Why the fascination with subwoofers?

@noble100 -- 

I'm not a Bass-Head but I admit I enjoy the bass weight and power that viscerally involves your whole body in the music or ht. 

I can relate to that - certainly. For bass to be able to be enveloping, effortless and visceral are vital aspects for bass to simply be uninhibited. 

But I also believe in setting the crossover frequency as low as possible so the subs only engage when required for accuracy and not for an artificial general system bass boost.

An "artificial general system bass boost"? I don't see why this would be the necessary outcome of a higher cross-over between the mains and subs. One may have a wider frequency span to adjust bass level and overall response, but to me - using an 80Hz cross-over - the goal is the same compared to using a lower XO: for the overall integration to be smooth and seamless. 

Perhaps one of the issues of using a higher cross-over point, apart from it being potentially problematic using several subs scattered throughout the listening room, is the thought of using a high-pass filter over the main speakers. This is understandable, I've been there myself, but I can attest to the positive outcome using a quality digital XO over the mains, and that any detrimental effect on transparency with a proper unit is perceived as zilch. Some may bark at this and claim such a component will inevitably have its say on the sound, and they may be right, but to which degree and in what context? Using a quality digital XO over the mains and high-passing them at at least some 80Hz have a plethora of other advantages that can easily (more than) alleviate a theoretically negative effect a given component may have being added to the chain:

WIN # 1)  Since you are now NOT putting in 20 Hz - 80 Hz into the mains you are not using up the available LF cone movement with bass, so the LF cone in your mains is able to play its higher freqs (up to IT'S crossover point) much more cleanly. You get an apparent 6dB or more dynamic range. You can play your system LOUDER, and also with less compression distortion in the LF driver when you're having that Saturday night dance party and you're playing urban bass technopop at 110+ dB. Really.

WIN # 2)  Since you are not putting bass into that same driver you are not Doppler modulating everything between 80 and 600, or whatever the next crossover point is. This means cleaner mids. By far.

WIN #3)  You are not sucking current out of your main power amp at low frequencies, so there is more current reserve to play those highs louder...

WIN # 4)  Since the cones aren't moving as far at the low freqs the driver itself is not generating as much back EMF therefore the damping factor and all of its issues are greatly negated. And you don't need to run silver plated cold water pipes to your mains as speaker wires because there is less current draw by the speakers.

WIN # 5)  Freqs below 80 are now NOT causing transient intermodulation distortion with the higher freqs (and vice versa) in your power amp. Cleaner still.

http://www.soundoctor.com/whitepapers/subs.htm

I've also discovered that bass quality is vastly more important than bass quantity. A leaner presentation without much extension is preferable to me than lots of bass if that bass is thick, colored, and sluggish. If the bass isn’t well reproduced, I think most would agree we’d rather not hear it at all. The poor bass performance becomes a constant annoyance and a reminder that we’re listening to a reproduction. 

Agreed.

I've learned that realistic reproduction of the majority of the bottom octave (16Hz–32Hz) doesn't require large woofers in large enclosures, 4 subs with 10" woofers in relatively small enclosures are equally capable. 

Equally capable compared to what? There are many iterations of using only a pair of subs that involves 21" units (or bigger) and/or horn subs that would leave 4 spread out 10" direct radiating subs sounding close to malnourished. Would 4x10" be sufficient in many listening rooms to many listeners? I believe so, definitely, but others would disagree, and it's not necessarily for them being "bass heads" as such; what is "realistic" to you may not be the case with others and their setups. 

It's also true that a system’s bass presentation affects such seemingly unrelated aspects of the sound as midrange clarity and sound staging. Thickness in the mid bass reduces the midrange’s transparency. A cleaner mid bass not only makes the midrange sound more open, it also lets you hear more clearly into the extremely low frequencies. Moreover, extending a system’s bottom end has the odd effect of increasing soundstage depth and our overall sense of the recorded acoustic, even on music with minimal low-frequency energy.  

I concur, only to add that these advantages are potentially more pronounced using a high-pass filter over the main speakers, for reasons outlined above. 

However, I'd suggest choosing subs designed for musical accuracy, not home-theater fireworks. Some subs exist to produce the highest possible sound-pressure-level at the lowest possible frequency for playing back explosions in film soundtracks. Others are crafted by musically sensitive designers with high-end sensibilities. Be sure which kind you prefer and are selecting.

I don't find musical accuracy and "home-theater fireworks" to be mutually exclusive. Watching Blu-ray movies I simply notch up the bass level by some 1.25dB's (some may prefer even higher HT-boost bass level). This "amalgam" of proficiency with regards to both music reproduction and movie playback I find is no doubt rooted in the specific topology, namely horns (a pair of 15"-loaded tapped horns, in my case). Horn subs deliver the most musical bass I've ever heard in being more refined, smooth, enveloping, dynamic and effortless than any direct radiating solution I've heard. Horn subs vibrate the air in quite an omnipresent fashion that gives the bass a floating quality even that's rather unique.  No multi-use of direct radiating subs can achieve the same, period, and predominantly it has to do with how the cone couples to the air. Horn subs take up space, though, and 20 cubic feet for 20Hz reproduction may be a hindrance for many, if not most audiophiles. A shame, really..

Dear @phusis  : I concur with what you posted because those were and are my first hand experiences in my room/sysrtem for several years now.


Through those experiences I decided to in 2005 to post this thread ( I already postyed here but you don't read it, here again. ) that goes/coincide with your takes in the overall bass subject:

https://forum.audiogon.com/discussions/do-you-think-you-need-a-subwoofer/post?postid=310058#310058


Btw, the planar speakers develops too Inter Modulation Distortions and are benefitiated by those subs and the high-pass filter. No matters what.

