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 |
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.
RUR is also something that some in the recording industry uses to make sure that all the data is on the CD master.
You might want to refer to the reviews on www.positive-feedback.con and www.stereotimes.com. These people give some reasonable descriptions about the inner workings of the MP.
And lastly, why not go to the Nova Physics website at
www.thememoryplayer.com
If you really want an in depth discussion about the CD, get Ken Pohlman's book "The Compact Disc Handbook" 2nd Edition. I got mine from Amazon.com in the used book section. But be prepared to be overwhelmed. I never realized just how complex and sophisticated the inner workings of the CD really are. |
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 |
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 |
Is playing off the memory chip considered a transport? Ask Mark Porzelli formerly of Melos and Pipe Dreams for a demo at next week's CES show. You will be there won't you?. Tom |
Sorry, but I am not in California. I'm on the "right" coast in NJ. I do not have the tube output option as I am using it as a transport with my tact 2.2xp and the tact amp s2150. The rest of my equipment consists of Piega P10 speakers, Talon subwoofer, Audience Au24 cabling and Virtual Dynamics Nite power cords. In a few words the sound is very clean but not forward or bright. The soundstaging and focus are excellent. The most striking feature however is the smooth and liquid (but dynamic) sound without any edginess. It has the ability to fool me into the live event more than anything before it. |
....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 |
Perhaps tomorrow's transport war is today's transport war. |
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 |
Well, I am one of the fortunate owners of the Memory Player (for just about a week or so) and I will post my extended opinion on this unit in the near future. However, for now my impressions are as follows:
1. the sound - the best I've heard in my system, period. Nothing more to say.
2. the ease of operation - very easy, considering you are using it more as a PC than a regular player. Quite straight forward.
3. software (you need a laptop to operate the unit) - very rudimentary, I would call it a work in progress. It needs a lot of fine tunning to satisfy an average customer like myself. Once this is taken care of, the MP will be the audiophile king of the source components. I am betting on this. |
Yeah, please Alex (or anybody), can you explain this? I'm lost! :)
I do understand that CD transports differ because data and clock is being transmitted in real time and are so suspectible to jitter. But reading from a storage device such as HD or Flash cards isn't done in realtime eh? The way I see it data is fed into a RAM buffer packet-wise as is normal in any computer, and clocked on the way out to the DAC - is this not so? If not, why not, and how is it done instead? |
Osgorth, We will need then "titanium" buffers ;-) APL!!!
Almost all DVD transports use buffers since the reading speed is much faster, Squeezebox uses also buffers...even so: they all sound very different, some better some worst.
APL has modded from Phillips to Teac, going through almost all Denons...mods are similar but the results seem to be very different even though the data is coming actually from a buffer!!! Alex, can you clear this up? |
Jsadurni: well, as Seandtaylor99 says, no matter which storage device you use, the data must hit the RAM first, since that's the only way to retrieve data off a hard drive, a flash card or whatever. They work as storage devices, so you read from them into a RAM buffer, and then you can forward it to the DAC or whatever you wish. :)
That's what I meant; I can't for the life in me understand how different storage devices would sound differently. IF there is a difference, it's got to be due to the implementation, e.g. what happens to the bits after being output from the RAM buffer. |
"The main difference of the Flash memory would be avoiding a spinning mechanical device and the problems inherent to these..."
I bet FLASH players and hard-drive players (and some CD-ROM based players, like meridian) actually play back via RAM, since they need to buffer and format data prior to transmission.
All can work well, but FLASH is currently disproportionately expensive. |
The main difference of the Flash memory would be avoiding a spinning mechanical device and the problems inherent to these...
Now we will soon find out that "titanium" flash memory chips do sound better than the "normal" flash memory chips and we will never agree if spinning disks sound better than what kind of chip...untill they sell no CD no more...and we will only find CDs in Vynil sites!!!
