How can I thicken vocals without it sounding like multiple voices? I just want one strong, present, clear voice.

purple MC77 :-)

or Sonitus Compressor... maybe two instances one slow one fast.

Clone vocal track twice.
On 1st clone, pan hard L, apply Cakewalk > Pitch Shifter > +01 cent
On 2nd clone, pan hard R, apply Cakewalk > Pitch Shifter > -01 cent

For soupy thick Ozzy vocals,  bump the pitch shift up a few cents and throw some compression on the cloned tracks.

Cool. Thanks fellas, I'll try these tips out tomorrow.

Well, mine's a little harder...but it works great.

I sing one in a normal register for the song, the second in a different register; If the main is soft, I sing the second one loud, etc.

I put the two tracks next to each other, then add a volume envelope to the double track. I cut off all the begining and ends to each word, and using the main vox as a refernce, make sure the doubled track never encroaches on the silences during the main vox (also remove all "S"s). If you listen to the doubled track solo'd, it will sound like someone who rides the short bus singing...it's actually pretty funny!

However, dropping the volume to a 1/3rd of the main track blends it pretty seamlessly, and when the tune is going you will never hear the second track unless you are really trying to hear it.

Two words, "Fat Chicks", no here's how I do it, and I'm told my vox are pretty good?

1. Comp it. Many tracks, take phrases, cobble together your best lead vox.

2. Try singing with it, but in almost a wisper?

3. Clone that 1st comped track "several" times...

4. Send them all to a lead vox bus.

5. Send #1 dry, #2 with a send to a verb track, set a hard pan on that verb track?, it's a VERB bus, so lets say you set it to 75 or 80% left?

6. Put another send, 3rd track? To a delay buss? Time the delay so it meets the BPM or doubles your BPM i.e., your BPM for the song is 75? Set the BPM on the delay bus to like 150?

7. Send another clone? 4th track? To a HARD compressor (squash it).

Take all 4 of these tracks + the wisper track? And send all 5 to the lead vox bus? And put a channel strip on the lead vox bus? i.e., Sonar Pro comes with a nice channel strip. Find a preset that works for you? Hard vox? Soft vox with air? etc... Send that combined "lead vox" track to the master...

Also, in places? You may want to "double" for effect? Not all the way through? But you may have a lead2VOX bus, where you sign a separate track, in places? For effect? To double lead 1? you can try some of the same tricks... Send both to the master. Then there's a BGV bus? Same tricks can apply... It adds up. I've done songs with 20 or 30 vocal tracks? And "IT'S FAT".

Also, if Vox1 buss is stero? which it should be? So take track 1 and pan it 6 left, 2, 3 left, 3 to the center, 4 3 right, 5 6 left, etc...

And maybe do the vox verb send like 75 left? And do the vox delay bus 75 right? Do all of this, and "I guarentee you..." You will have a FAT hot vox track with wich you will be "amazed...."

How can I thicken vocals without it sounding like multiple voices?

Double-tracking is the best way I know to fatten a vocal.

It worked for the Beatles and it worked for Pink Floyd. Of course, the singers in both of those bands were masters of double-tracking and capable of re-singing a part that matched up very closely to the original. On old Beatles recordings, the only giveaway is often hard consonants that didn't line up perfectly.

Nowadays, we don't have to be that good at it. We've got AudioSnap. Use it to line up the words and phrases, paying special attention to the hard consonants (e.g. "k", "t"). If you care to take the time, use V-Vocal or volume automation to soften all  the hard consonants in the double so that the primary vocal track alone carries them. Doing this is the key to getting the fatness without making it obvious to the listener what you've done.

But the key is actually singing the overdub in a separate take. You can't get the effect by cloning a track and adding delays and compressors and reverbs and kitchen sinks. You can get a cool effect that way (listen to robby's stuff - click on his sig), but it's going to sound effected, not quite the "one strong present clear voice" it sounds like you're looking for.

http://www.stillwellaudio.com/?page_id=267

How can I thicken vocals without it sounding like multiple voices? I just want one strong, present, clear voice.

 
What are you using for a mic?
If the mic isn't capturing a good full vocal sound, that's where I'd start.

From what I understand, Ozzy doubles each phrase as he sings it.  In other words, he sings a line or a half a line, stops, then doubles it.