There are several reasons why your disc may be rejected and this varies among manufacturers. I will cover a few of them here and give you a few pointers on how you can ensure that your audio will transfer from your DAW to the final product with as few technical issues as possible.
The first and certainly the most common reason that discs get rejected at the plant are because they have a large error rate which in turn causes the disc to drift out of Red Book specs. These errors can be caused by several different things including cheap blank media, cheap burners, and vibrations while burning the disc. Other reasons a disc might be rejected could be CD-Text with unrecognizable characters, and other incompatible or incomplete subcode data.
"What steps can I take to make sure my disc doesn't have any errors?"
1. DON'T TOUCH THE DRIVE OR MOVE/BUMP YOUR COMPUTER WHILE BURNING! If using an external drive be sure to isolate it as much as you possibly can. Foam Auralex type pads that are used to isolate studio monitors are great for this purpose.
2. MAKE SURE YOU USE MEDIA OF EXCELLENT QUALITY! It's widely accepted that media currently manufactured by Taiyo Yuden is among the best out there. I recommend their Watershield products. The error rates reported are very low especially when coupled with and excellent quality CD burner.
3. BURN AT A LOWER SPEED! The ideal speed to reduce errors really depends on the media/burner configuration you are using but speeds between 4x and 16x are typically used. Just because your media has a maximum speed rating of 52x does not mean that it will perform it's best at 52x. What works best is really hard to gauge without any type of in house error checking but burning at a lower speed definitely seems to help.
4. USE A GREAT BURNER! If you have the spare cash lying around it's a good investment to put some money toward a burner that is dedicated to burning audio CDs. Collected data shows that most CD/DVD/Blu-Ray combo drives report higher errors than those drives that only operate on CD media. A lot of mastering houses swear by Plextor Premium and Premium 2 drives for their reliability and error checking capabilities. Pioneer is also known for quality drives. Read up on what current production models are recommended by searching at the Hydrogen Audio and Gearslutz forums.
The Plextor Premium drives ship with software called PlexTools that lets you check for the same errors a CD replicator checks for before they approve your disc. If you are putting out releases on a regular basis, having one of these drives available for error checking is an invaluable tool that will save you a lot of time.
Understanding the C1/C2/CU errors reported by PlexTools is fairly easy. C1 errors (also known as the BLER rate) are correctable errors and 100% of the discs you burn will have some amount of C1 errors. The Red Book specifications allows for a 220 error per second averaged over any 10 second period. This is, in my opinion, way too high. But it gives you an idea of what is playable without a lot of noticeable degradation of the source material. C2 errors, while correctable in most modern players, are definitely undesirable and I will burn the disc again if it contains even a single C2 error. CU errors are the worst kind. Completely uncorrectable and a disc with even one will most certainly be rejected by the manufacturing plant. If your disc has even one single CU error you need to burn your disc again.
Lower values are always preferred, but this disc is well within spec and will have no problems producing a high quality glass master.
Is there a better way available to transfer my disc to the plant?
Why yes, Billy, there is. There is a 100% infallible method of transferring your disc to the plant digitally without ever burning your project to a disc and that method is known as a DDP (Disc Description Protocol) image. A DDP image is similar to that of an ISO disc image with built in error checking so if there is some problem in the transfer and it arrives to the plant without being 100% bit for bit identical to the original it will be flagged and you will have another chance to transfer the image.
Of course, you need to have software that is capable of exporting your final sequence as a DDP image. Fortunately this is no longer as cost prohibitive as it once was. If you have Apple Logic installed you most certainly have WaveBurner installed along with it which is great for final sequencing and it can export a totally compliant DDP image. Standalone solutions for both PC and Mac include DDP Creator by Sonoris Audio Engineering.
In conclusion, it's because of these reasons that I really push to do the final editing and sequencing for my customers. In addition to the above there is also the possibility that bad edits can leave your final product full of pops and clicks at the edit points. I've never charged any extra for this service and have always factored it into my rates but music is near and dear to it's creator and I understand the need to exercise as much control over the final presentation as possible. At the very least I recommend letting your mastering engineer check your final edit for technical errors before it's sent off.
If you have any questions, comments, or additions please be sure to let us know below. Until then, keep making that excellent music.
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