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[#19] Blogs: 數碼音樂重播專欄 (1) Says who? Like many acronyms, the term CAS is informally invented by people for pure convenience for the benefits of quick communication. AS far as I know, this is mostly a Hong Kong/Asia term. Countries with English as second or third language tend to make up short forms for convenience. It is not as commonly used by the American/UK audio press for instance. For all I know, CAS could be "Computer Assisted Surgery" or thousands other representations. So to laugh as someone as being "wrong" about an informally spread term is silly. Just because someone else mentioned it before does not make it the official term. As far as I am concerned, "Computer Audio Source" does not sound right in English anyway. To me, "Computer based Audio" sounds better; "Computer as Source" also "gels" better grammatically.		agentsmittie 正式會員 219.xxx.xxx.6	2011-04-30 14:04

[#20] Blogs: 數碼音樂重播專欄 (1)
The term CAS.
I first learned about it in Kent Poon's web, HiFitrack and Design With Sound. It stands for computer as source.
Then I came across the term elsewhere that is supposed to mean Computer Audio System.
Then we have the web Computer Audiophile.
It is not in Wikipedia.
The "C" stands for computer, that is, using it or a varied form of it, for example, a storage system or a server to play digital tracks.

momei

正式會員
218.xxx.xxx.88

2011-04-30 14:44

[#21] Blogs: 數碼音樂重播專欄 (1)
CAS for computer audio playback not really a standardized or academic abbreviation, no absolute right or wrong term, actually calling such playback based on studio master file from download, can be play back by mobile phone, memory player, universal transport, network streamer and of course computer, as "file based audio playback".

probably a few years later, broadband speed and cost much lower, cloud computing and storage (what amazon doing now), we don't have to purchase physical media or file anymore, we may purchase audio/video subscription fee based on usage or quality (24/96 or above premium quality, 16/44 CD quality and mp3 lossy), you can access to all media stored on server, streaming to device by wifi/3g, so the content not require to store, or not allow to be store and re-transfer (well, if the subscription allow to access all media, why taking extra effort?), just access to playlist and ready to go!!

Last.fm is doing so, just not reaching audiophile quality yet, until records company willing to release Hi-Rez source.

hercules

正式會員
202.xxx.xxx.106

2011-04-30 15:06

[#22] Blogs: 數碼音樂重播專欄 (1)
"""AS far as I know, this is mostly a Hong Kong/Asia term. Countries with English as second or third language tend to make up short forms for convenience. It is not as commonly used by the American/UK audio press for instance."""

totally agree. at first when i encountered this term i had no idea what it was.

traditionally computer is the cpu with other items put in one box. these other items like sound card, memory hard disks or storage media are peripherals. one can stores data from a remote storage device and that can be the source. so computer as source is misleading.

i can see the trend will go with pay as you play on demand. it is more like renting instead of owning the software. who still want to have piles of cds and keep your library showing locations/numbering.

there are many software which may help split big wav or flac files using splitter or cue. split files can be transfer to dvd discs as data and then rejoin together at later stage.

最後修改時間: 2011-04-30 15:36:16

cpu8088

正式會員
115.xxx.xxx.214

2011-04-30 15:32

[#23] Blogs: 數碼音樂重播專欄 (1)
Korea HiFi show system.

DWS

正式會員
117.xxx.xxx.150

2011-04-30 17:00

[#24] Blogs: 數碼音樂重播專欄 (1)
System 2

DWS

正式會員
117.xxx.xxx.150

2011-04-30 17:01

[#25] Blogs: 數碼音樂重播專欄 (1)
Dynaudio with Linn

DWS

正式會員
117.xxx.xxx.150

2011-04-30 17:16

[#26] Blogs: 數碼音樂重播專欄 (1)
JBL with Mark Levinson

DWS

正式會員
117.xxx.xxx.150

2011-04-30 17:20

[#27] Blogs: 數碼音樂重播專欄 (1)
.

