[gattaca]

Funny you mention Life of Bliss, his videos were a huge inspiration for wanting to go big or go home haha. ...
But yes, I rewatched the video the other day and I think he did say he was pushing 4000 watts to each one, but maybe that was just burst and not RMS? I'll have to go back and check.

... I didn't even remember that Life of Bliss used the Stereo Integrity's, they just came up in a discussion I was reading, then after deciding on them I remembered he had used those as well haha.

But yeah, if I'm not mistaken you can use the MiniDSP 2x4 HD as a limiter, correct? That's one area I need to research more on but I already use the 2x4 HD in my system for time alignment.

1. Yes, LoB is using a well-known direct-from-China clone, Simbosen FP20000Q 4 channel claiming 2000W RMS x 4 with peaks to 4000W.. and it's operating on a 230/240V circuit. The SP2-12000 is the nearest Made-in-USA equal with solid measurements and super important for me, a real UL listing.
2. Yes, LoB is using SI 24 and has an unboxing vid for them too - check'm out.
3. Yes, turning on the MiniDSP's compressor/limiter is one of the first things the REW+SMEs setup instructions tells you to do immediately as I recall.

You have quite a journey planned! I'll continue watching this thread. I think you should reach out to the SI (Nick and team) about the HS24 when you are ready - assuming you don't go for the DSS 24" units - delivered ready-to-roll - to your door, option.
Stay safe, stay alive! Peace.

 

[Vince_B]

The 24s are awesome but also so are the hst-18. Two 18 will theoretically out displace a 24 but with the absolutely ludicrously large surrounds I’d question if they actually do in reality. (Edit, the hst18 area is smaller on specs. If you look at the old ht18 with its smaller surround the sd is more- so yeah the 24s for sure) Two 18 will be more flexible placement wise if that’s a concern. I have two 24s sealed in front and added two hst-15 nearfield and they do add some serious tactile. It was good before it’s just good-er now. The 38mm Xmax of the SI drivers would seem to have an edge in the ulf department although the harbottle looks great as far as doing everything well.

 

[noah katz]

I'm talking about acoustic coupling and ways to see it.

So was I.

Acoustic coupling is what enables the cone to make sound.

Or perhaps your comments, which I thought were about the effect of cone shape on SPL, were actually tangential.

 

[Chris Popovich]

You do eventually get there. Consistently even!

 

[noah katz]

You do eventually get there. Consistently even!

?

 

[Chris Popovich]

I'm teasing you Noah. You're clearly an engineer with the linear thinking, which is why it's fun to blue-screen you from time to time with a sideways comment. xoxo

Chris

 

[noah katz]

Good job, you really gave me 'dem blues

 

[BassThatHz]

The frequency is merely a matter of how often it changes direction in time.
At 10 Hz, it changes its mind 20 times in a second (twice per cycle).

Yes I mentioned that as well in my post.
That said, the cone speed and frequency are two different things. Although both related by motion...

If you have a cone, make a copy of it, and you move it similarly to the speaker at a distance X (for excursion) the volume between the two cones (the volume displaced) is exactly the same, no matter if that cone is short, long, or just a flat plane circle, because regardless of the volume of the cone, the volume will be exactly the same as if it were a circle that was just the base of the cone.

This example makes much more sense and is generally correct. I'd just add that there might be particle diffraction in an open space, so the displacement could be slightly higher when not restricted by a walled tube; and some parts of the surround don't move which will slightly decrease the displacement, so there is that to consider.

In any case, box modelling software does a fairly good job at calculating the SPL for a given frequency for us. Allowing us to drink beer and watch movies, rather than crunching numbers for hours by hand and pulling our hair out. REW and winISD (and programs like it) have been a lifesaver for everyone...

 

[BassThatHz]

I'd recommend reading the various SI24" threads here, there are days worth of reading available. Most of us with them tend to disappear from the board after finishing our builds, I think because most of us won't ever want more than they can provide, so we move on.

I've seen it happen more than once!
That said: I have a 24, and other subs, and I'm still here (and still wanting lots more! 🙃)
But yes, most...

 

[BassThatHz]

I think he did say he was pushing 4000 watts to each one, but maybe that was just burst and not RMS? I'll have to go back and check.

