BOSSOBASS Raptor system 3

[SME]

As for tactile transducers (TTs), I see the Crowson name dropped on this forum a lot, and I also see Buttkicker mentioned above.  Out of curiosity, is anyone familiar with Clark Synthesis and has an opinion about that brand, one way or another?  At a glance, they appear to be a bit more refined/high-end than Crowson or Buttkicker, but we all know how much looks deceive in audio.

 

I do find the whole discussion of tactile sensation very interesting.  It's definitely a phenomenon that's not well understood.  Here we have one person arguing that on concrete slab, TTs are like a night-and-day difference even with full ULF capability, but another argues that it doesn't matter at all.  I do have a suspended wood floor and enjoy the tactile sensations I get, but between it and the sofa, there are some mid/upper bass frequencies that resonate more than I'd like.  I could try adding damping to the floor, but I'm not sure how well that would work and might miss some of the lost tactile input.  TTs could replace some of that.  If I did get TTs, I think it would be interesting to try to EQ out the resonances and experiment with signal shaping to achieve the best psychoacoustic balance between vibration and sound.  This would probably work out better using a floor that's well-damped to begin with.

 

I find it hard to believe that TTs can adequately replace subs.  Where noise control is an issue, it's surely better than nothing.  Perhaps for ULF, TTs get most of the way there, but they can't reproduce the room pressure effect.  I also suspect there's a difference between feeling the seat shake your body and feeling the air shake your body directly.  It's hard to tell which is which in actual listening, but I do often feel like the shaking is coming from the air rather than the floor.

[MemX]

But I don't want to live in a world were everybody has sealed subs anyway. That would be boring.

What would we all argue about? lol

 

Personally speaking, my ported SVS is a lot of fun but I have found the sealed setup to sound a lot 'tighter', presumably to do with impulse / transient response and all the other things that make my head hurt lol

 

Audyssey seems to agree too - SVS distance was set at c.20ft, sealed distance is basically bang on to the actual distance, which is under half of 20ft!

[maxmercy]

Crowsons are superior to Clarks, IMO.  They do not attach to the seat frame nor riser.  They support and move at least one leg, and at most the entire seat/riser.  The best Crowson installations I have heard of place them under a riser, so that your feet are not decoupled from the impulses (like a suspended floor resonating).  The benefits of a suspended floor without the resonances if you build the riser rigidly enough.

 

JSS

[maxmercy]

While I would not trade my new multiple sealed system, my old system of two THTs was very economical for the SPL it produced with under 400W powering the whole shebang.  But the 2 octaves of extension I have gained are well worth it, even if it requires 10x the power.

 

I know this may sound like blasphemy, but if you get 16Hz extension already, getting to 4Hz was not nearly as big a leap as going from 30-40Hz to 16Hz was, IMO.  But my leaps were haphazard in terms of SPL.  I went from -20dBRef at 40Hz to -15dBRef at 30Hz, which was quite impressive.  Then it was to -10dBRef at ~16Hz, even bigger jump.  Now I am at -7dBRef at ~4Hz.  The last leap was not as 'big' as the second, IMO, but there are significant biases.  I built my current system with the least amount of free/me time I have ever had in my life, so for the effort expended, it did not seem as big a jump.  

 

I can only imagine what going from a 30Hz system to a 4Hz system in one jump would be like.

 

JSS

[SME]

Crowsons are superior to Clarks, IMO.  They do not attach to the seat frame nor riser.  They support and move at least one leg, and at most the entire seat/riser.  The best Crowson installations I have heard of place them under a riser, so that your feet are not decoupled from the impulses (like a suspended floor resonating).  The benefits of a suspended floor without the resonances if you build the riser rigidly enough.

 

JSS

 

Hmm.  Maybe I'm confusing Crowson with another brand whose measured frequency response was very peaky with big resonances around 40-50 Hz versus Clarks that are fairly flat.  In any case, if I were to purchase TTs for this room, I'd likely opt to install them (more than one for smoother response, of course) underneath the sub-floor via the basement, so I'm not sure how much advantage the Crowson design would have in my application.

[SME]

I know this may sound like blasphemy, but if you get 16Hz extension already, getting to 4Hz was not nearly as big a leap as going from 30-40Hz to 16Hz was, IMO.

