My first foray into stereo audiophile quality sound

Anyway if you say there isn't much compression in ELAC then why not just copy Audio CD on the hard disk?

oh well, you could do that, you could save your CDs as 100% bit perfect PCM wave files, and obtain all the data present during playback

or you could save 40-45% of disk space by using FLACs and still get the same data during playback

I think we need to study the algorithm used in ELAC coding and understand how it compresses with loss.

Regards

Sanjay

Here

( http://en.wikipedia.org/wiki/FLAC#Comparisons )

are some portions from Wikipedia...


Comparisons
FLAC is for efficient packing of audio data, unlike general lossless algorithms such as ZIP and gzip. While ZIP may compress a CD-quality audio file by 10–20%, FLAC achieves compression rates of 30–50%.

Lossy codecs can achieve ratios of 80% or more by discarding data from the original stream. FLAC uses linear prediction to convert the audio samples to a series of small, uncorrelated numbers (known as the residual), which are stored efficiently using Golomb-Rice coding. It also uses run-length encoding for blocks of identical samples, such as silent passages. The technical strengths of FLAC compared to other lossless codecs lie in its ability to be streamed and in a fast decode time, which is independent of compression level.

Technical details
FLAC supports only fixed-point samples, not floating-point. This is to eliminate any rounding errors to ensure bit-perfect reproduction. It can handle any PCM bit resolution from 4 to 32 bits per sample, any sampling rate from 1 Hz to 1,048,570 Hz in 1 Hz increments, and any number of channels from 1 to 8. Channels can be grouped in cases like stereo and 5.1 channel surround to take advantage of interchannel correlations to increase compression. FLAC uses CRC checksum for identifying corrupted frames when used in a streaming protocol, and also has a complete MD5 hash of the raw PCM audio stored in its STREAMINFO metadata header.

For those more curious, there is a good comparision of Lossless Encoding Formats at:

http://members.home.nl/w.speek/comparison.htm


(Performance comparison of lossless audio compressors)

and

http://web.inter.nl.net/users/hvdh/lossless/lossless.htm

(Compression and speed of lossless audio formats)


Cheers.

Cool stuff. Thanks amp_nut

just got myself a 300gig hard drive and a firewire adapter for the hdd....
time to rip off all my cd's

must share an analogy from a similiar discussion from another forum, another place and another time

Optical storage and playback systems are a series of complex engineering challenges. Without getting technical, reading information from an optical disc is like trying to read a book on the bus during the rush hour; it’s noisy and you have to keep adjusting to remain focused. Reading information from a solid-state source, by way of comparison, is like reading a book sat in a deck chair on a deserted island beach. The bogeymen of transport jitter and phase noise are vanquished once and for all.

of course it is only an analogy and we can take it further by saying that the advanced transports have better suspensions (Volvo ?).

Just a concluding ( ? ) comparision of Digital compression formats (approx) :

1. Uncompressed Digital Music on a CD : 10 MB per minute

2. Lossless compression 6 MB per minute

3. ( Lossy compression ) 128K MP-3. 1 MB per minute.

To me it appears that the 128K mp-3 compression throws away 5 MB per minute of digital data. Almost a miracle that it still sounds the way it does....

A particular format...regardless of whether is is lossless or compressed - is never going to be as good as the original..unless you have a few expensive equipment like what JVC uses to manufacture its XRCD.

For example, the WAV files ripped by "Windows Media Player" is horrible. I have tried another software (Can't remember the name now ) - which corrects errors that occur during the ripping process...and actually creates better WAV copies of the original.

Just copy a CD on your PC (in the same PCM format) and play the two versions (original and duplicate) in your setup. ... you will hear the difference yourself.

Aspects like Jitter, Quality of analogue output stage, quality of the PCB layout and wiring, power supply, mechanican isolution, etc.. etc., are various factors to consider....in order to either reproduce or copy/RIP a music CD.

