The high range on my speakers are harsh...

In addition to my first post (they may come through out of order), in the last paragraph, I made this statement about the speaker,"If you could do this no cost speaker swap trial with soft dome tweeters." I'm referring to the speakers as a whole, not just a tweeter swap. Just a tweeter swap, is not a good idea. Too much engineering involved there.

Also, if swapping a receiver, or another amp might be easier for testing, you could see if you still hear that harsh problem. It may be less harsh, but if the harsh sound is still is a problem, that would lean toward the speakers in my opinion. A TV, and computer shouldn't have the same problem most of the time. Sorry for the late night goof-ups.

I'm just guessing on this one. Assuming all of your equipment is OK, since you said this was there from the beginning of this system. First off, I would substitute another pair of speakers, if possible. The crackling statement is a concern, thinking that it could be something else, like too much volume, or another problem. I'm going mainly on the harsh part of your description.

This would help verify if anything is wrong. Also, Paradigm speakers like these have a metal dome tweeter, that some people just can't handle. They usually have a resonance that is right above 20 kHz. That resonance will cause some people that are sensitive to it to not listen at all. I'm one of these people. Also, I've seen several people state they have a problem with fatigue, using speakers like these.

Another problem may be that your amp can be accentuating the problem some. The only thing I have to go on stating this is this review from Italy. They say the amp is a little bright also. That could definitively be making this problem worse, if this is what is happening with the speakers, assuming all the equipment is functioning OK, and again, not being played too loud.

If at all possible, see if you can try another pair of speakers, that have a soft dome tweeter. Maybe something used, or from a store that has a try, and return policy.
Don't try anything that has a metal tweeter in it, at all. Some soft fabric dome (even soft silk dome) , or a soft poly/polymer type of dome tweeter. These don't normally have this ringing resonance that is common with metal dome tweeters. They talk some about the tweeter resonance here on another similar model. Also this model is another example of that tweeter resonance (I call it noise) frequencies not heard by a lot of people. You could see the peaks at the right side (high frequency tweeter side) of the graph called "Frequency in Hz."

If you could do this no cost speaker swap trial with soft dome tweeters, that may be the answer your seeking. This would be what I would try first, if it was me. This is the best I can picture might be happening with your description, except the crackling part. But that may be how you hear it, if your sensitive to it. I hope this helps.

If you had a CD player in the system, then it may be easier to find the problem. A CD player has fairly consistent sound quality, in comparison to a computer, or TV for the source. I'm not too knowledgeable about computers, but the ones I've used listening to something off of the net, can vary a lot in my experience.

A TV can be inconsistent with sound and picture also. When I hear a commercial on one channel, it may sound good. Hearing it on another channel can give good, or bad results. So a TV doesn't always help in finding a problem.

Then the computers themselves get moody, and change at times. So I'm thinking something more consistent like a CD player, or DVD player may help in this case.

You mentioned streaming YouTube. If you download something that sounds good to you using RealPlayer may help a little. When you get this sound problem, play that video that you downloaded to RealPlayer, and see if it sounds OK. This isn't as good as a standalone CD player for consistency, though. But still, may give you more of an idea.

Using the output from a computer using these (streaming) sources you mentioned don't have the sound quality, like a CD does. All of my computers own sound outputs, vary a lot too. Even if I play a CD in them.

Your speaker and amp combination, is probably really accentuating any small problem.

A poor connection is a possibility, but you are using two different sources (TV and computer), with separate cables for each. So, I'm thinking the odds are slim that both are making a poor connection, since this problem existed, since you bought the system.

I guess what I'm still saying is a CD player, DVD player, may help a lot in finding if it's your system, or the inconsistent (computer/TV) sources you're using, causing your problems. If you don't have a CD player, see if you could get one for testing. This is the only other thing I can think of, since its sound quality way more reliable, especially using the same good sounding discs. Other than this, I'm kinda out of ideas. I hope you find an answer to this.