northman,
I've been monitoring this thread and realized I had the urge to reply to almost every post, because I thought my comments would be beneficial to the posters, but have successfully been resisting these urges until now.
I've changed my mind, however, and now believe citing a previous post and adding my comments will not only be hopefully beneficial to the posters, but it will likely also help you in your quest to better "understand the swarm in the broader audiophile world".
Before I begin, I just want you to know that I'm just a fellow Audiogon member and AK Debra complete DBA kit user who's a big advocate of the multiple sub concept in general and the 4-sub DBA concept in particular. My comments are solely based on my personal knowledge and experience gained by researching multiple sub theories and concepts and trying them out in my own system and 23'x16' living, 2-ch music listening and home theater room. Basically, I'm just an A/V hobbyist with no formal relevant schooling, training or A/V company affiliations that believes in full disclosure.
Okay, enough of that, below I'll list the poster with their partial post quote and add my comments below each. My current thinking is that this format could be beneficial to multiple thread participants but also that I could quickly get in over my head. My intention is not to hijack this thread but to summarize, clarify and to assist the OP in better understanding the swarm concept:
mapman:
"
Audio Kinesis (Duke) is also very knowledgeable and big on sound dispersion in general and I believe tries to enlarge that sweet spot with his designs. When that is the case ( a larger sweet listening area) the case for a more evenly distributed bass is also better."
I believe this is generally true but wanted to add specifically how I implement the swarm since my goal was to broaden the bass sweet spot in my room for HT but to restrict the midrange, treble and stereo image to a traditional sweet spot, meaning a pair of main speakers precisely positioned in relation to a single designated listening seat to optimize the midrange, treble and stereo sound stage illusion.
Here are some relevant facts to consider:
-Deep bass frequency tone sound waves are omnidirectional and exceptionally long (a 20 Hz very deep bass sound wave is 56' long).
-Humans typically cannot localize (tell exactly where the sound is coming from)
bass sound waves with frequencies below about 80 Hz and down to the audible limit of 20 Hz.
-Midrange and treble frequency tone sound waves are highly directional and decrease in length proportionally as the tone frequency is increased (a 1,000 Hz midrange sound wave is 1.13' long and a 20,000 Hz very high treble sound wave is a fraction of an inch long).
-
Humans are typically very adept at localizing midrange and treble sound waves beginning with frequencies above about 80 Hz and up to the audible limit of 20,000 Hz.
-
Sound waves from 20 to 80 Hz are mono and perceived by us as mono whether separate L +R channels exist or not.
-Sound waves between 80 to 20,000 Hz are actually mono but perceived by us as stereo if separate L + R channels exist.
-All sound waves continue to bounce, or reflect, off of room boundaries (walls, ceiling and floor) until they run out of energy, are absorbed or are diffused.
-Humans require at least one full cycle sound wave to exist in the room to perceive any sound no matter the frequency. Additionally, humans require multiple full cycle sound waves to exist in the room to perceive a change in pitch. This only becomes an important factor on some very deep and very long bass frequency sound waves, which can potentially exceed the length of a room's dimension, and require a room boundary reflection for the full cycle length of the sound wave to exist in the room before being perceived, along with multiple sound waves existing to notice a change in pitch.
The above facts result in bass sound waves behaving, and being perceived by us, very differently than midrange and treble sound waves in any given room. Because of this, I decided to take the approach of treating my system as two systems: a bass system and a midrange/treble/imaging system.
The bass is typically the hardest to get sounding right in most rooms. My main point is that, while the Debra delivers near sota bass in mono throughout my entire room that serves as a solid foundation for all music I play on my system, I still position my main speakers precisely, in relation to a single designated listening seat, to optimize the midrange, treble and sound stage imaging. My main speakers only have a rated bass extension down to 35 Hz and I run them full range with the Debra set at slightly less than 50% with the crossover frequency set at 40 Hz. This results in a seamless integration of the bass with my main speakers.
Even though the Debra subs and my main speakers are all outputting the fundamental bass tones below 80 Hz in mono that cannot be localized, I still perceive a full range stereo sound stage because the harmonics or overtones of these fundamental tones, which reach frequencies above 80 Hz and can be localized, are being reproduced in stereo by the main speakers.
