How does adding a second subwoofer improve your systems SQ?

Thank you for the kind words @hilde45

It's hard to tell without measurements, honestly, but before you get to your second subwoofer, the room treatment and EQ could be considered. With 1 sub, and good room treatment, properly set up, it can be magnificent.

A second sub, if you are free to place it anywhere, can certainly compensate for any big nulls, but what if you don't have any, or what if you use an open layout which does not lend itself well to standing waves to begin with?

Best,

E

Please pardon my ignorance, but what is SQ?

sound quality

markj941 OP
How does adding a second subwoofer improve your systems SQ?

Amazingly so! because bass is done in stereo on more albums than you think.
People that use one subwoofer have no idea that they’re screwing up any stereo imaging that the bass has. You need two subs L & R close to the mains if you are to faithfully reproduce what the studio recording engineer wants you to hear.

I have many albums (CD’s) even from the 80’s 90’s that have <100hz bass notes that come out of either left or right channel. So to mon’ize these recordings into just one mono sub is not what the recording engineer wanted you to hear.

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.
And the harmonic structure of bass notes like this above go right up into the midrange
Another that comes to mind is Ricky Lee Jones self titled album, it also has tracks where the bass only comes from one channel or alternates

Cheers George

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.