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Devices => PC's and Other Hardware => Topic started by: benn600 on December 20, 2007, 10:04:06 pm

Title: Live CDs Are Horrible
Post by: benn600 on December 20, 2007, 10:04:06 pm
I have a stack of live concert CDs from one of my favorite artists.  They were purchased on eBay a year or two ago.  I've finally worked up the guts to add them to my library even though I don't have cover art for them (I may make some).  So I started ripping them.  They are ripping horribly!  Often getting 15-85%, the rips are unbelievably horrible and almost every track rips horribly!  I'd like to maintain my 100% record for 100% rips and am don't want to add them.

The CDs look fine, though.  Is there an explanation for this?  Could bad bits be encoded into the written data?  What prompts the re-read errors?
Title: Re: Live CDs Are Horrible
Post by: glynor on December 20, 2007, 10:42:59 pm
Are they pressed CDs or CD-Rs?  CD-Rs in particular (but pressed discs as well) suffer from all kinds of problems that aren't always detectable by the eye.  Two biggies are:

1. Initial burn quality (and burn speed).  Drives throw out all kinds of errors.  There is error correction built in, but it doesn't always work very well.  Also... the faster you burn, the more errors they throw.  Some drives are also better than others at burning, more compatible with different media types, and respond better (or worse) to different burn speeds.  If you're curious, you can use Nero's CD/DVD Speed Utility to test your burner (the tab called Disc Quality).

2. Light exposure is the mortal enemy of CD-R discs.  The dye layer is what it used to record data onto the disc (the laser "burns" a series of pits in the die, allowing the light from the reading laser to bounce off of the reflective layer and back to the lens of the drive).  Sunlight and artificial light will degrade this dye layer too, just like the laser cuts through it.  Of course, it does so in a mostly uniform pattern, but not perfectly so (reflections and whatnot), which introduces some imperfections, and the overall degradation increases the signal to noise ratio on the disc (and makes reading more difficult).

I would probably just attempt to re-download them.  Etree.org has all kinds of live shows, from all kinds of bands.  As does the Internet Archive and Lossless Legs, among other places.
Title: Re: Live CDs Are Horrible
Post by: benn600 on December 20, 2007, 11:49:27 pm
They appear to be burnt CD-Rs.  Thanks for the info!
Title: Re: Live CDs Are Horrible
Post by: jgreen on December 22, 2007, 12:02:46 pm
benn, are these live CDs "bootleg" or otherwise audience-based recordings?  If so, I think that's where the issue is.  Studios spend a lot of money on the ANALOG aspect of recording which only becomes apparent when it's missing--such as in a concert venue. 

I'm not sure how format issues with the CD-R would express themselves in sound quality, other than an outright refusal to play. 
Title: Re: Live CDs Are Horrible
Post by: benn600 on December 22, 2007, 09:36:18 pm
Can you explain the whole live concert issue: bootlegs, studio, etc.?  Are bootlegs recorded from the audience perspective by someone's personal microphone?  Any other info would be helpful.
Title: Re: Live CDs Are Horrible
Post by: JimH on December 23, 2007, 08:09:15 am
You could try wikipedia or google.
Title: Re: Live CDs Are Horrible
Post by: benn600 on December 23, 2007, 09:03:40 am
I'll have to Yahoo those terms to learn about where they can take me today.