XRCD is one good example..it's not a separate format...it's only a better CD manufacturing process that makes the sound so much better...even on a normal system

A particular format many be designed to eliminate Jitter, which is good...but in my opinion not very practical (meaning - does not help in technical perfection). This is because the masters available to us is only PCM !! - ...and when you are rip the original "PCM" disc on you computer...the jitter and other distotion caused by the computer (during the ripping process) has done damage to the sound, even before the music is converted into this "jitter free" format.


But then again....it's a big pain to keep changing CDs in my CAR...mp3 is best solution. It does not matter whether it sounds as good as the original...as long as the format serves its purpose. I guess we need to balance the two ... practicallity vs technical perfection and for a lot of us practicallity is more important.

Cheers
Siva.

sivat schrieb:

A particular format...regardless of whether is is lossless or compressed - is never going to be as good as the original..unless you have a few expensive equipment like what JVC uses to manufacture its XRCD. For example, the WAV files ripped by "Windows Media Player" is horrible. I have tried another software (Can't remember the name now ) - which corrects errors that occur during the ripping process...and actually creates better WAV copies of the original. Just copy a CD on your PC (in the same PCM format) and play the two versions (original and duplicate) in your setup. ... you will hear the difference yourself. Aspects like Jitter, Quality of analogue output stage, quality of the PCB layout and wiring, power supply, mechanican isolution, etc.. etc., are various factors to consider....in order to either reproduce or copy/RIP a music CD. XRCD is one good example..it's not a separate format...it's only a better CD manufacturing process that makes the sound so much better...even on a normal system A particular format many be designed to eliminate Jitter, which is good...but in my opinion not very practical (meaning - does not help in technical perfection). This is because the masters available to us is only PCM !! - ...and when you are rip the original "PCM" disc on you computer...the jitter and other distotion caused by the computer (during the ripping process) has done damage to the sound, even before the music is converted into this "jitter free" format. But then again....it's a big pain to keep changing CDs in my CAR...mp3 is best solution. It does not matter whether it sounds as good as the original...as long as the format serves its purpose. I guess we need to balance the two ... practicallity vs technical perfection and for a lot of us practicallity is more important. Cheers Siva.

I was waiting for this!!
Since I am not a technical person so explaining things technically is a bit far off to me. I was expecting people like Siva and Viren to come up and explain the technical side of why CDs and along with a good CDP take us to the last mile of satisfaction.
XRCD is one good example, which proves that there is so much scope for improvement even within the same ACD format so how can we say that FLAC or any other lossless format doesnt have scope for improvement ????

Moreover as Siva says the CDs are generated from a referrence source thats much higher in resolution than the CD itself that too using very hi-tech machinery and softwares whereas FLAC is generated keeping CDs as referrence that too using commercially available softwares and hardwares...it can only try to get closer but achieving the last mile would be very very difficult IMO.

Anyway as I have already said in my previous posts, in audio its the "EARS" that decide which is right and what is wrong, any amount of theory is redundant if your ears dont certify them finally. ACD playback is a proven media and is accepted universally with a lot of respect so to displace that kind of a stature, you need to do a lot more than simply giving logic. OK agreed that there is some substance in the logic so it can definitely be used as a guideline to move ahead in quest for equivalent or better sound but it cant never used to conclude that A > B IMO...Audio is much more than technology, buddy superczar.

This is because the masters available to us is only PCM !!

But the original masters in the studio are not in PCM they are in uncompressed ,uncoded 2 track stereo in most cases.

The studios encode it to PCM for mass production.

Well if the original masters are encoded directly into flac and we had a dedicated FLAC player (maybe not optical disks) , and we have a very good dedicated flac player with hard disk inside, then theoretically it would sound better than 90% of all cd players mass manufactured i guess


Also i have tested that when an unscratched CD is encoded with bit good rippers like EAC (Exact audio copy) we do indeed get bit perfect copies . This I have tested with 3 different cd /dvd drives on my computer with various good recordings and did a bit to bit comparision.


