Why I'm not adding a sub to my 2-way monitors for music

It's simple, if you are serious about achieving great sound there are two requirements: room treatment and a DBA system. Read articles from Welti, Floyd and Geddes

This will lift your system above the pedestrian, that is any system not employing subs.

There is a scientific goal with treatment where the quest is to get the sound to decay a certain amount in a certain time and only broad-band absorption including bass traps will provide this. Those mentioning books as diffusers and drapes and other silly things have little effect.

EQ of course can not know how long the sound takes to decay and even if it did what can it possibly do? All it can do is boost or attenuate and there is a limit how much it can boost before your amp runs out of steam. EQ is not necessary in a good room.

I helped a friend where we installed 3 small 8" subs, the lowest we got from some scavenged drivers is about down to 45Hz. which does not really count as a sub but overpowering bass was not the reason for doing this. These 3 small sealed boxes provided a large number of peaks and partial nulls that were very much less than before. So what we ended up with, beyond the 32Hz of his main speakers was a smooth response from about 50HZ upwards. Some full nulls had been filled in that had previously cancelled any music info. In other words music previously completely absent was now heard and the overall effect was truly amazing with a sweet spot the width of the speakers. Everything improved. Consider also that no component upgrade can do what I have just outlined.

As I said, if you're serious!

No subs are the domain of the bootless and unhorsed 😁 

subs don't have to be 12" or even 10" they can be 8" or even 6". They don't have to be boxes either they can be tubes

Yes, indeed. The 3 subs I mentioned in my earlier post were discussed with my mate and his wife where I made suggestions about how they could be integrated into their room. The boxes had a small square footprint and were built to the height suited to their purpose. One was placed next to a bookcase and painted the exact same colour. The second served as a stand for a large pot plant and the third served as a side table replacing the table that had been there before. The whole installation was unobtrusive and took up very little extra space.

Where there is a will, there is a way.

The tube MC referred to allows more options. They can be used horizontally and vertically. As well as placing behind a sofa they can be used in the horizontal corners formed by the wall/ceiling junction.

6.5" drivers are common and they do not need to be specifically designed for 'subwoofer' use. If you regard them as 'acoustic equalisers' they will do something that is difficult to conceptualise if you have never heard a DBA. You get the music robbing nulls filled in and the shouty peaks tamed.

The above is suggested for owners of small rooms always complaining that they just don't have the space. If you do have the space then go to 10" or 12" drivers and enjoy the benefit of muti-subs down to a lower frequency.

The number of subs and their size depends on who wears the trousers in the house. In the above example my mate definitely wears the trousers, he just has to ask his wife which ones he can wear!  😉

Absorption, diffusion and bass trapping will take this to the next level. I have been playing with this for some time and I can tell you that some of my mates who were always introducing new and expensive components, endlessly chasing their tail, have mellowed out and are basking in their glorious sound, being more interested in the music now.

Room treatment + DBA : Audio's best kept secret.

I encourage everyone who is on the fence about adding a subwoofer or not to read and comment.  I think that either way you'll be able to make more informed buying and configuration choices.

Oh dear, the OP seems bent out of shape. You assume too much. How do you know that the fence sitters have even heard about a DBA let alone know it's purpose? To make an informed choice one needs information, does one not? Helloo ?

You encourage people to comment yet when they do and when it does not fit in with your approach you ask them to desist.

If you wanted only alternatives to subs to be discussed then you should have put that in the post's title and not added that fact in later when members have given the time and effort to inform.

By the way, calling someone a fanboy is contemptuous. I was in no way disrespectful, so clean up your act.