The secret sauce is then provided by our brains, which are capable of associating the bass harmonics or overtones above 80 Hz with their related fundamental bass tones below 80 Hz, and create the perceptions of where specifically the fundamental tones are coming from. This whole process is seamless and results in our being able to perceive the deep bass drums being located at the rear center of the sound stage image, for example, and the upright bass being located at the front left side of the sound stage image.
mitch2:
"
Based on my experience going from one sub to two, as well as what I have read about the subject, I would like to try adding a third SW12 placed asymmetrically in the room. If I were starting over, I would definitely try Duke’s Swarm Subwoofer System but as
@erik_squires points out, you need to be willing to have four additional boxes in your room."
Yes, I know with certainty that a good quality multiple sub bass system can be created using as few as a pair of good quality subs, provided they're properly positioned/configured and good bass performance is only desired at a single designated listening position and not throughout the entire room.
Three subs have also been proven to be sufficient, in some rooms, to form a DBA that is virtually as effective as a 4-sub DBA and is claimed to provide good bass performance throughout the entire room, not just a single designated room location. I
recall reading this in the Earl Geddes article linked below:
https://mehlau.net/audio/multisub_geddes/
Mitch2, you also may be interested in one or more of these good quality wireless subs that have received good reviews:
https://www.underwoodhifi.com/products/syzygy-acoustics
atmasphere:
"
In a nutshell this is an education thing and nothing more.
Those that denigrate a distributed bass array are apparently simply ignorant of its advantages. Many dealers don't sell them, so their comments can be sidelined safely enough.
If your front speakers actually make bass, then what you do is add a pair of subs elsewhere in the room to break up the standing waves that often cause bass cancellation at the listening chair."
I agree, the whole 4-sub DBA concept is not overly complicated but does require some education, self provided at online sites or at least read this book I'm currently writing. I think a good understanding of the underlying principles as well as proper setup and configuration procedures should be sufficient.
teo
"
Actually Eric is correct in the idea that it does not fix the room. This swarm idea. It overwhelms the problems and buries it under noise, in an area where the human ear is least sensitive. Like Styx said, "you’re fooling yourself if you don’t believe it..."
First, Fix the room."
I believe teo_audio and Eric are correct that the swarm does not fix the room.
As I understand the swarm concept, the 4 subs actually create an abundance of more bass room modes throughout the room and uses a well known psychoacoustic principle, mainly that our brains process an abundance of bass room modes present in a room by summing and averaging these room bass modes by frequency, which results in our brains creating perceptions that the bass is smoother, faster and more detailed.
During the first four years of using the 4-subb Debra system in my system, I utilized zero room correction software or hardware and the only room treatments existing in the entire room was wall to wall carpeting and a few live house plants.
This wasn't because I disagreed with, or wasn't aware of, the importance or effectiveness of quality room treatments in attaining optimum full frequency range audio performance. I did, but just hadn't gotten around to having my room professionally analyzed and treated.
I've since had a full professional room analysis done by
GIK, purchased several thousand dollars of a variety of their suggested room treatment products and have had them all installed about a year ago.
GIK's recommendations included floor to ceiling bass traps in all 4 corners of my room, 3-5 additional bass trap panels scattered about and and about 20 midrange/treble frequency range absorbing and diffusing panels at strategic locations along the perimeter 4 room walls.
My main point is that I was initially leery about so much bass trapping treatments because the 4-sub Debra DBA had worked so exceptionally well, with virtually no treatments at all in my room, for the previous 4 years that I was concerned the abundance of bass trapping might negatively effect the Debra's excellent bass performance.
After reassurances from GIK and Duke that the added room treatments would not negatively effect the bass performance of the Debra DBA, I had all the GIK recommended room treatments installed in my room, including all of the bass traps. I anyone is curious, you can view the room treatments on my system pics.
Overall Duke and GIK were correct, the Debra's bass performance remained exceptionally good. I noticed significant improvements in my system's midrange, treble and imaging performance, mainly a substantially lower noise floor, improved detail and an even more realistic, deeper, wider and 3 dimensional sound stage imaging.
So to those stating to fix the room first for Pete's Sake!, my experience is that it minimally effected my room and system's bass performance but dramatically positively effected most everything else. Definitely worth the dough overall, IMHO, but obviously not required for very good 4-sub DBA performance.
Okay, sorry for the War & Peace length of this post but I prefer my books be thorough.
I hope this tome helped someone,
Tim
