"never Buy A Downward Firing Sub!" (1 Viewer)

[BrianWoerndle]

Right now I have a single 20-39CS in a 1300 sqft room with plaster walls, hardwood floors, and 4 fiberglass acoustical panels to help deaden the room. My 1 SVS can flap my pants legs, but I need (read: want) more. I like to watch movies at reference level, and in my small room 1 SVS does not quite cut it. So I am looking into getting another one.

A single SVS should be sufficient for most people at most volumes, but true reference levels are very hard to achieve.

 

[Mitch Stevens]

I think that John was WAY over-exaggerating. Even though my B4+ is ultra powerful, and I sit exactly TWO feet away from it (it's right behind the couch) my pants never, ever, ever flap around. And we're talking about a sub that's 10x more powerful than a 25-31 Pci.

 

[Phil Iturralde]

Before pre-ordering it, I emailed Tom and Ron @ SVS since my room was large and they confirm that the SVS 25-31PCi (floor moving) sub-sonic impact w/HT (my priority) would just be glorious, ... and, ... it is!!! It's the best investment I've made!

Floor, couch, wall, air, pant-leg moving (@ all my seating locations) sub-sonic LFE effects when my blockbuster DVD's encoded LFE calls for it! My family and friends all love the glorious LFE tactile feel and sub-sonic impacts in I Robot and Sky Captain! Some of the felt air-moving pant-leg impacts started as low as 93 dBC @ my 'sweet spot'!

Phil

 

[Mitch Stevens]

I still don't believe it though. If a B4+ that is calibrated 11dB hot, doesn't move my pant legs, when I am sitting just two feet away from it, then I certainly don't believe that the 25-31 pci (properly calibrated) can move pant legs, when someone is sitting 9 feet away from it.

Reading Wanyne's post, it's clear that not even his PB2+ (which is also much more powerful than the 25-31 pci) can move his pant legs.

 

[Phil Iturralde]

Wish you could come over! John Garcia felt it with the DTS DEMO's (Private Ryan) I played!!!

Actually, I can feel my pant leg move from the kitchen table which is about 18 feet away with some blockbuster DVD's (Pearl Harbor; Phantom Menance; Toy Story 2; etc.) @ -10 dB below REF Level (approx. 105/106 dB FAST LFE SPL)!!!

Phil

 

[WayneO]

Well my post caused the debate, but I'm most definately gonna stand by my thoughts/recommendations. This whole "pants flapping" thing is just plain riduculous. The hyperbole is just pathetic IMO. Get a damn video of your pants "flapping" and I'll condede. It's damn embarrassing some of the BS that's tossed around about these subs and why SVS owners piss other people off so much. If my pants ain't a "flappin" at 115+ dB's, my sub must be broke and positioned wrong.

 

[Mitch Stevens]

I couldn't agree more, Wayne. If our subwoofers (yours, the PB2+ and mine the B4+) that are 10x better than the sub that Phil has, does not make our pants "flap" around, then there is just no possibly way, that a tiny no-good "entry" subwoofer (no offense, Phil) is going to outperform some of the very best subwoofers on the market. Who's ever heard of an "entry" sub being better than the B4+? Please. :rolleyes

 

[Scott Lawrence]

I'm not that familiar with the various svs models and how they differ but I think Wayne and Mitch are being a bit close-minded. There's a lot of factors other than the sub model in effect here. That fact that your sub doesn't shake your pants may in fact indicate that it's better, not worse--it may blend in better, you may have EQ'd around room-gain at certain frequencies, etc. Your subs are probably less boomy and have a more linear response. You may also be listening to very different things (different movies/music etc).

Other factors such as amp settings (xover point, whether you're using the "plus" or "main+lfe" type setting to steer additional bass from the main channels to the sub, etc). And then there's placement and where you are in the room.

Don't forget that LF sound has a very large wavelength and at least one of you mentioned being only a couple of feet from the sub--you may actually hear/feel less bass there than 9/18 feet away. Or you may be getting some frequencies reduced/cancelled due to relfections, etc.

