Subwoofers - crazy upgrade!

@lewinskih01    A good analogy is each of your subs are capalble of generating a certain size wave. All 4 of them are generating the same size wave in different locations evenly around the room.

If you stack them they now become 2 units instead of four but they each push double power and double cone area and can create 2 much LARGER waves. Almost double the size!!! Big powerful waves instead of 4 little waves.

It's physics. It's how it works.

@gdaddy1 

sorry, but it's not. At the same sound level in the room, the 4 subs/amps put out the same energy whether they are stacked one on top of the other or spread out. When stacked, acoustically both subs behave as one larger one, but still outputting the same energy as if they were spread out. The advantage of spreading out is the more even bass response in the room across different locations.

Stacked subs provide larger headroom, but that's rarely the issue with multiple good subs in a living/audio room. Stacked subs can push twice the power and surface, but that's headroom and not SPL at a given sound level in the room.

@lewinskih01  At the same sound level in the room, the 4 subs/amps put out the same energy whether they are stacked one on top of the other or spread out. 

That's just not true..it takes LESS energy to get the same sound level in the room. When you stack them, without changing any of the settings, you would get a 3db to 4db boost in your room just by making stacks of two instead of 4 seperated locations.

Acoustic coupling vs. amplifier power

People often confuse these.

Case 1

One sub.

100 watts.

Reference SPL.

---

Case 2

One sub.

200 watts.

Cone excursion increases by about √2.

Pressure increases by √2.

Result:

+3 dB

---

Case 3

Two identical subs.

100 watts each.

Total amplifier power = 200 watts.

Pressure doubles because both cones radiate together.

Result:

+6 dB

 

@ozzy I have 4 subs, placed in the corners of the room. But I wonder if stacking 2 in the front would be better?

In 2011 when I slightly asymmetrically corner positioned two Velodyne 12" Plus, one DD-18" and a 15" Earthquake Nova in a large vaulted living / dinning room.This eliminated ALL that rooms standing wave bass modes. The Velodyne Auto EQ and gain were changed substantially. This distributed bass array became my audible low frequency reference experience even today.

In 1967 a recording engineer sold his Octavium Subwoofer cabinet to me and demonstrated how to find any rooms bass modes for optimal sub positioning, now referred to as the subwoofer crawl. While the distributed bass array essentially eliminates the need for the crawl, it's still nice to know a rooms modes. 

Other than a brief time with a huge REL Studio III "Sub-Bass System" using its corner placement instructions I have found corner or front wall positions to be very problematic for -3dB rated subwoofers. The -6dB Studio III simply didn't play low enough to excite the rooms standing waves, as a result it could be located most anywhere in the room.  All the best.

@gdaddy1 

I believe you are confusing how the physics at play work.

For a given in-room SPL, using a given cone driver, a 200W amp won't sound louder than a 100W unless the former is asked to play above 100W. A 200W amp provides more headroom - that's it.

Anyway, I'm not interested in debating what seems to me like a moot point. I just wanted to make sure newcomers didn't take away a magical solution that won't pan out. Anybody with an SPL meter can validate this for oneself.