Originally Posted by Matt Fowler
So I just watched a Dracula on Netflix a bit ago and the experience was pretty sensational, I heard no ill sounds and the mix and TR seemed top shelf. It could be I just don't know what distorted bass sounds like.
So Mike, using my compression chart and my below ramblings can you convince me what I'd gain from upgrading to pb16ultras?
TR is covered down to 5hz by the Crowsons, SPL is covered by PB3000s over 20hz (114.5 max output at 20hz (possibly distorted but I don't know if I could describe what that sounds like), should be good enough).
1. I like to run 10db hot for alot of material(that would be the brown line). My system sounds/feels great to me as is and for most things I don't hear distortion at that level. If I do its port chuff and the worst offender in my experience is A Quiet Place. I back that one down to 6-8db hot. 99 percent of movies I don't get port chuff. For example I don't get it in BR 2049 intro until I'm running 11db hot.
2. If there is audible compression I don't know what it sounds like perhaps because its masked by 20-55hz being loud and the crowsons being capable of producing TR that feels like my teeth are vibrating if I turn them up.
3. Even the best subs start compressing when you go low enough. So if we have a 10hz note in a movie that is -15dbfs (doable with BEQ) or even lower then surely all but the top tier of ID subs are going to compress. At that point are even those subs suffering in the 20-40 range) due to the compression happening at 10hz?
4. One thing I haven't experienced is a sensation of true pressurization and its always something I've wondered about. Are dual PB16s even enough to do this in a room as large as mine? I'm sure I've experienced close to 120db in room, I know I've hit 117db with a C weighted mic (Sicaro explosion near start) that would be down 3db at 31hz and 6db at 25hz. I didn't feel the air move when that happened. Is air movement pressurization? Would have thought 117-120db in the 30hz range would have been enough? And is sub 20hz extreme volume necessary to feel it? At what frequencies do we start to feel pressurization? Is 120db in a 3k cu ft room going to be different pressurization vs 120db in a 6k room cu ft room? Is it possible to pressurize a 6500 cu ft room w/o JTR Captivators?
Also I really appreciate your generosity in answering my ramblings and your contributions to the community in general. I hope others have the same questions as me and just haven't felt like articulating what I am above.
First of all, you are very welcome for any help I have provided! Trying to answer all (or even some) of your questions will be quite an undertaking, but I will give it a shot.
Let's start with room pressurization. Room pressurization occurs when the air in the room literally becomes compressed, or condensed, due to air pressure. The sensation we feel is similar to that which we feel when an airplane cabin pressurizes. First, our ears start to tingle, and then our ear drums feel substantial pressure, and ultimately we may feel pressure in the head and face. I don't particularly like that sensation, but I have experienced it in my 6,000^3 room.
It is easiest to experience cabin pressurization in a sealed room, and smaller rooms can be pressurized more easily than large ones, partly due to room gain. Although I haven't attempted to measure the exact SPL (or frequency) at which room pressurization occurs in my room, I believe it happens with content in about the low to mid-teens, with about 115dB (or more) of volume at those frequencies. The thing about ported subs, though, is that we usually feel so much tactile ULF, before we feel cabin pressurization, that we never need to go quite that far. I certainly don't anyway!
With sealed subs, ULF TR can be somewhat insidious. It may not be an extremely overt sensation, at the listening position, as it is with ported subwoofers, although there may be vibrations occurring in the room or elsewhere in the house. Instead, with sealed subs, there is usually just a gradual build-up of pressure (from the right SPL at the right frequencies) until we feel our ears start to tingle, and then the rest of the sensations I described. Room vibrations may also be occurring, especially on a suspended wood floor. With enough pressure, we can feel it in other parts of our bodies, as well. This is one of those YMMV issues. As noted, those sensations are not something I particularly care for.
What I do like is the sensation of ULF energy running throughout the whole room, even on a concrete floor. With low-tuned ported subs, playing the right frequencies at the right volume levels, that can be a very forceful and memorable sensation. In my room, I have described it as making the whole room ripple with ULF energy. And, it is not exactly the same sensation that you feel with your Crowson's, even as good as they are. It's not the sensation of you and your chair moving, as much as it is the sensation of energy (air particles creating particle velocity) moving within
Brian Ding, of Rythmik, described the difference as similar to the sensation of having a baseball thrown close to our heads. We may hear the passage of the ball through the air, but we will also feel the energy of the air displacement occurring as the ball moves through the air. Brian went on to say that film mixers were well aware of the difference between sound and sensation and developed their low-frequency special effects in movies with that in mind.
I can't speak to that last part, but I can say that very low-frequency sounds, and the tactile sensations that accompany them, are not identical. They are hard for our brains to separate as two discrete events (as I think we can more easily with chest punch) but we are aware that both sound and sensation are occurring. I think it is especially difficult to separate <20Hz sounds and sensations, and yet in my opinion, that is where a lot of the real magic happens.
