I agree. I never understood why people make expensive full range speakers with no way to adjust the bass response except room placement. It's just not a complete design IMO.
Dear Audioarcher: We can't saying for sure but seems to me that busine$$ is part of the subject as is the audiophile/customers ignorance level. In passive full range speakers maybe 2/3 of its price goes or belongs to those 1.5/2 bottom octaves, these are the most expensive ones. With out those octaves the manufacturers can't charge you: 100k+ big dollars in the price.
The real " problem " is that a pair of well designed monitors alond a pair of self powered subwoofers can outperform the magabucks full range passive speakers for only a small price fraction but this alternative/solution is not very good looking for we customers because our ignorance level on what's important down there: why the existence/main target of speakers and how achieve the best way that main targets?
I want to think that that's part of the AHEE convenience and not because ignorance level of the speaker manufacturers too...
I learned that the main target to add subs in an audio system is not to go deeper on the bass or quantity or that " boom boom "/ w/o sense but to improve both: the quality performance level of the system main passive speakers and to improve the quality performance level of the bass management that IMHO is where in a home audio system belongs the music: the foundation reside down there, as better ( better means lower distortions. ) the audio system bass management as better the overall audio system quality performance level. No doubt about.
Speaking of passive speakers manufacturers the AHEE " rules " are: not speaks or give measurement on their speaker different kind of distortions either: THD or IMD at different SPL. Take a look to passive speakers designs manufacturer specs and you can't find out no figure about.
Here are Wilson owners: can any one of them share those distoprtions measurements ? Some one pointed out here that his speakers goes down 3-7 hz and we have to questioning our self: so what, is it important? why we need a speaker goes so down? which are the distortion levels during playback at 120 db SPL? the owner knows that at that low bass exist several electronic artefacts coming from the amp and " somewhere " that could be amplified by the speakers at the fundamental and the harmonics causing deep distortions that contaminate everything? , could be " nice " to have a system that goes down to 3hz but IMHO is more important to know its distortion levels.
Btw, speaking of LPs I think that the recording with the lower bass notes was the Telarc 1812 Overture at: 8hz, I think that 3-7hz speakers can honor that so low frequency range.
As everything in audio in this important audio link each one knowledge level is the key to success level. Numbers/measurements makes no sense if we can't understand its meaning or if we don't measures what's important or even worst: if we don't know how it mesure it.
If an active/self-powered subs involve several problems that end as distortions a passive subs only increment in an exponential way those distortion problems because it does not matters what powerful will be the amp to mate that passive subs problem is that: we can't control nothing, we are at random with higher distortions. Amp power in this regards means almost nothing.
In a home audio system what we need is a self powered subwoofers not passive ones. IMHO what we have to look down there is quality not quantity, in this regards when we can I think that when choosing subs we can have some advantage with sealed/acoustic suspension designs over ported ones because the formers normally has lower distortions.
Regards and enjoy the music,
R.