What am I hearing???


~~~~Hello,
I hope someone can explain why on some cd's the long piano notes sound slightly warbled. Not the normal vibration from the piano's wires. Am I hearing laser trying to track info on a non-concentric disc? I noticed a lot of cd's data area slightly non-concentric to edge of disc. Shouldn't the laser be able to trace imperfections? Warranty time? Starting to bug me, RATS!

Just The Facts
By
fbi
Greetings,
Please excuse me for ringing in with a,some what, related question. What is smearing? What does it sound like?
Many Thanks,
Steve Bennett
Literally, upgrade CD!
There are still a number of variables:
a) CD has been manufactured with a defect;
b) CD was recorded with a defect;
c) CD-player has poor or bad analogue end;
d) CD-player hasn't sufficient drive for your headphones(btw which ones?)
Sbennet268, I was afraid somebody would ask. And somebody please correct me if I am wrong.

I believe time-smear has to do with the way the audio signal is transmitted through the cable.

In essence, a poorly designed cable will produce or generate the exact same (moment in time) musical signal muliple times before the signal completes it's travels to the other end of the cable. Thus a 'smearing' affect. Which really translates into a sound that is a bit mushy, grainy, or hash in the detail with a definite loss of articulation.

This is supposedly not uncommon with some to many cables. In fact, I believe that the vast majority of cables invoke this time smearing affect at least in the lower bass regions. So much so that most people have no idea what real bass sounds like and feels like without this time smear.

I'll go so far as to even state that some speaker manufacturers will voice their speakers with this time smear either knowingly or unknowingly.

I also believe that some cable designers are fully aware of this time smear affect and have either completely eliminated or at least absolutely minimized it in their cables.

-IMO
Good explanation Stehno.

One reason for time smearing in cables (or any device passing an electrical signal) is the dielectric effect of the insulation layer. Since no insulation except a vacuum is perfect, some of the signal will travel through the insulation instead of through the wire itself. The propagation speed of the signal through different materials is different, so by the time it gets to the other end of the cable the effects can be audible. It is easily audible if you compare, for example, zip cord to a decent speaker cable.

Mechanical time smearing often occurs in LP playback. TT designers go to great lengths (or should do anyway) to make sure their decks run at perfectly stable speed. Any deviation is audible in instrumental timbres long before it gets to the point of pitch-wavering.

Fbi - you say this problem is only on SOME CD's. Any chance you're hearing tape stretch or tape deck motor irregularities from original analog recordings of less than stellar quality? Try the suspect CD's on another player before assuming there's something wrong with yours.
Stehno wrote:
"In essence, a poorly designed cable will produce or generate the exact same (moment in time) musical signal muliple times before the signal completes it's travels to the other end of the cable."

Not quite. Smearing in cables has to do with the dielectric absorption. It is simply charge stored in the cable dielectric that releases more slowly than air would.

Now, transmission-line reflections will cause a digital signal edge to reflect back and forth between the source and destination multiple times if the cable is low-loss.

I would suspect that an audible warble from a CDP is probably bad jitter or WOW from the transport mechanism. The servo is not keeping pace with the rotation.