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Subwoofers and Phase Question For You Sub Experts

I use a pair of Dunlavy SC-3 speakers, known for their time/phase coherent crossover design.

When the stars align the speakers completely disappear and there’s a sense of space and 3 dimensionality that I’ve heard from few other speakers/systems. It’s easy to destroy the illusion with things like poor placement, poor setup of room treatments, etc.

Adding subs to the setup is both a blessing and a curse. The Dunlavy’s need some support in the nether regions and a pair of HSU subs do add a solid foundation to music which enhances the overall presentation; however, it’s at the expense of some stage depth, width and image dimensionality. Placing the subs a few inches forward of the front plane of the speakers helps a little but that isn’t where they perform at their best as ‘subwoofers’.
Finding optimal room positions for bass augmentation always creates a clash with the phase aspect of integration resulting in the diminished soundstage described above.
Playing with phase settings has little impact on the problem since there’s just a toggle for 0 and 180.

Which brings me to the questions - 
1/ How does running a swarm setup, with 4 subs, affect phase/time integration with the mains? Does it create twice or half the issue or remove it altogether?

2/ Looking at subs such as the JL Audio F series with auto room calibration, does the EQ algorithm compensate for any time/phase anomaly or is it simply looking for a more linear bass response?

I don’t mind investing in more sophisticated subs so long as I don’t end up with the same problem. I’m not really inclined to mess with software and the like, unless there’s no other way.

Thanks

Rooze


128x128rooze
noble100's avatar
noble100
2,419 posts
 
     Audiologic's procedure for properly setting the phase control is the best I've found thus far.    
    With phase, it's usually easier to identify the setting that is most 'out of phase' ( the worst or least bass) than identifying the setting that is 'most in phase' (the best or most accurate bass). And all it takes is a simple phase inversion on a speaker. listening and setting the phase control accurately and the a simple reversal of the phase inversion back to normal.
    As I write this, I realize It is a bit confusing when written out.  
 I think audiologic better articulated the procedure than I did here.   I recommend rereading his post and striving for comprehension of the task at hand, it's easier than I make it out to be once you understand the goal. I'm going to shut up now.

Tim
handymann
384 posts
 
I have wrestled with sub integration for years, until I purchased a DBX Venue 360. You can control your main speaker delay or sub delay.  This unit is designed for live stage performance, but cured my subwoofer problem completely.  You should really look at the specs and try one.  It fixed my TT acoustic feedback, as well a a whole host of issues. I used to listen and worry about how I could make everything coherent. Now, I just listen and appreciate. 
noble100's avatar
noble100
2,419 posts
 
Hello handymann,

     Well, it seems like we now have a few contenders for high quality methods for integrating subs into one’s system; the distributed bass array, the line bass array and now, the DBX Venue 360 device. Since the DBX Venue 360 is basically an equalizer and room correction device, however, my main concern is that very high powered amps would also be required for it to operate effectively.
     I have little doubt this unit is able to correct all the frequency peaks it identifies in a room, since it merely needs to direct the amps to reduce power at the appropriate frequencies or filter out the excess energy.  But I do doubt this unit, without considerable amp power used in conjunction, is able to correct all the frequency dips it identifies in a room, since it needs to direct the amps to increase power at the appropriate frequencies. Correcting frequency response dips requires significant amp power, possibly even a doubling or more of power at bass frequencies.
So, the DBX Venue 360 could be performing its function perfectly but there’s insufficient amp power to correct all the room’s frequency dips it has identified.
     Handymann, how many amps and how much amp power do you utilize for your subs and main speakers? Do you have a sense of whether or not your system amp power is sufficient to correct all the frequency dips in your room identified by the DBX without straining these amps?

Thanks,
Tim
handymann
384 posts
 
@noble 100:
Ii have two Krell EV-600 monoblocks and two JL Fathom 13’s.  I have not had to increase the subs volume, or turn up my preamps volume since utilizing the dbx unit.  It has a max output of +22 dBu through balanced outputs.  You can also delay the subs or main speakers output, to properly align the subs and main speakers, as well as adjust phase of both on the fly.
chazzzy007
540 posts
 
@rooze 

I have a REL S5 and the sense of space that it creates with my PSB T3's in my listening area is amazing. Both on music and home theater. The REL mission statement is all about doing exactly what you want. The S5 was just replaced in the REL lineup 2 months ago by the S812.

GLHF!
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