Thunder from a nearby lightening strike is a great natural example of ULF SPL and TR. We hear the peal of the thunder, and we feel the whole house vibrate from the massive displacement of air which accompanies it. I could try to add more detail to this part of the discussion, but I think I have made the point. If you haven't experienced the combination
of ULF SPL and TR in your HT, you may not know what you are missing.
Now, let me try to talk about subwoofers a little. Yes, PB16's can theoretically pressurize a 6,500^3 room, as they can in my 6,000^3 room, although once again I would forget about the idea of room pressurization as a single specific goal, if I were you. There is a lot of ULF TR that can occur with ported subs, before room pressurization is achieved. Thank goodness, for those of us who don't enjoy cabin pressurization as much! (I have flown a lot
, and done some scuba diving, and having my ear drums tingle and my ears stopped-up is not one of my all-time favorite sensations.)
I have the equivalent of four PB16's in my 6,000^3 room, on concrete. (Three PB16's and a PB4000 located 22" behind my listening chair.) My room is very heavily-constructed, which adds to the boundary reinforcement and mid-bass containment, and I can seal the room when I want to. Could I get quite as much bass into the low-teens, as I would like (the low-teens is really what I want for most movies) with only two PB16's? I'm not sure.
I already had four PB13's when the PB16's came out, so it was easy for me just to move-up a model, and later to replace my nearfield PB13 with a PB4000. As a side note, I not only get a great frequency response with four subs, and extra TR with a nearfield one, I also get great bass envelopment with the way my room is set-up.
It's possible that you will need to use the one-year SVS upgrade plan to move to PB16's, or that you will prefer to stay with SVS subs for other reasons. Personally, I really like the form factor, piano black finish, and digital controls and display. But, I was able to spread my expenditures and upgrades out over time, so I could afford to get four of what I wanted. If I were advising you, knowing what I do about your room, listening levels, and bass preferences, would I advise you to upgrade to dual PB16's? Once again, I'm not sure.
Leaving form/aesthetic/feature/ease of upgrade considerations completely out of the equation, I would advise you to buy dual Cap 2400ULF's. (As you may know, they have a 10Hz port tune, with a lot of DSP pushed into the lowest-frequencies.) They are more costly than the PB16's, and you would have to independently sell your PB3000's, but they are available in either a low version or a tall version. (The tall version can also just lay on its side.) There would be a considerable performance difference with those subs.
The PB16's would stay even with, or slightly better than, the Cap 2400 from about 30Hz down to about 14 or 15Hz. But, the Cap 2400 would be about 5dB more powerful in the mid-bass frequencies, and would absolutely smoke the PB16 below about 14Hz. In a 6500^3 room, where your pressure vessel gain (PVG is the strongest form of room gain) will start a fraction below 15Hz, I think that dual Cap 2400's would be a better solution for you than dual PB16's.
The new PSA TV3612's would also be a very good solution for you. Those are dual pro-audio 18" drivers, in a large
cabinet volume, with a 13.5-14Hz port tune. They have a ton of mid-bass, and better low-frequency extension than the PB16's. They would be my second choice for your room, with the PB16's my third, based purely on SPL performance.
Sound signature and ULF TR are also considerations, though. And, these are somewhat subjective considerations, as are the observations which follow. The new PSA subs would have a slightly clearer sound signature and a more enveloping TR sensation, I think, compared to the Cap 2400's and the PB16's. The PSA subs might blend a little more with some content. The JTR subs would be more overt and violent, with the SVS subs a little more similar to JTR than to PSA. You really notice the <20Hz content, at high volume levels, when the JTR and SVS subs are playing.
I know that you said you had some work to do with your wife on this whole upgrade issue, which is still better than "She will kill me!" But, that is about the most objective answer to your questions that I can give you. I am lucky enough to be able to have just what I want right now, and it was pretty painless for me to get there. But, in trying to advise someone else, I need to leave aside my own situation and preferences, and just concentrate on performance factors.
If you need to stay with SVS, then a pair of PB16's may work perfectly well for you. But, I am much more certain that a pair of Cap 2400ULF's (or their slightly smaller 2400 siblings) will be able to energize your room with bass, and deliver the strong <20Hz SPL that you are lacking now. And, they will be able to do it with less compression and distortion.
The 15.5" driver, and lower amplifier power of the PB16, is just giving up a little too much for a full frequency response, head-to-head match-up, with the Cap 2400 in my opinion. It is possible to make-up most of the difference with additional PB16 multiples, but head-to-head, the advantage has
to go to the JTR Cap 2400, and to the dual-driver PSA TV3612.
I hope this long post is helpful in clarifying some things that you and others may be curious about. If you want to understand more about room gain, or about some other things involving bass and subwoofers, additional explanations may be found in the Guide linked below.