Speaker/headphone buzzing issues, caused by projector

[kevdlandrig]

so I just got a new projector, and plugged it in to my headphones and computer. As soon as I put the headphones on, they were buzzing rather noticeably. I have done a bunch of searches on the internet and to troubleshoot the problem, and the solutions I saw on the other forums didn't work for me. I need to know if there is A box I can buy that is capable of isolating and removing the buzzing so I don't go insane. My headphones are some standard in-ear ones.

 

[HoneycombAG]

If your connections aren't inserted all the way in, they won't make a clean connection and makes that "buzz".

Also, buzzing is more noticeable at high volume than it is low. Try checking volume controls on the projector.

 

[carwiz]

You plugged your projector into your headphones? What exactly does that mean?

The buzzing sounds like it may be a ground loop. Are you sure you're using the correct plugs and jacks?

 

[HoneycombAG]

:warn: A laptop only has a mic in jack and a headphone out jack. Make sure you didn't plug it into the mic jack!

so I just got a new projector, and plugged it in to my headphones and computer.

You plugged your projector into your headphones?

Anyone can get sound and video through a projector, by connecting a VGA, HDMI, or S-VIDEO cable to it and a 3.5mm to RCA jack connector.

Like this:

The only problem is, did you attach an audio cable into the video signal?

 

[fireberd]

As previously noted it sounds like a "ground loop hum" problem.

Are you using the laptop with battery only or are you using the AC power adapter? If you are using the AC power adapter, try the laptop with only internal battery power and see if it makes a difference.

 

[kevdlandrig]

I probably should have mentioned that I am extremely competent with computers. Now to answer some of the questions:

My Laptop is connected via a 25 foot HDMI cable to my pico projector. From there, the projector is connected via some splitters to a subwoofer, a pair of regular computer speakers, a 25 foot cable that runs to the front of the room, which is connected to another 2.1 speaker set. Finally, I rigged the splitters so that if I plug in my headphones, all of the other speaker can be muted from the splitter with a volume adjuster. Just to make sure i'm understood, the projector has a headphone out port on it.

All connections are secure and tight. I even tried twisting the connections because I know that they can be insecure sometimes even when the appear to be fully connected. They are/were before I tried. The buzzing is equally noticeable even when the speakers are muted by the computer. If I adjust the volume on the self powered speakers, the buzzing goes down for the obvious reason. If I have my headphones plugged in, the buzzing is constant, even when I mute them from the computer.

I will make sure to check on the laptop power issue tonight, as during the day it is too bright outside to use the projector. (my room has lots of windows without adequate shading and the projector isn't very bright)

One last thing. I tried unplugging the speaker/splitter mess and attempted to use the headphones directly connected to the projector's 3.5 mm jack. The buzzing changed from the crackling-type buzzing that I've been hearing and began sounding more like the 60 hz hum that I heard about somewhere else on the net. I'm pretty sure this means that one of the wires in the system is unsheilded, and is picking up the electrical signals from the house. The amount of wiring im using could definitely act like an antenna for this kind of sound.

if you need me to draw a map of how everything is connected, I would be happy to oblige.

 

[fireberd]

I used to work as a guitar amp tech (in Nashville). Ground Loop problems are very common with musicians that use multiple powered devices or amps together. Even two AC powered devices connected to the same AC power outlet can have the ground loop problem.

Since you are hearing the 60 Hz hum from the projector, disconnect the HDMI cable, leaving the projector by itself (no external speakers connected) and then see if you have the 60 Hz hum. If you do, the problem is in the projector (probably defective power supply) and not with the PC.

The other speaker problems need to be isolated to what is causing that. I would only use shielded cable to connect to the external speaker systems.

 

[kevdlandrig]

Sorry. When I mentioned the 60 hz hum I was thinking of something else. The sound I am really hearing is more like a fuzzing sound, like distant rain or something. The sound is quite tolerable compared to that other electrical crackling noise, but I still want to eliminate it.

I did try running my laptop on battery power, but the electrical crackling was still a problem.

I mentioned in the first post that I am aware that the noise probably cannot be eliminated by changing the wires, and I would like to remind everyone that I am looking for a piece of equipment that can scan an audio input for noise, and remove that noise through software. Alternatively, something that mutes sounds that are below a certain decibel level would work as well. I don't want anything too fancy, but something just enough to get the job done.

All of my equipment is powered by DC, not AC. The conversion boxes are several feet away from any wiring, although they are all plugged into the same power strip. Is it still possible that they are generating interference?

 

[fireberd]

There are "noise gate" type devices that will limit noise. The ones I've seen are "VST" plug-ins for recording studio software or a small external unit that connects between low level audio guitar signals and the guitar amplifier or a "rack" type unit that is designed for higher level audio signals.

As the PC audio out is more like "line level" the rack type would probably be more appropriate, if you want to spend the $$ for something like that. Here is the lowest priced one, that I've found, that would work for what you want. It is four channel (you only need two for the two channel stereo out from the PC). Behringer MULTIGATE PRO XR4400 Quad Expander/Gate | Musician's Friend