Tech - Ground loop problem in video signal.

That is the fun part about ground loops. Even when you think you know what's causing it, there is something else not working right and dumping power on the ground.

 

Well that box I bought removed the lines in the screen. but it did not seem to removed the hum in the audio. so it helped some.

 

Well the waves in the screen seem to be completely gone with that device powering the satellite box. But still if I hook up a ground to the projector the lines come back. Also I can still hear a faint hum in the audio. I traced the entire cables and they only cross power cables ones and its at 90 degrees.

I seem to be messing up my mid range speakers. Had three of them start making really bad cracking sounds rather than sound. Not really sure whats going on. The guy I bought the speakers off says I am not pushing enough watts to blow them out but something is happening to them. And its usually right after I push them some. These speakers say 60W on the back of them. So I am assuming thats there max. Which my crossover is suppose to keep them from getting more than that. My receiver is only pushing 75w total to each channel. Hes sending me some new ones but I really do not see them working much better.

 

A few things:
1: Your amp and speakers should be matched, your amp is overdriving the speakers
2: No, that's not what a crossover does
3: A run that long should really be a balanced audio signal from the source to the amp

 

So if my speaker says 60W on the back of it. I will pretty much always blow it if i turn it up to loud?

Also what do you by balanced audio signal?

 

Well I got new mid range speakers. Same as b4 as he replaced them for free. But I am a little scared to turn them up as I do not want to blow them. These are 8ohm speakers and my receiver puts out 75 watts per channel. But that 75W goes to the sub/mid/tweeter so I wouldn't think it would be to much for these 60w mid range. I am pretty new in the speaker building.

 

Wait, so you're building your own speakers and it's just a pair of cones you're replacing? I'm not quite sure what you mean now. You probably won't blow anything immediately unless you're really pounding them, but overdriving the speakers will cause damage over time and your sound quality will be diminished.

As far as balanced audio, the Wikipedia article explains it well. http://en.wikipedia.org/wiki/Balanced_audio

 

MSD. I had a set of jensen speakers. they had 15" subs in them. And a blown out mid and tweeter. So I replaced the mid and tweeter in them. But the mid's i put in started sounded really bad after a day or two. both of them. So I got replacements for those. And so far they are doing well.

I also built a center channel speaker. Well I cut out the box and hooked up the wires.

 

Hmm, speakers should really have an expertly designed (which is above my head) crossover and cones matched to that. For speaker stuff I usually browse the DIY speaker stuff on AVSforum until I'm convinced I know enough to be dangerous, or buy manufacturer-matched stuff at work since we're going for usability rather than hi-fi in classrooms.

 

The voodoo of speaker building is mostly hype. There are only a dozen or so driver manufactures. Most entry level speakers use the same drives as mid level speakers. Better box materials to reduce non-driver noise, packing for frequency response, non-corrosive connectors and better cross-overs are the difference. There are a few Sub box (for car audio) Mfg's that have free software on their sites to calculate volume and airspring. All driver manufactures publish a frequency graph for all of their drivers (most catalogs do too), so it's easy to find the sweet spot for each driver. Use quality MDF or HDF, a good cross-over, and gold or silver connectors, make sure everything is sealed and your good to go.

 

Just a update.

Still have the ground loop issue. But with hunting season coming soon and the cold ohio weather hear the man-cave is not being used much. But come next warm season we are just going to have a receiver installed in the garage to fix the loop issue. Hopefully that will fix all of those issues. Will also add HD to the man-cave!

Got most of my speakers 1/2 built. Hopefully after deer season I can finish them. I should post some pictures of the two I have finished.

 

very true. Pull apart a Bose home system and you'll find some simple $20 paper cones. Not necessarily the case if it's a display model, but out of the box they're the same low-end stuff as you find in a lot of computer speakers.