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Others experience re: subs and Magmepan 20

I have a pair of Magnepan 20r’s. Have enjoyed them for years. In my room they go to about 30Hz, response way down at 25Hz.

I am experimenting with a pair of Janis subs. This gets the response to about 25 Hz then down a lot at at 20Hz. It adds a little something but not I am not bowled. over. I hear and feel a bit (in my chest) on some music.

I would like to hear about others have experience with adding subs to nearly full range speakers?

Did you feel you got your money’s worth for "a few silly Hz"?

Thanks
imdoc
noble100's avatar
noble100
1,093 posts
 
randy 11,

     You stated in a previous post, I believe in response to comments I had made about the attributes of my distributed bass array utilizing 4 subs and that I've never had my room's bass response analyzed via mics and software:

" you might be surprised about the bass....
whether it is worth changing the look of the room is another issue."

     Since I wasn't certain what you meant by the comment "you might be surprised about the bass", I requested you elaborate and be more specific in order to clarify your meaning.  
     Since you haven't responded in the few days since my request, I wanted to point out that your comment "you might be surprised about the bass" can be interpreted in 2 opposite ways:

1. It could mean that, if I analyzed the bass response produced in my room of my 4 sub DBA (Distributed Bass Array) system utilizing a mic and software, I would be surprised how well the in-room bass response actually measured.  
    I don't believe this is your meaning, since I would not be surprised in the least to discover that the excellent bass response I consistently perceive in my room is validated by excellent in-room measurement results.

2. It could mean that, if I analyzed the bass response produced in my room of my 4 sub DBA (Distributed Bass Array) system utilizing a mic and software, I would be surprised how poorly the in-room bass response actually measured.

    This is more likely your meaning, since I definitely would be very surprised to learn that the excellent bass response I consistently perceive in my room is not validated by equally excellent in-room measurement results.
     If this were the case, I'll admit I would be initially very confused.  How could something that I perceive as sounding so good measure so poorly?
I think my initial reaction would be that either the measuring equipment or the measuring method are at fault. Either the equipment is not properly measuring the in-room bass response or the specifics of what is being measured do not correlate to how bass response is actually perceived by our ears and brains.
    Even in the highly unlikely possibility that the bass response in my room was measured accurately as poor, however, I'm not sure I would search for an alternative bass system/subs to replace my current DBA.
    I say this because our 'perception' of the sound of our systems is our 'reality'.  
    If the bass system I utilize sounds as extended, as detailed, as seamlessly blended with my main speakers and as close to the real thing as the DBA does, how well or poorly it measures in my room is much less important to me than my perception of how it sounds.
     As I've stated, I use absolutely no mics, DSP, room analysis/room correction software, equalizers or room treatments.
     I am curious, though, how  my system/room's bass response would measure.
     I should point out that when Dr. Geddes and Toole performed testing on their DBA theory in numerous rooms of various sizes and shapes, however,  the bass response measurements of the rooms deploying a DBA system were consistently very good.  I have no reason to think my room using the DEBRA 4 sub DBA system would not measure the bass response at least as equally 'very good', if not even better.  
     

    And finally,  I'm also not certain what you meant when you stated:" whether it is worth changing the look of the room is another issue."
     Why and how would I change anything?


     I still hope you respond and clarify your comments.

Thank you,
  Tim  
randy-11
1,913 posts
 
if a living room it cannot be too odd looking

you  may well have standing waves as most rooms do, so need to test
noble100's avatar
noble100
1,093 posts
 
randy 11,

    You haven't even explained your comments from your previous post and you're just going to make more cryptic comments?

     I'm not sure why you're avoiding coherent comments in your posts.

 Are you just a poor written communicator?

Are your comments deliberately incoherent and confusing?

Do you care that your comments are completely ineffective and of no value to those they're directed toward because they're so incoherent and confusing?

Are you capable of explaining, elaborating on or just plainly and directly clarifying your comments?

Am I the only one having difficulty making sense of your comments?

Are you just messing with me by being so cryptic?

     I'm honestly uncertain if any, all or some combination of the above explanations apply.  But since your comments are of so little value to me, I suggest you might want to make them understandable or just avoid responding.

