Best bass in Earth! Bass that just smells right...

@haywood310 --

From my experience so far.if you have two subs run them in stereo next to your mains. Basically creating "TRUE" full range speakers. No matter what your mains claim to be on the brochure. If you have more than two Mono is the way to go and aim them away from you like Duke says. Swarm Subs aka more than 3 can act as room treatments by cancelling nodes or adding room nodes to make you smile. Although I am going to test this theory in my room this week. Getting another AMP tomorrow to have 4 independent channels of amplification with separate X overs, phase, and volume control for each of the four 4 subs. I will run them both ways and see what I like best. Also side note 16 ohm with the subs can sound better than 4 ohms even though your getting more juice outta the Bass Amp at 4 ohms. Its past my IQ but it does change the sounds better sometime sometimes not.

Just my 2 cents.

Allgood!

Thanks for your reply and sharing your experience on the use of dual subs, and where and how to connect them. That's exactly how I'm running mine, closely flanking the mains and in stereo (see my profile). I did consider placing the subs diagonally, but for now the current configuration will remain. I just recently implemented a few acoustical tweaks and a subtle PEQ correction on the subs, and it made a worthwhile difference making the response down low flatter while having a positive influence through the midrange on up. It's amazing what minor tweaks can do, when you know where to put them into effect. 

There is no stereo information at the lowest frequencies. Even if there is, there isn’t. I’m not gonna get into a technical spat over timing either. None of that matters. The simple fact is human beings cannot even hear low frequencies at less than one full cycle. Yes that is a fact. Yeah, science! So timing information or no timing information either way it doesn’t matter because you simply cannot hear it.

Both the physics and the psychoacoustics of really low bass are so radically different than midrange and treble I am about ready to give up trying to explain. One in a hundred pays attention and thinks. The rest already have their closed minds made up.

But wait! Miller! You are famous for saying your system has taut articulate 3D holographic bass! Liar liar pants on fire!

And that’s intellectual and tightly reasoned compared to the mindless repetition that is sure to come.

Whatever. Look. What people hear at low frequencies is volume. Period. Higher up we hear all kinds of detail. Down low its volume. Our brains and ears take the volume down low with the detail higher up and from that combination construct the 3D experience of stereo bass.

That’s the only explanation that fits all the observable facts. It explains why my 4 and 5 sub systems have exactly as much holographic 3D imaging when run mono as stereo. Exactly. The. Same.

So there is stereo, in the sense it can be heard. But there is not, in the sense its really mono.

@millercarbon --

There is no stereo information at the lowest frequencies. Even if there is, there isn’t. I’m not gonna get into a technical spat over timing either. None of that matters. The simple fact is human beings cannot even hear low frequencies at less than one full cycle. Yes that is a fact. Yeah, science! So timing information or no timing information either way it doesn’t matter because you simply cannot hear it.

Let's indeed, to some extent, leave out technicalities - as you already proposed. And yet, you're all over it, right? I'll give you this: whether there is, or how frequently stereo information below, say, 100Hz is actually in the (digital) source material, is debatable. I doubt there's a comprehensive study on this, but I'd welcome more thorough insight on the matter - should it materialize. 

If stereo information is actually there down low in the source material, you're claiming it wouldn't matter because, as you write, we're not able to hear it. Ok. For stereo in general to matter, where we can aurally perceive it, it'd certainly nail the importance of placement re: timing. In regards to the lowest frequencies, however, what we hear may not be that important, and this could explain why some people fuzz about the importance of symmetrical placement of dual subs:

Stereo or not, I'd wager variations of pressurization in the lowest frequencies in regards to the distance and (possibly) direction of two bass sources, are perceivably felt. We may not be to tell exactly where they're coming from, but more importantly some of us can distinguish whether the pressurization is in unison as a combined output with the mains, i.e.: coming from equally distanced and directed sources (again, in relation to the mains) or not. The marker to me is for the integration with the mains to feel the most compelling, and to my experience this comes from placing the two subs symmetrically to the mains, preferable near them. The sonic image just falls into place here. I've tried close to endless combinations of placing my current subs non-symmetrically to my mains in my former listening room, and they never "clicked" the same way with the mains compared to the symmetrical solution. I speculated whether a diagonal placement of the subs in my current abode would make a worthwhile difference in regards to room mode cancellations, but so far I've chosen to trust my findings made earlier. 

This is not about stubbornly maintaining a position, but rather questioning a categorical approach presented by you that goes contrary to the experience made by some. You say it doesn't matter, but there are those of us who says that it does. Do you think telling us how things (presumably) work suddenly inverts our experience - why the urge to speak for all? 

Both the physics and the psychoacoustics of really low bass are so radically different than midrange and treble I am about ready to give up trying to explain. One in a hundred pays attention and thinks. The rest already have their closed minds made up.

Well, you certainly made up yours on this matter, supported by your beloved science. I can buy "paying attention" - indeed that's paramount when listening and evaluating. However, the thinking part comes up short when failing to take into account the "intel of listening" in forming an opinion that tries to dictate perceived impressions.

I read somewhere from an acoustical engineer that in "older recordings records then digitized" most of the deep bass was only in the left channel anyways??? Is this correct or does anyone know? If so all classic rock music (some of my favs) would be a boon to be in mono not a negative.

millercarbon: " There is no stereo information at the lowest frequencies. Even if there is, there isn’t. I’m not gonna get into a technical spat over timing either. None of that matters. The simple fact is human beings cannot even hear low frequencies at less than one full cycle. Yes that is a fact. Yeah, science! So timing information or no timing information either way it doesn’t matter because you simply cannot hear it."

