Why the fascination with subwoofers?

Dear @noble100  : Yes, with two true self powered subs for one seat position. We don't need more for that target. The Harman white papers confirm it.

I think that even that we agree in some bass management subjects the reality is that we can't agree and not because " we can't " as is but because looking your streamlinen system your targets and mines are totally different.

I don't use my system for HT and two channels listening MUSIC. My system was and is developed exclusively for listen two channels MUSIC, nothing more. Music coming from digital and analog alternatives.

As I told you my main target is to stay " nearer/truer " to the recording and to achieve that target I need a very high resolution room/system that means very high quality performance of any single link in the overall audio system chain with true accuracy and the lowest any kind of distortions I can achieve.
Obviously that to achieve all these we have to take care for the minimum details where in HT no body cares and even in two channels system some audiophiles not cares either. 

I gave that little explanation due that you said that using the high-pass filter you was not aware of differences in the quality level performance in the mid/high frequency ranges in your system.
After looking your system I understand now why you been not aware about: your system has not the resolution need it for even that very wide frequency bass range in the Magnepans.

As a fact you are not trying to put all kind of distortions at its minimum you can and that's why you gave me an answer that THD in the quasi-subs you own was not so important when in reality is way important with true self powered subs in a only two channels system. Everything is important and with high priorities in a two channels room/system when we want to stay not so far aways of live MUSIC as normally we are. 
Mi reference to achieve my target is live MUSIC seated at nearfield position ( 2-3m. ) that's where the  recording microphones are positioned.

For me is really important and was one of the reasons I choosed my servo controled Velodyne's that check every second 16K times the woofer excursions to mantain at lower than 0.5%  the THD. Other than Velodyne I don't know other true subs where the manufacturer gives the THD in its products.
I think I already mentioned that the JL very well regarded subs measured through Stereophile review around 6% on THD other subs reknowed subs are worst that that and certainly far away from that Velodyne figure.

I totally understand your fascination for your 4 quasi-subs bass array because for that price is almost imposible to achieve what you like in your system.
The manufacturer design must had to make " serious " compromises to stay at that so low price for the complete bass 4 array.

Anyway, at the end you have what you and me were looking for and if both of us achieved our targets then this is the more important fact.


Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

@atmasphere --

This statement is false. If you encounter a standing wave, it often cannot be fixed with only 2 subs. And it can't be fixed with room correction or room treatment.

Now if you **don't** encounter a standing wave then its all good. But in many rooms a standing wave is highly likely- unless the room is irregular in some way. But any rectangular room will have a standing wave which will be a different locations throughout the room depending on the frequency. In such cases while that bass might be good at the listening chair for certain pieces of music, it may not for others. This is a simple fact of physics.

With a distributed bass array this problem is solved. 

There's nothing categorically false with poster @rauliruegas statement; you CAN have bass that is accurate, detailed, smooth, natural and effortless with two subs, end of story. Both room correction and -treatment can do wonders here, I find, and can (and should) be used sparingly for a successful outcome. Honestly it's becoming trite hearing the constant babbling about what a pair of subs can't, and the double count can. We know by now - 4 subs can be a hoot, and they ease up on the need for PEQ, definitely not trivial. Moreover, all things being equal a double-up in sub count gives a theoretical 6dB's more headroom, and I can certainly vouch for the importance of that. 

You could however take a pair (or more) of bigger, more sensitive subs placed symmetrically to the main speakers, horn load them even, and have a different kind of awesome with other advantages. I know, size is banned in audiophilia, but the simply fact of physics, to use your own words, also has size as a main priority that numbers can't alleviate. Big subs in high numbers, however..

And what's the issue and argument made with smooth bass coverage over a wider listening (position) window? One sub is a narrow sweet-spot, two is wider and so forth, and while a single sub may boarder on the head-in-a-vise sweet-spot, two is definitely good for a pair of listeners to have decent coverage. I don't know about you guys or ladies, but mostly I tend to listen to my setup by myself (and if not I give the other listener the sweet-spot, usually placing myself on a chair behind and to the side of the listening sofa), and I don't need for bass to be swell in every goddamn place in the listening room; the listening position (with room for two, if need be) will do just fine, thanks. Actually this is mostly dictated by the main speakers; I would never listen seriously any other place than smack in the middle between the mains, but that's just me. 

atmasphere: Certainly you need to learn a little on the whole bass management subject.

