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Can SVS PB2+'s be stacked


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20 replies to this topic

#1 of 21 OFFLINE   Chuck Watwood

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Posted September 17 2003 - 11:10 PM

Ron or Tom,

Just received my PB2+ last week and I love it. I will probably be purchasing a second one early next year. This is one solid enclosure. Can they be stacked one on the other? I want to tune them to 16hz and two ports plugged. With two of them, I should have little fall off on the high end db level. Stacking them would save a little room. It is feasible? Or would I be better off just purchasing the B4+? Would 2 PB2+'s outdo the B4?
Chuck Watwood

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#2 of 21 OFFLINE   Edward J M

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Posted September 18 2003 - 01:54 AM

Hi Chuck:

Yes, the PB2+ can be stacked. I weigh 210 pounds and I've layed on mine while inserting port plugs and adjusting controls with zero problems.

Dual PB2+ owner "JoelS" has stacked his both on top and sideways. I think he settled on sideways and has some pics on his website. The closer the drivers are, the more coupling effect you will benefit from, so I like the sideways stacking method. In fact, SVS is working on a grille that can be used if the baseplates are removed and the drivers are exposed.

My experience with the PB2+ in room extension is that it digs VERY deep with one port plugged and the SS filter set to 16 Hz. It has no problems whatsoever reproducing full bore 16 Hz organ notes in this tune configuration. I personally feel the PB2+ is somewhat underported in the 1/16 tune, and I did not hear/feel any benefit in deep extension over the 2/16 tune, but I did definitely notice a loss of overall output.

The B4+ and the dual PB2+ in the 16 Hz tune would be a close race. Vent space would be the same. The B4+ would have all driver reactionary forces cancelled due to the push/pull design, but the dual PB2+ would have the edge in enclosure volume. I think Tom V has it too close to call at this point.

Regards,

Ed
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"What we do in life, echoes in eternity."


#3 of 21 OFFLINE   ScottCarr

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Posted September 18 2003 - 02:28 AM

These are very solid enclosures. Stacking them would not beof my concern. I would be MORE concern with the structural integrity of the corner they will reside.

There is a PB2+ owner who has simply set his SSfilter to 16hz and says he has achieved plenty of output below 25Hz without sacrificing output.

I currently have two PB2+ one one each side of the room.
They have been run in every concievable configuration without stacking them. This includes removing the baseplates and having the drivers facing the seats to upside down, one is still running baseplate up.

Good luck
Scott

#4 of 21 OFFLINE   Edward J M

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Posted September 18 2003 - 03:11 AM

I prefer the 3/16 (i.e., 3 ports open, SS filter to 16 Hz) for my particular room and needs. This configuration allows full port use and output in the >25 Hz region, and also lets the sub naturally roll-off below the tune point and maintain pretty decent extension into the high teens, taking advantage of available room gain. The smaller the room, the more room gain you will realize. In a huge room, the 3/16 tune might not provide as much benefit.

In any event, the 3/20 or 3/16 tune increases the risk of bottoming the drivers below the tune point at very high playback levels. With all ports open, the enclosure lacks the proper restoring force to control the woofers below the tune point and they will bottom if sufficient infrasonic signal content is present. That is why SVS wisely includes the subsonic filter and its effect is obvious in the 3/25 tune; it immediately and sharply ramps down the response below 22 Hz and protects the drivers.

In a large room and/or at Reference Level, I would not advise the 3/16 configuration or you may be contacting SVS for a set of replacement drivers. The 3/25 or 2/20 configuration provides the best combination of output, extension, and woofer protection and SVS explicitly states this in the tuning guide.

In my moderate size (2000 ft3) HT room at levels up to -15 to -10 Reference Level, I have not bottomed my PB2+ in the 3/16 tune on even the most bass intensive DVDs and I'm hitting anywhere from 112-114 dB at the seat on C-Weighted Fast, and that's a true 116-118 dB. That's damn loud in anyone's book and the PB2+ delivers the goods without audible strain. I have only needed to plug a port (2/16) for some recently obtained organ music (32' pipe stuff) and this config really lets the PB2+ easily troll to 16 Hz with extreme authority. Anyone who doubts the 2/16 tune can get the job done at a true 16 Hz need only to stop over at my place and feel the steady woosh of air coming from the 2 open ports when the organist leans on the long pipe notes. There ain't no cobwebs behind MY PB2+! Posted Image

Regards,

Ed
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"What we do in life, echoes in eternity."


