Aqualung Leg3nd MBS - good or bad? vs Elite?

[CapnBloodbeard]

G'day helpful brains trust!

Another reg question - this time specifically the Aqualung series (I know there are a few threads on Aqualung/Apeks/Atomic, so I'm not looking for that here).

MBS vs Elite - only difference is the 2 breathing controls are combined in one knob on the MBS.
So....is this a good or a bad thing? What I don't understand is - how does the venturi (dive/pre-dive) work in that regard, because aren't you then mainly using it for cracking pressure?

Anybody with any experience or knowledge able to give any feedback? The Elite is $200AUD dearer, so significantly more expensive, just wondering if it's worth it for just a breathing control or if the MBS actually does a decent job - I haven't really found any feedback at all on this feature of theirs.....

 

[Sevenrider860]

The Aqualung website used to have a video that described how the MBS works. Basically the venturi and opening effort are tied together. Reduce your opening effort and you reduce your venturi. Previous generation of Legends with the MBS have always been great breathers, so I would not expect it to be any different with the new version. I think it comes down to personal preference.

 

[rsingler]

Leg3nd Elite v MBS

 

[CapnBloodbeard]

The Aqualung website used to have a video that described how the MBS works. Basically the venturi and opening effort are tied together. Reduce your opening effort and you reduce your venturi. Previous generation of Legends with the MBS have always been great breathers, so I would not expect it to be any different with the new version. I think it comes down to personal preference.

thanks.....I'm just a bit stuck on how they've incorporated it.

Now, I was never taught how to use the 2 adjustments properly (not even dive/predive).....but I'm gathering that on a typical dive, I could flick that as I'm going under, maybe tweak the breathing adjustment knob as I go deeper or get into a current.....or maybe I can leave that alone the entire dive......

I'm still trying to get my head around how the 2 are incorporated in a real world sense.........does it mean I'd have to be completely screwing/unscrewing the knob every time to deal with the dive/predive adjustment?

I have no doubt they're great breathers.....I'm just wondering if this actually results in more fiddling and adjusting than the standard 2-adjustment system, but its annoying that the Elite is so much more expensive....

 

[rsingler]

For the most part, if your reg is tuned properly, you'll leave the knob fully out all the time for your primary second stage. I virtually never change my separate cracking effort knob.
I'll increase cracking effort on my octo for a shore entry, and you'd increase the MBS knob for the same reason. Same with your octo for a giant stride boat entry - whatever you can to prevent a freeflow.
The only difference is how you'll dive your octo once you're submerged. I'd recommend that you crank in your MBS a half turn. That will help reduce an inadvertent freeflow if the reg gets banged, while not making breathing effort much stiffer if you hand it off to a panicked OOA diver.
If you're primary donate, then you'll know to expect a slightly stiffer aux reg when you hand off your primary, and can quickly unscrew it if you want.

Mostly, none of it matters. Primary wide open; aux tightened a little.

 

[Mr. Dooley]

I demo'd the MBS in the pool - felt good, breathed very smoothly, and you could definitely feel the difference in air delivery when adjusting the MBS (master breathing system = combined venturi / cracking effort knob). On some other regs I couldn't even perceive the difference when adjusting the venturi - not so here.

I was at one point considering getting the Elite or the MBS - after doing some research and testing the MBS, I could see no practical reason to pay more for the Elite. Literally the only difference is having the controls separated or combined. For an octo you'd probably want the unit desensitized - both venturi and cracking effort - so you won't "lose" anything meaningful by having these features combined. Unless a diver is so finicky as to want say, an easy cracking effort with less airflow (tuning these features in the "opposite" direction) or vic versa, I don't know why I'd opt for the Elite.

My instructor received his MBS as a product sample from Aqualung, and he uses it as his default reg for what it's worth.

 

[CapnBloodbeard]

For the most part, if your reg is tuned properly, you'll leave the knob fully out all the time for your primary second stage. I virtually never change my separate cracking effort knob.
I'll increase cracking effort on my octo for a shore entry, and you'd increase the MBS knob for the same reason. Same with your octo for a giant stride boat entry - whatever you can to prevent a freeflow.
The only difference is how you'll dive your octo once you're submerged. I'd recommend that you crank in your MBS a half turn. That will help reduce an inadvertent freeflow if the reg gets banged, while not making breathing effort much stiffer if you hand it off to a panicked OOA diver.
If you're primary donate, then you'll know to expect a slightly stiffer aux reg when you hand off your primary, and can quickly unscrew it if you want.

