Upgrading sub to get a live feel.

Hello watcher,

     Congratulations on your decision to give the 4-sub DBA concept a try.  Prepare to be amazed! 
      Pay no attention to critics claiming there'll be a lack of output, poor integration with your JBL 4319s, the 4367s or literally any other imagined shortcoming of the DBA concept because it works like a charm in virtually any room as well as with any pair of speakers. The only criticism of a 3-4 sub DBA system I consider even faintly valid is having the room space to accommodate  3-4 subs, but this is easily solved by using smaller subs and a little redecoration imagination.  I'm sure they mean well, it's just that they have a complete lack of knowledge and experience with DBA systems.  They just don't know what they don't know.
      But you made a very wise choice and I know you're going to gain the knowledge and experience of what a good DBA is capable of soon enough.
      Choosing to add two PB-1000s to your existing two SB-1000s will extend your system's bass response down to the audible limit of 20 Hz.  It shouldn't matter whether you alternate between sealed and ported or use the two taller ported subs as end tables.  The reason is that your brain is going to just sum and average all the bass present in your room by frequency; your perception of the bass will reflect the average by frequency.  Psychoacoustics in action.
      If you'd like, I can offer specific further advice on sub positioning and the setting of the volume, crossover frequency and phase controls on each sub.  I can also answer any questions you might have, you won't find a DBA advisor charging lower fees.


Enjoy,

 Tim 
     
   
  
     

Tim,

I think you are failing to see the forest through the trees because you are so focused on obtaining the smoothest in room response for the maximum number of listening positions (what a distributed array accomplishes).  In doing so, you are missing another side of the equation, the OPs issue of wanting to get a live feel in the bass range.  

Lets step back a moment.  In regard to the distributed array, there is no question, it provides the smoothest response over the widest listening area.  The same studies that have demonstrated that time and time again, also show two subwoofers can get the same smoothness at a single listening position.  So far the OP has not indicated he has listening parties.  

The second part of the equation is output.  Your argument is that it will be sufficient, but here it isn't.  The OP is in an entirely different position than you or I, both of whom are using large Magnepans.  Even 3 series Magnepans with 500+ watts per side are hard pressed to hit 102-104 db.   Your swarm hits about he same in down to the 30hz range.  

The OP is using a speaker that will comfortably hit 115db on peaks.  He mentions live sounding bass.  For a full scale orchestra, that is 105+ db.  Move it to a rock show and you are talking 115db+.   The OP's requirements are much more like a home theater than someone that wants to listen to string quartets.  

The guys over at the AVS forums are bass nuts that are also very measurement focused.  Many of them use distributed bass arrays, but not with small subs, but large Seatons, SVS, HSU, or Rythmiks.  The reason, sufficient power for reference levels (which is 115db for movie soundtracks, the 105db for the mains and the +10db requirement for the sub channels).   It is simply impossible to hit those levels with smaller subs.

Let's put it another way, lets do a really cool distributed array with eight subwoofers.  Except in this case, we are going to use 4" drivers (there are 4" drivers that will go down to 20hz).  It won't work worth a crap, as the subs won't put out more than about 75db.  Even with the gain of multiple subs, you might be at 90db.  Obviously this is not sufficient.  

We don't know how large the OPs room is (but unless it is tiny, there is going to be little room gain).  We also don't have an MLSSA for his room to see what the response looks like.  We do know that with his current setup, he is not seeing more than 100db from his subs when his mains are capable of 115db, a 15db shortfall. 

We also know the OP has considered a JL F113, which runs about $3,900.  The OP can get smooth response AND THE OUTPUT HE IS SEEKING within that budget, but it isn't going to be with PB-1000s.  With SVS, he needs to step up to the PB-3000 ($2600 a pair) or better yet the 4000 ($3400 a pair) which will get him the output, but also a 3 band parametric in each that can be used to further tune.  

Or the OP can go with a Seation SubMersive HP+ and Slave (4 15" drivers in total).  For $3,800 this will net him enough output to even keep up with the larger JBLs should he get them in the future.  At this point the two SB1000s will be useless, but again, he can get great frequency response with two subs at a single listening position (and being the Seaton's are bipolar, they will load the room more evenly than a monopole sub, just by virture of the fact the two drivers are a couple of feet apart).  

Hello mcreyn,

     I agree with you that a pair of higher output subs such as the Seatons, JL Audios and larger SVS subs, properly positioned and configured, are capable of providing good bass response performance at a single designated listening position sweet spot at a higher volume level than a pair of SB or PB 1000s subs are capable of. 
     I'm not certain, however, whether a pair of SB-1000s and a pair of PB-1000s setup as a 4-sub DBA system, would provide a sufficiently high bass volume level to meet the OP's requirement or even exceed the bass volume level of a pair of larger and more expensive subs are capable of at his listening position sweet spot.
    Just as we're unsure of the exact size of the OP's room, we're unsure of the OP's actual desired bass volume level requirements, "live sounding bass" is not very specific.  I can only rely on my own perception of loud bass but the four relatively small Swarm subs in my room are capable of providing very good bass performance almost flat down to 20 Hz and at extremely high wall- shaking volume levels, much higher than I prefer.
     Of course, it's the OP's preference on bass volume levels that matter.  Hopefully, he'll respond again soon and let us know.

Tim

I agree with a lot of what has been said but in my experience ported subs for music reproduction is a no-no. Using ported subs can create phasing issues. You will hear thick rich low end but will loose punch and clarity, specially if your main speakers are also ported. I do not have any experience with a DBA system ( and I wish I did) so this effect maybe reduced. I do achieve a very live feel with my system with a pair of SVS SB4000s and a pair of book shelf speakers.

Hey Tim, its great to read you love your four subwoofers.  I may be wrong but it kind of seems like I read it before.