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 1 response by audiologic

My 2 cents.

 A pair of JL Fathom subs positioned near each SCIII and budget permitting a CR1 crossover.  Crossover the SCIII and the Fathoms at 80 Hz. bypass the crossover in the Fathom subs built in control.  Run the correction on each sub.  Then phase align them.

Play an 80 Hz tone. 

Disconnect the right speaker and subwoofer.

Reverse the polarity of the left speaker by connecting the positive speaker wire to the negative terminal and the negative speaker wire to the positive terminal.

With your head placed equidistant from the speaker and the subwoofer, slowly rotate the subwoofers phase control knob until you notice the bass drop off significantly, then begin to rise. With the speaker and subwoofer playing the test tone at the same level, but 180 degrees out of phase, a null point is created, and the bass cancellation should be easily discernible.

Set the subwoofers phase control at the position where the bass appears to have the least amplitude.

Reverse the polarity of the speaker again by connecting the positive speaker wire to the positive speaker terminal and the negative speaker wire to the negative speaker terminal.

Repeat for the right side.

>The CR1 has damping and and sub/sat balance controls for fine tuning.  Do a Google search and read the reviews.