The do "roughly" 2kW rms and 5kW burst. Although it may differ from brand to brand, or even batch to batch.
It's a LOT of power in 2RU, only dual PowerSoft X8's have a higher density than that...

 

[BassThatHz]

I'm not sure how I'd do it exactly, but a version not unlike used in wind tunnels to "see" how the air moves. Obviously in a wind tunnel it's one way flow, and with acoustics we're talking about alternating

I thought you were saying: burp it until it smokes. But you actually meant a real smoke-test.
There are a few videos on youtube with people vaping with subwoofers using cellphone 240fps. Not-exactly what you are looking for. You'd need the Slow-Mo-Guy camera to capture that visually in sufficient detail. Would make for an interesting video...
B&W has a system that can do it smokeless. It uses lasers instead. I'm sure it costs even more than a Phantom camera though; and probably runs custom PhD-level software too, I couldn't imagine the complexity... (LIDAR etc.)

 

[BassThatHz]

If I model an NSW vs an HS24 or Harbottle both of those subs appear to be inferior to the NSW until you start digging below about 16Hz (upper bass range difference is even greater with the NSW in a devastator). From a cost perspective one 24 costs more than 2 NSWs which then pushes the SPL advantage for a 24 down another 1-2 Hz and the difference at 16Hz and above increases even more.

I haven't modelled it myself, but you are probably correct.
Big or Overly-expensive woofers don't always equate to better.
They are (hopefully) better built, but that doesn't always or necessarily increase SQ or SPL... at the desired target frequency range or otherwise.

After seeing a number of posts on this I have to ask - does one really know what they are after when they want big response in single digits? Seems like I've seen a number of posts where the priority seems to be 1-15Hz over 16-100Hz (16Hz+ is where the vast majority of content is). I'm sure I'm showing my lack of knowledge here but am I missing something?

I can't speak for others, or what they need/want/enjoy.
I could make a general blanket statement and say: yes, most don't know what they are getting themselves into or what they want. Some do, but I'd say most may not / don't.

The 20hz cutoff, isn't a hard number, it's an average-human figure, done with headphones (like 1970's headphones...)
Just about everyone can hear single digits if you get it loud-enough. (Think rotary woofers or arrays of large subs...)
Most people haven't heard or experienced it because they don't have a system that can do it. Mine can barely do it...

"I think I can" hear or sense 1-7hz notes in the InfrasonicDeath song, but I'm not completely certain I'm not just hearing higher harmonics / THD. When I play raw sinewaves I can hear them easily down to 12hz in my system. From 12hz to 1hz things get a bit weaker and uglier, as per normal.
Hearing 12-19hz is no problem in my system, for me.
I can't speak for others but I enjoy it, personally I wouldn't want a system that couldn't play down to 1-4hz, you couldn't pay me to do it.
I don't even know WHY I like single digits so much... I mean why does a lion like killing everything in sight? Why do trees Apple? Why does the earth People? I don't know what others need/want/enjoy... But I can tell you that it gets very expensive and is (probably) wasteful of time/money/breakers/room-volume/resources😅,
but I'm in no position to tell anyone not-to-do-it. (i.e. keep going!)

 

[michael hurd]

I well understand the simple math, none the less I'd like to see a smoke test of a deep conical woofer vs a flat cone woofer at high excursion. Might be too much of a mess to see anything worthwhile, just curious if there is any difference in coupling at extreme levels, particularly around the surround area.

Schlieren photography. No smoke needed.

Schlieren photography - Wikipedia

Jump to 15:50 if you want to see the effects of a baseball going supersonic :

 

[xb1032]

Yeah BassThatHz you're definitely the exception even around here and you can speak to this in specifics.

The 24s do have an intimidating size advantage with more excursion that the pro audio drivers don't have (and are betting looking too) but from a price/performance perspective I don't see the advantage. I suppose the same could also be said about comparing 18s to 21s but the price isn't as great (unless you are talking an NSW).

 

[Gorilla Killa]

I have 2 Harbottle 24's and 4 NSW. There is a difference in the sound and primarily the heft of the 24's. 2 will pound as hard as 2 NSW but consider there is more cone area.

You have to experience them, I have zero regrets buying the 24's and consider the NSW second fiddle even though sim comparisons say otherwise.