Mostly, none of it matters. Primary wide open; aux tightened a little.

So that's what I'm thinking....if usually you leave the cracking effort knob alone and just flick the venturi switch as you're going down, then does the MBS change that, meaning you need to twiddle a knob from 'fairly closed' all the way through to 'almost wide open' every dive, and again on the way up? Just wondering it this setup might increase the chance of freeflow as you ascend if you don't adjust it back....?

As for the Octo - it's the base level leg3nd with just the venturi.

I demo'd the MBS in the pool - felt good, breathed very smoothly, and you could definitely feel the difference in air delivery when adjusting the MBS (master breathing system = combined venturi / cracking effort knob).

I was at one point considering getting the Elite or the MBS - after doing some research and testing the MBS, I could see no practical reason to pay more for the Elite. Literally the only difference is having the controls separated or combined. For an octo you'd probably want the unit desensitized - both venturi and cracking effort - so you won't "lose" anything meaningful by having these features combined. Unless a diver is so finicky as to want say, an easy cracking effort with less airflow (tuning these features in the "opposite" direction) or vic versa, I don't know why I'd opt for the Elite.

My instructor received his MBS as a product sample from Aqualung, and he uses it as his default reg for what it's worth.

That does help - so having the features combined, do you find that you need to tweak it much in a dive? (I know you probably don't get much sense in a pool as you're not going deep).....I just wonder if a normal reg you'd, say, flick the venturi and the cracking effort might pretty much remain the same where this might need a bit more turning....

 

[Mr. Dooley]

That does help - so having the features combined, do you find that you need to tweak it much in a dive? (I know you probably don't get much sense in a pool as you're not going deep).....I just wonder if a normal reg you'd, say, flick the venturi and the cracking effort might pretty much remain the same where this might need a bit more turning....

True I definitely didn't go deep, but I used the reg for a pretty extended pool session, shall we say. That being said, I think once the thing's in your mouth, you can pretty much set it and forget it. If you have one as an octo, desensitize it to prevent free flow. Even at it's "stiffest" setting, it's not like you need iron lungs to draw breath so that wouldn't be a major concern for me in an OOA situation.

Even when I have dived deep (34 meters), I never felt the need to adjust the venturi on my reg at the time (Apeks XL4 second stage).

Honestly the MBS is like a Cadillac - it's all about a smooth ride. Breathes almost as if you're not using a regulator at all. It performed respectably no matter your orientation in the water, and because it has a wider diameter than some smaller regs (like my old XL4) it's perhaps better suited for deep diving in the sense that it'll have an easier time meeting a diver's breathing rate even when under duress or while exerting one's self.

 

[rsingler]

if usually you leave the cracking effort knob alone and just flick the venturi switch as you're going down, then does the MBS change that?

Only to the extent that you have to increase your cracking effort as part of decreasing freeflow likelihood - you can't just change Venturi like you can with the octo. But since you'll have the primary in your mouth, there's no reason not to have the knob fully open.
The only times you might ever need to crank in the knob are
1) at the end of a service interval, where the poppet seat has taken an indentation and the reg tends to freeflow slightly with the knob fully out;
2) on a really deep dive where increased air density tends to accentuate Venturi effects, and the reg might "blow" at you during inhalation.

Unless you're an equipment geek, you'll rarely see a need for separating the functions.

 

[Tom Howe]

Only to the extent that you have to increase your cracking effort as part of decreasing freeflow likelihood - you can't just change Venturi like you can with the octo. But since you'll have the primary in your mouth, there's no reason not to have the knob fully open.
The only times you might ever need to crank in the knob are
1) at the end of a service interval, where the poppet seat has taken an indentation and the reg tends to freeflow slightly with the knob fully out;
2) on a really deep dive where increased air density tends to accentuate Venturi effects, and the reg might "blow" at you during inhalation.

Unless you're an equipment geek, you'll rarely see a need for separating the functions.