#5 of 21 OFFLINE   ScottCarr

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Posted September 18 2003 - 07:04 AM

Ed,

thank you for that post. today I changed the 3/25 setup and switched the subsonic filter to 16. There wsa a little difference in Das Boot and other movies.

Having a small HT and 2 PB2+ bottoming out is never a worry. Saturday with hearing protection 120db was easilty achieved. Back to reality. What I have notied with the ports open is there seems to be a much better output at the lower volumes.

The PB2+ are an amazing box with a great deal of versatility. Tom was correct saying I only needed one but I am sure he is happy, but not as happy as I am , that I purchased 2.

time to enjoy.

Have fun

scott

#6 of 21 OFFLINE   Chuck Watwood

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Posted September 18 2003 - 07:51 AM

Thanks for the replies guys. At this point, I think a second PB2+ is the way to go, it would also appear to be the cheaper option. Unless I hear different from TomV or Ron, I'll be purchasing a second one soon.

Edward: I would assume that I could set the subsonic filter to 16 on both, with all ports open, and have no problem reaching reference level playback without bottoming drivers? Would you recommend facing the woofers toward the listening position or facing the wall in the corner? I assume I can use the supplied rubber feet and place them on the sides. You mentioned a grill that SVS is making if the baseplate is taken off? Do you know how soon this will be available? Thanks
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#7 of 21 OFFLINE   Ned

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Posted September 18 2003 - 09:23 AM

Ed-

If you're hitting 116-118db when at -10db under reference, that would indicate your subs are running 11-13db hot Posted Image Rather aggressive Posted Image

#8 of 21 OFFLINE   Edward J M

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Posted September 18 2003 - 09:24 AM

Chuck:

Without knowing the specifics of the room and your sub placement, it's hard to make that call over a forum. No one (especially SVS) wants anyone to damage their sub by operating it in a non-conventional manner possibly not envisioned by the designer. I think a call to Tom V with a detailed description of your set-up is in order before you run 3/16.

He can also give you the best guidance on the particulars of placement and orientation. I know other owners are experimenting with different orientation and coming up with another dB or so in output with small changes in position (this is probably more of a room acoustics phenomenon than anything else).

AFAIK, the grille is still being conceptualized by SVS and I would ask Ron/Tom when it will be available.

Scott - to my ears, all ports open sounds the best at all volumes and particularly for music. The sub has a muscular and effortless nature with all ports open. Even at low volumes the impact on bass transients is solid and precise, with great body.

There is no question it digs lower with a port plugged, and is still capable of prodigious output, but the drivers work harder against a higher enclosure resistance and obviously breathe out less port area, and to "me" this difference, albeit small, is discernible.

IMO, this sub is a hot rod and it was meant to breathe deep out those three big bark holes and I let it. Fortunately, the 3/16 tune is adequate for 98%+ of all music and DVDs out there; it can dig really strong to 18-20 Hz in this tune.

BTW, try the Daredevil (dts) barfight scene in the 3/25 tune and then again in the 3/16 tune. The 3/25 tune knocks out a few critical seconds of infrasonic information that the 3/16 tune lets through in full glory. See what you think. Just be careful; at -10 Ref Level my cone excursion looks like it's approaching 3/4" (one way) during parts of that scene in the 3/16 tune.

Regards,

Ed
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SVS

www.svsound.com

"What we do in life, echoes in eternity."


#9 of 21 OFFLINE   Edward J M

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Posted September 18 2003 - 09:32 AM

Quote:
If you're hitting 116-118db when at -10db under reference, that would indicate your subs are running 11-13db hot Rather aggressive


Ned:

My PB2+ is running 3-4 dB hot for HT and flat for music. What you might be forgetting is that some DVDs are mastered obscenely hot and others are not, so the overall playback volume can be drastically different between DVDs. Star Wars PM and AOTC are perfect examples of this. I can play PM at Master Volume 00 and I can only play AOTC at Master Volume -12 for the exact same bass SPL peaks. The lack of consistency in the DVD sound mastering industry is scary.