Also i found out that dvds skip more often in my DVD player (which is a pioneer elite one, reasonably good) than in my PC dvd drive .....

which is indeed alarming and tells something about the state of the mass manufacture of cd/dvd players except of course some very good ones...?

Well yesterday i saw a news clipping about a dedicated media pc as a source released by ONkyo !!

It comes with 3 GHZ processer and a 300 GB hard disk and has all input outputs of modern sources (firewire,dvi) etc etc .....

A good change of direction maybe ......

XRCD is one good example..it's not a separate format...it's only a better CD manufacturing process that makes the sound so much better...even on a normal system

XRCD's better sound results from the use of the best mastering process coupled with good pressings not on good pressings alone!!!!!!

In fact the transformation chain should not lose much data ...in good recordings
( recording, mastering , mixing , duplication) .....
this is most important ....

I have said this before.... and perish the thought .... but I believe that XRCDs are Equalised differently.... to make them sound more phenominal... ( ie they use tone controls, to selectively cut / boost freqs )

to my ears my lossless media into my DAC is giving me noticably better resolution than my pioneer DVD transport. (agree not the best.. but not bad either)

no sense in discussing this theoretically as theoretically lossless is the same as the source !

will try it with my NAd player as a transport when i get a chance sometime.

There may be a case for them but since dedicated transports are really really expensive,(more than twice the price of the cdps we are talking of here) spending that money on a speaker will give far better results

Arj schrieb:

will try it with my NAd player as a transport when i get a chance sometime.

Hi Arj,
I believe you had a modded NAD CDP, I am really curious to know if your lossless media + DAC beats the SQ of your ACD + CDP combo (please consider good recordings as referrence here).

There may be a case for them but since dedicated transports are really really expensive,(more than twice the price of the cdps we are talking of here) spending that money on a speaker will give far better results

Fully Agree...
But at one point of time one may want to tweak his sources (in case its the weakest link) rather than play around with his well chosen speaker then it may make sense IMO

abhi.pani schrieb:

Hi Arj, I believe you had a modded NAD CDP, I am really curious to know if your lossless media + DAC beats the SQ of your ACD + CDP combo (please consider good recordings as referrence here).

ill be able to get around to it only in a couple of months..since it is not with me now.

but honestly i do not expect any great changes since the NAD as most transports actually us a computer CDROM as a transport. the diffence if any may be more due to the damping that has been done to the tray and the casing !

I actually have a well damped external HDD connected via a very short USB cable with one of those magnetic rings and and a dedicated PC to stream digital wireless into my DAC. Also I have a Monarchy DIP just before my DAC for reducing jitter

The following is from another forum..I dod have a mail on similiar lines from someone else but cannot really find it now !

