- #502 [addyg], 19-09-29 10:22MQA CD 機好貴
- #501 [addyg], 19-09-29 10:18MQA-CD 係2019年先開始多。普通CD機用digital 出個MQA dac 就播到。 新款CD機留意佢係咪已MQA certified .
MQA-CD是包含MQA格式的聲源的CD。通過將兼容的播放器或通用CD播放器/ BD播放器與支持MQA解碼的DAC組合使用,您可以享受高分辨率的等效音質。另一方面,普通的CD播放器可以將其作為CD播放。
環球唱片公司和華納音樂公司將開發使用UHQCD的MQA-CD,該產品通過改善碟片的材料和製造方法而改善了音質,被稱為“高分辨率CD”。
MQA-CD本身的第一個標題是2017年3月從OTTAVA Records發行的。後來,在2018年4月,環球公司發行了100張高分辨率CD作為具有UHQCD規範的MQA-CD。第二版也於同年7月發行。這次,華納音樂將發行第一張“高分辨率CD”。 - #500 [addyg], 19-09-29 09:53MQA係可以係任何dac 播放。但,,如果未有MQA certified licensed 你部dac係唔可以解碼佢(環境噪音-音場)個part。
所以市面上話play 到MQA就叫MQA dac係錯。你部機一定要有MQA certify 先可以100%全解MQA。
MQA music can be played back on any device, although only MQA-supported products (of which there are now several, some of which are included above) and software will be capable of unpacking the MQA stream’s full quality. -
- #499 [kayue], 19-09-29 09:29其實分開兩部份 "MQA 錄音認證"、"壓縮為傳統播放系統能向下兼容"
咁我就能理解。
當然,我仍然覺得 MQA 應該係去開發 DAC。
MQA decode 完仍然是一般音頻訊號,而 pre-rining 係在 DAC 時發生。
即即使 MQA 保證了檔案內容完美,在臨門一腳依然係用傳統 DAC,問題仍在。(假設用 software decode mqa 先啦) - #498 [addyg], 19-09-29 07:01MQA 同 flac wav dsd 另一個非常重要分別係 official encoding.
flac wav dsd 大多係私人自己rip + 升頻 + reformat , 而且係由16Bit 44.1hz 普通CD做source. 器材係家用級。
MQA 係 official encoding 由唱片公司專業制作。無論source ,器材,人員,都有優勢。 - #497 [長長影子], 19-09-29 02:39點解要壓縮除咗係為傳統播放系統能向下兼容外,原因係傳統 hi-res file 當中包含咗好多亳無義嘅數據,因為喺 24/32-bit 嘅 bit depth 內,部份數據只係表達遠低於 h/w thermal limit 以下無意義嘅 noise。 因此壓縮本身唔係問題,問題在於點善用壓縮嘅方法。 相對遠遠低於聽覺系統所能察覺嘅 noise floor,甚至係低於所有器材本身嘅 noise floor,人類聽覺系統對整個錄/放系統時域變化更為敏感、更為重要。 因此 MQA 所 care 嘅係整個錄/放系統嘅時域表現,係指由聲音訊號進入 A/D 之前直到 D/A 輸出嘅原音重現,而唔係傳統 PCM/DSD 單單只局限於 A/D 到 D/A 中間所謂嘅 lossless 數據。
最後修改時間: 2019-09-29 02:53:29 - #496 [長長影子], 19-09-29 01:52"如果 AD / DA 咁不完美,而 MQA 又有技術去改善,咁佢應該開發一個 ADC / DAC ,而唔係一個壓縮 file format"
<- AD/DA 的確唔係完美,AD/DA chipsets 主要由幾間大嘅半導體廠開發、生產,MQA 唔能夠完全解缺所有問題,但 MQA 嘅方案主要係針唔同用喱啲 AD/DA chipsets 嘅廠家造出嚟嘅 AD / DA 器材,用佢嘅修正方案去解決 temporal blur 對音質影響嘅個問題。 亦在於用 MQA 去統一修正後嘅結果去確保錄音過程中用唔同廠出產嘅 AD / DA 器材都能達到一致嘅音質表現。
