Life After Your Magnepan’s

Good news to report; using three SVS SB4000 sealed subs in a “swarm” configuration works exceptionally well in my large room !  Very please with the results!

Using the basic guidelines of the Geddes approach, Sub one was placed in the front center just behind the plane of my 20.7’s.  Using a good microphone and RTA software on a Windows laptop we adjusted one large suck-out and two medium peaks with the subs built-in peq  and set the cutoff at 60hz.  Volume was set at -16db.  Then we added the second sub on the left side wall about 2 feet in front of the Maggie’s with the woofer firing across the room.  Re-ran the test tone and made a few minor adjustments to sub one and set sub two.  Sub two’s volume was set at -15db.   Adding sub one was a noticeable improvement, adding sub two made a minor noticeable improvement.  Adding sub three made a larger difference than when sub two was added.

Sub three was placed on the right-hand rear wall against the wall and about two feet from the corner, firing down the length of the room.

Overall a very successful effort!  Bass is much more evenly distributed throughout the room, sound field grew noticeably wider and deeper, and bass is better extended, better detailed, better realistic decay, and just sounds more REAL! 
I’m done for now!

Congrats!I'm a Swarm convert since last summer.What an amazing positive difference multiple subs achieve.

Hello stickman451,

     I’m glad you attained much better bass in your large room using a 3-sub custom DBA system. I can’t state I’m surprised since the 3-4 sub DBA system seems to work very well in any room and with any pair of main speakers. Welcome to the club!
     I’m also glad you noticed the soundstage, what you refer to as the sound field, grew wider, deeper, more detailed and more realistic overall. This very noticeable improvement in the soundstage size, detail and realism was something I wasn’t expecting but I’ve since learned this is a consistent additional benefit of deploying a 3-4 sub DBA system.
     I really enjoy this benefit as well as the way even the deep bass instruments are properly positioned within the soundstage. This is interesting, because I run all 4 of my subs in mono, humans can’t locate frequencies below about 80 Hz (tell where they’re coming from) and there’s no such thing as stereo deep bass because virtually all commercial music has the l+r channel bass below 100 Hz summed to mono. Despite all of this, it’s impressive to me that the deep bass is perceived to be in stereo with a 3-4 sub DBA deployed.
     How is this possible? It’s true that the very deep bass tone fundamental frequency reproduced by the DBA cannot be localized but all the bass overtones/harmonics of this fundamental bass tone frequency, that are higher in frequency and are reproduced by the stereo main speakers, can be localized.
     We humans are very adept at localizing the bass overtones/harmonics that reach frequencies above about 80 Hz and, fortunately, our brains are able to associate these bass overtones/harmonics with the much lower bass fundamental frequency and therefore determine specifically where in the soundstage it’s originating from. This process allows us to perceive the entire soundstage illusion in stereo precision over the entire audible frequency spectrum. This allows, for example, to perceive an upright bass as being located at the front left side of the soundstage and some deep bass drums being located at the center rear of the soundstage.
You stated:
"Bass is much more evenly distributed throughout the room, sound field grew noticeably wider and deeper, and bass is better extended, better detailed, better realistic decay, and just sounds more REAL!"

     I think that’s a very accurate summary of what a 3-4 sub DBA system provides in virtually any room and with any pair of main speakers. I would just add that the bass seamlessly integrates with the main speakers and even the deepest bass notes are remarkably perceived as being in stereo and coming from the appropriate specific positions within the entire soundstage illusion.
     I believe the power, impact and dynamics of deep bass, especially in the bottom 2 octaves, is what usually distinguishes the sound of music heard played live in person from music recordings heard played on a home audio system. 3-4 sub DBA systems are excellent at reproducing bass that is not only heard but felt in a very powerful, smooth, fast, detailed and natural manner, just like live music heard in person.
     These are the main qualities of 3-4 sub DBA systems, in my opinion, that enable them to provide what I consider to be near state of the art bass reproduction that puts a smile on my face on a daily basis whether listening to music or HT.


Enjoy,
Tim