Weeding - Audio discs or data discs ?

As a longtime lurker, I am very happy to see the weeding of some NO discs. I'm very intrigued by the Rehersals and will be very happy to get a weeded copy at some point.

The below is not an attempt to start a flame war or to discourage the generosity of those starting and spreading the weeds. My motivation is to ensure the quality of the recordings being distributed.

My question - Are the discs plain audio discs and if so, would it not be better to weed SHN discs ?

Copying an audio discs is not a trivial matter and it is very easy to add extra noise on the copied discs that is not present on the original. Some software and/or CD drives are simply not capable of accurate DAE (Digital Audio Extraction). Tools such as EAC (see link at bottom of post) do help in this regard.

Most groups that distribute recordings start by spreading audio discs that people copy and pass on. After a while people start noticing DAE noises and it all gets ugly after that. It turns out that even if everyone uses EAC errors can still be introduced as the tracks are being ripped. The group generally then switches to compressing the WAV files into data files and distributing them instead.

The process is fairly straightforward :-

The originator of the weed will use a tool such as EAC to accurately rip the audio CD to WAV files. The WAV files are then losslessly compressed to SHN and a MD5 checksum calculated. The SHN files and the MD5 checksums are then burnt onto the discs being weeded. The SHN files on the CDs are then validated using the MD5 checksum file to ensure they burnt with no error.

When a wedee receives the discs they first of all copy the SHN files and the MD5 checksum file to their hard drive. They then verify the SHN files using the MD5 checksums. If all files pass the checksumming they know that all files are OK. They can then decode the SHN files to WAV and burn an audio CD using DAO (Disc At Once), and voilà, they have an exact copy of the original disc.

To continue the weed, the SHN files and the MD5 checksum file are burnt onto CDRs again. Prior to them being mailed the SHN files on the CDRs should be checked against the MD5 checksum file.

The above involves some learning and using a few simple tools, but does maintain the quality of the recordings as the most critical stage - the ripping of the CD - is done just once.

Some Links: EAC - http://www.exactaudiocopy.de/ One SHN/Md5 tool - http://home.att.net/~mkw/mkwact.html

IAP

Normal service has now been resumed.

So, Grandmother. How do you suck those eggs again ?

Welcome Ian. Ignore my comment above, I'd much rather read an interesting post like yours than the ones from septics who shout "WHEN ARE NEW ORDER PLAYING AMERICA AGAIN ?"

I'm not sure that everyone who has volunteered to join the weeding is sufficiently switched-on in terms of the finer points of audio engineering and sound reproduction to follow what you say. It's a bit of fun, rather than a science, and the day it becomes scientific is the day it ceases to be interesting. Those participating are all producing same standard stuff, nobody has complained about the sound quality or anything - inevitable these recordings will never be crystal clear, because we can't do anything about the originals.

...um

what's weeding? Is that like starting up a bootleg tree?

but yeah -> data cds you are guaranteed to get perfect audio. W/ audio cds... you have the chance of mistakes, esp if people use different types of cdrs