After copying a certain CD (Californication -- Red Hot Chili Peppers -- no copy protection) without any errors using EAC, I decided to playback a segment of my shiny new WAV out of sheer curiosity. To my surprize, I discovered a very audible click not present in the original recording. A quick re-copy fixed this, but now I'm genuinely worried.

Can EAC output errors without listing them? Have all my previous copies been inaccurate without me knowning? What's going on?

Obvious question: was this in secure mode?

Obvious answer: yes.

My obvious answer: You didn't pass EAC the correct features for your drive.

My obvious response: I did. Doublechecked every feature and even cross-referenced AccurateRip.

Don't get me wrong -- my EAC often detects errors -- but this time it missed one.

My obvious question: what drive & features are you using with EAC?

My obvious response: NEC DVD+RW ND-1000A

Secure Mode w/Accurate Stream and C2
Autodetect Read command
Actual speed selection
Speed reduction allowed
CD-Text Read enabled
Gap method "A" -- Accurate
+48 read offset

No audio data caching, "Big Endian", channel swapping, spinup, or overreading.

(by the way, what do those last two do? should I enable them?)

I remember hearing people claim problems with NEC drives. I suggest trying with Accurate Stream disabled & I bet all errors are detected.

Edit: Less likely but could also be that you have C2 enabled

My vote goes to c2. For extremely secure ripping, c2 should be disabled.

So I should uncheck "Drive is capable of retrieving C2 error information"?

Yes, according to other member's recommendations.

I see. Thank you.

One more thing: the HydrogenAudio Wiki states: "...the NEC drive is totally unreliable for audio extraction". Does this statement apply to ALL NEC drives? What does "totally unreliable" mean? Will disabling C2 detection yield perfect copies, or will undetected errors still appear?

I think I recall reading something on here about NEC drives having trouble reading audio on any audio CD at a certain area of the disc (I think at around 42 minutes, I'm not sure).

this happened to me as well at times. a pop here and there, or even a dropout. I disabled C2 and sofar nothing of the sort happened again... Ive had pops and clicks since, but they seem like artifacts on the cd, as im not the only one with them (ive a recent thread in this forum about mistakes and EAC as well, not the exact same subject but may have some info for you.)

Are you sure you need that option ? Usually (That means everything I've ever seen or heard.) it should be disabled.

He wrote that it's disabled [:
Having it enabled when it should be disabled (and vice-versa) would result in totally distorted sound, impossible to not notice.

BTW, I have a NEC NR-7900A CD-writer and it's a good drive for DAE (very accurate C2).

So, wait a second... disabling C2 increases security, right?

I read on the RAD site that C2 should be disabled for best security. But, I have never read a description as to why. Can someone provide a link to such a description?

Is disabling C2 universally advisable, even when using a recommended drive such as the Plextor Premium?

I have seen very little proof that C2 produces significantly less accurate error detection than non C2 with a typical modern drive using EAC, just theory's & claims no tests performed on a wide variety of drives yet.

C2 is an error detection algorithm, but unfortunately, it is very rarely implemented correctly.

When I use C2, I always rip with test & copy ... you'd be surprised how many tracks show a CRC mismatch.

Nero CD-DVD Speed has a nice C2 accuracy test (Extra/Advenced DAE Quality Test/Error Test/Run Test...). Some months ago I created a test CD, damaged it slightly, and use it to evaluate C2 accuracy of my drives. Problem is that it's not compatible with some drives (for example it claims that LG GSA-4120B has no C2 at all), and I'm not sure how it handles the drives which cache audio.

There is no proof of this either. A synch error is not a C2 error, and if you've got C2 enabled, all synch errors will be undetected.
...but if you've got C2 disabled, some C2 errors may be undetected.

When media is so damaged that it causes a sync error, won't it also cause a C2 (read) error?

Doesn't EAC read more times if C2 is disabled ?
I've already had several problem discs when disabling C2 seemed to do better than enabling. Enabling is OK for CDs in perfect condition and results in higher speed, but is less secure - just my impression.
JeanLuc's experience looks quite sensible for me. I've even already had a CRC match, but still a different rip if C2 disabled !

I second that. Test & copy could be seen a kind of self-test and is a good protection against all kinds of trouble (not only a doubtful C2).


I believe that, but such a thing should be extremely rare. I once encountered something similar: CRC matched, but every time I cleaned the CD the resulting rip would show a new (different) set of (matching) CRCs.