發，通過認證的線都能勝任準確的傳輸。造成聽感影 ...

合理的原因，這也解釋了為什麼fiber converter 有用。不好的LAN 缐不是傳輸有問題，而是附送了其他雜訊

hitimfuk

也想請問有沒有師兄用過不同Ethernet media converters比較，有些大陸品牌比DLink便宜一半的，是否真的表現出聲音差很多？

mahi

大如麥當當都會係大陸出事，好難講呢! 好多大陸品牌只不過係一張印水紙，是沒有價值。賣完一批貨隨時又貼第二個牌，有乜問題當然會馬上消失。買平野就要預埋呢d風險。

charleslinnfans

Checked DLINK (dealer HK) no longer import media convertor few years ago.
So no hong goods for DLINK brand. DMC-300SC was year 2007 product.

Beside buying in Taobao (may take as fake risk), is there any other hong goods brand of Media Converter (e.g. TP-Link, LevelOne, Netgear) that any chings have tried and has as good result as DLINK ?

mahi

I think all 3 brands you mentioned are sold in HK, another one is Planet of taiwan. Level one and Planet are similarly priced and look alike. They should be at least equal to Dlink in performance if not better.

You can inquire about their performance in shops, these are networking equipment after all.

diamondblack

i chose levelone gvs-3110 because of its metal enclosure.

charleslinnfans

diamondblack 發表於 2014-7-29 20:14
i chose levelone gvs-3110 because of its metal enclosure.

Gvs-3110 is 1/3 expensive than dlink (if available).
Is gvs-3200 ($200 cheaper) having the same effect ?

diamondblack

charleslinnfans 發表於 2014-7-30 08:05
Gvs-3110 is 1/3 expensive than dlink (if available).
Is gvs-3200 ($200 cheaper) having the same ef ...

I don't have experience with 3200. I think they should be more or less the same on the assumption that we are using only a very small fraction of what the devices are capable of. but when the difference in price is $200, I will take the higher spec 3110.

obee

攪左咁多版, 最後原來係 fiber converter 跑出

diamondblack

obee 發表於 2014-7-30 09:14
攪左咁多版, 最後原來係 fiber converter 跑出

在CAS路上不同階段各取所需罷了。

obee

diamondblack 發表於 2014-7-30 09:32
在CAS路上不同階段各取所需罷了。

好話!