Its all technique, there's no trick to it... I can get squeals like that on my acoustic.. you can't?? Hmmm... there's no hope for you then, sorry.. :eek:
Wouldn't it be horrible if that was the truth?!! Hey, just teasing and I have GOOD NEWS... well, sort of. Now, this is debatable and may stir the pot, but before you do anything, go check out some vids or songs by Neal Schon from Journey, and then continue reading.
Ok, here's the deal... it may cost you some bucks, but what a lot of guys from that 80's "Big Hair" rock era were into back then was a device called a "sustainer". Neal Schon loves his, uses it a lot, and I'll wager the guy from the Skid Row solo is using one too.
The sustainer is a special, powered (active) pick-up that keeps the string vibrating no matter what. It's what allows those crazy in-coming mortal shell dive bombs that made bands like Poison popular. A sustainer will make your pinch harmonics squeal like that. Its also great when doing lots of hammer-ons and pull-offs, legato etc because the string is very "active" and "hot"... just touch it to the fretboard, it will make a tone, and that tone will sustain literally until the battery runs out. You can dial it in so that you get a sustain that really starts to sound like feedback, or mellow it down a little bit.
Now, the bad news is that sustainer systems aren't cheap, and require moding your favorite guitar or buying a new one.
Check out Fernades Sustainers (
http://www.fernandesguitars.com/sustainer/sustainer.html)
Also do a YouTube search for sustainers or Fernades Sustainers and you'll see lots of demos showing you what it does.
By the way, before someone writes in saying "but dude, check out the guitar in video, it doesn't have a sustainer..!" yeah, I know, but its a video. That is not likely the guitar he recorded with. When you hear all the demos of sustainers, you'll recognize it when you hear in songs, and to my ears, the "I Remember You" solo (great solo by the way, I have the song on my i-Phone) is played on a guitar with a sustainer, most likely.
Jackson used to make a sustainer system called something like "the sustainac"... don't know if they still do.. it came with some of their guitars. Fernandes sells both the kit, and guitars that come with the sustainer.
Lastly, you don't have to use the sustainer to make crazy squeals and dive-bombs... Neal Schon does this solo in the video "Journey-Live in Manila" where he does all this flashy (yawwwwn...) guitar stuff, and then out of nowhere goes into this gorgeous melodic solo section that's using a sustainer... gave me shivers I tell ya! Oh sweet jesus... I just checked YouTube and found it... JUST the solo section... is nothing sacred!?
Ok, here it is, now check this out:
http://www.youtube.com/watch?v=6tZrn3-pMsAFreeze it at exactly 50 seconds in... see the two little black switches on his guitar near the back? Those are the sustainer switches. Later in the video, you'll see the extra plates on the back if you watch carefully, that hold the extra electronics for the sustainer.
At 1:00 he does this descending riff... listen carefully and you'll hear the sustainer at work... he dips the whammy bar quite low, then comes back up to a sustained note... that's the sustainer at work... that note will keep going forever, until the battery dies...
Finally, check out the solo that starts at 1:10... all of you guitar guys reading this far check it out too... its a complete, text-book example of how to be a total ROCK GOD! Man, sure is a great solo and some great looking video... I'm hoping that they'll come out with that Matrix thing where you can jack and be someone else for $5000 per minute because that's the program I'm going to blow my wad on... "yeah, fire up the Neal Schon epic solo program!"...