 

I figure as much.  Musically speaking, two octaves is a lot, but in terms of energy, adding 4-16 Hz adds no more energy than adding 16-30 Hz does.  It is only a small fraction of the energy to be found in the entire 0-200 Hz bass range.  I won't for a moment argue that content < 16 Hz is inaudible or irrelevant or whatever.  It certainly matters a lot more, IMO, than response > 20 kHz which many people spend stupid amounts money for.  However, as a compromise, 16 Hz extension at reference is damn good, and I would bet that there's a lot more SQ improvement to be had for most people by improving response over the 50-200 Hz range using near-field subs, signal processing, and especially room treatments where appropriate.  I'll take slam over ULF, especially in so far as music is concerned.  Of course, I'll happily take both when I get around to it.

[Bossobass Dave]

What rooms sizes are we talking about here?  I specifically qualified that LLTs hit a nice spot for large rooms and low budgets.  Those 8x15" *might* be enough to get me < 5 Hz at reference level in my 9k+ cube space if they are high excursion like the HSTs.  I still need a beefy amp to drive those, like an A14k at a "cheap" $1700.  In small rooms, the economics are indeed much more beneficial.

 

Boxes also aren't "nothing".  Apart from the cost of materials, there's labor.  DIY boxes require wood working skills and time.  Don't forget the opportunity cost due to lost time that could be spent working on something else.

 

 

And for large commercial and outdoor spaces, it's probably reasonable to compromise on < 15 Hz for bass that's loud enough to actually hear.  Would you really try to argue for using multiple sealed woofers for bass support at an outdoor dance party?  Supposing you can get 103 dB/2m GP at 20 Hz from a single 15, to get 109 dB at 16 m takes no less than 16 woofers and a hell of a lot of power.  With room gain completely lacking, resonant designs start to look quite attractive again.

 

9k cube space is irrelevant. Reference at 5 Hz is approximately 105dB peaks. The room does the lion's share. 9k cubes has no effect on a 220 foot wave length. This is 101.

 

To qualify... boxes are nothing... for a sealed system. all other alignments increase complexity and size exponentially. Sorry, but DIY implies requisite skill, tools and time, so I don't get your point here.

 

Outdoors?  Dancing? Whatever are you on about, young man?

[Bossobass Dave]

I can only imagine what going from a 30Hz system to a 4Hz system in one jump would be like.

 

JSS

 

I built two 1x18" dual-chamber ported subs in the ProLogic days, circa 1995. They were tuned in the upper 20s Hz. I went from that to a sealed L/T system that was flat to <10 Hz, anechoic. I used 1/12 octave sine tones, a RS meter and C weight correction files, drew my own graphs and ran them off on a copier and plotted and drew the traces with colored pencils.

 

Here's one, before and after L/T. I seem to remember holding the meter about 1 foot over the sub. There's an 80 Hz LPF in line. I transposed the FR onto a TrueRTA empty graph and smoothed the trace in software:

 

 

Needless to say, this is why I preached sealed from that first 1x12". Of course, the ported 18s could go LAF in comparison, but the difference in accuracy was all it was about. If you had 2 loudspeakers and one was flat to 20k Hz and the other rolled off 4th order at 5k Hz, but went way louder, which would you prefer in your system?

 

And, apparently I have to say this repeatedly for some reason that remains a mystery to me, the 15 cubic feet external dual chamber reflex boxes were magnitudes more complex to plan, build and find a place in the room for than the small sealed cylinder with a hole cut in it for the driver.

 

I built the first dual opposed 2x15 in early 2003 and, coupled with the Marchand Bassis, that made it stupid-simple to change F3 and Qs, there were no doubts left in my mind and I haven't seen anything to change that since.

 

In the meanwhile, I bought and held listening sessions with the Hsu, SVS and PE ported stuff and wrote about their virtues in various forums over the years. I did a system using AV123 bookshelf and a rosewood VTF-3 that was quite nice and fit the bill for the H.O. I measured and tested it and held a listening session with young musicians comparing it to a sealed sub. I posted in the Hsu forum.

 

 

I've also enthusiastically endorsed the SVS PB13-Ultra countless times because it is a great commercial sub. So, the whole "Bosso hates ported" is bullshit. I got the rep from having to incessantly debunk the port-heads posted baloney about subwoofers in general, content, human hearing, equal loudness curves and all else related to "My sub are better 'cause dey are cheeper and Bosso is just a frequency response Nazi whose head will explode if you don't believe sealed is the master race.".

