Distributed Bass Array configuration

Seems that the term non- directional is getting mis-interpreted also. The low frequency sound waves from a subwoofer emanate in all directions and although seemingly an oxymoron is called non-directional because of that fact. As opposed to high frequencies that emanate from a tweeter in a single and focused direction.

soundspectacular,

     Yes, I prefer the term omnidirectional, as opposed to non-directional, to describe the dispersion pattern of deep bass sound waves being launched into the room from a bass driver, whether from the main speakers or a sub.
     The difference between this and how the midrange and treble sound waves are so much shorter and are dispersed into the room in such a highly directional manner, couldn’t be more stark.
     The truth is that bass sound waves behave very differently than midrange and treble sound waves behave in our typical domestic-sized rooms. My experience has been that it’s much more difficult to get the bass sounding right in a room than it is getting the midrange, treble and stereo sound stage imaging sounding right.
      Due to the above, my system system building philosophy has evolved to the point that I now consider my system as 2 systems: A Bass System and an Everything Else System.
I      like to install the Bass System first in the room, before even bringing in and setting up the main speakers. I use 4 subs positioned in a distributed bass array (DBA) configuration since it provides optimized bass performance and does so throughout the entire room, which is important to me but may not be for others.
     If an individual only requires optimum bass performance at the primary listening position, however, very good results can be achieved utilizing just 1-3 subs in the room, provided they are positioned and configured properly in the room and in relation to the LP. In general, the more subs used in the room, the better the bass performance.
     Once the bass is sounding very good in the room, the final step is to position the main speakers in the room, and in relation to the LP, to optimize the midrange, treble and stereo imaging performance, which in my experience, is typically much easier to get sounding right in the room than the bass is.

Tim

👍 bass is Omni not non directional. 

So many confusing terms and uses.

Stereo recordings may not have special attention to the bass, so yes, it could be recorded in stereo.  Especially with purist, 2 or 3 microphone recordings, re-mixing the bass so that both L and R speakers had equal bass output is not something every mastering engineer thinks about. HT is very different.

The reproduction of the lowest octaves is omnidirectional due to the ratio of the wavelength to the driver.  You could make a directional bass driver, but it would be 10' or more in diameter.

The human ear / brain mechanism cannot place 80Hz and lower frequencies in a stereo sound field if the following conditions are met:

1. Lack of room rattles or other noises which can clue the brain in.
2. Equivalent room mode excitation/reinforcement.
3. Steep enough low pass filter to prevent higher frequencies from playing through.
4. The listener is placed reasonably central to the stereo speakers.

As a result a single subwoofer, properly integrated into a system (which is very rare) is not audible as a subwoofer nor can it's output be placed while listening from a fixed location.

The only clue in my listening room if my 1 subwoofer, placed stage left, is on or off is the bass extension. If you don't have that experience it's not because you have magic ears.  It's your room or the subwoofer integration.

Lastly, your main speakers will sound much better if  you high pass them at 80 than at 40 Hz.

Thanks for coming to my TED talk.

Erik

Lastly, your main speakers will sound much better if you high pass them at 80 than at 40 Hz.

Depends on the room, main, sub and processing available. My mains are -3dB @ 31Hz measured pseudo-anechoic. ≈40Hz integrates better than 80Hz.

When I used Spica TC-50, ≈90Hz.

The clarity obtained by LF attenuation in the mains with good subs should not be ignored:

1. Increased apparent amplifier power
2. Reduced voice coil heating which preserves XO frequency to the mid driver.
3. Reduced IM & THD in the woofer
4. Reduced current demand and its consequent mid & tweet modulation.