speaker vibration

[Astro]

I was listening to a dvd the other day (rob thomas dvd) the song was the last song on the album and I had it playing in 5.1 mode. I had it at a fairly decent volume, and as the piano kicked in I noticed a vibrating sound, so I went to each of the 7 speakers, (I have 5.1 plus 2 precence speaks) and I narrowed it down to the left precence, I was fidling around with it and noticed that also the left front speaker was doing it to. I put my ear down for a listen and it sounds like something inside the speaker near the inputs is vibrating? I put a cd in this time with a piano on it also. This time it still did it but had to be at a fairly loud volume for it to happen.
Any ideas???, is it possible that any speakers do this at some point in time if the source is loud enough? :confused:

[kexodusc]

On the surface it sounds to me like a screw on the crossover board might be loose and either the screw or the crossover board might be vibrating....if not the terminal itself...possibly wiring vibrating a bit against the surface of the cabinet. Depending on the frequency and intensity (loudness of the signal), your speaker cabinet might be resonating and exciting an object inside, causing it to vibrate and make noise. Screws can get loose over time like the some times do in your car or on furniture. How close to the speaker inputs is this noise, would you say? I actually use a stethoscope thing to pinpoint noises, my 2 year old Honda Accord has some pretty annoying trim screws I've tightened, I used it for a speaker cabinet I built with cheap machine screws too. Many places that sell tools sell these, they aren't all that expensive and aren't the kind your doctor uses.

How loud were you playing?...would you describe this vibration noise as a rattle or a buzz?
Many crossover boards aren't screwed to the cabinet, just glued or stuck there with two-way tape. They don't sit flush on the cabinet and can vibrate a bit, think of an edge of a circuit board quickly vibrating against the inside of the cabinet.

You seem sure its coming from near the terminal, so I will assume it's not merely the audible flops and distortion you could hear from a woofer trying to extend beyond it's frequency of resonance.

It's also possible it could be cabinet vibrations and loose internal bracing but I'm not holding my breath on that one.

Try reproducing it and then, with a screwdriver or your finger, press on the screws on the inputs to make sure it's not one of those.
If it isn't you're pretty much going to have to either open the speaker up yourself or take it to your dealer or someone to do it for you. If it's under warranty, I'd recommend this. This can be an interative process, trial and error, trying to localize the noise.
Or if you can, just play at a level where it doesn't occur.

What kind of speakers are these? Floorstanding, bookshelf? Which model?

[Astro]

On the surface it sounds to me like a screw on the crossover board might be loose and either the screw or the crossover board might be vibrating....if not the terminal itself...possibly wiring vibrating a bit against the surface of the cabinet. Depending on the frequency and intensity (loudness of the signal), your speaker cabinet might be resonating and exciting an object inside, causing it to vibrate and make noise. Screws can get loose over time like the some times do in your car or on furniture. How close to the speaker inputs is this noise, would you say? I actually use a stethoscope thing to pinpoint noises, my 2 year old Honda Accord has some pretty annoying trim screws I've tightened, I used it for a speaker cabinet I built with cheap machine screws too. Many places that sell tools sell these, they aren't all that expensive and aren't the kind your doctor uses.

How loud were you playing?...would you describe this vibration noise as a rattle or a buzz?
Many crossover boards aren't screwed to the cabinet, just glued or stuck there with two-way tape. They don't sit flush on the cabinet and can vibrate a bit, think of an edge of a circuit board quickly vibrating against the inside of the cabinet.

You seem sure its coming from near the terminal, so I will assume it's not merely the audible flops and distortion you could hear from a woofer trying to extend beyond it's frequency of resonance.

It's also possible it could be cabinet vibrations and loose internal bracing but I'm not holding my breath on that one.

Try reproducing it and then, with a screwdriver or your finger, press on the screws on the inputs to make sure it's not one of those.
If it isn't you're pretty much going to have to either open the speaker up yourself or take it to your dealer or someone to do it for you. If it's under warranty, I'd recommend this. This can be an interative process, trial and error, trying to localize the noise.
Or if you can, just play at a level where it doesn't occur.

What kind of speakers are these? Floorstanding, bookshelf? Which model?

its defenetly like a buzzing sound, the speakers are db dynamic titan series floorstanders and the precence is bookshelf. i was playing it loud, but not that loud i have never heard it before untill now, i guess it was just the right freq and the right amount of volume to make it happen. i'm prety sure its directly behind the terminal also

[Astro]

i just found it wierd that it was doing it with not just the floorstander but the precence as well?,.. maybe a coinsidence

[N. Abstentia]

Never seen DB Dynamic speakers...where did you get them?

[kexodusc]

i just found it wierd that it was doing it with not just the floorstander but the precence as well?,.. maybe a coinsidence
Could be, but if they use just any kind of screw available, and not mdf or wood screws they might have a common problem in all their speakers...but we're way to early for speculation like that.

