Will I be able to slap with flatwounds? If so, which ones?

Lots of good stuff here already.

I'll add that, when you are first learning a technique, the easiest way to progress is to emulate others who play and sound the way you want to. Whether you are into Marcus Miller or Flea or Victor Wooten or whoever your favorite slapper is, you're probably going to spend a lot of time watching videos, mimicking techniques, and learning their songs.

That process is going to be hard if your bass has a radically different sound than the one you are trying to copy. How can you even determine how had to pluck (or pop) the string if you have to yank your string halfway across the room to get a proper snap out of it? Or how can you dial in a good crisp high end tone if your strings are fighting you tooth and nail to produce the opposite?

If you want that bass to slap then really set it up for slap. Put on some lighter round wound strings, set the action as low as it will go without buzzing or dead notes, and learn to manage your technique. You may have to change how you EQ your amp, if you are constantly cranking up the treble until you get a lot of hand noise then that's a whole different journey of skills, too!
 
If you slap on flats, Larry Graham and Marcus Miller will both come to your house and personally berate you. Heaps of shame will be on your family for 7 generations.

Sure, if you want to slap flats, go ahead. It won't sound like rounds being slapped, but then again, slap was a real departure from what came before - when I was a kid, if you went into the music store and did that to a bass, they would have thrown you out of the place for abusing the merchandise. So, forge your own path - if slapping flats trips your trigger, go for it.
 
Actually: Slap was invented by Larry Graham on flatwounds, then performed (slap and pop, or just pop, or double thumbing à la Doug Rauch) by many players on flatwounds for years before players standardized on slapping on roundwounds.

Here are some examples released between 1969 and 1981:










Aware of that but there is a whole legacy of slap bass beyond that time of players using roundwounds for that singular kind of tone that only happens with roundwounds. People seemed to like "deadened" sounds in the 1970s- that "1970s dead drumhead studio sound". and then the 1980s and beyond happened.

Maybe these things, flatwounds for slapping, and dead drumheads on drums will come around in vogue, again...
 
True that Larry Graham invented slap on flats, but notice how he pinched the plucks etc. The technique has continued to evolve, and I suspect you won't get the lightning facility you hear nowadays without rounds.

If I slap my flats the the volume spike is pretty bad. Major compression?
 
In the end it (the squeaks) are a non issue since you are playing with drums. You need actual sandpaper or scrape the strings with a pick or a coin for this to matter. Regular callouses will not create a squeak that becomes unbearable.

Get a drum track and play it loud through a PA or powerful stereo and then you play the bass gig volumes. Many times the squeak you hear is not amplified as loud if your bass amp is at gig level. You are actually hearing the non amplified squeak over your low volume amped sound.

The classic slap sound are new to broken in stainless steel roundwounds (Marcus Miller etc). There is also the slapped flatwound sound.

To help minimize squeaks, do 1 string scales and try to minimize the squeaks, by lifting your finger couple a right hand mute as you are thumbing.
 
I haven't seen anyone mention this yet, but have you let strings break in? I find they sound their best after 6-10 hours of play time. It removes some harsh zing and sound how they are supposed to.
I doubt I have 6-10 hours of play time on the bass that has the Slinkies on it. It hurts my ears whenever I play it. I guess I'll need to push through.
 
There's nothing wrong with slapping on a bass strung with flatwounds. As others have noted, it was done for decades and still is by some famous players.

With that being said, using flats to "mask" bad technique is a wrong approach in my book and is likely to prove as counterproductive in the long run.
 
There's nothing wrong with slapping on a bass strung with flatwounds. As others have noted, it was done for decades and still is by some famous players.

With that being said, using flats to "mask" bad technique is a wrong approach in my book and is likely to prove as counterproductive in the long run.

How do flats mask bad technique? That never occurred to me.
 
How do flats mask bad technique? That never occurred to me.

Probably because your technique was never bad to begin with.

Rounds are far less forgiving of finger noise, improperly done slides and pull-offs etc. At least IME.

Slapping should be learned with rounds, IMO. Once the skill is brought to a satisfactory level, one can move to flats, tapes...whatever.

My $0.02 only...
 
Actually: Slap was invented by Larry Graham on flatwounds, then performed (slap and pop, or just pop, or double thumbing à la Doug Rauch) by many players on flatwounds for years before players standardized on slapping on roundwounds.

Here are some examples released between 1969 and 1981:










Thanks for posting this. I knew there was a lot of Slap using flats but didn't have specific examples. To my ears, Cobalts on a Spector NS-2 sound good, So do Dogal JH Flats on a Stingrays and even Rick 4003's and P-Basses.