How does adding a second subwoofer improve your systems SQ?

You are getting a just sample of what’s going on down there, you are drawing conclusions about the Roger Waters track with regards to hearing it with two L and R subs, it’s obvious. Because if you did you wouldn’t be saying what you just said.

It acts the same way on my main system, which has bandwidth to 20Hz out of the main speakers (Classic Audio Loudspeakers Project T3.3).

It appears that bass traps have their cultists too. The simple fact is they are not always practical. A local customer of mine has been using them for years; I finally got him to try a DBA and it solved his bass issues which he's been fighting for over 20 years. His room is arguably the most treated room I've seen anywhere. He was pretty adamant about how great they were until the DBA showed up.  At this point he's running only about 1/5th of what he had before. In my room I simply don't have the space to place them at all, but adding a pair of subs (thus creating a DBA) is easy since they can hide under a couple of tables in the space. No way could I get bass traps to do the same job in my room, and the GF won't stand for it anyway. Science works so much better than myth for solving these problems.

EG: Just listen to the second last track "It’s A Miracle" on Roger Waters "Amused to Death" at the end there is a kettle drum roll that rolls around the room on the ground from right to left and back again. If you had just one sub it would ruin that mesmerizing effect totally.

This statement is misleading. I get exactly that effect using only one sub in my bedroom system.


The issue is that below about 80Hz in most rooms, the ear cannot distinguish where the bass is coming from because it cannot detect a sound until the entire waveform has passed by the ear. In most rooms at about 80Hz, the waveform is so long that it has bounced off of the rear wall and is already passing the ear in the other direction before the waveform has completely passed the ear on its way to that rear wall!

It is harmonics of bass instruments like the string bass, bass drum, tympani and the like that convince you that the sound is emanating from in front of you and whether it is to the left or the right. So a single sub works, 2 subs better, 3 better than that and beyond 4 you're at the point of diminishing return. It is important however to make sure that bass information is coming from both main channels to the sub system!


However this is only true if the sub or subs do not attract attention to themselves and to do that they can't put out anything above about 80Hz. If they do, now the subs have to be time-aligned with your main speakers and its a royal pain in the rear and at that point a DBA doesn't work. So as a general rule, make sure your sub never ever goes over 80Hz.