We will buy music from sites and down load it to our computers, we will listen to the radio through our computer and if you like the song you can buy it instantly, only the song or the whole Long play...or a seleccion. I am sure there will be playlist sites that sell the whole potpurri like Buddha Bar CDs, those of us with a Good CD transport will have to burn a CD in order to play it from our transport, or will decide to go directly from the computer (which by then will be Full Flash memory anyway) even if it really doesnt sound as good!
But these will be Tomorrow`s Transport War....
Vynil anyone? |
>>playing back from "flash" memory (and NOT the hard-drive)
And the difference between these two are what, exactly? Both are digital storage devices. Both methods can easily handle the 1411kbps bitrate required for Red Book playback. Any differences perceived must be due to implementation artifacts, hardly due to the storage devices used. |
You are correct that he does not single out RUR. I had read HP's comments at the same time and the concept was top of mind when I wrote my post.
Still, it seems to me that RH would maintain that RUR is nonsense for the same reason he takes issue with their claims about CIRC: errors are not a big deal, so the basis for what they claim is the value of RUR is false. If the MP sounds better, it is not because of how it handles errors in reading the bits, is how I interpret his comments. |
Guys, guys, please let's keep the data straight.
The subject is alredy too technical for most us so let us not make things any more confusing.
I am referring to Drubin's comments on "Robert Harley's comments on the Memory Player" in TAS (Dec. 2006 issue, page 121). RH did NOT once refer to Read Until Right (RUR) in his comments. He DID made some very strong statements disputing the claims made by Nova Physics about CIRC (Cross-Interleved Reed-Solomon Code)error correction scheme, uncorrelated errors and error-concealment circuits. RUR is an extraction process used by Nova Physics to get the data off the CD and thus has nothing to do with CIRC.
Even if the claims by Nova Physics regarding CIRC are in dispute, their use of RUR and playing back from "flash" memory (and NOT the hard-drive) makes the MP a unique and technically superior digital playback component. Call it a transport if you wish, but it is a transport unlike any other. |
I just re-read Robert Harley's comment on the Memory Player in a recent TAS. He had not heard it, but was so appalled at their claims about errors in reading discs (their Read Until Right process) that he felt compelled to speak up. Harley's a pretty cautious guy and has decent credentials in this area. Unusual for him to take such a strong position like this in print, and I commend him for doing so.
As I said earlier, I was mighty impressed with the sound I heard from the MP, and I have read the other reviews. Harley's point was that, if they are getting great sound, it is not because of Read Until Right. I hope we can get to bottom of this in the near future. It feels like an improved understanding of what's really going with transports and the like is just around the corner. You'd think, at any rate. |
Before jumping to conclusions about the Nova Physiscs Memeory Player go to their website www.thememoryplayer.com and read why their approach to get at the data on the CD is completely novel and does NOT resemble buffering, reclocking, oversampling, etc. Also remember that the Nova MP can only play back what has been recorded. It cannot reverse or correct any problems in the recording process and/or manufacturing stage. There is no DAC on this earth that can correct errors due to insufficient transport capability.
There are also two reviews out there on Positive Feeddback Online www.positive-feedback.com and The Stereo Times www.stereotimes.com |
Jsadurni/others: I reached a personal conclusion on this over two years ago.
Fingertip access to my 9000 songs through iTunes is IT for me.....NO going
back. Having all my music on iTunes lead me to listen to more of my
collection
than ever before. I have not had a conventional CD player in over a year. To
me,
ACCESS IS EVERYTHING and having almost 900 albums on iTunes gives me
at-a-
glance access that I cannot duplicate with the physical media (CD's) no matter
how I organize it (racks, shelves, binders, etc.).
That said, I initiated this thread to try and better understand some of the
technical aspects of the current deabte going on about computer playback of
music versus conventional CD transportation. I have learned much from this
thread and appreciate the input of everyone who has participated.
The conclusion I have reached from this thread, and my other reading on the
subject, is that a thoughtfully implemented computer transport can compete
with all but maybe the most tweaked hi-end conventional transports. |
Steve I am probably a future costumer of yours (after analog), I will need my current DAC to sound the same as it sounds with my current Transport..thats all!