 

[ChrisBee]

I might believe some of this pant-flapping could be port flow jetting across the room. But the subs in question are downfiring cylinders.

I've never experienced any flapping with my 16-46PCI. Even sitting two feet from it while I'm browsing and listening to organ music. But I've never bottomed it out either. Even at near 110dB C-slow RS-SPL uncorrected in a leaky 30 x 17 feet open-plan room, wide open to the downstairs lounge.

Deep bass is funny stuff. Nobody has the same room or exactly the same sub or settings or position. Allow others to feel what they will. You cannot deny them the right to have experienced something just because you haven't.

Nobody has ever explained the slow waves that sometimes seem to pass slowly across the room on loud and low bits. I wouldn't have believed it if I hadn't experienced it myself. Nor the fuzziness of vision on some bassy music moments. You never know what will happen on the next new track or film. A new 12Hz trance track and the while floor shook itself with a violent rattle yesterday. It brought my wife from the kitchen to see what had happened. All this from an entry-level SV Sub? :b

Inexplicable? Who needs to exaggerate? You couldn't make this stuff up.

Regards
Chris.B

http://mysite.wanadoo-members.co.uk/...ic/index.jhtml

 

[Ilkka R]

I believe some people think differently about the word 'flap'. I've experienced "flapping" with PC+ and even with PB10 (levels have to be near 100dB or over). But it's not like your pants are *moving*. You can't see it with your eyes or record with a cam recorder. You can FEEL it with your sences and it feels almost like your pants are moving. Of cource they move just a little bit but that is just fractions of inches. If you are standing next to a vent or a woofer you could maybe see some actual movement also. But they don't *flap*. Flapping means something moves like one inch both ways etc. Your woofer flaps at 110dB.

Maybe we need to find out a better word to describe this feeling? Flapping is too extravagant. Vibrate, shiver?

 

[Edward J M]

Mitch, your B4+ is not calibrated 11 dB too hot. If anything, it is calibrated about right or possibly 2-3 dB cool.

Read the hotlink in my signature block if you want all the gory details.

But the nickel tour is that DVE has a 10 dB encoding error on the subwoofer calibration tone which is further exacerbated by an extremely wide bandwidth signal with strong content down to 15 Hz.

With a deep extending subwoofer and typical room gain below 30 Hz, the DVE sub calibration tone will appear about 13 dB too high at the proper subwoofer calibration level.

So what you thought was 11 dB hot is actually just about right. Learn to trust your ears more - an experienced audio and HT aficionado such as yourself would never like the sound of the bass if it were actually running 11 dB hot.

If you want to see how 11 dB too hot really sounds, turn your current subwoofer level up ANOTHER 11 dB. Yeah, I know.....yuck.

 

[Cees Alons]

Come on guys, just cool it a bit. A tiny bitsy bit of exaggeration is to be allowed if you're an enthusiastic owner, no?

May also depend on the, uhm, type of movie you're watching isn't it?


Cees

 

[Mitch Stevens]

This, I won't argue with. You can't expect a teen movie like "She's All That" to have as much bass as LOTR, or "The Haunting DTS."

Still, even when watching LOTR, Haunting (DTS), Saving Private Ryan (DTS) and Underworld - Dolby Digital (the DTS track has much less bass) at -5 dB from reference, and sitting right next to the B4+ my pants don't even come close to flapping around. I will say one thing though, "Underworld (Dolby Digital)" has so much bass at reference level, that it actually makes me sick to my stomach, and I'm not exaggerating. This DVD probably has the most "dangerous to your health" bass of all the DVDs out there. I can't play this DVD too loud, or I feel like vomiting.

 

[Lewis Besze]

Does he have hardwood floor or carpet?

 

[Michael Brand]

This is pretty hilarious, I can't believe people are debating whether their sub-woofers make their pants "flap" or not! The scary thing is, I can't resist joining in!!