DWS

正式會員
117.xxx.xxx.150

2011-04-30 17:21

[#28] Blogs: 數碼音樂重播專欄 (1)
Wilson with Meridian

DWS

正式會員
117.xxx.xxx.150

2011-04-30 17:22

[#29] Blogs: 數碼音樂重播專欄 (1)
i hate to ask this question " can computer audio source (cas) really win cd transport for dac?"

batmanames04

正式會員
124.xxx.xxx.173

2011-04-30 17:40

[#30] Blogs: 數碼音樂重播專欄 (1)
I don't invent the term. I didn't know what it means at the first time, nor understand why someone would like to make scene of it.

CAS to me has been "民安隊". I also heard Eric (Editor of AV Magazine) mentioned it. Our government has a web page: www.cas.gov.hk.

People I met (consumer audio world) speaks it as "CAS System". At the first time I thought they mean "CARS System". Singapore, Malaysia audiophiles all speaks this way. They do not pronounce as independent C. A. S. system but "CAS".

I agree cloud base music library will become the majority of mass culture too.

Computer Audio System
Computer As Source
Computer Audiophile System
Computer Audio Server

as you like.

DWS

正式會員
117.xxx.xxx.150

2011-04-30 17:53

[#31] Blogs: 數碼音樂重播專欄 (1)
" can computer audio source (cas) really win cd transport for dac?"

u are asking if 16/44 cds can win over 24/88 96 176 192 and above.

theoretically the higher the bit rate and length the closer towards continuous analog as there are less gaps for the algorithms to do the guess work.

similarly in video u are comparing 576i dvd quality with 1080p blu ray video quality. if u consider 1080p better than the 480 or 576 output then the same principle applies to audio too.

最後修改時間: 2011-04-30 22:49:13

cpu8088

正式會員
115.xxx.xxx.214

2011-04-30 22:47

[#32] Blogs: 數碼音樂重播專欄 (1)
hey, I mean cas comparing with cd transport playing 16/44.1 to dac

one more thing, our human ears cannot hear more than 20khz sound , why 24.96 (around 48khz) sound better than 16/44.1?

batmanames04

正式會員
61.xxx.xxx.217

2011-05-01 06:28

[#33] Blogs: 數碼音樂重播專欄 (1)
one more thing, our human ears cannot hear more than 20khz sound , why 24.96 (around 48khz) sound better than 16/44.1?

----------------------------------------------------

If you treat PCM is sampling (snapshot) of analog waveform, at audible frequency, let said 4Khz, 96Khz have double number of sample compared with the one at 44khz sampling rate, more true to original analog waveform.

Secondly, the Low Pass Filter roll off will push beyond 22khz to 48khz @ 96 sampling frequency, the sound deterioration near the top end (16-20Khz) of the audible range, the sound quality may improve.

最後修改時間: 2011-05-01 09:13:12

hercules

正式會員
112.xxx.xxx.58

2011-05-01 09:11

[#34] Blogs: 數碼音樂重播專欄 (1)
there are many theories about hearing beyond 20khz

here is a good read

http://www.earthworksaudio.com/wp-content/uploads/th_world_beyond_20khz.pdf

cpu8088

正式會員
115.xxx.xxx.214

2011-05-01 09:27

[#35] Blogs: 數碼音樂重播專欄 (1)
Hi Kent,
Could you share with us the DAC part of Devalet dpremier compare with Weiss DAC2.

mr_chan

正式會員
218.xxx.xxx.13

2011-05-01 10:25

[#36] Blogs: 數碼音樂重播專欄 (1)
"""I mean cas comparing with cd transport playing 16/44.1 to dac"""

assume u have a cd with no scratch and u rip the data to a hard disk with perfect bit which should be the same as u download the same music data file from internet, this should be the same as when you play a perfect cd thru a cd transport.

the difference lies with scratched or imperfectly made cds.

when u rip a scratched cd to hard disk it all depends on your chosen software how to handle the errors and make corrections by guessing. this error correction can be made many times like 20 to 50, for example.

with cd transport it is a different matter. cd transport has limited time frame to make error corrections in may be say 3 to 5 times read and then the inbuilt software will make rougher guess work and transmit the info through to the digital analog converter. a good cd transport may handle error corrections better than crappy ones but no match to more reliably ripped data.

does this make sense?

