Center Channel ? [Archive] - Audio & Video Forums

PDA

View Full Version : Center Channel ?



s dog
07-31-2005, 08:30 PM
A while back i posted a ? about vibration lines in my dvd picture at loud volumes. I tryed everything i could think of to fix it but nothing i did helped, like differnet cables, new panamax surge protector, tryed different electrical outlets through out the house but nothing worked. Last night i was watching LOTR and i noticed during loud vocal parts the lines in the picture got worse. So for some reason i got wandering if that dam center channel speaker was shielded ccorrectly [ klipsch sc-3 which i have setting on a stand right in front of my 57'' toshiba crt HDTV] So i moved it about a foot forward away from the tv and guess what the lines went away. I cant believe that center would not be shielded better than that , i should have caught it earlier, it all started when i brought the dam thing home, just never had this problem before, just wasnt thinking. So my ? is can i fix this problem myself some how, i really like the center speaker and i hate to spend the money on a new one if i dont have to, and i dont really like it setting a foot and a half out in front of the tv,dont look to cool like that. could use some help ,thanks

N. Abstentia
07-31-2005, 08:41 PM
Doesn't sound like a sheilding problem. If if was sheilding your picture would be all screwed up with green spots and swirls and all kinds of cool stuff.

Sounds more like the speaker is vibrating something loose in your TV, doing it only at loud volumes is the dead giveway. If it was sheilding the volume wouldn't matter. It would even do it without the speaker even being hooked up.

s dog
07-31-2005, 09:08 PM
Doesn't sound like a sheilding problem. If if was sheilding your picture would be all screwed up with green spots and swirls and all kinds of cool stuff.

Sounds more like the speaker is vibrating something loose in your TV, doing it only at loud volumes is the dead giveway. If it was sheilding the volume wouldn't matter. It would even do it without the speaker even being hooked up.
I know what your saying, but it done the same thing on my old standerd toshiba crt tv.I just got the hd tv a few weeks ago, i wouldnt think it would do the same thing on two different tvs if it is not a shielding problem, but then maybe it could not sure what to think

nick4433
08-01-2005, 01:09 PM
I know what your saying, but it done the same thing on my old standerd toshiba crt tv.I just got the hd tv a few weeks ago, i wouldnt think it would do the same thing on two different tvs if it is not a shielding problem, but then maybe it could not sure what to think
Klipsch has at least a five year warranty on their speakers. Just ask them to replace the darn thing and that's it.

Quagmire
08-01-2005, 03:19 PM
I know what your saying, but it done the same thing on my old standerd toshiba crt tv.I just got the hd tv a few weeks ago, i wouldnt think it would do the same thing on two different tvs if it is not a shielding problem, but then maybe it could not sure what to think
If it's a shielding problem, the speaker will effect the picture just by being placed on the TV: It doesn't need to be powered up at the time or even attached to speaker wires to cause the distortions. On CRT sets, try placing the tv on a video channel that is not in use to get a blue screen. If it is a shielding problem it will most likely cause discoloration near the top of the set like a purple color and the discoloration will move with the speaker as you move it around the set. Just something for you to try to either confirm or eliminate improper shielding as the problem.

Q

N. Abstentia
08-01-2005, 09:05 PM
Could possibly also be a power problem..or lack of power. Since it happens only during loud passages the amp is going to be sucking juice during that time. Maybe it's robbing voltage from the TV?

s dog
08-01-2005, 09:35 PM
Could possibly also be a power problem..or lack of power. Since it happens only during loud passages the amp is going to be sucking juice during that time. Maybe it's robbing voltage from the TV?
But the thing is if i move the speaker 15'' away from the tv the problem goes away, But on the other hand i tryed a little experiment i unhooked the speaker and set it on top of my 27''crt in the bedroom and nothing happen to the picture at all ,so that would tell me it is not a shielding problem, one of the guys at work said maybe the magnetic field will increase as the volume is turned up causeing the problem, I think im going to go to the near buy hi-if shop and bring another klipcsh center home and see if it does the same thing. thank for all you guys help ,i still wander why it go away when i move the speaker away from the tv,

kexodusc
08-02-2005, 05:34 AM
If you have a 57" CRT TV, shielding shouldn't be a big problem for you. If at all. I have a 51" Toshiba and I have a large dual 6.5" center channel, and a 15" subwoofer (unshielded) within inches without any problem at all.
Placing the Center at the bass of the tv near the guts might cause some interference, but I've only ever heard that happening with large, unshielded woofers (like my 15" sub), not more modest center channels. Ever try placing it on top of the TV angled towards your listening position? It'd be a few feet away from causing problems up there.
These TV's should be pretty much immune to magnetic disruption, so I wouldn't be surprised if it's another problem, but based on what you've said, I can't imagine what that could be.