the name S/PDIF which is the abbreviation for Sony/Philips Digital Interface. The signal is created inside the CD player decoder chip which is connected to the laser pickup via a simple HF amplifier. What comes out of the decoder chip is SPDIF and is the same for all brands of CD player and CD transport ever made. It is standard, it works for everyone and is universal. If somebody tries to adapt S/PDIF in some way they will fail because both transmitter and reciver must agree with the standard. The following is a simplification. An online search for S/PDIF will turn up lots of technical texts on the subject. SPDIF is an electrical serial data format made up of 1s and 0s arranged: 4 preamble data bits + 4 auxiliary data bits+ 20 audio signal data bits + four status and parity bits. This is a subframe and contains one sample word for either left or right channel. It is followed by a a subframe that contains the other channel word. Then the next left channel word is written followed by the next right channel word and so on. The data rate of this fortmat is about 3MHz and it is present on the RCA jack on the back of the player "Digital out" Exactly the same data is given to an optical data converter module and this is present on the "Toslink" connector. So far as differences are concerned the SPDIF standard allows for numerous variations, such as the word bit size from 16 to 24 bit. There is some error correction. Codes are contained in the data format that define things like consumer or professional operation, digital copy management, and engineering details that is used by creators of digital audio. You can look it up in the standard. But within the standard there is only one quality standard by which i mean everybodies 16bit 44.1kHz S/PDIF is the same, there are no variables which can be used to adjust the quality factor of the data format, it does not have any variable quality factors in it to be adjusted. It can be set up as 24bit 96kHz if you wish but again the quality is single, just one standard for 24bit 96kHz. The process of extracting the data from the CD disc is under the control of a numerical processor called the decoder IC. This IC creates two outputs. The first is a serial data stream for the CD player DAC to process back into audio. This serial data stream for the left and right DACs is mostly the same as the S/PDIF signal but with non-audio data removed. The second output from the decoder IC is the S/PDIF output signal which is the left and right data with the extra engineering data added and formatted to the S/PDIF standard. In principal because S/PDIF contains only clock and left right data it cannot affect the sound quality. This was believed to be true until the concept of timing errors called jitter were found and analysed. Jitter is only a problem when the DACs use the dirty incoming data stream clock to time the audio output conversion. It was always intended that DACs would have their own precision output clock. Unfortunately some economies were made and in many consumer CD players there is no precision clock only a cleaned up data word clock. Although I myself have not witnessed the audible effects of jitter on CD audio quality it is claimed that audible changes do exist. If in doubt purchase a DAC having a precision output clock and data buffer. It is interesting to note that one piece CD players with DACs inside do not use the S/PDIF signal, that is presented on the rear panel for the connection to an external DAC which is optional. The serial data stream used directly by one-piece machines does not have be traverse the RCA interface between player and DAC, this may provide an opportunity for one-piece machines to perform with less jitter corruption than player - DAC two box combinations.

Arj schrieb:

abhi.pani schrieb: Hi Arj, I believe you had a modded NAD CDP, I am really curious to know if your lossless media + DAC beats the SQ of your ACD + CDP combo (please consider good recordings as referrence here). ill be able to get around to it only in a couple of months..since it is not with me now. but honestly i do not expect any great changes since the NAD as most transports actually us a computer CDROM as a transport. the diffence if any may be more due to the damping that has been done to the tray and the casing ! I actually have a well damped external HDD connected via a very short USB cable with one of those magnetic rings and and a dedicated PC to stream digital wireless into my DAC. Also I have a Monarchy DIP just before my DAC for reducing jitter :)

My point is if you play a CD through your CDP and connect the analog outs of your CDP to your amp directly (no DAC in between) and on the other hand use your HDD + DAC combo, then which one sounds better ??? That would basically give an idea about the capabilities of both.

Sie täuschen!

He Sie Esel, wie Sie digitales Signal benutzen können, Ihr Ampere von Verdichteraustrittsdruck zu Verstärker einzuziehen. Sie benötigen ein DAC, eine und null in Entsprechung umzuwandeln.

abhi.pani schrieb:

My point is if you play a CD through your CDP and connect the analog outs of your CDP to your amp directly (no DAC in between) and on the other hand use your HDD + DAC combo, then which one sounds better ??? That would basically give an idea about the capabilities of both.

From what I have seen, comparing an entry level CDP to a Mid level DAC is really not very fruitful. The maximum change to the sound is via a DAC and a dedicated DAc with its own correction and PSU is bound to give you a better sound than the usually design flawed but cost effective NADs DAC stage.


The difference between the two is the transport. hence I need to compare the sound of
1. NAD + DAC with HDD+DAC.

2. and then compare NAD as CDP with NAD+DAC.

point 1 is what I am not sure of and expect very little difference.

Point 2 i will compare it but expect the DAC to really beat the CDP (Considering just the used DAC costs twice the cdp)

I did a comparison betwen my iPOD direct output to my NAD CDP last year and found surprisingly little differences (Primarily in detail and treble smoothness)

While when I compare the difference with the Wadia and the ipod, the difference kind of jumps out. the detail (more instruments, a blacker background and deeper and tigher bass).