Even though I have dual SVS PC+ 20-39's in a medium sized room, I must say my pants have never "flapped". However, they have vibrated where I felt like they were moving on my legs. My youngest son lays on his bean bag chair, and at times he swears the subs are sucking him out of his bean bag!! That's probably because the vibration is causing him to slide down in his chair more. Who cares, he thinks it's cool!

I thought Wayne O's comment on finding out what kind of pants someone was wearing was really funny! You KNOW if some company came out with special clothes that claimed to enhance the audio experience, some people would line up to buy them. I can see it now, "Our Audio Pro line of boxer shorts are guaranteed to flap during reference level low frequency effects, and have built in automatic phase adjustment so any cancellation caused by flatulence will be limited immediately". :wink: :wink:

 

[Ilkka R]

Check this post!


This is just what I have experienced also.

Waiting for that first video clip where we can see some actual movement...

 

[ChrisBee]

This may be way too technical for some of you:

But there is no reason why an area of pants material couldn't act as a diaphragm to vibrate in sympathetic resonance with airborne LF. A sort of remote ABR.

If the frequency was low enough then an actual sense of flapping is indeed possible. We all know the feeling that you could count the beats per second once you get below about 20Hz.

It all depends on the area and weight of cloth involved, the tension applied by the occupant at any particular moment and the frequency being played by the sub.

This introduces so many variables that none of us is adequately qualified to question each others' "good vibrations". :wink:

ChrisBee

 

[Seth_L]

No it can't. You need a lot more woofage to hit 121dB at the seats (true reference levels).

 

[John Garcia]

So now we are debating about the definition of "FLAPPING"? Ikka has it right, flapping is probably the wrong word, but the fact is, I could FEEL a vibration in my pant leg - just basic Levis.


I'm glad to see that you can tell me what I'VE experienced and you have been proclaimed the only one who knows everything about subwoofers. I guess we should direct all questions about subs to you from now on?

SVS themselves said this sub should be sufficient in Phil's room. Are they also LYING?

I guarantee it's not port turbulence with the sub 9' away. There is a good chance it is a room mode that causes this in Phil's room. The room is pretty uniformly shaped, almost cathedral like, and would tend to contain the sound quite well. With the vaulted ceiling, it would likely direct the sound toward the center of the room, roughly to where the seating areas is. Phil's room is also long enough that some frequencies are actually able to setup a complete waveform, rather than the typical small room where you are only getting 1/4 or 1/8 wave patterns. In a smaller room, the standing waves cancel eachother out enough that even a large sub, properly calibrated, will not cause this to happen; however in a longer room the wave does not cancel out before this effect occurs in Phil's room. Just a theory.

My PB-10 does not cause my pant leg to VIBRATE, but it does start other things in the room rattling - I can hear the stove in the kitchen start to vibrate as are the glass doors on the fireplace.

It's not important to me if you believe what Phil and I and others have said, or that you experience it too. I'm glad that Phil's particular setup works so well for him, and I know he and his "Friday Movie Night" crew will continue to enjoy it for a long time.

 

[steve nn]

In my 12 X 24 X 10' leaky main, I could hit 111 db on the first fly-by in SW II using 1 25-31CS+. With 2 colocated it was 117 and with 3 25-31CS+'s it was 120 db uncorrected. Push the calibration up, I then could hit 124 db uncorrected and that was it. Add 3 db correction value and you can imagen that was one hell of a ride I think I can hit around 117-118 corrected with the PB12-Ultra/2 at -0? My seating is up against the back wall.

In my 12 X 12 X 9' den with the PB10-ISD, I notice it sounds better out in the main rather in the closed off 12 X 12. So many things play into the factor but John is definitely on the right track. Cant say my pant legs have ever moved but plenty of things have vibrated (including myself) and items have fallen off shelves in other rooms. The room sure has been pressurized to the point of a pressure cooker though My daughters told me their windows were bowing out-stiars during that one 127 db test.:b