Beware of public domain-- as crazy as that sounds, I would consult a lawyer if you really want to be legit about it, since there may be technicalities. Also, record labels constantly re-up copyrights on behalf of the artist (especially as they get older.) This is not legal advice, but depending on the project, sometimes clearing samples should be avoided, especially if you are aware of the owner of the sample.
Here's a story from my experience on this particular issue:
I remember working on an album for an artist on Interscope and the best song off the album contained an extremely chopped up Sting sample. The sample itself was unrecognizable and it had just a touch of Sting going "aaah" on it. Really great sample to an awesome beat. It was also one of the songs that helped get the artist signed.
The song could have been an A-rotation hit on the radio (with the right promo money greasing the wheels, of course.) It was by far the best song on the album and would have definitely moved units for the entire album (this was back in the very early 2000's, when people actually bought the entire CD.)
So I tell the rapper's manager-- who was a newbie to the business-- that we should let the sample clearance on that song slide. Don't let the sample clearing company managing Sting's account know about our usage of the sample. Let the song be released and keep it on the low. If we get caught, no problem, we'll pay up and have a radio-hit that's a loss-leader for the rest of the album (kind of like how "Bittersweet Symphony" put Verve on the map and helped them go multi-platinum, even though they used a Rolling Stones sample and literally get paid no royalties for the song-- the Rolling Stones collect penny in royalties, from what I know.)
I remember trying to persuade the manager to keep the song "as is" and not try to bring in musicians to replicate the sample in the studio, since the song was literally perfect.
The manager was green, so basically he said "no we need to keep it legal." I pleaded with him not to call the sample clearance company. Even the A&R was like "uhhh, maybe God is right, man." The problem, I explained, is once we're on Sting's radar, we're screwed and we can't see if the song "hits" or not. For example, he could deny us usage of the song. If it doesn't hit, big deal, no sweat off our back and we'll chalk up the loss. I believed if we didn't release the song, we would literally doom the album.
The dumbass manager didn't listen to me and called up the sample clearing company administering Sting's catalog and told them about the song and the project. If I remember, they wanted 75% of all royalties for the song. Crazy, right? I told him to still keep the song "as is" and use it as a loss-leader for the album. We should pay Sting the royalties (since the cat is out of the bag) and we should all be glad it's not a higher royalty rate-- or even worse, we could have been denied usage entirely.
Anyway, the idiot manager ordered me to try to bring in musicians and singers to replicate the sample in order to create an interpolation, which means we'd pay significantly less in sample fees. I argued with him, it was tense. I had to capitulate in the end.
We brought in a ton of musicians. They all played and sang the "aaah" part right. But you just didn't have the same feeling that excited you about the song anymore. It was different, it didn't have the "hit factor" to it. I A/B'ed the songs with folks who never heard it and they all liked the original version containing Sting's sample a whole lot better.
I remember trying to craft the sound, adding effects in ProTools, etc. to the instrumentals and vox we recorded to replicate the original, it took forever and I got it sounding nearly right. But the "feeling" just wasn't the same.
The manager and I took a listen to it, along with the artist and the entire gang of idiots who were part of his entourage. Everyone agreed it didn't feel right.
I told the manager, "look, just use the sample, pay Sting his exorbitant royalty and you and the artist will make the money back on royalties from the rest of the songs on the album and live shows," (this was before iTunes when CD sales were still good.)
The manager said "no, I ain't giving anyone 75% percent of any song."
I pleaded with the dude about how the song would get surefire radio-play. He didn't want to do it. I told him A&R would need evidence to show their bosses that the song contained a hit, which would help the artist get more marketing dollars. The answer? "No."
The artist, being a talented moron, followed whatever the manager said. Initially the artist saw it my way, but the manager proved too persuasive.
So what happened?
The song wasn't added to the album and the record execs ended up shelving the album. It was NEVER RELEASED. What did the A&R guy tell me after the debacle? "They should've listened to you. That song was a hit."
From what I know, the artist now sells insurance for a living. The manager owns a small clothing store. Both are not involved in the music business anymore to any "real" extent.
The lesson? Sometimes it's best to release a song without clearance (legally, I have to say I'm against this, however), especially if it's good-- and just pay through the nose once it becomes a hit. You want recognition and fame, which a hit song can give you. Even if you're not collecting royalties on it, there are other ways the artist can continue to make revenue.
I really think they lost a great opportunity with that song. I believe it would have sold well had that song been on there, since it was such a hit.
Sample clearance can be tricky. Heck, even the biggies like Kanye West release stuff without clearance. Specifically for the reasons I alluded to in the story. If they get caught? So what-- you pay royalties to someone else, but you maintain fame and recognition, which is the most valuable currency in the music business. That opens the door to opportunities for licensing an artist's name on clothing or even other things.