Thanks,
  Tim
noble100's avatar
noble100
1,093 posts
 
randy 11,

I forgot to respond to your only comment I understood thus far:

" you  may well have standing waves as most rooms do, so need to test"

    You are correct, most rooms do have bass standing waves
   However, the whole point of a properly setup DBA is to eliminate the vast majority of bass standing waves in the room it is deployed in.  
     The DBA's main benefit and reason for being is its extraordinary ability to eliminate the vast majority of bass standing waves in any room.
     This is why DBAs are such an excellent solution for providing top quality bass response in any system no matter one's room size or shape.and without the need for mics, room analyzing and correcting software, equalization, DSP equipment or room treatments.
     The result is powerful, life-like, detailed, seamlessly integrated with the main speakers and seemingly effortless bass that is well dispersed throughout the entire room; not just at a designated sweet spot.
     In my opinion, and I would think in the opinion of many, this describes  the type of in-room bass response we are all in search of.  

     Do I have any bass standing waves in my room since installing my Audio Kinesis DEBRA DBA system?  Maybe but so what?.  
     The sole instruments I have available to detect them are my ears and attached brain.  I have spent what I consider a large amount of time walking and even crouching around my entire living room searching for the symptoms of bass standing waves: any spots at which bass sounds over/under emphasized and spots at which bass sounds nonexistent.  
     I'm as certain as I can be, lacking the necessary equipment for a complete room analysis, that there are no bass standing waves at any of my 6 seating positions in my room.  Perhaps there's 1 or a few in my room but I'm not going to worry about it or them since they obviously have virtually no affect I can even remotely detect on bass performance in my entire room.

Thanks,
  Tim   
      
audiokinesis
1,872 posts
 

I designed the Swarm subwoofer system mentioned above, and worked with Jim Romeyn on his conceptually-similar Distributed Bass Array system.

The Swarm was originally designed with dipole speakers in mind, specifically Maggies and Quads. Briefly, dipoles have smoother in-room response in the bass region than monopoles do (according to a peer-reviewed paper by James M. Kates). Smooth bass is fast bass, subjectively and literally - in the bass region, in-room peaks happen where the energy decays more slowly, and vice versa. In fact, the two are so interconnected in the bass region that if you fix the frequency response, you have also fixed the time-domain response. So the key to matching the "speed" of dipoles is, match their in-room smoothness.

Two subs intelligently positioned will be roughly twice as smooth as one sub. Still not as smooth as two dipole main speakers, but definitely better than one sub. Four intelligently positioned subs will be twice as smooth as two, and comparable in smoothness to a pair of dipoles.

The improved in-room smoothness that arises from using multiple subs intelligently distributed may seem counter-intuitive, so let me try to explain: Imagine you are looking at the in-room frequency response of a single sub. You see a few big peaks and dips. The problem is not only their magnitude, but also how far apart they are - you see, the ear/brain system tends to "average out" peaks and dips that are within about 1/3 octave of one another, but these are almost always going to be further apart than that. Small rooms are typically worse than big rooms in this respect.

(Also, the ear is especially sensitive to changes in loudness - peaks and dips! - in the bass region. This is shown by the way that equal-loudness curves bunch up south of 100 Hz. So there is usually a LOT of room for improvement in the bass region.)

You can move the sub or move the microphone location and those big peaks and dips get shuffled and changed, but they do not go away. Now imagine that you add a second subwoofer in a different location. It too generates a big peak-and-dip pattern. But unless the second sub’s peaks and dips overlay the first’s (which can only happen if the two subs are in the exact same spot), the sum of the two will be significantly smoother than either one alone. Mathematically, it will tend to sum to half as much average deviation (or "twice as smooth"). The same trend holds as we add more subs. And not only are the peaks and dips smaller in the summed response, but they are also more numerous and therefore closer together, so the ear/brain system’s averaging characteristic comes into play, and the subjective improvement is probably greater than one might think from eyeballing the summed curve.

Anyway my point is, there is some solid acoustic and psychoacoustic science behind the distributed bass array concept. Credit to Earl Geddes for sharing his ideas with me and allowing me to use them.

Duke

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