 

[djdanny]

I have 2 Harbottle 24's and 4 NSW. There is a difference in the sound and primarily the heft of the 24's. 2 will pound as hard as 2 NSW but consider there is more cone area.

You have to experience them, I have zero regrets buying the 24's and consider the NSW second fiddle even though sim comparisons say otherwise.

not sure what your NSW’s are in, but if you’re running the 24’s in sealed they’re probably playing with much more distortion on the low end 30hz and below than the typical 21” (Lavoce, B&C, and NSW) in a ported enclosure and my guess is that’s why you notice more “heft”. Just compare the low end of the sealed Funk 21” versus the 21” B&C 21ds115 in the ported X21 cabinet on data-bass. The funk has way more distortion with less output in the low frequencies above theX21’s port tune.

 

[BassThatHz]

not sure what your NSW’s are in, but if you’re running the 24’s in sealed they’re probably playing with much more distortion on the low end 30hz and below than the typical 21” (Lavoce, B&C, and NSW) in a ported enclosure and my guess is that’s why you notice more “heft”. Just compare the low end of the sealed Funk 21” versus the 21” B&C 21ds115 in the ported X21 cabinet on data-bass. The funk has way more distortion with less output in the low frequencies above theX21’s port tune.

Box-type advantages and disadvantages are well-known and well-documented.
I think to make the comparison fair they'd both have to be in the same box-type, and preferably both in their optimal-boxes with optimal-power. Only then are we actually comparing the driver apples-to-apples. Otherwise we are just comparing various box-types & random complex-systems.
Ignoring WAF and space constraints, there is no reason they couldn't or shouldn't be.

The amount of mid-bass pro woofers can spit out, especially the high-end ones is unbeatable.

For what it's worth my SAB-24 has more excursion than the Funk-24 or SI-24, it's closer to an SHS-24 in that regard. I'd say your system still needs both. I wouldn't want to be without my MBM's or ULF subs. They both do specific things the other doesn't. One is 16x ~98db/w/m worth of efficiency + 16x18's worth of cone-area, and the other has ~104mm of xmech with a 24" bore. I wouldn't want to be without either... you need both IMO!

My system can be a bit overwhelming because it can reproduce all frequencies with full dynamic range, all concurrently and instantly, with little strain for all but the lowest of low frequencies. Like dynamic-swings of 96db, the full 16bits. One second it can be at 50db and the next second it can be at 140db! One second the cone can be doing next to nothing and the next second it is trying to fly out of the box!
Things that would otherwise strain, melt or explode smaller systems.
The mic can't even comprehend what it is hearing half the time, heck... 100% of the time! 😅
There are at least a dozen members here with systems equally or more nutty! I'm not alone and that comforts me knowing that the other crazies are also running the asylum when I'm asleep or running around in a pink tutu like Jim Carrey bagging my head and knees together online.

 

[Gorilla Killa]

not sure what your NSW’s are in, but if you’re running the 24’s in sealed they’re probably playing with much more distortion on the low end 30hz and below than the typical 21” (Lavoce, B&C, and NSW) in a ported enclosure and my guess is that’s why you notice more “heft”. Just compare the low end of the sealed Funk 21” versus the 21” B&C 21ds115 in the ported X21 cabinet on data-bass. The funk has way more distortion with less output in the low frequencies above theX21’s port tune.

The Funk on DB is old tech, they have improved upon them. Difference in distortion is negligible, currently everything is all sealed. This is basically the levels I would listen at the mlp with all running sealed.

This is a close mic of 1 of the sealed uHT, 2.02% is as high as it gets across the bandwidth.

This is the NSW close mic, never goes above 1.79%

 

[xb1032]

2 Harbottles vs 2 NSWs is a different story (the sims I posted were also NSWs in devastators which also boosts midbass). Have you compared 1 Harbottle to two of the NSWs? What box sizes are being used and is the NSW ported?

 

[Chris Popovich]

Doing a close-mic sweep will tell you nothing about distortion at real world playback levels. You're still basically small-signal, which I bet you a ham sandwich and a bottle of your favorite vodka, is absolutely nothing like what happens when you turn things up. Increase excursion to an inch or so and your distortion will go up an enormous amount. That's no slight on the drivers, they all do that. I love sealed too, but low distortion isn't one of the advantages of it.... which is why we need MORE subwoofer drivers! Yeah yeah!