[Infrasonic]

Everyone talks about "multiple sealed" like you need a dozen 18s.

 

Yeah and?

 

 

The answer is "yes". Yes, of course you need a dozen 18's.

[Infrasonic]

It seems obvious to me that resonant systems are about loud and nothing else.

 

"Obvious" to you maybe. Resonant is not all about 'loud' or else the LLT alignment would not exist. It's all about balance and you don't seem to get that sealed is not the answer for everyone and every situation.

 

You're preachin' to the choir with all your reasons why sealed is the subwoofer 'master race'. I get it but that doesn't mean it's the right choice for everybody. It's not for you. Nothing wrong with that but idk man, not everybody needs or wants what you like.

 

I knew that multiples of sealed was the next logical step for what I want cuz like you, I want to reproduce the whole signal (within reason) but I also want a boatload of SPL capability so I did what I did and so do several other of us ... "nuts".

[SME]

9k cube space is irrelevant. Reference at 5 Hz is approximately 105dB peaks. The room does the lion's share. 9k cubes has no effect on a 220 foot wave length. This is 101.

 

To qualify... boxes are nothing... for a sealed system. all other alignments increase complexity and size exponentially. Sorry, but DIY implies requisite skill, tools and time, so I don't get your point here.

 

Outdoors?  Dancing? Whatever are you on about, young man?

Reference at 5 Hz is only 105 dB?  Then what's all the fuss about?  I'm sure that's enough to notice, but only just.  In this recording of a real life space shuttle launch, 5 Hz looks to be at almost 115 dB at reference.  That's a difference of only about ... 4X the displacement, and I'm sure that 5 Hz is noticed a lot more at 115 dB than at 105 dB.

 

I can say with confidence is that 4 HST-18s should get me 12 Hz at around 115 dB at "the CEA distortion threshold", and I'd rather avoid hitting that threshold if possible.  Accounting for reduced surface area and less excursion capability, I reckon that's similar to what I'd get with 8 of your 15s.  My house is 48 feet long, so that number includes the effects of the room mode at that frequency.

 

At what point can I expect 12 dB/octave room gain to come into play?  I realize it's a very complicated question because it depends on so many things other than just room dimensions, and of course, no one actually gets the full 12 dB/octave gain because of leaks.  While I have the benefit of brick construction, I also have substantial leaks into a basement and garage totalling another 11k cuft or so (to say nothing of the attic space).  I think > 105 dB @ 5 Hz is realistic to expect with 8 15s but definitely not 115 dB.  If you have reason to believe otherwise, I'm all ears.

 

Outdoor electronic dance parties are hardly a new thing.  My own musical preference is for Psytrance which got its start in Goa, India way back in the 80s and gradually spread across the world.  The preferred setting for parties is outdoors with parties often not getting started until well after midnight and continuing well into daylight or even multiple days and nights.  One of the more well known performers, Goa Gil, is known for his sets that span over 24 consecutive hours.  To say the experience of attending such a party is memorable is a huge understatement.  The music is typically high BPM and much of it is bass driven very bass heavy.  Unlike with most rock music, the 40 Hz extension provided by typical PAs leaves a lot of that bass on the table.  Honestly, I don't get the hype over Dubstep because most of that kind of sound was around long before in other lesser known genres and was used to much better effect, IMO.

[Ricci]

I know this may sound like blasphemy, but if you get 16Hz extension already, getting to 4Hz was not nearly as big a leap as going from 30-40Hz to 16Hz was, IMO.

 

JSS

 

 

+1

 

Sub 15Hz content is a cool effect and was definitely worthwhile at my old place with the suspended floor that would dance my coffee table at REF level playback, but at my new place it is much more subtle and most people other than myself don't really notice the ULF stuff unless it is a high level and blatantly hotly mixed signal. I wouldn't want to give it up of course, but about 98% of the enjoyment is the stuff >15Hz without my old suspended floor. YMMV.

 

What rooms sizes are we talking about here? 

 

And for large commercial and outdoor spaces, it's probably reasonable to compromise on < 15 Hz for bass that's loud enough to actually hear.  .  With room gain completely lacking, resonant designs start to look quite attractive again.