Odd that it affected the RPTV and not the 27" CRT. One would expect it to be the reverse if it was a shielding issue.
The magnetic field will increase as volume is turned up, but not really in a fashion that it would affect your TV anymore than with no volume at all. If the speaker is shielded it should be stopping that anyway.

Some times ground loop can manifest itself in distorted, dark horizontal lines in a television, but what you are describing doesn't sound like ground loop.

Here's a fast, neat trick. If you have a shielded bookshelf surround speaker or front main speaker, place it in the same position as your Center channel, does the same thing occur? If not, I'd be tempted to believe there's something funny going on in the center channel.

Quagmire
08-02-2005, 12:19 PM
But the thing is if i move the speaker 15'' away from the tv the problem goes away, But on the other hand i tryed a little experiment i unhooked the speaker and set it on top of my 27''crt in the bedroom and nothing happen to the picture at all ,so that would tell me it is not a shielding problem, one of the guys at work said maybe the magnetic field will increase as the volume is turned up causeing the problem, I think im going to go to the near buy hi-if shop and bring another klipcsh center home and see if it does the same thing. thank for all you guys help ,i still wander why it go away when i move the speaker away from the tv,
Just as another possibility, the only time I ever had picture distortions in the form of lines was when I had a bad video cable from the receiver to the tv. I had wires (audio and video) tucked under the carpet near the wall and I had accidentally punctured the video cable on one of the carpet tacks on the tack strips. It was still hanging there when I found it. As I recall, it produced nearly horizontal lines that slowly crawled upward accrossed the screen. I don't remember if they varied with the power output of the receiver, but I guess if the shielding were broken and the wire was laying adjacent to speaker wires, in theory it would be possible to induce interference from one cable to the other. At any rate, what you're describing doesn't really sound like a shielding problem to me. It does sound more like a cabling problem or interference from another source. Good hunting.

Q

s dog
08-02-2005, 10:10 PM
If you have a 57" CRT TV, shielding shouldn't be a big problem for you. If at all. I have a 51" Toshiba and I have a large dual 6.5" center channel, and a 15" subwoofer (unshielded) within inches without any problem at all.
Placing the Center at the bass of the tv near the guts might cause some interference, but I've only ever heard that happening with large, unshielded woofers (like my 15" sub), not more modest center channels. Ever try placing it on top of the TV angled towards your listening position? It'd be a few feet away from causing problems up there.
These TV's should be pretty much immune to magnetic disruption, so I wouldn't be surprised if it's another problem, but based on what you've said, I can't imagine what that could be.

Odd that it affected the RPTV and not the 27" CRT. One would expect it to be the reverse if it was a shielding issue.
The magnetic field will increase as volume is turned up, but not really in a fashion that it would affect your TV anymore than with no volume at all. If the speaker is shielded it should be stopping that anyway.

Some times ground loop can manifest itself in distorted, dark horizontal lines in a television, but what you are describing doesn't sound like ground loop.

Here's a fast, neat trick. If you have a shielded bookshelf surround speaker or front main speaker, place it in the same position as your Center channel, does the same thing occur? If not, I'd be tempted to believe there's something funny going on in the center channel.
I tried what you said ,I had a older rat shack pro55 center out in my shop so i put it in place of the klipcsh in front of the tv and turned up the volume on a loud dvd sound track and the picture looked just fine, so there must be something wrong with the klipsch, Now the next problem will be gettting best buy to do something about it , i do have the 4 year extended warranty but i know how best buy is, they will try to get out of replaceing it ,you can bet your a** on that one. thanks for every ones help