I did a comparison betwen my iPOD direct output to my NAD CDP last year and found surprisingly little differences (Primarily in detail and treble smoothness)

Astonishing....my Creative ZEN sounds better than a iPod but looses out miserably to my NAD cdp
Whats this phenomenon ?

thats very very interesting !


In fact I have a 40 GB ipod (3rd geb)
My wife has a creative Zen Microphoto 8 GB.

From what I understand the 4th/5th gen ipods are not as good to reduce size, the DAc and the digital amp was changed

She is someone who is not really into "Audiophile sound" but the difference in the same song played out from both is very obvious and she prefers the iPOD when played out from our stereo .

although the smaller size of the cretive wins out when mobile !

Arj schrieb:

She is someone who is not really into "Audiophile sound" but the difference in the same song played out from both is very obvious and she prefers the iPOD when played out from our stereo . although the smaller size of the cretive wins out when mobile !

Do you mean to say the SQ of an iPod is better while connected to the amp but the SQ of the Creative is better using a headphone ????

no no.. i have only checked it out on an AMP. not on an ear/head phone..

dont really have a audiophile grade earphone.. I use a B&O while my wife has a entry level senn..both not the ultimate in transparency/neutrality.

it is only the small size + features of the creative (Photo + FM + mic capability) which win out.

I did try out iPod (not the latest video version) and Zen Touch with MS-1, and was convinced that Zen sounded better but the same guy when connected to the amp via headphone out (no line out in zen) sounded crap comparing with my CDP.

thts because the output power from a creative is extra low. if the load is a bit tougher then its bass will go for a toss and sound tinny !

the problem is not with the file or even perhaps its decoding..but it is just not able to supply the constant current into the amp.

usually in these cases the source becomes a constant vaoltage source instead of the constatn current ..hence the poor sound quality.

in case you had an active Pre or a tube buffer the sound would have been very very different.

Hi Guys,

Would appreciate it if you could Vote on the survey :

iPod & MP-3 Player Users

I created today.

Thanks !

in case you had an active Pre or a tube buffer the sound would have been very very different.

whats that ???
Is there some kind of accessory for Creative which can be attached to it to give a proper lineout ??

no !!
eg a musical fidelity X10D or XV3 etc..


or any active Pre amp..

Wow, and in this whole long discussion , seems everyone forgot the original post

So coming back to it, apart from changing the source ( I suppose i'll stick to my Macintosh Mini + DAC) what else can I do to improve the setup

1) Move the speakers further apart and away from the walls: Done

2) Change the RCA splitout cable: Can't find good ones, can someone please suggest me where to find good 1/8" - RCA cables in Chennai?

3) Replace the cables that came with the speakers with something better ?: Would it really make any difference, the cables that came with the speakers seem to be of very good quality

4) Biwiring... Should I do that?

ANy other comments on the setup welcome(But please , let us try avoid the source )

Pay good attention to speaker placement and your room. The tiled floor & walls appear to be highly reflective and may be affecting the sound quality. The left speaker is too close to the corner and right close to the wall. Try bringing then well into the room and tip them slightly inwards towards your listening position.

Regards

Sanjay

Replace the cables that came with the speakers with something better ?: Would it really make any difference, the cables that came with the speakers seem to be of very good quality

If I were you I would first try and get the best out of positioning and then try to enhance by opting for good cables. And if I recall you have acquired the speakers new, so just listen , listen and listen until you get the sound character up in your brains with rest of chain remaining same and only then you can start fooling around with cables.
Until later enjoy what you have as I'm sure the tweak bug will bite you later..

4) Biwiring... Should I do that?

No, I would suggest you could spend money better off on good cables than go for a moderate ones for biwiring.

Our sweetest songs are those; that tell us of sadest thought! "Hai sabse madhur woh geet jise; hum dard ke sur mein gaate hain!"