情況就如你買去個顯示屏返屋企駁電腦用嚟執你影嘅相,你可以因應你自己對顏色嘅喜好去執相,但唔同廠出產嘅顯示屏,你買返嚟用時色彩表現可以唔相同,不過只要本身色域夠廣亮度足,你仍然能夠透過用相同嘅校色標準去達到同幾乎一樣嘅顏色及亮度嘅顯示效果,咁你自己望個顯示屏嘅顏色同幫你晒相嘅人睇同晒嘅時候顏色同你屋企個顯示器中所睇到嘅顏色效果一致,MQA 嘅方案有啲類似提供顯示器嘅校色方法同最佳校色標準而唔係負責做顯示器。
"同埋 MQA 所講 "the signal chain from the modulator in the A/D to that in the D/A is certainly not lossless",有 d 偷換概念。一般 lossless 係指某 format 同原始檔 (eg wav) 比較,而唔係同把人聲比較。"
<- 喱段我由其中一份 Journal of Audio Engieering Socieity 中取出嚟,我諗經過咁嚴謹嘅審核後刊出嘅 Journal,能夠用 "lossless" 喱個技術詞彙,我相信應該都會係合理。
"AD / DA 科技當然唔係百份百還原把人聲。但 DAC 有各種各樣數據去 measure performance。 AD 唔熟,但至少 noise floor 之類掛?"
<- noise floor 等等參數當然可以透過 objective 嘅量測方法去比較。 宜家講嘅問題可以從 impulse response, noise floor 等數據中反映。
"而 MQA claim 的 analog 原聲係無從比較。佢做得好唔好無人知"
其實又唔係完全唔得,我之前一直強調用乜嘅 source 係做 reference 係好關鍵,先唔計好唔好聽,正如我之前舉嘅例子用 blind test A/B 去比較聽唔聽得出處理後有冇分別。 我就選擇自己錄、自己聽、自己測、自己比較去求證。
"(唔係想同影子兄拗,只係唔理解 MQA 要用咁既 marketing / business approach )"
<- 大家理性討論集思廣益,我盡可能提供客觀數據資料,我都唔係想上嚟同大家結怨。 雖然我一直喺度補充技術上嘅數據等資料,但字裡行間我仍覺得兄台仲未能明白我放嘅資料嘅重點,亦可能係我一向表達能力差。 傳統 PCM 如果 filtering 唔去做正確修改/修正,系統嘅 pre/post ringing 會限制咗佢嘅時域反應,達唔到相對空氣喺某個距離內空氣傳聲嘅時域表現嘅要求。
最後修改時間: 2019-09-29 02:07:45 - #495 [kayue], 19-09-29 01:04如果 AD / DA 咁不完美,而 MQA 又有技術去改善,咁佢應該開發一個 ADC / DAC ,而唔係一個壓縮 file format。
同埋 MQA 所講 "the signal chain from the modulator in the A/D to that in the D/A is certainly not lossless",有 d 偷換概念。一般 lossless 係指某 format 同原始檔 (eg wav) 比較,而唔係同把人聲比較。
AD / DA 科技當然唔係百份百還原把人聲。但 DAC 有各種各樣數據去 measure performance。 AD 唔熟,但至少 noise floor 之類掛?
而 MQA claim 的 analog 原聲係無從比較。佢做得好唔好無人知。
(唔係想同影子兄拗,只係唔理解 MQA 要用咁既 marketing / business approach ) - #494 [長長影子], 19-09-28 23:54
"Internal blocks in now widely used delta-sigma A/D and D/A converters, shown connected as PCM.
The high-speed small-word-size modulators are the critical stages, while for the PCM passed from one to the other, the transmission sample rate may almost be chosen arbitrarily at a fraction of the modulator rate.