 

Exactly...I am involved with live music, reinforcement and large spaces and a lot of guys are. A lot of my time is spent in that realm rather than home audio. Sealed is not the answer for that stuff. There is a reason I've designed some of the cabs I have. I never intended for people to use them in their homes at all. I don't even employ them that way myself. I have sealed at home. Different tools for different applications.  

 

We are getting pretty far OT in Dave's thread though...

[MemX]

While we're off topic...

 

 

I also have substantial leaks into a basement and garage totalling another 11k cuft or so

 

You have 11k cu ft of garage and basement?  I think my entire apartment must be under 5k cu ft... lol

[Archaea]

Bosso,

 

I've gone from a very capable ported sub setup with my two JTR captivators to a very capable sealed system with eight 18" Ultimax 18 drivers.

 

Your strong opinion that sealed is the only palatable answer and frequency responses below 15hz is vital, is simply that --- your opinion.  I personally add my name to the list of those that disagree here.

A sub that reaches to 15hz is all I need, and having owned both capable sealed and capable ported systems -  I can say I would be perfectly pleased with ported subs tuned to 15hz, in anything other than a room with a suspended wooden floor.   On a suspended wooden floor - sealed do come into their own and manifest some fun parlor tricks.

 

My frequency response is now flat to below 10hz, and nearly 7Hz on a basement slab in my big room.  See FR capture here taken by DesertDome at the recent KC crawl this last weekend.  This is a no smoothing capture with his omnimic.v2.  It was taken from the MLP.

http://www.avsforum.com/forum/15-general-home-theater-media-game-rooms/1525397-archaea-s-multi-purpose-home-theater-room-28.html#post33827977

 

Besides my use of the nearfield sealed I don't get any perceived value out of the sealed subs below 15hz when they are placed at the front of the room.  I do think the sealed nearfield are worthwhile (so much so that I'd probably take one sealed nearfield 18" over the other seven subs loaded at the front of the room) - but quite honestly the two captivators were 95% of the performance of these eight sealed, and they were tuned to 20hz natively.  Considering I paid nearly double the money in total for these eight sealed (amps, boxes, wiring, drivers) over the two ported captivators -- I wouldn't be disappointed to go back to a pair of caps or equivalent tuned to 15hz, and put nearly $3k back in my pocket.  Real world performance was only a hair different in my experience.  If I went to different subs up front I'd probably want to keep the sealed nearfield --- I've grown quite fond of them in that position.

 

I guess I'm just pointing out that you seem to maintain that anyone who disagrees sealed is the only game in town hasn't experienced otherwise - and that's just not accurate.  I now own one of the more capable sealed systems, and I'm certainly still excited by a pair (or more) of high capability ported subwoofers, or horn subwoofers.  (Orbit Shifters, Gjallarhorns, etc)

[Shredhead]

Hahaha, you ported dudes are awfully sensitive. 

[Infrasonic]

And so are some of you sealed guys.

[SME]

Sub 15Hz content is a cool effect and was definitely worthwhile at my old place with the suspended floor that would dance my coffee table at REF level playback, but at my new place it is much more subtle and most people other than myself don't really notice the ULF stuff unless it is a high level and blatantly hotly mixed signal. I wouldn't want to give it up of course, but about 98% of the enjoyment is the stuff >15Hz without my old suspended floor. YMMV.

Very interesting.  This almost seems like a "chicken and egg" sort of problem.  Dave describes "reference level" capability at 5 Hz as 105 dB.  I gather this figure is based on assessment of a wide variety of content, presumably including the heavy hitters like HTTYD or maybe not.  In any case, if you rarely ever hear 5 Hz at > 105 dB, that capability might not add all that much.  If you are on a slab or your room does not resonate well, then it might be barely enough to notice.  But what if you play that Space Shuttle launch recording I referred to with ~115 dB to 5 Hz and below?  At 5 Hz, that 10 dB difference is a big f-in deal!  Even on a slab that might be strong enough to really push your body around.  That might make that capability seem a lot more worthwhile.  The problem, of course, is that there are many recordings with ULF at that SPL, and as long as everyone "writes off" ULF response as unimportant, such content will rarely be made.

 

One workaround is to just run the subs hot.  Obviously, a lot of people here are very happy to do that, but I personally doubt I'll run hotter than 85 dBC calibrated reference.  So is it really worth it me?  For that space shuttle launch, it may be, but having only a handful of recordings (Space Shuttle + maybe some of the Danley stuff) that hit the ULF at high levels is a drag.  It might ultimately compel me to take up recording as a hobby.  After all, there's no shortage of impressive ULF to be recorded out there in the real world.