Doc your signature hints at you being too emotional..are you?? Not one of your good old medical student days crush..

Too emotional ? Yes, but only about music !! Rest is all noise.

The signature is as emotional as the poet who wrote and the other one who translated it.

Well said Doc!

sivat schrieb:

For example, the WAV files ripped by "Windows Media Player" is horrible. I have tried another software (Can't remember the name now ) - which corrects errors that occur during the ripping process...and actually creates better WAV copies of the original. Just copy a CD on your PC (in the same PCM format) and play the two versions (original and duplicate) in your setup. ... you will hear the difference yourself.

I'm a newb in audio so I wont comment on that but if what you say is true, then CD would not be a storage medium for all sorts of software. Unless the CD is horribly scratched, reading it on a 5$ CD/DVDROM drive will yield exactly the same output as a 50000$ state of the art CD player. CDs have inbuilt error correction and checksumming mechanisms in them and you'll get the exact same data everytime you read them. Else do you think software distributed on CDs suffers from bit errors on every machine its installed in An audio CD is no different... its just a simple data CD with PCM encoded files on them and reading them everytime will yield the same output. The only thing software like Exact Audio Copy (EAC) does is it reads scratched discs multiple times and tries to guess the value in the particular area where the scratch exists. For good discs, it'll read the same value everytime. There's no voodoo or magic involved in this... its a deterministic process like any other digital encoding method. Why you felt WMP is horrible is probably cos you didn't change the default encoding method from 96kbps WMA (pathetic sounding IMHO) to WAV or WMA lossless. I fail to comprehend why the original CD would sound better than a ripped CD encoded in uncompressed/lossless format otherwise.

reinofchaos wrote
'I fail to comprehend why the original CD would sound better than a ripped CD encoded in uncompressed/lossless format otherwise'.

I say
Welcome to audiophilia!!

Jeeves schrieb:

reinofchaos wrote 'I fail to comprehend why the original CD would sound better than a ripped CD encoded in uncompressed/lossless format otherwise'. I say Welcome to audiophilia!!

Heh so do you call opinions without any scientific basis as audiophilia :P? Thats like following the herd philosophy without using one's brains.

Not really...audiophilia uses both sides of the brain in my opinion

Science can often defy senses (or vice versa). So guys don't get driven be technology (or the tech jargon) - be driven by music.

Here is an illustration:

SET (Single Ended Triode) amplifiers perform pathetic at all the benchmark tests - the produce power RMS less than 10 Wpc and have THD levels more than 10 % and need highly sensitive speakers with high impedence.

But when you listen to them with the rightly matched speakers they sound wonderful.

So let's play music not machines !

Regards

Sanjay

reignofchaos schrieb:

I'm a newb in audio so I wont comment on that but if what you say is true, then CD would not be a storage medium for all sorts of software. Unless the CD is horribly scratched, reading it on a 5$ CD/DVDROM drive will yield exactly the same output as a 50000$ state of the art CD player. CDs have inbuilt error correction and checksumming mechanisms in them and you'll get the exact same data everytime you read them. Else do you think software distributed on CDs suffers from bit errors on every machine its installed in An audio CD is no different... its just a simple data CD with PCM encoded files on them and reading them everytime will yield the same output. The only thing software like Exact Audio Copy (EAC) does is it reads scratched discs multiple times and tries to guess the value in the particular area where the scratch exists. For good discs, it'll read the same value everytime. There's no voodoo or magic involved in this... its a deterministic process like any other digital encoding method. Why you felt WMP is horrible is probably cos you didn't change the default encoding method from 96kbps WMA (pathetic sounding IMHO) to WAV or WMA lossless. I fail to comprehend why the original CD would sound better than a ripped CD encoded in uncompressed/lossless format otherwise.