     As a user of the Audio Kinesis Debra 4-sub distributed bass array (DBA) system for over 5 years now in my fairly small 23'x14' room, I agree with everything millercarbon stated in his quote listed above.  
     The same debate over stereo vs mono deep bass was being debated over 6 years ago when I first began reading about the DBA concept and was considering buying the AK Debra or Swarm 4-sub complete DBA kit system.  I remember the price was $2,800 then and I didn't want to spend that much money on a bass solution, to pair with my then Magnepan 2.7QR main speakers, without being as certain as possible that it would work well and I was still a bit confused about the whole stereo vs mono deep bass issue. 
      My main concern was the possibility that the mono bass of the 4-sub DBA would smear, or otherwise degrade, the very realistic and detailed 3D stereo sound stage imaging I had achieved in my room and system at that time.  I also didn't want to wait for the cows to come home to find out whether or not stereo deep bass was worth pursuing. 
     
     I've come to the conclusion that 4-sub DBA systems, in combination with the main speakers, reproduce bass in a very natural and life-like manner.  When we listen to live music in a venue, we hear the fundamental sound of an under 80 Hz deep bass tone from an instrument that we're unable to localize (discern specifically where it is coming from) but we also hear the harmonics or overtone sounds, naturally produced and associated with the fundamental tone, that extend above 80 Hz and we are able to localize.  Our amazing brains are able to process these different sounds if heard within about 5 milliseconds of each other, determine they're related to each other and create the perception of specifically where the deep bass sound originated from.
     A 4-sub DBA system is creating the same audio conditions as live music, the only difference being that the 4 mono subs are reproducing the fundamental tones that are under 80 Hz that are omnidirectional and naturally heard as mono, anyway, and the main speakers are reproducing the harmonics or overtones that are above 80 Hz that are directional and naturally heard as stereo. 
      Add in our amazing brains to this mixture and we're perceiving all our reproduced music just as we perceive live music..  My opinion is that the above makes the whole debate over stereo vs mono deep bass moot.  The truth is we all perceive bass below about 80 Hz as mono and bass above about 80 Hz as stereo.       I
      Of course there's also the unfortunate reality for the promotion of stereo deep bass reproduction that, even if an individual owned an audio system capable of reproducing stereo deep bass down to 20 Hz with discrete left and right deep bass channels, there's an apparent complete lack of commercially available recorded music source material in any format that contains any stereo bass content below about 80-100 Hz.
     I've learned that it's been standard practice for at least the past 70 years for recording engineers to sum all recorded left and right channel bass below about 100 Hz to mono on their mixes for all recording formats. If anyone reading this knows of a single example of a music recording in any format containing stereo bass below about 100 Hz, please post it because it will be the first that I, and I believe most others, would be aware of.

     Given all the above facts, the approach that makes the most sense to me is treating our systems as 2 systems: 

1. a  Mono Deep Bass system for reproducing all frequencies below 80 Hz. 
     This serves as the solid foundation of the audio system, is operated in mono mode and these deep frequencies are best reproduced through the use of multiple, independently positioned subs with rated bass extension as close as possible to the audible bass frequency lower limit of 20 Hz. 
     The position of each sub in the room and in relation to the listening position are important. For best mono bass performance, a minimum of 2 subs is recommended but 4 subs have been scientifically proven to provide even better bass performance.  The optimum position of a pair of subs in a room is highly unlikely to be in a stereo or symmetrical configuration, with a sub located near each main speaker. If sophisticated and expensive measuring equipment is not available to determine the optimum position of each sub in the room, I've found the free 'sub crawl method' (google it) to be equally reliable. 
      Also, due to the omnidirectional radiation pattern and very long lengths of sub-80 Hz bass sound waves, the deep bass sound waves detected by our ears at the listening position are a combination of direct sound waves and reflected sound waves that have previously bounced off at least 1 room boundary (floor, ceiling or wall).  It's not uncommon for reflected deep bass sound waves to be the initial sound waves reaching the listening position.
     None of these deep bass sound waves have a left or right channel identifying sonic signature and all are perceived as mono.  Variations in pressure to determine direction, or perceiving deep bass sound waves as left and right channel, makes little sense sense in this context.  There is no stereo image created or perceived on bass frequencies below 80 Hz, it's all perceived as mono.

2. a Stereo Mid-range, Treble and Sound Stage Imaging system for reproducing all frequencies above 80 Hz.
     
     This serves as the detail center of the audio system, is operated in stereo mode and these higher frequencies are best reproduced through the use of a pair of independently positioned main speakers with rated bass extension that typically does not reach the audible bass frequency lower limit of 20 Hz.  
     The precise positioning of this pair of speakers in relation to the listening position improves mid-range and treble performance as well as optimizing the stereo sound stage imaging.  Our brains are also able to use the deep bass fundamental tone's harmonics or overtones frequencies, that are above 80 Hz and reproduced in stereo by the main speakers, and associate them with the deep bass fundamental frequencies that are below 80 Hz and reproduced in mono by the subs.  This process is what allows us to properly perceive the sound and location of the deep bass instruments within the overall stereo sound stage illusion.
     I believe this 2 system approach makes it initially simpler to understand how to create a very good quality overall home audio system and then how further improvements to either individual system will result in the overall audio system's performance improvement over time.

Tim