Current Trends in the Recording Format Arena P1 - page 2

Part 1: Is Louder Better?

The following are excerpts from a thread that includes some of the best Recording Engineers and Manufacturers of studio gear today.

Q: What is one of the biggest problems with CD production/mixing methods today? Please note the distortion figures below and try to remember that at 0 db full scale a typical CD player can typically have -90db or better distortion

A: General Misconception on maximum recording levels for 16bit systems

"Actually, it's the only way to do it, insofar as a distributed medium is concerned. I didn't say you had to clip or limit! You could have a single sample at -0.3dBFS and only the oldest 16-bit DACs would have any problem at all, if at all. Any DAC with 18bit processing, or better, has no problem".

"That's precisely the misunderstanding I would like to correct. Most recent pop CD releases contain frequent signals that are severely distorted in nearly *all* consumer devices. DACs are only designed to accommodate signals up to the level of a sine wave at 0 dBFS asynchronous to the sample rate. In the real world, Anno 2002, level above that can be present more than 30 times per second.

Average distortion figures over a variety of players are:
-32 dB (2.5%) for a +0.69 dB intersample peak,
-25 dB (5.6%) for a +1.25 dB intersample peak,
-18 dB (12.6%) for a +3.00 dB intersample peak,

To make things worse, there is an aftereffect (latch-up, recursive filters etc.) which prolongs the distortion period, so you end up with an ear-fatiguing sound because the equipment is in more or less a permanent state of distortion. A net result that may not be better than a highly data reduced MP3 delivery without (that kind of) artifacts.

Because most new releases contain peaks above +3 dB, you would have to lower the limiter threshold to -3 dBFS for the method you propose to make sense.

Point is: Single sample peak detection is futile, and I expect us to shortly publish more papers and audio examples of this to get it across."

Thomas Lund
T.C. Electronics

Q: How can a Producer guarantee the finished CD sounds as good as the Master Tape? The gentleman below is not the only one to complain of this problem.

A: "I don't think I've ever had a CD come back from a plant that sounded as good as the PMCD I sent them (really unscientific claim, sorry...but in an a/b comparison using the same d/a converter the difference is obvious to the CLIENT). I actually do believe that 16bit/44.1kHz can sound really, really good, but rather than fine tune the medium we seem to be jumping onto the next big thing without getting the best out of what we have. Bob K. has suggested that a consumer CD player with a built in up sampler would go a long way toward improving playback of ALL existing CD's, but as far as I can tell, we're tossing the medium as flawed because there's something "better" up ahead. I can understand the appeal of surround, but that doesn't negate the stereo (or mono) production process. If more data is better all the time, than a 5.1 mix of a song will be better than a stereo mix (wow, six times more information!), and no one in their right mind (who reads marketing hype) will be buying CD's anymore...so I guess I should just sell all this stuff and go flip burgers."

Tom
Thomas Eaton recording

First find a pressing plant that will work with you. If you ask a potential plant what speed they burn their glass masters at and you get a "dah" at the other end of the phone hang up quickly and find some one who is knowledgeable and willing to provide a quality product at a reasonable (notice I did not say "cheap") price. Too many times today people are going for the bottom line and they want to get 1000 CDs pressed with artwork and jacket for $1,000.00 and then they complain about the final quality of the project. There are lots of really good duplication plants out there and someone, the likes of Glenn Meadows, could probably give you a list of ones to use and ones to avoid.

I know what your frustration is all about. We recently did a project and the test pressing came back sounding NOTHING like the master I had send the plant. When I contacted the plant I was told to talk to their "mastering" engineer but I would have to call back after 3 pm since he did not get out of high school till then. When I talked to him he was very nice and very concerned about the quality of the product the plant was producing but his boss was more concerned about getting projects out the door than worrying about individual projects or the concerns of one or two people that could hear the difference.

The "mastering" engineer told me that he did the transfers for the company and that his boss had told him on numerous occasions that "digital is digital" and it all sounds the same anyway. He further told the "mastering" engineer that the most people who could hear the difference were NOT buying their products.

The student told me that the job was better than flipping burgers at MacD's but he was trying to find another job that was more rewarding and that he could feel good about.

There are a lot of really bad pressing plants but hopefully as people trade stories and listen to the final product the bad ones will go away and the good ones will stay around but as long as people want "cheap" pressings that is EXACTLY what they will get. I am not saying this is your case but a lot of the "bottom feeders" we deal with want quantity not quality.

Best of luck in your quest for the perfect replication plant.

Tom Bethel

Note: Some studies, though informal, have found that higher burn speeds of the glass master at the CD production plant cause the "digital pits" that are inscribed on the CD to be less uniform. The lack of precision will cause higher timing jitter and increased errors. Typically timing jitter will cause more distortion of low amplitude signals, and more distortion of higher frequency signals. There are ways of insuring that what you put in to the production house is what you get. Comparing the digital files at each step of the way is one way of insuring the continuity.