[SME]

On a suspended wooden floor - sealed do come into their own and manifest some fun parlor tricks.

 

If it takes a suspended wooden floor to make < 15-20 Hz capability worthwhile, then do sealed subs really offer anything above ported subs paired with TTs like Crowson?  It is interesting to me that Dave argues < 15-20 Hz very worthwhile even on a slab, in contrast to some others here.  Maybe it's only worthwhile if the bass is run at hotter than reference?

[maxmercy]

Having gone from a 16Hz to a 4Hz system, I can tell you that <10Hz stuff is definitely noticeable, and I am on a slab, and listen at 78dBC with subs at 79-80dBC.

 

Is it as game-changing as the folks with the same capability on a suspended floor?  Probably not.  Going back and experiencing films with <15Hz content with the new setup has been lots of fun.  Eventually I would like to experience Crowsons, but the price of admission is pretty steep. 

 

JSS

[Ricci]

  Dave describes "reference level" capability at 5 Hz as 105 dB.  I gather this figure is based on assessment of a wide variety of content, presumably including the heavy hitters like HTTYD or maybe not.  In any case, if you rarely ever hear 5 Hz at > 105 dB, that capability might not add all that much.  If you are on a slab or your room does not resonate well, then it might be barely enough to notice.  But what if you play that Space Shuttle launch recording I referred to with ~115 dB to 5 Hz and below?  At 5 Hz, that 10 dB difference is a big f-in deal!  Even on a slab that might be strong enough to really push your body around. 

 

I have a difference of opinion from Dave on that. I think if you look at the total energy below 20 or 25Hz on some tracks, it requires quite a bit more than that. I always plan for the absolute worst case scenario. With 7.1 that is 125dB with redirected bass added to the LFE and that is run with the bass relatively flat. Will a sustained 7Hz sine wave ever come along at that level? Not likely. I could see some wider band 5-20Hz effects that are really mixed hot though. In my system the excursion demands after signal processing aren't that much different over that range. I never like to push my system anywhere close to its limits either, so I figure I need an extra 4 to 6dB of dynamic headroom on top of whatever REF level WCS might require. That's where I'm at and why I have a confirmed 130dB+ of peak headroom below 20Hz.

 

Trust me I've heard the 5-10Hz range at >115dB in my current room with test signals. Now if I go upstairs to the room above...Now we are talking, the floor ripples and it feels like a damn earthquake.

[Infrasonic]

^^^^^

This.

[Bossobass Dave]

Bosso,

 

I've gone from a very capable ported sub setup with my two JTR captivators to a very capable sealed system with eight 18" Ultimax 18 drivers.

 

Your strong opinion that sealed is the only palatable answer and frequency responses below 15hz is vital, is simply that --- your opinion.  I personally add my name to the list of those that disagree here.

A sub that reaches to 15hz is all I need, and having owned both capable sealed and capable ported systems -  I can say I would be perfectly pleased with ported subs tuned to 15hz, in anything other than a room with a suspended wooden floor.   On a suspended wooden floor - sealed do come into their own and manifest some fun parlor tricks.

 

My frequency response is now flat to below 10hz, and nearly 7Hz on a basement slab in my big room.  See FR capture here taken by DesertDome at the recent KC crawl this last weekend.  This is a no smoothing capture with his omnimic.v2.  It was taken from the MLP.

http://www.avsforum.com/forum/15-general-home-theater-media-game-rooms/1525397-archaea-s-multi-purpose-home-theater-room-28.html#post33827977

 

Besides my use of the nearfield sealed I don't get any perceived value out of the sealed subs below 15hz when they are placed at the front of the room.  I do think the sealed nearfield are worthwhile (so much so that I'd probably take one sealed nearfield 18" over the other seven subs loaded at the front of the room) - but quite honestly the two captivators were 95% of the performance of these eight sealed, and they were tuned to 20hz natively.  Considering I paid nearly double the money in total for these eight sealed (amps, boxes, wiring, drivers) over the two ported captivators -- I wouldn't be disappointed to go back to a pair of caps or equivalent tuned to 15hz, and put nearly $3k back in my pocket.  Real world performance was only a hair different in my experience.  If I went to different subs up front I'd probably want to keep the sealed nearfield --- I've grown quite fond of them in that position.