You mention it is a buzz...at this point I'm curious if there could be an electrical problem causing the buzz, rather than a physical one.

If it is a loose screw or crossover board or just a wire too close to a wall, then this shouldn't be too hard to fix. Either way, if you're 100% sure it's inside the speaker and not being caused by speaker wire going into the terminal then there's really not much else I can think of to troubleshoot this buzzing noise without being there.
I'm afraid someone is going to have to open your speaker up to look inside. That won't hurt anything. I'll leave it to you to decide if you have the skill to take apart your speaker or not. You might need a bit of soldering skills. If you aren't sure if you can, then you probably shouldn't. Pay someone else to do it. Better safe than sorry. Hopefully there's warranty or a very good dealer in your area...

Can you post a link to a picture of your speaker?

[Astro]

Could be, but if they use just any kind of screw available, and not mdf or wood screws they might have a common problem in all their speakers...but we're way to early for speculation like that.

You mention it is a buzz...at this point I'm curious if there could be an electrical problem causing the buzz, rather than a physical one.

If it is a loose screw or crossover board or just a wire too close to a wall, then this shouldn't be too hard to fix. Either way, if you're 100% sure it's inside the speaker and not being caused by speaker wire going into the terminal then there's really not much else I can think of to troubleshoot this buzzing noise without being there.
I'm afraid someone is going to have to open your speaker up to look inside. That won't hurt anything. I'll leave it to you to decide if you have the skill to take apart your speaker or not. You might need a bit of soldering skills. If you aren't sure if you can, then you probably shouldn't. Pay someone else to do it. Better safe than sorry. Hopefully there's warranty or a very good dealer in your area...

Can you post a link to a picture of your speaker?

is it ok to have the terminal hanging out a bit and the circut board also out a tad while playing just to see if its anything to do with that vibrating? Also the wire that goes from the board to the speaker its self, how do i get the board out completely because it seems the wire has no slack between the board and the speaker.

[kexodusc]

The circuit board should be attached firmly to something so you can't get it out, did you slip it throught the terminal hole? I'm surprised if you did, the crossover boards are usually bigger than that. I'm not surprised there's no slack from the crossover board to the woofer...this is normal they usually cut just enough wire.
Do the wires have quick disconnects on them that allow you to pull them off or are they soldered to the board? If they are you'd have to cut them and resolder them. You migth not want to get into that.
Playing with that big hole in the back will change the pressure and tuning of the cabinet, it will affect the sound and the volume output, though I don't know by how much that depends on size tuning etc.. You might not be able to reproduce the buzz. You could play it, just start at a low volume and increase gradually, but I'd rather you didn't unless your handy with electronics...esepcially if your hands and face are close by. I don't want you to get a nasty shock...this really isn't something that can be coached step-by-step over the internet, especially since I'm not familiar with your speaker.

Proceed with caution at your own risk.

[Astro]

The circuit board should be attached firmly to something so you can't get it out, did you slip it throught the terminal hole? I'm surprised if you did, the crossover boards are usually bigger than that. I'm not surprised there's no slack from the crossover board to the woofer...this is normal they usually cut just enough wire.
Do the wires have quick disconnects on them that allow you to pull them off or are they soldered to the board? If they are you'd have to cut them and resolder them. You migth not want to get into that.
Playing with that big hole in the back will change the pressure and tuning of the cabinet, it will affect the sound and the volume output, though I don't know by how much that depends on size tuning etc.. You might not be able to reproduce the buzz. You could play it, just start at a low volume and increase gradually, but I'd rather you didn't unless your handy with electronics...esepcially if your hands and face are close by. I don't want you to get a nasty shock...this really isn't something that can be coached step-by-step over the internet, especially since I'm not familiar with your speaker.

Proceed with caution at your own risk.

ok I did some more playing and found out that when I press hard on the speaker terminals at the back of the speaker the vibration dosnt occur.

[Astro]

if i press hard enough i can almost completely illiminate the vibration

[Astro]

ok i did one more thing, i put it on a different system with different speakers and it did the same thing at roughly the same volume level,. the vibration was in one speaker and inside the terminals, although not as loud as mine but still did the same thing.

[Astro]

ok i might have found the problem, on the inside of the terminals are a bit of metal strip , one end is screwed under a nut that is holding it in place onto the spear terminal inside and the other end the wire is solderd onto it. i think what is happening is this metal strip vibrates and when it is played loud, the strip vibrates against the inside of the terminal cover.

[kexodusc]

Good Work!!!

Astro, what size speaker terminal is it?...you can buy these for dirt cheap at many places...possibly radio shack, and take care of this all at once.
Here's a few for starters, maybe you'll find one compatible...I'd replace them all if it's a common problem.
http://www.partsexpress.com/webpage.cfm?webpage_id=3&SO=2&&DID=7&CATID=48&ObjectGroup_ID=417