While I am indeed calibrated to 85 dB with Avia (sub 88-89 dB) at Master Volume 00, I have found that Reference Level is more defined by the playback volume than it is by an absolute setting on the Master Volume control. Remember, Dolby Labs defines RL as 105 dB bass peaks in surround channels and 115 dB bass peaks in the LFE channel. Combine simultaneous bass in a surround channel and in the LFE channel and you will realize an even higher SPL - upwards of 120 dB in some cases where the bass hits in all channels at once.
Ed Mullen
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SVS

www.svsound.com

"What we do in life, echoes in eternity."


#10 of 21 OFFLINE   MikeLi

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Posted September 18 2003 - 01:07 PM

Crap you guys always do this. I finally got rid of my two puny NHT subs and got an SVS PB2+ that absolutly killed them. I am very happy having it feel like my vaulted roof is going to cave in when the expolsions happen but I wonder if I could get the hairs on my chest just alittle more movement with a second PB2 in the room.... Dawg gone it... now what to do...... Of course my wife thinks I'm nuts and I dont even drive the thing loud at all....

#11 of 21 OFFLINE   ScottCarr

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Posted September 18 2003 - 01:47 PM

Come on Mike,

I put up with your crying about not being allowed to order a second one over at the other forum.
Order it already!!!!!Posted Image Posted Image Posted Image Just kidding

I have found having two, even at lower volumes the bass produced it very solid and smooth. Whe I order my first PC+2039 I quickly wondered what 2 would be like. I could sleep. Then I ordered the second and it arrived. Again I could sleep but this time it was because I could not get enough of them.

Order it Mike, buy the wife some diamond earings.

Scott
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#12 of 21 OFFLINE   Zack_R

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Posted September 18 2003 - 01:59 PM

Quote:
I can play PM at Master Volume 00 and I can only play AOTC at Master Volume -12 for the exact same bass SPL peaks.


AOTC starts making my Samson amp clip fairly strong at around -5 to -4 db from reference. This is with my set-up calibrated and corrected flat to Avia (At least the best I can tell anyway). I'm not sure that it's recorded as hot as we may think but I do suspect that it could be one of the few DVDs that sends alot of LFE bass through the rear surrounds. If this is the case, it could account for as much as 6 dbs more. I'm assuming you're refering to the opening ship landing and subsequent explosion.

On the other hand PM may not send max LFE to the mains,though it does send plenty. If I my memory serves correct, when viewing your graphs you are peaking in the 25 hz range and this is probably a few dbs above perfectly flat. If this is the case you are likely achieving higher SPLs on certain scenes and have more headroom availible than you may think.

#13 of 21 OFFLINE   MikeLi

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Posted September 18 2003 - 02:28 PM

Actually my wife would not care I just will always wonder you know.... Shes already got the earrings anyway. I think I am going to slow down my upgradeitis for awhile. I have been on a HT binge for about two years and probably a good time to give it a rest until the BP8++ is announced. I'll then be first on the list. haha

#14 of 21 OFFLINE   Chuck Watwood

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Posted September 18 2003 - 06:41 PM

Wow,

I decided to experiment with my PB2+ tuning last night. I went ahead with the 3 open ports, 16 hz tune. I popped in Blade and watched the opening sequence with the bloodbath rave and subsequent fight scene where Blade kicks ass. I have to agree with Edward that the 3/16 tune is beautiful. At reference it did not bottom out and kicked some serious butt. (my sub is set 5dbs hot) I had my alarm system set for perimeter monitoring, which means doors and glass break sensors were activated. When the fight scene was almost over, I suddenly realized that my alarm system was going off!!!! The sub had set off a glass break sensor in the kitchen. This sub was vibrating the walls and floors and I was so focused on the wonder of it all, I though the alarm was just part of the movie!!!! I called the alarm company right away and found that they had just called the police to dispatch them my way. They called back and cancelled the police call and I had a good laugh with the alarm company dispatcher. Wow, I won't be able to use the alarm system when watching at reference levels, thats for sure. That problem resolved, I popped in The Phantom Menace and played the pod race scene with my SPL meter set for fast and C weighted. PB2+ tuned at 3/16. I hit peaks of 116 db with lots of 106-112 mini peaks as the pod racers blew by. Once again, no woofer bottoming out sounds. My room is approximately 14 x 20 x 9 with a hallway at one end and a 5 foot opening going into my kitchen adjacent to the hallway and on the opposite side of the room from my sub. My sub is position behind my couch in the corner of the room. I think I will leave it in this tune configuration and will be careful when playing extremely hot DVD's. I know that Attack of the Clones has a hot scene or two but what other DVD's should I be wary of? I still can't believe how good this sub sounds. 3/16 absolutely rocks with this sub. Much better than 2/20 for Ht. I can hardly wait to complete my HT room downstairs and stack two of these puppies. Posted Image Posted Image Posted Image HT addicts are scary.
Chuck Watwood

