Most of the oomph in an audio system is delivered by a subwoofer. Not only do subwoofers add oomph and strong bass reproduction but they also free up the other amps from most of what they have to do. They only need a handful of watts to handle mid and high frequencies. You are using a subwoofer aren't you?
Again you have promulgated a common misconception. There is actually little acoustic power in the last two octave below 80 Hz. It just seems that way because so many subs are terminally inefficient. The bulk of the acoustic power is from 80 Hz to 2.5 KHz and there is still quite a lot of power out to 5K.
The major power band is from 80 Hz to 1000 Hz or so. That is why for a powerful system, bookshelf speakers are a bad bet. If you have an efficient bass system like I do, you find that the below 80 Hz range takes actually very little power. You can see why on the power band requirements of instrument and bass fundamental frequencies and harmonics. We have displayed them often.
What a sub does do, is limit cone excursion of smaller drivers. This does reduce doppler distortion and other distortions. It does very little to off load the receiver.
One of the huge limitations of accurate reproduction is severe limitation of the power band room response between 80 and 1.5 KHZ, and especially 80 to 800 Hz.
This is where you need to devote resources.
Next subs do not create slam, there is no slam at those frequencies. What creates slam is accurate transient response of the whole wave form. That requires accurate time/phase response across the whole audible spectrum and uniform FR on and off axis, to create an accurate uniform in room power response.
This also requires cutting retained energy in the mechanical parts of the speaker system to the minimum
Unfortunately analog crossovers significantly disturb the time/phase response, but to varying degrees, depending on the overall design.
This is where active speakers, with DSP time alignment offer the prospect of much improved results.
Lastly there is now increasing evidence that Ted Jordan was right, that separating a fundamental from it harmonics in time is a bad thing. I have always believed that as Ted was one of my mentors. So placing subs away from mains, is a bad idea. That is why I designed and built highly integrated front speakers.
As you really work on this and minimize the the above aberrations, the improvement becomes truly astonishing.
A lot of the the current practice of the last 20 years has been 180 degrees wrong!