The planar owners must test it before post it does not works because this is the idea they have. I posted the link og those Apogee The grand speakers that says it works and I have first hand experiences with the top of the line big and great sounding Soundlabs with and with out that high-pass XO and difference is for the better through that XO. But is up to flat speakers owners. 


Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Hello phusis,

     Your post brought up many good points and I believe most come down to your personal preferences being different from mine.
     I think we both agree that the 4-sub distributed bass array (DBA) concept is something that works incredibly well in virtually any room and with any set of main speakers, even fast speakers such as planar-magnetic and electrostatic panels.  I think this is bourn out by the fact that we both use them in our own systems.
     All DBA systems will provide accurate, detailed, smooth and natural bass that has an effortless quality to it.  But I consider the DBA concept to be an especially elegant bass system solution because of its scalability and flexibility that allows for customization based on personal preferences. 
     DBA's are scalable mainly by the choice of the 4 subs utilized.  I use the relatively small subs standard with the AK Debra DBA system that have a 1 sq ft footprint, are about 2 feet tall and contain 10" drivers.  Although this provides bass response in my room that's flat down to 20 Hz it's not quite able to reproduce the entire lowest octave of 16-32 Hz but this bass response has plenty of power, impact, extension and dynamics on music and ht for my preferences.  Others who may have a preference for more bass power, impact, dynamics and sufficient bass extension to reproduce the entire lowest octave have the option to choose subs that are as powerful, extended, expensive and large as they prefer or can talk their spouses into.
    DBA system's are flexible mainly by the choice of system settings such as the crossover frequency, whether the main speakers are run full-range or restricted and the overall bass system volume relative to the main  speakers.  I prefer setting the crossover as low as possible, typically in the 40-50 Hz range, because I run my main speakers full-range, they only have accurate bass extension down to  36 Hz, I find the bass sounds better integrated when the subs only engage when the content requires it and I perceive the bass as boosted overall when the crossover is set much higher.  
      You've stated you prefer setting your crossover at 80 Hz and using a high quality digital xover to restrict the bass output of your main speakers. This not only demonstrates the flexibility of DBA systems but allows other significant benefits as well that you detailed.  I understand your point about perceiving the bass in your system as still natural and well integrated even at your much higher 80 Hz crossover.  Perhaps it could be we just differ a bit in how we perceive moderately deep bass as it approaches  frequencies that we're able to discern where the bass is coming from.  But the DBA flexibility still applies since we're both just using the available DBA settings to attain the system performance and other benefits that we enjoy and prefer in our systems. 

      The overall DBA system volume relative to the volume of the main speakers volume is another important setting that allows significant flexibility.  I prefer a bass system volume that is slightly less than half volume on the sub amp which allows the deep bass to be independently powerful, detailed and dynamic while still integrating well with the mid-range and treble of the main speakers as the overall volume level is varied from soft to loud.  
     But like you, I'm not adverse to increasing the relative bass system volume on certain Blu-ray movies or even some music.  Just our personal preferences easily catered to by the flexibility of our DBA systems,right?

Tim

Dear @noble100 : """ All DBA systems will provide accurate, detailed, smooth and natural bass that has an effortless quality to it. """

as can do it non DBA subs system. As you said maybe a different way " to see things " but DBA is not the only or best option. Clearly is for you and other gentlemans but exist other very good alternatives to it.

Not only you but other audiophiles are running their passive main speakers in its full range way and I can’t understand yet why what @phusis and before him me posted here and in other related subs threads ( at least me. ) the main critical advantage when any one integrates two or more subs to his system using a high-pass filter that permits to put at minimum the main speakers IMD kind of distortions.

The rewards doing that with passive speakers is not some thing tiny, no it’s more significant perhaps that to have those additional low bass octaves. Of course that we can understand it only when we have that experience.

I posted in that linked thread that my main discovery when I integrated my subs to my system ( where my main speakers goes down to 16hz. ) was the overall " impact " that was developed by lowering the main speakers IMD kind of distortions. Yes I know your targets are different from pussin or mines but you must try it in some future time and if you test it then the XO point can be at around 80hz and subs wired in true stereo fashion.

I think that we can’t diminsh the IMD developed distortions by the main speakers no matters what if I was you at least I will try and if you don’t like it then always come back at the original status.

Normally the owners of planar type speakers are " against " to run the main speakers as a " satellite " one that is the " rigth " way to go ( for me. ) because that high-pass filter makes a paramount difference.

Yes, my high-pass filter is inside my 20.6s amplifiers where I don’t need to use any kind of external active/passive XO due that my amps are coupled by small caps.

Anyway is up to each one of us, only an opinion that can improve our daily MUSIC pleasure.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Dear @noble100  : I did not knew which is the crossover frequencies in your 2.7qr and now I find out:

Low-Pass 12dB/octave @ 650Hz

Band-Pass 6dB/octave @ 500Hz-950Hz

those " numbers "  makes me to tell you it's almost and " emergency " and your speakers are " shouting " for that high-pass filter ! !

Rigth now you have good bass and you can have an exceptional mid/high ranges in your system adding that high-pass filter.

IMHO it's a must that you do it because the IMD distortion levels is to high and in a very wide range up to over 900hz. It's a serious compromise to leave it that way.
A compromise is that you can have a better  quality " equilibrum " with your bass range if you can achieve better quality levels in the mid/high frequency ranges. As I said before is up to each one of us.

Btw:   you said that the CD's and other digital sources you own/use does not goes below 20hz. Maybe you are rigth but always exist a dude because your system does not have the ability to shows you if in reality goes only to 20hz or below it.

R.