Check out Spectral Cleaning on Samplitude / Sequoia. Its excellent for cleaning up unwanted noise, forensic editing and things like your request. How clean you could get it, not sure.

I'm thinking it may be possible to extract the snare rather than remove everything around it. I'll do some research for you and post back when I have an answer.

About 30 years ago at the AES a specialized manufacturer was demonstrating a device that they built for the FBI. It was designed to take speech out of incredibly noisy environments. It was positively remarkable and it wasn't for sale. Except of course to the FBI and probably the CIA. This was way before we ever had computers and software like we do today. So that technology is out there. Back then, I think they told me their box was $20,000 nearly 30 years ago? But it was made to extract speech from traffic, music and construction noise background and it did quite well in fact. It was breathtaking and scary at the same time.

One of the analog ways I would try to do what you want is to simply utilize a noise gate with a sidechain. You insert the equalizer, bandwidth limit to the snare drum and you will pretty much just get snare drum from the output of the gate. This can be done in hardware or software as I have done essentially both to already mixed recordings for others.

Big Brother is not only watching he's listening to everything and everyone.
Mx. Remy Ann David

You can remove certain things with programs like Algorithmix's Renovator, but it works best on pure(r) tones. Elements like snare drums have harmonic structures that are too complex to remove convincingly.

I would wager that the FBI thingy that Remy is talking about would incorporate some sort of comb filtering and band splitting / phase reversal to extract voices. I can't imagine anything else that it would be, barring some sort of bizarre magical technique none of us have ever heard of.

Let's not forget that in audio, all we have is time and amplitude to manipulate. Those two parameters are from which all audio processing originates.

Cheers :)

That manufacture I mentioned, whose name I cannot remember, did not produce any professional audio equipment whatsoever. They told me that what they were doing was highly classified and it was just there for demonstration purposes and the wow factor. This was before the end of the Cold War and I think they were likely utilizing highly classified DSP technologies? It was certainly not like the DSP-based noise reduction in common use today from Cedar, iZotope, others. It was like Outer Limits, Star Trek, War of the Worlds. And it probably wasn't just for the FBI but also for the United States military and its allies? Maybe not even for its allies because the United States military will not sell the B-2 bomber even to its allies to this day. Or at least about five years ago when I did my last Air Force Association Convention. Because I was talking to the guys from Lockheed Martin about it. So there is still some stuff that has yet to be released if ever. We don't have any true digital microphones yet but the FBI has had them for quite some time. They're not high fidelity devices. You point a laser at a building blocks away at a window and you're listening to conversations in that room. That's creepy stuff. You don't even see that on the Discovery Military Channel. Though we did find out that back in the 1960s the Russians gave the Americans a beautiful wall hanging piece of artwork, for one of our new embassies. And it had a little Pieazo Electric thingy buried deep inside of it. Everything that we have is 20-30 years behind existing technologies. It has to be that way. National security and all that you know.

I'm also sneaky.
Mx. Remy Ann David