You don't mention any of your equipment.
My first guess would be your speakers and their drivers potentially not being phase coherent especially at or around the crossover frequencies (most dynamic speaker drivers are not phase coherent to one degree or another).
Perhaps in your case, your speaker drivers lack phase coherence to a larger more obvious degree. If what you hear happens on many cd's and on another cd player.
Second guess is that it could be your cabling is producing a pretty good time-smearing effect.
Third guess would be a combination of 1 and 2.
-IMO |
~~~~Stehno, I appreciate you taking time to reply! To eliminate speakers/cabling issues, I'll give it a whirl from direct cd through headphone output. Could I be subconsciously trying to find an excuse to upgrade cd?
Is the laser able to accurately track the non-concentric data without affecting sound? How much would it have to be off center before it started to have an influence upon sound?
Just The Facts,
By |
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. |
The most probable explanation is that you are listening to CDs originally recorded to analogue tape, and what you're hearing is the speed variation of that tape.
Things it is definitely not:
--non-concentric CDs
--laser problems
--"time-smearing" of cables
--transport "wow"
None of those things can cause the effect you are hearing. |
I have what i believe is a similar problem...i notice it only on piano music, it sounds like the tweater of my left speaker is distorting, simmilar in sound to when a speaker clips, only not nearly as loud, but audible from my listening location...it also seems to be frequency dependent..ie. only occures, or occures to a much great level within a certain frequency range.
when i first noticed the problem i returned the speaker and they replaced the tweeter with a new one, but the problem persists...
my system is
totem arros
nad c350
kimber 8pr cable
eichmann express 4 interconnect
dennon dcd 3520 cd player
any idea what it could be...I wouldn't think two tweeters could both exhibit the same problem unless its a design flaw with that model of speaker (unlikely)... i thought mabey the piano notes happened to fall right around the crossover point of the speakers and that somehow caused the distortion...
any ideas... |
Following the logic of using your headphones to isolate the problem,use a cd player you know is good and substitute it for your cd player to see if it your source or not. |
Bomarc, 2 or 3 posters above gave their explanations of time smear in cables. It sure sounded convincing...why are you so categorical in saying that this is definitely not the cause of what Fbi is hearing? |
Calanctus: Well, given that those posters all gave *different* explanations for time smear, which of them sounded convincing to you?
Given that this is a problem with only some disks, the source of the problem is almost certainly the disks themselves. I'd hate to see this guy sent on a wild goose chase to find a cable that will fix a problem that can't be fixed. |
I agree with Bomarc. Regardless, you don't need a reason to buy a new CD player other than you want to buy a new CD player. |
My guess is that piano may be slightly out of tune. What you describe is the beat frequency of 2 or more strings that are not quite in tune. If oyu hit or pluck 1 string then hit or pluck another that is out of tune, they will sound as 2 distinct notes. As you tighten the 2d string to match the 1st, you will hear a distinct wavering, rapid at first, then as they approach in-tunedness, the wavering slows, then disappears. You say you hear it on more than 1 CD - maybe pianos are harder to keep in tune than we think.
It seems hard to believe cables could store and release enough energy to produce something so clearly audible, especially since the storage times are so short (they occur at the speed of electricity, which is much faster than sound), and since the amount of energy storage is so short. In order to get a beat frequency, the cable would have to be altering the frequency of the signal it is storing and releasing. My understanding - tho limited- is that cables store and relesase a tiny fraction of the signal, resulting in out of phasse remnants dumping back into the signal, but still the same frequencies, with differences in amplitude relationships. The effects I've heard from cable changes are more of a focussing of low level detail, and changes in dynamics, especially at frequency extremes. It is unusual for any component other than a source (i.e. a wobly turntable, stretching tape, etc, as mentioned) to be able to change the actual content of the music.
I've also heard clipping sounds coming from tweeters. This happens when there is a lot of upper midrange content, like soprtanos, fairly high piano notes, especially fairly pure tones, held for a while. I think it is the tweeter screaming its head off at the lower end of its range before crossing over to the midrange. While it may not sound like the music's that loud, it is the same proinciple as driving a bookshelf speaker with very large amounts of bass - you get similar distortions. |
Calanctus,
I'm one of those who offered an explanation of dielectric effect in cables causing time smearing, but I was only responding to Stehno's mention of that effect. I did not mean to imply this could cause piano note warbling. Sorry if I was unclear about that.
I quite agree with Bomarc that cable time smearing, while often audible, could never cause note warbling. The usual audible effects of time smearing in cables are harshness, haziness and the smearing of multiple voices into a homogenous mass of sound. Pitch change is never a result IME.
I also agree with Bomarc that laser problems, transport speed irregularities and non-concentric CD's are not to blame. Neither is jitter. A CD player is not a turntable, digital is not analog. I've already suggested tape stretch or speed irregularities in the original (analog) recording and mastering equipment, as well as a way to test that hypothesis. |