Science can only answer to what you know. not of what you do not know, but it should definitely not be used as an excuse to explain what does not really fit in areas where not enough research has gone in !
The question you asked is excatly the same question which prompted some research and the existance of something called "Jitter" was found out and understood. jitter exists in some form every time a digital medea is read from a mechanical/electrical device and can be measured.

funnily before that folks used to use the excuse of science to say there was no proof and refuse to believe it § untill someone found it out. now Jitter is the scientific phenomena used to measure problems in digital outputs

look it up, and thou shall have your answers

(The problem lies in both the SPDIF interface which does not have a separate clock stream as well as lack of error correction information in the cd.. at that time cd was deemed as "sufficiantly accurate" hence no need for error correction redundancy etc etc)

reignofchaos wrote: CDs have inbuilt error correction and checksumming mechanisms in them and you'll get the exact same data everytime you read them. Else do you think software distributed on CDs suffers from bit errors on every machine its installed in An audio CD is no different... its just a simple data CD with PCM encoded files on them and reading them everytime will yield the same output.

An Audio CD is VERY different from a data CD. The Data CD has FAR more robust error correction than an audio CD.

I have elaborated this, about 2 weeks ago, on this forum. Do check the archives...

Although rarely observed in a well designed player, jitter is a worthy topic of discussion because of both its misconceptions and the large amount of press it has received. Jitter is basically defined as time instability. It occurs in both analog-to-digital and digital-to-analog conversion. The latter instance is the only concern here. Jitter occurs in the compact disc player when samples are being read off the disc. These reads are controlled by the pulses of a crystal oscillator. If the system clock pulse inaccurately (an unlikely event), if there is a glitch in the digital hardware, or if there is noise on a signal control line, the actual reading time will vary from sample to sample thus inducing noise and distortion in the extreme case. A great deal of money has been made by shrewd marketeers preying on the fears of the consumer worried about jitter. Such products marketed include disc stabilizer rings to reduce rotational variations, highly damped rubber feet for the players, and other snake oil remedies. However, the careful engineer has beaten the marketeer to the punch by having the samples read off the disc into a RAM buffer. As the buffer becomes full, a local crystal oscillator can then "clock-out" the samples in a reliable manner, independent of the transport and reading mechanisms. This process is referred to as timebase correction and as stated before, any quality piece of equipment will implement it.

http://www.tc.umn.edu/~erick205/Papers/paper.html

We should be much more worried about the quality of the CD and the way it was made than the jitter in our transport. Its more or less non existent in properly designed drives... especially for computer DVD drives which have 2MB to 8MB buffers. Also you can always do bit by bit comparisons of the extracted and source data. (This is exactly what EAC does) My apologies for comparing audio cd and data cds. It was not apt cos cdroms use the yellow book standard which does have error correction mechanisms whereas audio cd redbook has barely any. But still the fact remains that a cd will be read equally well on a device that doesn't have jitter. So unless you use a really old drive for extracting audio which has no buffer, jitter should really not cause an issue.

Jumping in late and stirring up a few hormets...

USB introduces quite a bit of jitter into an audio signal. USB is an asynchronous bus, not realtime (PCI is also async but its jitter is unmeasurable given a benign system load) so USB is not the perfect interface everyone thinks it is. Over a data stream the timing of the data bits may go off, and since its async it will always be lower system priority. A PCI device, on the other hand, can operate at realtime priority all the time (if the system is up to it).

The 300 GB harddrive is actually a superb idea, it's almost bit-perfect playback, something that most CD players cannot lay claim to. There's a technical reason for it, given below.

Ripped files (as long as it's lossless, and the decoder algorithm is correctly written) may be closer to bit perfection than any CD transport reading in analog mode. Same applies to CD ROM drives reading audio CDs in digital mode.

Audio CDs when read in analog mode, and use error correction on the fly, so what gets put in is not always what comes out. Error correction does not result in bit perfect playback. Sounds paradoxical but that's just the truth. The only way to get an error-free stream is to repeatedly read the incorrect data bits again and again, till the correct bits are read. In case of a scratched disk, this method may result in clicks, pops and distortion in the ripped data, whereas the CD itself may play back correctly.

