There's a lot more bass in a 6.5" driver than most of you think

Thank you all for participating so actively, especially those who can share personal, specific experiences and who read the nuance in my original post.

I was thinking of something that I think has helped this discussion: I used a DIY speaker as my example, otherwise many would accuse me of shilling for a particular brand. At the same time, I don't mean to imply only this speaker can output this much bass in a modest listening space, I'm sure many others can as well.

 I used a DIY speaker as my example, otherwise many would accuse me of shilling for a particular brand

you used your own DIY designs. And all the effort youve spent making that response curve as flat as a pancake has been a waste because that was the wrong curve. You will need it completely retuned now. We need to examine the off axis curve too.

I think I read somewhere (KEF I believe) that the natural resonant frequency of a 15” woofer is lower so therefore it generates lower frequency bass with more ease? Is there truth to the notion that a smaller bass driver (6.5” - 10” etc.) will be quicker sounding / more resolving than 15” drivers? I’ve heard many biG horn / compression driver JBLs with 15”woofers that sound very fast and agile in the bass. I had a pair of KEF Maidstone R109 that had huge 15” drivers that sounds very agile and ‘big’ too.

Hi @adameos

Is there truth to the notion that a smaller bass driver (6.5” - 10” etc.) will be quicker sounding / more resolving than 15” drivers?

No, but that’s what we are touching on here. Less bass = low risk.

I’ve heard many biG horn / compression driver JBLs with 15”woofers that sound very fast and agile in the bass.

There is simply no substitute for surface are when it comes to deep bass and high output levels, especially in a test chamber or outdoors with no reflection points.

The trouble really is the room. Small rooms, untreated are much friendlier to smaller speakers with limited bass output. And that’s the blog post. :)

     I think most bookshelf speakers, just like most tower speakers, begin at a disadvantage in terms of providing good bass response at the designated listening position regardless of the size of the bass drivers; which is that the drivers for all frequencies are positioned in a single cabinet in some sort of fixed alignment. The bass drivers acually require their own cabinets and the capacity to be independently positioned in the room in relation to the listening position, in order for bass performance to be optimized. Ideally, these independent modules would also have independent controls for volume, crossover frequency and continuously variable phase settings, just as good quality traditional subs possess for optimizing performance and seamless integration with the midrange/treble drivers on the main speakers.   
     The main issue with this is that the optimum position for the midrange and tweeter drivers, in relation to the listening position, for midrange/treble and imaging are highly unlikely to be the optimum position for the bass drivers in relation to the listening position. 
     If good bass response at the listening position utilizing the much larger bass drivers of tower speakers is highly unlikely because of the above, I see absolutely no reason to believe that using smaller bass drivers, even multiple smaller bass drivers, would be expected to perform well.
     However, I'm certain that even a good quality pair of subs with 10" drivers are capable of vastly exceeding the bass performance at the listening position than the bass drivers on most bookshelf and tower main speakers are capable of providing, regardless of their size. The primary cause of my certainty is the tremendous bass performance advantages gained from the independent room positioning capabilities of sub drivers and subs.  
     One of the main advantages is ensuring that there are no bass room modes (room locations with obvious bass peaks, dips or nulls) at the listening seat.  It's easy to check if your current listening seat is positioned at or near a room bass mode; just listen to the bass response at locations near your listening seat and check if the bass quality varies at various other spots in around your room from.  

Tim