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#15 of 21 OFFLINE   ScottCarr

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Posted September 19 2003 - 12:25 AM

Upside down is fine..Posted Image

There is a risk of damaging the drivers when mismatching the subsonic filter setting and the port configuration. At low to moderate output levels there isn't much to worry about...but if you pop in a DVD like Star Wars or Monsters Inc at loud to very loud levels all bets are off.

Tom V.
SVS

Having 2 in the HT I found placing the subs on the oposite sides of the room outstanding. Stacking them was incredible but a bit overwhelming as I sat closer to them. The fear of loosing 2 to 4db is laughable. These monsters are powerful and any loss is easily made up with a small tweak to the gainand I mean small.

Scott
HT addict and I need help (tomorrow I want to watch a movie today)

#16 of 21 OFFLINE   ScottCarr

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Posted September 19 2003 - 12:39 AM

MikeL

that is probably a wise move. After experiencing the PB2+ I think this sub has a lot more capabilities than I will be able to drag out of it in my HT.

My main problem is I wanted the PB2 Ultras. As the preorder day draws closer and closer the I want bug is thinking "sell the PB2+ for $1000 each", pick up only but how many people would be willing to drive to pick them up.

Scott

#17 of 21 OFFLINE   MikeLi

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Posted September 19 2003 - 02:29 AM

Scott the same thing has crossed my mind a few times.....
Mike

#18 of 21 OFFLINE   Edward J M

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Posted September 19 2003 - 02:41 AM

Quote:
I have to agree with Edward that the 3/16 tune is beautiful. At reference it did not bottom out and kicked some serious butt. (my sub is set 5dbs hot)


Chuck:

I think that Reference Level with the sub 5 dB hot in the 3/16 tune is a recipe for damaging the woofs.

I think we agree the sub sounds and feels best breathing out all three ports. The only thing dropping the SS filter accomplishes is it allows the sub to naturally roll-off and play a bit lower. The 3/25 tune lets the sub play down to 22 Hz before sharply cutting the response.

There are really very few DVDs that go much lower than 22 Hz and if you are playing at Reference Level with the sub at +5, I'd definitely run it in the 3/25 tune. It sounds like you really appreciate the sound quality, plaster cracking SPL, and the kick in the chest that three ports open provides (me too!), so give those woofs the max protection they need at that extreme playback level.

When I'm giving demo's at/near Reference Level, I always up the SS filter to the 25 Hz setting. I imagine it would be VERY hard to bottom a PB2+ in the 3/25 tune.

At lower levels, like Tom said, there isn't too much worry and go ahead and let the woofs troll a bit deeper in the 3/20 or 3/16 tune.

Regards,

Ed
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"What we do in life, echoes in eternity."


#19 of 21 OFFLINE   Tom Vodhanel

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Posted September 19 2003 - 02:43 AM

Hello All,

Please match the subsonic filtering with the port configuration if you are going to listen to bass heavy material at loud to very loud levels. With a 25hz tuning point, and a filter setting that BOOSTS output down to the 15hz range...it will be possible to damage the drivers before you could even reach for the remote.

Tom V.
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#20 of 21 OFFLINE   Jon_Krug

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Posted September 19 2003 - 04:15 AM

just out of question... what do u usually put your gains at?





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