Can someone please explain ?

Unfortunately your question doesn't really have a simple answer...

First off, to get anything approaching the sound quality of you exisiting CD or Vinyl system (you don't say the level of these so I'm going to guess that is mid level Naim system) you are going to need a DAC. This takes a digital input in some form - could be via SPDIF (coax or TOSLink), USB or FireWire - and converts it into an analogue signal which can be amplified and sent on to your speakers. There are a vast range of DACs at different price points from (for example) a Beresford TC-7510 at around £170 to a complete dCS stack consisting of Upsampler, DAC and WordClock which will cost you around £20,000. And within each price point, there seam to be wildly varying thoughts as to how this compares to Naim CD players - some people may comment that their computer with a Cambridge Audio DACMagic (£225) sounds as good as their Naim CD5 (£900) where as others think you get that level of quality only when using a Lavry DA10 (for example). Remember also that alot of the difference in quality between DACs isn't in the conversion of digital audio data into an analogue signal - it's in the analogue portion of the DAC which converts the output of the DAC chip into something you can pass into your pre-amp.

Some of this descrepency can be accounted for by variations in the "transport" used to feed the DAC. The average SPDIF output on a computer motherboard is not of High Quality. It was added to give the average user access to digital audio, mostly for connection to AV systems rather than high end audio. By virtue of how the clock for the digital audio is created, combined with fairly unstable power supply and a digitally noisey environment (amonst other factors) the digital output will contain high levels of jitter. Now some DACs will deal with this better than other, but in the end of the day there is only so much that the DAC can do - no DAC can eliminate all jitter from the digital signal. Now to improve on this, people go to great length to modify devices such as the Squeezebox to have higher quality (read more stable) clock sources, etc; or add external interfaces to their computer, via USB, FireWire or PCI(e) card to improve the output.

Thirdly the software used to play back the audio files can make a difference too. It is the source of much contravercy and discussion, but there are two camps - one says that uncompressed audio (AIFF or WAV) sounds identical to lossless compressed files (Apple Lossless / ALAC, FLAC and others) because the lossless compressed files can be restored to their original data without error in the same way a ZIP file can be returned to a Word document (for example) without change. The other side say that the extra processor cycles required to do this can alter the output in a way to make the analogue output of the DAC different. The same is said of using different software to play back the files - two programmes can play back the same file and when read at the SPDIF output of the computer the data is identical, yet there is difference in the sound quality. Only through personal listening can you decide if such factors are (a) noticable to you and (b) affect your listening pleasure.

Computer Audio CAN match (and even exceed) the highest quality CD reproduction - lets face it digital data is digital data stored on a shiny silver disk, on a spinning magnetic disk or stored in electronic memory (SSD). And as I noted earlier, only through personal listening can you decide what factors you notice when listening and affect your pleasure. For some people only the very best will do whatever the source of their music, for others, they may choose a slightly lower sound quality computer source where the convinience and functionality far outweight any minor reduction in sound quality.

I hope I've helped a little with your questions...
Eloise

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I hope I've helped a little with your questions...

Hi Eloise
Thanks, you have a little. But, (in my profile I list my equipment BTW) and I was kindha hoping that given that iTunes has had very favourable comments in other threads for listening pleasure via a Mac Mini for example, that any computer linked to a DAC would give me close to the output from my CDX.

Also you say that the SPDIF output is not of high quality, would I be using that method if I play through a firewire interface using the M-Audio DAC for example ??

I looked up SPDIF on the web and Hardware secrets says of the SPDIF = "Digital transference, as opposed to analogue transmission, is immune to noise and according is the kind of transmission loved by audiophiles," ??

As usual this thread is turning into something more complicated than I originally intended and I do appreciate that the listener has a huge bearing on the acceptable quality of the output, in terms of accepting certain standards of listening quality and the ease of using the system which will effect that listening experience. My question could be put more simply - "Do I need to buy a dedicated HDX or Linn DS to be able to get CD quality audio, when I already have a hard disc playing music in my computer or iPod?"

A good first step might be to connect the analogue output of your M-Audio FireWire device into a spare input of your NAC...

SPDIF (digital audio) transmission is simple in concept, but more complicated in implementation. Your M-Audio device probably has a SPDIF output which will probably be higher quality than the majority of SPDIF interfaces built into motherboards.

To answer your final question ... YES you can get comperable (or better than) CD player quality audio from a computer without needing a Linn DS or HDX; however you would need to buy a good quality DAC.

PS. Sorry I think I over complicated your original post!

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PS. Sorry I think I over complicated your original post!

Hmmm, My M-Audio is already a DAC (I believe) and yes it is connected to the PreAmp, but to ask my question again - "would I be using the SPDIF transport, if I play through a Firewire interface using the M-Audio DAC for example ??

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interface using the M-Audio DAC for example ?

Well, to anyone interested, I thought I would try a comparison. I took a CD which I have also ripped with iTunes, I played this via VOX which is a small Audio player app for the MAC, I then played the same track (started in the same place) on the CD through my CDX (full equip list in my profile).

The output from the computer goes via FireWire through the M-Audio DAC and out via the normal outputs to the spare input on my PreAmp.

With the NAIM remote, I flicked between sources and tried to discern any difference. I came to a conclusion and then called my wife in to do a blind comparison.

We both felt that the Computer playing the music sounded better.

May not be the best way - but it was a good enough test to see whether I needed to spend another £5k to get similar quality digital audio, to my CD player.

I admit a NAIM DAC would be the next improvement to this system, but I am detecting weaknesses in the KEF Ref Series 3's that maybe are showing their age - so next question, "Which speakers do I buy?" - only joking for now, but it will come.

Colin your findings don't surprise me in the least,mac and a good dac is better than a cdp player what is VOX/ I use Amarra playback software which improves the quality of itunes.

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better than a cdp player what is VOX/ I use Amarra playback software which improves the quality of itunes.

Thanks for that - I noticed that both Linn and NAIM use FLAC as audio files, iTunes can't play these, so I searched the net for a FLAC MAC player and found VOX. Its cute (small) and works fine, playlists are supposed to becoming soon :-)

I will now audition Amarra against it and iTunes as players, although as you already said it appears that Amarra improves iTunes playback.

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Originally posted by Colin Woolf:

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better than a cdp player what is VOX/ I use Amarra playback software which improves the quality of itunes.

Thanks for that - I noticed that both Linn and NAIM use FLAC as audio files, iTunes can't play these, so I searched the net for a FLAC MAC player and found VOX. Its cute (small) and works fine, playlists are supposed to becoming soon :-)

I will now audition Amarra against it and iTunes as players, although as you already said it appears that Amarra improves iTunes playback.

Colin,

Try "Pure Vinyl". I have both PV and Amarra Mini. PV is cheaper, I prefer it and I'm not alone. It would be worth the free demo to find out for yourself whether it works for you.

If you haven't found it, the Computer Audiophile forum is worth a browse for more detail on music server software and other DA stuff.

Joe

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not alone. It would be worth the free demo to find out for yourself whether it works for you

Thanks Joe for the input - I have just been and looked at both PV and Amarra, they look good. I am using BIAS PEAK to record my LP's so do not need a heavyweight (read cost) additional software.

Also I cannot trial those as I had hoped, alongside VOX at the moment (computer running older OS), perhaps someone else could help in this way

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heavyweight (read cost) additional softw

Talking of PEAk - I have been using this with the waveform editor for removing clicks etc - VERY VERY tedious - just bought ClickRepair which is amazingly good.