As the signal passes through the A/D converter, each stage of down-sampling adds quantization noise and increases temporal blur; while in the D/A converter each corresponding upsampling stage adds further noise and blur. The properties of the decimation and upsampling filters and quality of processing at each stage significantly impacts the overall sound quality.
So, the signal chain from the modulator in the A/D to that in the D/A is certainly not lossless – it’s not even linear since device-dependent aliasing, thermal and modulation noise and temporal blur are all introduced. The conversion gateways present a major obstacle to transmitting archive-standard analogue audio."
最後修改時間: 2019-09-29 00:01:28 - #493 [長長影子], 19-09-28 23:48同 MQA 嘅邊一個 level/bit rate 比?
- #492 [addyg], 19-09-28 23:40MQA vs 16bit CD 係唔公平,應該是MQA vs 24bit SACD 先公平。
重有其實CD都係數碼嘢同佢有容量限制約650MB 除10首歌 - #491 [長長影子], 19-09-28 23:30
"Examples of background noise in 192 kHz 24-bit commercial releases. Also shown is TPDF dither noise for 192-kHz 16- and 20-bit quantization. Curves plotted as noise-spectral-density in 1-Hz bandwidth."
#留意 y-axis 係 re dBFS, 如果 0 dBFS re 120 dB SPL,咁 -120 dBFS re 0 dB SPL
最後修改時間: 2019-09-28 23:37:44 - #490 [長長影子], 19-09-28 23:18
"Shannon diagram showing the capacity of various digital channels (area is equivalent to data rate)."
# 留意 thermal limit & min. recording noise
最後修改時間: 2019-09-28 23:20:08 - #489 [長長影子], 19-09-28 23:05
"Here, on a finer time-scale, we are looking at the two impulses spaced by 26µs and showing that MQA system resolves similarly to 5m of air."
最後修改時間: 2019-09-28 23:05:17 - #488 [長長影子], 19-09-28 23:02
"Here we are showing that 192-kHz sync sampling doesn’t provide the detail separation of 10m of air and probably also fails to separate the two events. Note also the significant ‘false-alarm’ in the pre-echo"
最後修改時間: 2019-09-28 23:03:11 - #487 [長長影子], 19-09-28 23:00
"Here we are just comparing the 48-kHz sinc system with air. Graphically we can infer that the 48-kHz system puts us somewhere closer than 25m away and the twin impulses cannot be distinguished. In this and the next two figures the response follows a power-law as an estimate of detectability."
最後修改時間: 2019-09-28 23:00:46 - #486 [長長影子], 19-09-28 22:55
"Impulse response of a typical CD channel showing the dispersion in time over +/- 4ms."
最後修改時間: 2019-09-28 22:55:44 - #485 [DYreal], 19-09-28 22:53有趣有趣。
未講MQA呢個格式之前,唔少師兄都一面倒認為CDP贏CAS。
但一講到MQA,情況就180度改變。
就算一部普通嘅手機傳輸MQA檔案去MQA DAC都完勝CDP。
似乎個主旨應該要改改,唔係將來應該改做現在。 - #484 [長長影子], 19-09-28 22:49
"End-to-end impulse magnitude response of MQA compared to typical 192- and 48-kHz systems and Air at STP and 30% RH.
Compared to typical 192 kHz sampling, temporal blur of the example is lowered by an order of magnitude. Note the expanded timescale and that only part of the 48 kHz response is shown (it extends +/-4ms"
最後修改時間: 2019-09-28 22:54:20 - #483 [長長影子], 19-09-28 22:44
"When an analogue sound is converted into a digital signal, temporal ‘blurring’ occurs, smearing transients through time.
This is because common digital audio filters impair time resolution, causing ‘ringing’ both before and after a transient.
As a result, our ears can’t tell where individual sounds are coming from, and recorded music sounds flat compared to ‘live’.
MQA reduces this pre-and post-ringing by over 10 times compared to a 24/192 recording, cleaning this distortion from the original master recording to capture a truly accurate soundstage."
最後修改時間: 2019-09-28 22:44:24 - 下一頁 (2 of 27)
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