How much to you low cut the master/final?

I prefer a gentle slope for guess what ? Less phase problems unless the filter is phase corrected The point is by ear but I never have pushed below 25HZ. 25 with a phase corrected 48 db per octave slams the subs.
A good learning experience is to listen to a bunch of stuff you like with 1/6 octave RTA FFT app so you can see what works for you.
Once again (I should get a commission or an endorsement deal at least ) AudioTools should be on every AE’s phone!

I could send you a mix without vox if that is good.

Some digital software and hardware based filters correct for the associated phase shift. The example I use are the BSS WHISEWORKS Neville Thiele method.

You know - maybe the question is more like what is “flub” in a kick? That’s the only thing that’s going to reach down that low for me. (No moogs or sub bass).

Ah, like this specific question better.

Truly, kicks have very LITTLE extreme low end content in nature. If you are catching extreme sub content, it is due to poor directional mic placement; LF air gusts (wind) compounded by proximity effect. IOW, Synthesized by the mistakes in recording process.

Though my day job is mastering, I still pledge that the recording phase is king. Closest phase to the artists, after all.

Now, If that phase went wrong then re-record. If the discipline doesn’t exist for that then try to address as best one can in the mix.

If discovered in mastering then RECALL the mix.

Don’t panic! Don’t make poor choices at the mastering facility if the longevity of royalty potentials would be compromised.

I'd also start at 30 Hz and hear what it sounds like. Usually my mixes don't have too much sub as i check for that on the channels, better to get that right befor it hits the bus. Not all lowcuts sound fine to me - i can remember one instance when i recorded solo flute that had its sound changed when i inserted a lowcut around 50Hz that "should" have done nothing two octaves up... and there was a software by zynaptiq (unfilter) that had the most neutral lowcut in there and i spoke to them please, pleeeease make that lowcut a dedicated plugin.. which he never did, allthough a few people came to him that asked for it.
I had a few mastering engineers ask me if i can leave in stuff around 30 Hz, so they can tailor that - i get it, as my monitoring goes well below 30 and it's a nice sound if there's some energy down there.

What he said with one other factor, the instrument itself plus a bit of position in the room. This is where a great drum tech is worth their weight in gold. Drums and particularly kick are so mechanical that you need someone who knows how to tweak everything from the beater to the head. I’ll admit I suck at it.

The other thing is it can be how the monitor presents it.

30-60 hz. Pass filter varies.

Absolutely. I'd rather kill the mastering engineer.

The 40 hz and 15 khz filters on a v76 work great for the real world. The plugs are convenient. I love the Neold v76u73 and will even turn down the gain all the way on it and hit it soft with a trim just for the filters and a minute bit of fat.

Yeah, funny enough on Monday I was talking to this guy who was bragging about his “ Mastering” setup telling me about his B&W’s thinking I would be impressed, 800 series? Nope there cheapest little desk tops that do almonds nothing below 60hz I would be better off mastering in the Tesla🤪

Curious about why you're all doing this. Is this more an ITB thing?

I understand the idea of getting rid of stuff most people can't hear or most systems can't reproduce, but why not do that on the channels? Most things are going to be hi-passed much higher (vocals, guitars, etc) with only a few instruments going deep down.

Is there a benefit to one master HPF for the whole mix as opposed to each track getting it's own? I know when I use HPFs I pretty much end up with different points for all the low stuff (kick, bass, synths), if I'm using them at all.

Is there a benefit to using both, assuming the channel's filters aren't gentle slopes starting really low?