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

Showing 10 responses by aplhifi

The Noiseball (aka computer) converts audio data many times, uses questionable performance clocking, has switching mode power supply and uses poor interfaces (mostly USB and Wi-Fi packets or combination of both) to transmit audio data to an external DAC. It does not really matter if the USB signal is converted to S/PDIF, I2S or anything else, it still comes from that same USB port! Same applies for Wi-Fi connection where the middle of the audio track may be sent first and then the beginning of it and so on in random packets which are then decoded and reconstructed by a DSP (talk about error correction). There are some nice pro-audio computer cards available allowing much cleaner data transmission and slave mode to the DAC clock, but please realize that all you slave to the DAC is the clock of the computer card DSP, nothing else.

Even a cheap $149 universal player spins the CD, SACD or DVD-A at higher speed allowing for memory buffering using both FIFO and large SDRAM buffers which results in “jitter free” clocks and “bit perfect” data. It is not true that the DAC in a CD/DVD/SACD player has to be PLL-ed (and what’s up with the “evil PLL” thing? Latest PLL techniques are great achieving as low as 30pS jitter!). Good example that comes to mind would be the famous, faulty and long discontinued Philips SACD1000. This player has its main 16.9344MHz non-PLL audio master clock (low noise powered) next to its DACs, the perfect scenario. This non-PLL, low jitter master clock oscillator is also clocking the audio DSPs. Then, PLL is used to generate the 27MHz clock for the video circuit. The SACD1000 spins the CD at much higher speed and uses combination of FIFO and large SDRAM buffers. The “jitter free” and “bit perfect” PCM data/clock transmission in the SACD1000 is carried by our beloved I2S but without any data conversion or long cables and connectors resulting in about 5-6 inches cleanest possible signal path. WOW, isn’t this amazing! It looks like the perfect CD player, the perfect solution, right? Well, I am sure that many around here know for a fact that the stock SACD1000 performance is nothing to write home about, although it was a nice machine for its time. The moral of the story; not everything is as easy and simple as it looks.

IMO and IME, a carefully optimized (key word), vibration/error free “classic” digital front-end using memory buffering and latest error correction engines, with built-in dedicated, specially designed DSPs, shortest signal path, no data conversions to completely irrelevant to audio data transmission formats, ultra low jitter clocking and low noise power supplies simply can not be outperformed by computer based audio, at least not for now. Hopefully in the future the time will come when proper technology will be developed so one is able to load favorite music onto a computer based audio solutions and play it back while achieving the same audio quality as with the classic dedicated stand alone digital front-end is possible today. So let’s stay optimistic.

Regards,
Alex
I much prefer this to spinning CD's because of the lower jitter and superior sound quality.

Sure! :-)

Regards,
Alex
We are not talking about the "external converter” and associates Steve, we are talking about the transport or the Noiseball which can not hold a candle against another transport featuring quiet linear power supplies. It's a fact. What good is external battery power supply when your data comes form the Noiseball? And BTW, the so called “super clocks” actually add jitter. But it sounds better right? So here is another puzzle to solve. :-)

Otherwise any DVD player or computer would sound satisfactory. Unfortunately, they don't. As far as I know Olive has a computer based solution (single box with control and HDD inside) with linear PS so that would be my best bet for starters.

But then again, it really depends on the level of audio quality one is after and what is his/her reference. Other than that Noiseball audio is more convenient, I admit. But what is up with evolution and mankind getting lazy? It was CD against Vinyl before now is the Noiseball against CD. It's funny! And why everyone around here forgets the High-Rez digital formats to which a CD is inferior, regardless of how it was processed.

Regards,
Alex
The computer serves only to provide readable 1s and 0s, and evidently, despite their "noiseball" characteristics PCs are perfectly capable of reading 1s and 0s from CD roms, and hard-drives and streaming them over ethernet or USB without a single bit error. That's how you're reading this web site.

If this is what you believe in and makes you happy, so be it.

An external DAC can have its own power supply, and isolating any noise from the USB or ethernet inputs is not rocket science. Finally RAM based FIFO buffering and reclocking will feed the DAC a bit-perfect signal with noise removed and ultra-low jitter.

Simpe, isn't it? If you don't care how the "perfect" data was processed and transmitted that's fine too.

I understand that Alex produces respected machines, but I see no coherent engineering based arguments that refute any of what Steve (or I, or others) have said.

Thank you for the nice words! I am sorry but I can not further elaborate.

Regards,
Alex
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
Alex, can you clear this up?

I am sorry but I can not clear up this matter. What can I say though is that, IMO, the best digital would be the perfect fusion of technology advancements, actual design implementation and art.

Regards,
Alex

....the MP will be the audiophile king of the source components. I am betting on this.

Great news Olesno! It seems like everyone who heard and reviewed the MP at "Stereotimes MP" :-) is using it as a digital transport only. Are you in the same boat having the MP hooked to your TACT or you're using it as a stand alone player (using the analog outputs)? Do you have the $5K tube output option? Would be great if you list the associated equipment too.

Lastly, are you in California? SF Bay area by any chance? I'd love to get together some day so I can take you up on your bet.

:-)

Regards,
Alex
Thank you Olesno! This explains it....I am sure that compared to your Sony 777 the MP is night and day better when used as a transport with the TACT.

Regards,
Alex
01-03-07: Theaudiotweak

Is playing off the memory chip considered a transport?

Of course, most of today's DVD based players (even $70 Toshiba) take the audio data off a memory chip, not the transport.

Regards,
Alex
RUR is not nonsense. I am pretty sure Harley would also not call it that.
Instead of getting the data off the CD in a single pass, RUR reads the disc until a predetermined level of the total data on the CD has been extracted. In the case of the MP that level is 99%. This level is adjustable, but Porzilli found that going beyond 99% does not result in better audio performance. Besides that, going above 99% is far more time consuming. If I read it correctly, the RUR technique changes the angle of the laser pick-up when it finds data that is difficult to read.

Laser pick up angle is called Tilt adjustment as found in many DVD/CD players. Note: the Tilt adjustment is NOT included in the CD servo system. It is a part of the DVD servo system. The range of the Tilt adjustment is calculated for DVD pits, not CD pits, so it makes very little to no difference while reading CDs.

Check out the “amazingly severe” error rates below (whooping 3.3 average per sector) reported while extracting a clean commercial CD (Nojima Plays Liszt, RR-25) at x10 speed.

PlexTools Professional V2.32a Q-Check C1/C2 Test
Copyright (C) 1999-2005 Plextor SA/NV

C1 :
Avg/Sec : 3.3
Max/Sec : 27.0
Total : 12012.0

C2 :
Avg/Sec : 0.0
Max/Sec : 0.0
Total : 0.0

CU :
Avg/Sec : 0.0
Max/Sec : 0.0
Total : 0.0

And this is while using a $100 Plextor CD/DVD-ROM drive.

I trust the ears of several audiophiles who reported that the MP sounded very good so there is no doubt about it, but the fact is that RUR or Laser angle adjustment have very little to nothing to do with it, IMO and supported by the error report above.

Regards,
Alex