If you look at Red book Vs. Yellow book (audio vs. data), the error rates are much lower for data CD specifications than for audio CDs. Red book permits interpolation to assume bit position. Yellow book insists on the original bits.

Short story: rip the audio CDs in data CD mode and switch error correction off. If this leads to clicks and pops, switch the error correction on and rip again. It won't be bit perfect but it'll be playable.

Jitter in poor quality players may be as high as 160-180 ps, USB would be 30-40 ps, and a hard disk with wav files read from a CD in digital mode with error correction switched off, close to 0 ps. I don't recall anyone who mentioned anything about hard disk jitter. You are not permitted to have even one error off a hard disk data, there is no room for error correction.

Note I'm talking about the correctness of the digital stream. Not about its audibility. Yet.

Now we have a digital stream, how to get it out of the PC into analog? Opinions differ, but one solution is to use the best possible digital out you can afford. The Juli@ is supposed to have a very good digital out. The 0404 is a good option and it's optical, so even better. And then a DAC, again the best you can afford.

I think the original poster has hit upon a great system configuration. Issues like fan noise, DA conversion, quality of digital stream (if using coax and not optical) exist but are solve-able, given enough funds and/or time.

The only thing I would do differently (have done differently) is not compress at all. I find all compression kills sound quality, not because of losing bits, but due to the nature of the decompression algorithm. There is no quality loss on converting to and from these formats, but the playback of the format shows up listenable differences. And I've tried all of them - APE, FLAC, Wavpack, everything. Hard disk space is cheap. Use wav (in your case - AAC?) for best results.

Hi !

Either my funda of "jitter" is wrong or there is something warped in the way this concept is being thrashed out here - whatever be the case, we can all gain from this discussion...

According to what I have read, jitter is introduced when there is a "clock" mismatch between the transport & DAC. And mostly this happens at the S/PDIF interface. An audio signal is read by the transport & this combined with the clock data is sent to DAC. DAC inturn uses its own internal clock in tandem with the received clock data and converts the digital to analogue audio signal. It's the mismatch between these TWO clocks that produces JITTER. Jitter is not mechanical vibration of transport (correct me if I am wrong).

New one box CD players have the advantage of having the DAC on board and not requiring the S/PDIF interface and thus jitter is minimized.

High-end DACs & Transport have a separate clock ports where the DACs native clock signal is send to the transport and then received back with the audio signal (though separately). This eliminates jitter.

Some DACs have a buffer and jitter correction circuits which too minimize jitter.

One more fact: when COPYING digital data from one source to another e.g. from CD to HDD, the question of jitter does not arrive because there is no clock data involved. Moreover, reading from HDD has as much chance of introducing jitter as reading from CD.

The problem of jitter is not with READING but with syncronizing the clock of the transport to that of the clock of the DAC.

I am not an authority on the subject. I'm just sharing the info that I have gathered, so please feel free to correct me if I am wrong.

Humbly

Sanjay

dr saab, you are quite right on the exact definition of jitter..especially as we knew it. but these days any "Timing error" is also quite commonly/interchangeably put along with jitter.

typically they can be
1. Clock jitter (the "old" jitter)
2. Data Jitter (Thats what is being talked bout here..could be equipment/cable)
3. Other timing errors usually caused by distortion..quite random also called SRTE

you can read it up here by the folks who actually researched it.
http://www.dcsltd.co.uk/technical_papers/jitter.pdf

but yes..Jitter is an oft bandied about subject and sometimes thrashed around with other errors as well..

But in case of one box CDPs at the entry level an external DAC with a decent SPDIF connection will give you a definite improvement.. of cours above a certain pricepoint the point on internal connections mentioned by you becomes stronger

eric_clapton schrieb:

JUse wav (in your case - AAC?) for best results.

AAC gets only marginally better than MP3 over 128 kbps.. and still lossy. i guess FLAC/APE would do far better