Why do so many people have problems with bass?

@jumia , I will give you a hint. Stand in the middle of your room. Look around. You can probably see the problem source. Most people have 6 of them. Some have more. Large flat surface. They reflect. Your room is like a giant bath tub for bass. Slosh the water in the bathtub just the right speed and you can make a mess pretty easy. That is the main problem. Most audiophile have speakers that can put out enough bass for most music. Maybe not for movies, but for music, sure. But it goes everywhere, and just like that bathtub, it sloshes around, and you get high and low points, and because your 6 flat surfaces are all different distances from each other, the peaks and troughs are not all in the same spots. You can move your speakers and make it better, but never perfect. To do that costs money. More speakers or lots of things to absorb sound and bass takes a lot of space and mass to absorb. Audiophiles also seem obsessed with a single set of big speakers. If you happen to get two big speakers in the perfect spot for perfect bass and perfect everything else, go buy a lottery ticket or apply for your Nobel. If you can afford the room and pissing off your soon to be ex with enough things to tame the bass from two big full range, sure go for it. If you can't, and your want good bass, there are better ways.

@engineears while I agree with some of what you say, I disagree in principle and fact with a lot of it.

Bass nodes, the high and low peak are totally predictable. There are even simple tools on the web to help. Those nodes are always a function of the distance of walls from each other. How deep those hills and valleys are is impacted by speaker position. This is also fairly simple to understand, predictable, and again there are simple tools to help understand.

You also ignore some simple rules and simple solutions. A simple rule and solution is never use one sub. Always use two of more. More subs in the right spots, smaller hills and valleys. Simple rule, if your main speakers are in bad spots for bass out of necessity, then don't let them play that bass if you have that option. Let the subs do all the bass work. Your mains may be happier as well. Simple solutions, you can buy subs with room correction built in. You can also use external devices to control this.

@asvjerry - Deep bass in that song, but not really deep. Bass guitar does not have much below 40Hz, and very little below 35Hz. You were not wrong @daledeee1. Piano can go lower, but not used much, and electronic music can. Some orchestra instruments can but will not account for much of the music.

@jumia, volume = area * throw. Driver designers have gotten good at making longer throw woofers with low distortion. There are advantages to smaller drivers and a narrower cabinet. You can achieve better dispersion especially in a multi-way where the mid-driver and bass drivers may be the same size. It is easier to brace the cabinet properly. Multiple small drivers can take the place of a single large driver. It makes it easier to integrate bass and mid-driver due to move similar emission patterns. I think there is also the expectation you will add a sub for deep bass (most systems are dual purpose music/HT). Economies of scale by reducing the number of driver sizes probably helps for cost, and improves automation which is good for quality.

How do you add authority or anything when there is nothing to add because the music does not contain those frequencies? Some music does, but far from all.

2- 6.5" woofers have the same diameter as a single 9". From a physics standpoint, because the wavelengths are so large, they will do the same thing. 3 - 7" woofers has the same surface area as a single 12" woofer. Spacing is close enough for bass frequencies (they will be), then they will behave the same.

Too aid bass output at the frequencies we seem to be discussing, i.e. 100hz and under, the baffle would need to be enormous, but at those frequencies the bass is effectively omni-directional anyway so talking about baffle step has no place in the discussion.

Our ears pick up 20Hz as the cue for the hall space? Is that your own theory, or does someone who understand hearing tell you that? Close your eyes and I will play a 20Hz tone. You will not know if you are in a concert hall or small room.  RT60 as a function of frequency does not favour bass in large venues. In a properly designed venue, it will be controlled within practicality across frequencies.

A course with a unit or two on room acoustics but no practical experience. That would explain the over the top suggestion of needing an architecturally accurate model and professional level modelling software when the response is almost always dominated by simple room modes and placement with that simple knowledge, easily modelled with basic SW will get you far further than guessing. Microphones/SW will tell you how you are doing or present state.

In regards to your sub setup, unless you already have an exceptionally well treated room for bass, a FL, FR, C sub setup, whether floor, listening height, or otherwise makes no sense at all for cancelling room modes. If anything, it is going to make the bass much worse and really stimulate some modes. If you are going to go with the cost of 4 subs, I would be integrating LFE output with music bass management and optimizing overall placement. The subs don’t all have to match perfectly for room mode cancellation.

In fact your whole comment about your stereo system not needing subs to reinforce bass (only a small part of why you should use multiple subs) but your multichannel setup having multiple subs in less than optimal positions is strange..

I won’t say more but will leave to other readers to reach their own conclusions.

@mambacfa ,

Traditional rock is light on synthesizer. Orchestral instruments go deeper than any instruments in rock. Electronics music does have very low frequencies.