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


rooze

Showing 7 responses by tomic601

@audiokinesis Duke I emailed you a cool video of constructive and destructive interference and the nodal pattern , reflection matter :-) as I know you know
Vandertones are a free download, everyone should have them and an SPL meter in toolbox
So your subs are crossed over too high and mucking up image, 

what is the filter set at and what slope?

download Vandertones and get an analog SPL meter, pm me for process 

the vandertones are not built using 1/3 octaves like most RTA or DSP, based on typical nodes in listening roomed, RV is a practical dude, and he read and agreed w Geddes paper and work many many many years ago
Also for students of the bass, yes I am a hack but I can get around a fretless, the wave is BIG, bigger than most rooms....so reality is the wave is folded and truncated anyway, which IF ya think about it absolutely F the phase...

IF you like math, get Olsons excellent and of course still very relevant text: Elements of Acoustical Engineering

but you also need a reference for accurate bass, two that I use are Ray Brown - Soular Energy and JD Souther - Silver Blue off of Black Rose ( Stanley Clarke, man that cat can play )

both of these recordings will reveal image shift at between 80-150 HZ 

you can figure out the notes ;-)
First for the OP - great choice of main speakers, wish he was still alive along with Jim T
( yes I owned and sold both ) and have Vandersteen to this day , time and phase do matter and most importantly above 120 HZ) the Vandersteen sub 9 is a swarm with analog 11 band EQ for each of the 4 subs to fix room issues below 120 and w aysemetic cut vs boost. 
Swarm fixes freq response issues caused by room, analog EQ fixes bass at listening position

dsp probably screws up time and phase above 120

have fun, Tori Amos beackons....