I will use a little black box (Hag-usb, offramp, Lynx card, etc.) with a digital output, the input can be USB, Ethernet, Wifi; whatever sounds good!!!
I am soo happy with my cheap DAC, I am thinking twice about vinyl!!! |
Jsadurni - too bad about your experience with the SB. I have found that USB audio is much better quality than Wi-Fi (even though I sell an Off-Ramp Wi-Fi), but dont expect miracles if you buy a cheap converter. USB audio can outperform most transports IMO, but ONLY if:
1) you use a custom S/W driver - only comes with certain converters
2) you avoid the TI 270X chips - most of the converters are based on this
3) the converter is clock by a low-jitter clock, such as Superclock
4) you use a PC and SRC upsampler
5) you use the right ASIO plug-in
I know it's a lot to consider, but the results are well worth the effort.
Steve N.
Empirical Audio
Manufacturer |
Pardales; I hear you man, I was there and I have a bunch of *.wav files on my hard disc, then I noticed I stopped listening to whole CDs, I would just skip through songs, then I took longer looking for that song than listening to it (probably my inexperience), then I realized most of my favorite songs are not the HIT sinlge of the CD, but something I found by not standing up to change the CD, My Favorite movement from Bethoveen´s 9th is the Second while the Coral is the the Hit! (just an awful example, a symphony should be listened from begining to end).
Another thing; for critical listening I just could not bear knowing it could sound better hooking up the machine behind this one...but thats just me!
I am glad it is working out good for you though!
Maybe I will get a Hag-usb and try again!
How many favorite songs did you discover that are not the ones you bought the CD for?
What about vinyl? |
The best conventional transport I have tried is the newer CEC TL-51X (I think I
have that model right) it retails for $1500. It was equivalent to the set-up I have
now, but not better.
Seandtaylor99: You make some important distinctions. I guess what I am talking
about is the situation where you are taking a USB signal out of a comptuter and
sending it to an external DAC (not using the computer or a soundcard for D/A).
Jsadurni: You are right about being able to draw a personal conclusion even
when a general one is elusive. |
The Squeezebox streams digital Wifi and wired (I had less interruptions wired) via Ethernet, the buffer lasts for about a minute, it has an onboard DAC which was modded (power supply, clock, analog output, etc.) It "does stream digital", it sounds OK... "World Class" it is not.
So; all the bells and whistles are there;ram buffer, almost no jitter, Ethernet two way communication etc. one can argue about the implementation probably not being the best, so I got it modded...all the besll and whistles plus a much better implementation...Still sounded OK!
Much better through my outboard DAC, Extremely good with an outboard TRANSPORT!!!! |
I think it's important to distinguish the different types of "computer audio".
The DAC might be on the sound card. I see this being a bad idea for reasons of noise.
It might stream SPDIF : this is also a bad idea for reasons of noise.
It might be streaming via USB. I can't see a problem with this so long as the DAC has a RAM buffer of sufficient size and a well designed oscillator and power supply.
It might be streaming via ethernet .... ditto USB.
Saying "computers can't stream digital" is an over-simplification. |
Pardales, have you tried a top transport in your system?
How does it compare to the Hag-usb link?
As always a general conclusion will never be met, but a personal conclusion can be drawn....
I tried computer audio and a good CD transport makes a world of difference in my system, anyway I will some day buy a computer interface with SPDIF and try it out again, maybe the next generation will be better....but I will try again Analog first!!!
When a computer link sounds better than my Forsell in my setup I will be convinced!!! |
There will always be terms that need definition. I still think that where we are in this discussion is trying to answer the question of whether a computer can put out a digital signal equivalent to what a classical CD transport can put out. |
Good question. The Transporter's DAC kicks in before it releases the Info. The feed from my transporter sounds much better than from the squeezebox using the same S/P DIF digital cable. |
I'm confused. You say the Transporter has a great DAC, but it sounds like you are taking its digital out and using the DAC in your Audio Aero. |
Much of the above technical discussion is interesting and yes, I do accept that data stored on a computer's hard drive can be superior.