 

I guess I'm just pointing out that you seem to maintain that anyone who disagrees sealed is the only game in town hasn't experienced otherwise - and that's just not accurate.  I now own one of the more capable sealed systems, and I'm certainly still excited by a pair (or more) of high capability ported subwoofers, or horn subwoofers.  (Orbit Shifters, Gjallarhorns, etc)

 

I'm familiar with your opinions on the subject, but thanks for the refresher.

 

My "opinion" is that you should take a minute to check the content of the soundtracks that we rate in the content forum, so that you may re-familiarize yourself with the bandwidth of the content in those soundtracks.

 

Hopefully, that should cement your understanding of the bandwidth of the content we have to deal with in order to accurately reproduce that content.

 

BTW, with all due respect, the data you'll find there is not my opinion. I keep to the facts in this debate. I don't care what is palatable, but there should be no denying what is vital to achieve accurate playback... not "parlor tricks", whatever in the hell that's supposed to mean. You say that my stating the facts of the matter is really only stating my opinion on the matter then you talk about joining some imaginary list of people who prefer losing 2 octaves of playback because, in your opinion, it's all you need. Cool... got it.

[Bossobass Dave]

I have a difference of opinion from Dave on that. I think if you look at the total energy below 20 or 25Hz on some tracks, it requires quite a bit more than that. I always plan for the absolute worst case scenario. With 7.1 that is 125dB with redirected bass added to the LFE and that is run with the bass relatively flat. Will a sustained 7Hz sine wave ever come along at that level? Not likely. I could see some wider band 5-20Hz effects that are really mixed hot though. In my system the excursion demands after signal processing aren't that much different over that range. I never like to push my system anywhere close to its limits either, so I figure I need an extra 4 to 6dB of dynamic headroom on top of whatever REF level WCS might require. That's where I'm at and why I have a confirmed 130dB+ of peak headroom below 20Hz.

 

Trust me I've heard the 5-10Hz range at >115dB in my current room with test signals. Now if I go upstairs to the room above...Now we are talking, the floor ripples and it feels like a damn earthquake.

 

 

^^^^^

 

This.

 

Just semantics.

 

I'm talking about a single frequency and Josh is talking about total power over octaves of frequencies.

 

Your house doesn't have to be destroyed to say that <20 Hz playback is necessary. The whole 130dB thing is simply maniacal preference and has nothing to do with what I posted.

[Bossobass Dave]

 

Yeah and?

 

 

The answer is "yes". Yes, of course you need a dozen 18's.

 

Got data? Not that I don't want to take your statement at face value, but....

 

"Obvious" to you maybe. Resonant is not all about 'loud' or else the LLT alignment would not exist. It's all about balance and you don't seem to get that sealed is not the answer for everyone and every situation.

 

You're preachin' to the choir with all your reasons why sealed is the subwoofer 'master race'. I get it but that doesn't mean it's the right choice for everybody. It's not for you. Nothing wrong with that but idk man, not everybody needs or wants what you like.

 

I knew that multiples of sealed was the next logical step for what I want cuz like you, I want to reproduce the whole signal (within reason) but I also want a boatload of SPL capability so I did what I did and so do several other of us ... "nuts".

 

What I like is irrelevant. Never have I said anything close to that. Why do you keep saying that? Is it some kinda disability I should be more sensitive to?

 

LOL to the LLT thing. Sorry man, talk about a minority opinion.

[Ricci]

Just semantics.

 

I'm talking about a single frequency and Josh is talking about total power over octaves of frequencies.

 

Your house doesn't have to be destroyed to say that <20 Hz playback is necessary. The whole 130dB thing is simply maniacal preference and has nothing to do with what I posted.

 

Hey you have mentioned something about single frequency sine waves or even sweeps being irrelevant to actual playback a few times.  I was siding with you on that one and responding to the post about 105dB at 5Hz which I read as being all that was required for most users. You've said many times the wide band complex content is what counts for movie playback. In most cases a sealed system with 105dB of headroom at 5Hz will have similar headroom up till the 15-20Hz range in room. If the system is intended to be flat down to the sub 10Hz zone it is going to take way more than 105dB of headroom at REF playback levels for something like WOTW, Hulk, or HTTYD . Depending on listening habits, the room, etc, of course.

 

Hope that made sense. In a rush...