cpu8088

正式會員
115.xxx.xxx.214

2011-05-01 12:44

[#37] Blogs: 數碼音樂重播專欄 (1)
Batmanames04
Let me say something to complement answers to your question that I understand to be “whether CAS with a higher resolution track could sound better than a CD track from the same source, both played with the same DAC and audio system”.
WOULD KENT POON PLEASE CORRECT ME IF I SAY ANTHING INCORRECT RELATIVE TO YOUR PROFESSION.
Nowadays first hand digital recorders come with ADCs with higher resolution than the CD format. This was what a proprietor of a relatively new record label told me in our correspondence when I asked him why his “master” and DVD-ROM is at 32/192. You are probably aware Professor Johnson of Reference Recording uses 24/176.4, Morten Lindberg of 2L uses 24/352.8 etc.
Because consumers are stuck with the 16/44.1 format in the ubiquitous CD players, the music industry have to “master” down their native or original masters to suit. You may also be aware there are a series of masters coming out from the native masters and mastering, amongst other things, include, “improving” bad recordings to acceptable level; mixing down multi tracks into 2 for CD; and relevant to our topic here, down converting the higher resolution tracks to 16/44.1. Music industry personnel have us believe the higher resolution tracks contain no more musical data than in their CD offspring and recording at higher resolution merely facilitates subsequent mastering that may be easier carried out with flatter slope filters. The majority of consumers are convinced!
Now let us look at what that particular mastering process is doing to the high resolution tracks. A 24/352.8 DXD master has a bit rate of 16, 934 kbps and a file size of roughly 120 MB per 1 minute of music. A CD has a bit rate of 1,411 kbps and a file size of roughly 10 MB. In other words, the CD master only contains 1/12 of the data in the native or original master, meaning 11/12 of data have been filtered out! A CD in comparison with its 24/96 master, has 5/6 of the data filtered out.
Playing high resolution tracks with the computer means playing with the same bit rate and sampling rate as used in the native or original master.
Now you make your own judgement as to whether the 11/12 filtered out data are absolutely useless for our appreciation of the music in the track or perhaps there are overtones, upper harmonics and reverberation that enrich the fundamentals and harmonics within that hearing limit of 20 KHz.
One point to bear in mind is that when “mastered down” from higher resolution, the CD master loses the filtered out data. Therefore even when a CD track is up converted subsequently, the missing data previously filtered out are merely interpolations. The up converted track only resembles the native or original master. How close the resemblance depends on the algorithm used in the upward conversion.
Factually, MP3 involves similar mastering down. You may ask a similar question: whether a CD track could sound better than a MP3 track from the same source, both played with the same DAC and audio system. Say you have a MP3 track of 320 kbps that has about ¼ of the bit rate and file size of the CD. I wish the MP3 sounds as good as the master because I would be able to buy the albums of 2L in the iTunes store at a fraction of the price.
Another important issue relevant to the topic under discussion: We are often told our hearing is between 20 Hz to 20K Hz at best and based on Nyquist 20.05KHz (half of 44.1) is already beyond our hearing, thus CDs are more than good enough for practically all of us.
Don’t trust people like me in forums who may merely be talking crap. Listen to what your admired engineer, the mastermind for the Invicta DAC has to say in the Owner’s Manual that you referred me to. There are too many pages there to be reproduced here and I merely paraphrase the key issue. The human brain, as supported by tests that he quoted, is able to sense and fill in sound above 20 KHz, up to 50 KHz. Listeners are able to sense fullness if sounds above 20 KHz are captured in the recording and retained in the playback. And there are listeners able to detect differences when higher resolution tracks are played in comparison with CD tracks from the same masters.
Well observational listening to pick out the difference is another topic. If you want to talk about it, please tell us your previous encounters with listening to CD tracks and CAS high resolution tracks and why you have doubt about any difference between the two. We then start from there.
I must make clear I do not sell anything or help anybody to sell anything, thus no ulterior motive to convince people to use the computer and buy tracks or DAC.

momei

正式會員
203.xxx.xxx.61

2011-05-02 08:52

[#38] Blogs: 數碼音樂重播專欄 (1)
thanks momei, i need sometime to digest it

batmanames04

正式會員
203.xxx.xxx.116

2011-05-02 10:31