Certainly is not false my statement that was confirmed by the Harman white papers in his great bass management scientific abstract and I said abstract because they do not try to sell us nothing but only sharing critical information. From those WP:


" Four subwoofer at the wall midpoints (configuration 11) was the best practical configuration in terms of MSV. Two subwoofers at opposing wall midpoints (configuration 6) was nearly as good and also offered stronger low-frequency support. Configurations with more than four subwoofers were not found to be advantageous, especially when cost is factored in. These results appear to be generalizable to reasonably dimensioned rectangular spaces [19] . ""

Things are that I have no single problem in my system with two true self powered subs at one seat position.

R.


from those WP:

""" However, through the use of multiple subwoofers the seat-to-seat variation in the frequency response can be reduced significantly, allowing subsequent equalization to be more effective. Three methods to reduce seat-to-seat variation are described, including a novel approach based on simple signal processing. The desired result in each case is to allow the system to be equalized over a seating area rather than just one seat. Results are shown for several listening rooms. """

In my case I only need one seat and I’m " in ".

and remember: Why the fascination with subwoofers? when you are not using it yet but like to post and you have the rigth to do it.

I can't go on due that you have some " lawyers " here that will come to .............? ? 

Dear @phusis  : In the overall subs subject problem with some people as atmasphere is just igonrance levels/low knowledge level even this person has no subs in his system, go figure.

As you and me Noble 100 confirms that we can have really good bass managment with two true subs. Noble likes 4 because he used as HT too.

As you I only need one seat position to listen MUSIC and the only seat position is in front-middle of the main speakers because is where belongs the mid/high frequency ranges that only has one and only position to enjoy it.

At least we have first hand experiences that attest our coincident statements .

The other issue in almost all the bass threads in this forum is that almost no one cares about quality of that low bass ( only cares to room evenly bass reproduction. ) and many just do not care about the critical importance of the bass below 20hz but as you said: " that's just me ".



R.

Hello atmosphere,

     Agreed.  
     Standing waves result in room bass modes which are perceived as bass exaggeration, attenuation or even cancellation at the specific points they occur at in the room.  These room bass modes resulting from standing waves also vary by frequency and typically exist in the bass frequencies up to about 350 Hz.  
     As I understand how the distributed bass array concept functions, the 4 subs distributed throughout the room actually are intended to create more bass standing waves and bass modes that are fairly well distributed throughout the entire room.  
     Once there's a good distribution of bass room modes existing in a given room, the principles of psycho-acoustics are then utilized by the DBA concept.  Humans are very poor at discerning the originating source of deep bass frequencies (below about 80-100 Hz) but very sensitive in discerning the pitch and the volume of these deep bass frequencies as well as any changes in pitch and volume.  Our brains process these multiple bass room modes (bass peaks and dips at various frequencies)  by summing and averaging them which results in a perceived smoothing effect to the bass.   
      Scientific research by Earl Geddes, Floyd O'Toole and others has proven that the more subs in a given room the more the effects of bass standing waves are reduced and the more the bass response is perceived as good(accurate, smooth and detailed). They realized there's a practical limit to the acceptable number of subs in a domestic room, however, and their data showed that some of the bass smoothing effect began with as few as 2 subs in a given room but there was a threshold reached with 4 subs in a given room which mitigated the effects of the vast majority of standing waves in the entire room, with each additional sub beyond 4 only providing smaller and marginal improvements. 
        This means that 4 subs will assure very good bass response at all bass frequencies throughout the entire room, including the chosen dedicated listening position.  2 subs cannot provide very good bass response throughout the entire room, only at a single dedicated listening position and this very good bass response cannot be assured at all frequencies and with all recordings. 

Tim