[royewest]

This must have come up in the past, but I'm having a hard time finding threads that discuss it. Anyone know of links to a discussion of distortion on CDs?

I've been working a heck of a lot of hours lately listening to a Thinkpad XP sp2 with iTunes and lossless audio ripped from my CD collection > Airport Express > optical cable > Grace m902 > Senn 650s. There are a lot of tracks on a lot of CDs with a weird buzzing distortion.

The glorious CD "A Love Song" by Percy Heath is just one case in point. Track 4, "A Century Rag," at about 0:25 to 0:35 there is a piano solo that peaks with an annoying buzzing distortion -- as if there were a loose piece of sheet metal in the room. There are plenty of other tracks in my collection like this -- someday I'll compile an OC list...

Late the other night I decided to get to the bottom of this. I started swapping out components. I switched headphones. I listened to the CD instead of the ripped version on iTunes on the Thinkpad. I ripped the CD lossless onto my wife's g4 Mac laptop and connected the Mac's USB to the Grace. I used the wife's bookshelf JVC CD player to play the CD > optical cable > Grace. (Sure, the Mac sounded better than the Thinkpad -- fine, stop torturing me, there's nothing I can do about that right now.) But the same track, same spot, still has audible distortion.

So now I'm getting angry (as my friend guessed right away when I started this story with him - I was on a serious deadline at work). I drive to the office and pick up my Arcam CD-72 and connect that to the Grace with a Zu FireMine coax cable. Same noise.

The next day, in desperation, I put the CD into my livingroom rig. This is a nice basic-audiophile set of components that are hardly current or state of the art but a solid rig (Micromega Stage 6 > Linn preamp > borrowed Boulder AE-whatever power amp > Sonus Faber Grand Pianos -- all with decent but affordable interconnects). The point is, none of the components are in common with my work rig except the CD itesefl I turn up the volume on Century Rag and the distortion is still there.

OK, so what gives? Is this just bad studio technique on the recording? Is this a known artifact of the red book CD standard?

I'd sure appreciate any links to an informed discussion on this topic.

 

[bigshot]

Do a search for the term "hot mastering"

See ya
Steve

 

[memepool]

Percy Heath doesn't play the kind of music which would be mastered "hot" though.

Have you tried to find the same recording on any other format? tape or vinyl or high rez digital maybe. It could be that it's a sound on the orignal recording or else it could be some sort of artifact on the CD down to a poor transfer.

 

[Guss2]

Just try to listen to Rush "Vapor Trails",then you'll know what hot mastering is.Gary.

 

[sejarzo]

Quote:

Originally Posted by royewest /img/forum/go_quote.gif OK, so what gives? Is this just bad studio technique on the recording? Is this a known artifact of the red book CD standard?

It's not an artifact of CD's, but simply bad initial tracking that's the likely cause. It was recorded with the mic levels set too hot, somehow no one noticed, and what's done was done.

Hot mastering shouldn't create buzzy distortion, it would only compress the range and make it louder overall.

 

[OverlordXenu]

Sounds like a problem with your DAC/amp, or even headphones.

CD's are digital, when they are damaged, that part is just not read. They can't distort. They're 1's and 0's, bits.

 

[Febs]

Quote:

Originally Posted by sejarzo /img/forum/go_quote.gif It's not an artifact of CD's, but simply bad initial tracking that's the likely cause. It was recorded with the mic levels set too hot, somehow no one noticed, and what's done was done. Hot mastering shouldn't create buzzy distortion, it would only compress the range and make it louder overall.

Part of the problem with hot mastering is that if often uses heavy brickwall peak limiting which can cause the types of problems the OP describes.

 

[sejarzo]

Quote:

Originally Posted by OverlordXenu /img/forum/go_quote.gif Sounds like a problem with your DAC/amp, or even headphones.

Umm........the OP states that he hears the problem with that particular CD on any system on which he plays it....the only thing in common is the CD itself.

 

[sejarzo]

Quote:

Originally Posted by Febs /img/forum/go_quote.gif Part of the problem with hot mastering is that if often uses heavy brickwall peak limiting which can cause the types of problems the OP describes.

Your point is well taken. I forgot that a CD could show some "badly done hot mastering" as opposed to "correctly done hot mastering"....I mean, as if it could be done correctly.....

 

[OverlordXenu]

Quote:

Originally Posted by sejarzo /img/forum/go_quote.gif Umm........the OP states that he hears the problem with that particular CD on any system on which he plays it....the only thing in common is the CD itself.

Ah, sorry. I just skimmed the OP.

Bad mastering? Somehow produced incorrectly?

 

[bigshot]

skim this thread again

 

[esuko]

Hello

No answer from me but more questions.
I have also encountered this problem and find it realy annoying.
Would there be any computer program that could be used to cut the dynamic range a bit and this way cutting the distortion away?

 

[Riordan]

to sum up a LOT of threads in the music forum and elsewhere on music enthusiast sites: this is nothing equipment-related, but (as bigshot has already stated) hot mastering... the problem has become endemic especially in commercial pop and rock music.

read the music forum, search for "hot mastering". your eyes will open, your mouth as well.

 

[zipdisk]

When I record an LP to CD and have the digital recording level set too high, I get distortion that reminds me of what you describe. I know nothing of itunes, etc., but perhaps when you transcribe the CD to the new format, you are exceeding the allowable input sound level? Just my 2 cents worth.

 

[sejarzo]

Quote:

Originally Posted by zipdisk /img/forum/go_quote.gif When I record an LP to CD and have the digital recording level set too high, I get distortion that reminds me of what you describe. I know nothing of itunes, etc., but perhaps when you transcribe the CD to the new format, you are exceeding the allowable input sound level? Just my 2 cents worth.

That happens because you are doing an analog to digital transfer with the analog end set improperly.

CD -> lossless compression is simply an operation on data that does not change the digital signal level.