There are, however limitations. The first has to do with the format used to rip a CD. Everything is most dependant on the DAC used. I just purchased a Slimdevise TRANSPORTER which has a really high-end DAC and now my music on my computer as well as streaming audio is as good as my stand-alone CDs. Getting to this point took a while.
I had never been happy with my Apple G5's ability to play back my music. I have an Audio Aero Capitole CD player and I have a pair of bridged McIntosh 2102 amps and my speakers are Kef Referance 205s. Music from my computer, even using Apple lossless or WAV simply never equaled what I got from my primary system. I ordered a TRANSPORTER, but since they were back-ordered they gave me a squeezebox for free and this was an improvement. Then, the Transporter arrived and it sounds great. It has several digital outputs, including a balanced AES/EBU which makes it the first unit i have owned that actually outputs this signal. It also outputs toslink, coax and SP-dif. I have tried all three as my Audio Aero will accept any of these and the SP-dif sounds the best. Even streaming audio sounds good.
So, yes pure data well stored is fine; don't ignore the system's retrieval ability as cold science is still cold. |
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 Altmanns 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.) Novas Memory Player does away with spinning CDs in realtime. Playback is driven by a computer. |
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. |
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 |
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 |
"So, for now, I guess this is the question: is the average computer really putting out an inferior signal to that of the transport section of a good CD transport?"
I think the key here is to define "inferior", and specifically "inferior in a way that would degrade the design of a competently designed reclocking DAC". |
Based on your answers, Pardales, I think the question you meant to ask is, Can the average computer put out a signal equal to that of a dedicated CD player or transport? |
Okay, as of now (and this is just my read on the debate) the crux of the argument between the two positions I started this thread out with seems to be about whether the computer can send out a decent signal. Alex is suggesting that there is so much noise involved in the computer that it is not going to send out as clean/clear a signal as a classical CD transport will send to its internal DAC.
So, for now, I guess this is the question: is the average computer really putting out an inferior signal to that of the transport section of a good CD transport?
One camp says "no, not right now", and the other suggests, "yes, it now can". |
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. |
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 |
Regardless of the way we choose to play our Redbook, it makes me wonder if those in control of the CD mastering process are truly as critical as we are in our listening. How perfect is the mastering process? For that matter, look around and see how many professional recording devices these days have a USB port - what do you suppose that's for? Connecting to a "Noiseball" I reckon. Tells me that somewhere in the recording process our beloved 1's and 0's are quite possibly passing through a Noiseball. If so, is it possible that some of that noise generated garbage is being passed on to us in the final product? Are we just trying in vain to fix garbage that was already there?
I'm using a Meridian 518 to send my 1 and 0's from my computer to my DAC. My SPDIF converter is a Waveterminal U24 - which happens to be a professional audio device with , you guessed it, a USB port. The Meridian is supposedly a unit that (according to the manual) has been used in the final mastering process by Chesky records and Sony Classical, to name a few. Considering the above, perhaps I am doing no worse with the end product than what is being done in the studios in the first place? |
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.
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.
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. |
Yes the Reconstrction Theory.... |
Nova Physics Group Memory Player is the latest buzz and is attracting rave reviews. It's essentially a computer with a tube based dac ($15k). You also get it without dac ($10k). One reviewer comments on how it outperforms the highly regarded Zanden front-end ($40k+). So, yes its an evolutionary thing with a sweet benefit of lowering costs. |
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 |
Drubin - with a computer external converter, the power supply can be just as quiet, whether it is USB or Wi-Fi.
Steve N.
Empirical Audio |
Correct. But his discussion of the role of power supplies in creating jitter goes to Alex's "noiseball" doctrine. Or maybe I just don't understand this stuff well enough. |
Drubin, to me the Altmann article just says that you have to minimize the sample clock jitter at the DAC chip. It doesn't infer that this is better done via a one-box, multi-box, or computer design. |
The Altmann article seems to align with some of Alex's point of view, if I understand the two of them correctly. |
