Subwoofer shaking TV picture

[Kyle Lorenz]

My subwoofer shakes my TV picture a little. I don't mind it shaking but I'm worried that it will harm the TV. Could my subwoofer skaking the TV picture wreck it overtime? Thanks.

 

[j_garcia]

It sounds like your sub is too close to your TV. Is this a CRT TV?

 

[Kyle Lorenz]

What's a CRT TV? I'm a little new to this. I can tell you that I have a Sony Wega Trinitron.

 

[j_garcia]

CRT = tube, and that would be one. So is the sub pretty close to the TV? Is it a powerful/large sub? If the sub is close enough that the stray field affects the image on the screen, it would seem to me that it will eventually cause damage. Are they both plugged into a surge supressor? If the sub isn't close, maybe it could also be a voltage issue?

 

[Kyle Lorenz]

The sub is 250 watts 10 inch and they are both pluged into a surge powerbar. The sub is right beside the TV so I guess I got nothing else to do but move it. Thanks for the advice.

EDIT: I just got an idea. I have a 300 watt home subwoofer on the other side of the TV that doesn't shake the picture. The other sub I'm talkin about is a homemade box. So, I got to thinking. The 300 watt sub has cotton insulation inside and the homemade one doesn't. Does the insulation stop the viberation?

 

[j_garcia]

The other sub may have what is known as a bucking magnet that will help reduce the magnetic field coming from the sub, essentially like shielding. If you move the sub away from the TV and the problem stops, you know it is the sub. The polyfil shouldn't make any difference. Are you saying it physically shakes the TV or that the image on the TV shakes?

 

[Kyle Lorenz]

The image of the TV shakes. I wish I had a sub that could move the entire TV haha

 

[t3031999]

CRT stands for Cathode Ray Tube.
The ray is basically a photon and electron beam fired from a electron gun near the back of the tv towards the screen.

This beam can be affect in 2 main ways.
1. Magnetic interference.

The beam is aimed at the pixels on the screen using a magnetic field. With large magnets (unshielded speakers) nearby, this field can be messed up and can cause discoloration of the image, and a constant waving affect.​

2. Vibration

The electron gun is also sensitive to vibration. This would cause shaking corresponding to a specific impact from a subwoofer.​

Both of these can cause permanent damage to a TV and both can be fixed by moving your subwoofer farther away.
It sounds to me like you are dealing with the second one.
You can try adding some dampening material to the subwoofer
and ensuring that the subwoofer is not directly touching the tv stand and adding isolation spikes to the bottom of the subwoofer.

 

[snobgoblin]

I kind of had the same problem. When my sub hit hard the tv would get a little darker. Not really noticable unless your looking hard. It looked like the sub was sucking all the juice from the tv. I went out and bought another surge protector and plugged the protector and sub in another outlet. Problem is now fixed.

 

[Kyle Lorenz]

You can try adding some dampening material to the subwoofer and ensuring that the subwoofer is not directly touching the tv stand and adding isolation spikes to the bottom of the subwoofer.

What do you mean by dampening material? Like where would you put the material and what kind of material. Also, how would isolation spikes help vibration? I have four plastic spikes that are 2 inches tall just laying around. Would those work?

P.S. I tried plugging in the subwoofer to a different outlet and it's still the same problem.

 

[t3031999]

What do you mean by dampening material? Like where would you put the material and what kind of material. Also, how would isolation spikes help vibration? I have four plastic spikes that are 2 inches tall just laying around. Would those work?

The insulation in your other sub is a form of dampening material. Lightly packing the subwoofer cabinet with polyfill, fiberglass, acoustic cotton or similar will help reduce vibration. Also a layer of foam (around 1 inch thick) glued to all internal surfaces will also help. The also make dampening sprays such as this, that help reduce vibration.

The spikes on the bottom of the subwoofer anchor it to the floor increasing the vibrational mass of the cabinet, and therefore lowering its resonant frequency. To properly anchor the cabinet spikes generally need to have a fairly sharp point, so if your plastic spikes have decent points, can support the weight of the subwoofer, and won't waver too much when the subwoofer is on. Then go for it.

On the more drastic end, adding appropiate internal bracing with mdf (medium density fiberboard) will help a great deal.

On the less drastic end, placing a weight on some padding on top of the subwoofer will also help dampen vibration, but not as much as other methods.

 

[Buckeye_Nut]

My subwoofer shakes my TV picture a little. I don't mind it shaking but I'm worried that it will harm the TV. Could my subwoofer skaking the TV picture wreck it overtime? Thanks.

Dont worry about it. My subwoofer makes the screen on my 65" RP-screen wave, and the sub is sitting 20 feet away. It's only noticable when the room is lighted and I can see room reflections on the screen. Otherwise, you dont even notice.

 

[t3031999]

Dont worry about it. My subwoofer makes the screen on my 65" RP-screen wave, and the sub is sitting 20 feet away. It's only noticable when the room is lighted and I can see room reflections on the screen. Otherwise, you dont even notice.

I think Kyle means that the actual tv picture is shaking inside the tv and not just shaking room reflections off the screen.
The tv shaking (within reason) as a whole (all moving the same amount) shouldn't hurt it, but the electron gun shaking inside the tube can damage it.

 

[j_garcia]

Try some foam or rubber underneath the sub. Should stop the transmission of vibration to whatever it is sitting on. Damping the sub internally isn't going to help.

 

[bongobob]

Try some foam or rubber underneath the sub. Should stop the transmission of vibration to whatever it is sitting on. Damping the sub internally isn't going to help.

I use one of these:

http://www.auralex.com/sound_isolation_gramma/sound_isolation_gramma.asp

Not only does it decouple the sub from the flooring but my sub seems tighter too.

 

[Buckeye_Nut]

Yikes,

If his TV image is flickering to the bass, then the problem is a TV defect. If thats the case, then he's got a loose wire or part coming loose inside his TV. If he wants to correct that problem, he should focus on the TV or move the subs further away.

 

[Kyle Lorenz]

I forgot to add something to my orginial post. I have a cemet floor which seems to give no vibration through the floor to the TV so the vibration has to be from the sound waves.

 

[j_garcia]

I forgot to add something to my orginial post. I have a cemet floor which seems to give no vibration through the floor to the TV so the vibration has to be from the sound waves.

If you turn that particular sub off, does the problem go away?

 

[t3031999]

Your cement floor may be different that mine but i was startled at how much vibration mine will transfer, especially at certain frequencies.

 

[Kyle Lorenz]

If you turn that particular sub off, does the problem go away?

Yes, the problem goes away when I turned the sub off.