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Today's Transport War: Significant Differences?

I have been reading much these days about computer/hard-drive based transports as being a whole order of magnitude superior to traditional CD transports. In my reading, the camp who believes hard-drive based transports can render major improvements has been most notably represented by Empirical Audio. The camp which suggests that traditional CD transport techonology (or atleast the best of its sort--VRDS-NEO) is still superior has been most notably represented by APL Hi-Fi.

Each of the camps mentioned above are genuine experts who have probably forgotten more about digital than many of us will ever understand. But my reading of each of their websites and comments they have made on various discussion threads (Audiogon, Audio Circle, and their own websites) suggests that they GENUINELY disagree about whether hard-drive based transportation of a digital signal really represents a categorical improvement in digital transport technology. And I am certain others on this site know a lot about this too.

I am NOT trying to set up a forum for a negative argument or an artificial either/or poll here. I want to understand the significant differences in the positions and better understand some of the technical reasons why there is such a significant difference of opinion on this. I am sincerely wondering what the crux of this difference is...the heart of the matter if you will.

I know experts in many fields and disciplines disagree with one another, and, I am not looking for resolution (well not philosophical resolution anyway) of these issues. I just want to better understand the arguments of whether hard-drive based digital transportation is a significant technical improvement over traditional CD transportation.

Respectfully,
pardales
audioengr
3,282 posts
 
Alex - I dont know what you mean by "Noiseball", but I do know that once you remove the digital and analog conversions from a typical computer chassis, whether it is using USB or Wi-Fi, this provides the opportunity to generate an extremely low jitter data stream.

Likewise, if you speed-up the CD player and make it essentially a CD-ROM drive and buffer the data, you again have the opportunity to generate an extremely low jitter data stream.

As for the computer sounding unsatisfactory, you obviously have not heard a good computer source yet. This is like listening to a $60 Walmart CD player and then proclaiming that all CD players sound terrible......and BTW, the Olive will only challenge good CD players once it is modded.

I have superb native 24/96 tracks mastered from tape in .wav format. I would like to see you play these on a CD player.

Steve N.
jsadurni
210 posts
 
I do believe that the future of digital is through some kind of computer, Mr. Sprey from Mapleshade told me he has a wooden reinforced box for the computer in which he makes some kind of mixing. We all know the quality of Mapleshade recordings (amazing) He also said that going through a computer is hellish for audio.
I do think right now a computer setup can beat most high end players, but not the top notch CD playback systems.
We listened to the Olive and, though very good, when we compared against an Accuphase player (DP-75 I think)the diference was pretty obvious being the accuphase better(both stock) the related system was Halcro electronics and top Dynaudio speakers.

All the Best
ecka
41 posts
 
This has been a very interesting discussion thusfar. I have personally compared a purpose built computer with a very high end transport( not the esoteric, Alex)and have found the computer to nearly the equal of the transport for 16/44.1 playback. More recently, I have heard the computer via the USB converter that Steve Nugent makes and must say that for 16/44.1 the computer is the equal of and often betters the high end transport.
Whilst I can appreciate the pride of ownership that must accompany possession of a player such as the APL NWO 2.5 (which I must say I have not had the priveledge to hear), so far just from pure listening alone the computer is showing tremendous potential to be the ultimate "transport" IMHO.
aplhifi
515 posts
 
J. Sarduni, it's good to see you around! :-) How have you been?

I do think right now a computer setup can beat most high end players, but not the top notch CD playback systems.

This is exactly my point!

Regards,
Alex
cics
43 posts
 
By design a computer will always output a superior digital signal. Bit-perfect data is read from harddisk to memory then upsampled with much better precision. This happens in a ‘noiseball’ but critically outside of any realtime clocking mechanism and no bits are mangled/lost (essence of computing). Hence no jitter occurs during data prep stage.

Last stage transfers buffered data perfectly to sound output device (connected via usb, ethernet or internal bus). This device adds a clock and generates spdif signal for dac. This task will create jitter and needs to be optimal (clean power not sourced from noiseball, very high quality clock if dac does no input buffering and/or reclocking, etc.). All transports have same challenge here.

The way I see it, traditional transports suffers more jitter. In realtime, CD spins, data is upsampled (but not as good as a computer) then fed to dac – this all happens under a strict clocking regime. As noted in Altmann’s website (What is Jitter?):

“A simple CD player has multiple motors or actuators and associated control loops, in order to perform disc reading:
There are f.e. the spindle motor that turns the CD, the sledge motor that performs axial tracking, and actuators for focus and radial tracking.
Each of these motors / actuators will add a portion of noise to the power supply of the player and this noise will affect accurate switch timing.
So, each of the motors /actuators adds jitter to the digital audio signal and each adds a different kind of jitter (different in frequency, amplitude, waveform) and will affect audio reproduction in different ways.”

Put another way, jitter is compounded by the spinning CD which induces various types of power supply jitter. (I can see why esoteric built the VRDS Neo mechanism.)

Nova’s Memory Player does away with spinning CDs in realtime. Playback is driven by a computer.
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