millercarbon:
"Exactly. Two completely different animals. This may be one of the hardest parts of the whole thing to understand. Though granted, the whole DBA approach relies on a number of hard to understand concepts. No one of them really so much hard as different. At least I feel it must be something like that. Else why so many have explained so clearly and yet so few seem to get it?"
Hello millercarbon,
Besides Duke, I think we're both aware that we are probably the biggest believers and proponents of the 4/5-sub DBA concept on these forums. There are several other members that are strong believers in the DBA concept but you and I are likely the most prominent and vocal advocates. I believe this is due to us both doing a lot of research on the sound bass principles underpinning the DBA concept, being relatively early adopters of the concept and having years of practical experience actually using the concept in our own systems/ rooms and knowing first hand how consistently, reliably and exceptionally well the concept performs.
I think I have a fairly good grasp of most of the dynamics afoot in the behavior of bass soundwaves in any given room that enables the 4-sub DBA concept to deliver near state of the art bass reproduction in any room and seamless bass integration with any pair of main speakers.
I understand that bass radiates in a omnidirectional pattern, the length of soundwaves are inversely proportional to their frequency, the length of deep bass soundwaves can often exceed any of a room's dimensions, humans require the entire full cycle soundwave to be present in the room to even perceive a sound, we require 3 complete soundwaves to perceive a change in pitch, we cannot localize bass soundwaves at or below about 80 Hz, soundwaves continue to reflect off of room boundaries (floor, ceiling and walls) until they are absorbed, diffused or run out of energy, the multiple soundwaves reflecting around the room will typically collide with each other causing frequency peaks, dips and nulls.
Utilizing multiple subs will actually increase the number of bass peaks, dips and nulls in the room but our amazing brains are able to process these multiple peaks, dips and nulls by summing the bass by frequency and averaging it out and creating a perception that the bass is smoother, faster and more detailed. As a bonus, this excellent bass response perception is created no matter where in the room one's head is actually positioned. All quite amazing and very beneficial to music lovers desiring excellent bass reproduction throughout their entire room.
I understand all of the above but I'm still having difficulty recalling exactly why it's not important that the timing of the bass soundwaves reaching our ears matches the timing of the midrange and treble soundwaves reaching our ears. I know it's unimportant just by listening to my system, bass from 20-40 Hz reproduced by the 4 distributed subs and midrange/treble reproduced by a pair of carefully positioned Magnepan 3.7i main speakers. The bass deep, powerful, smooth, fast, detailed, dynamic and natural seamlessly integrated with the main speakers.
I know there's a logical and reasonable explanation but I can't, for the life of me, recall it. Hopefully, Duke will chime in again and explain it again. I'll write it down someplace this time if he does.
Tim
