Originally Posted by Locoliberty
I understand that multiple subwoofers have a positive effect on overall bass response in a room and better response in multiple positions.
I am weighing my options for subwoofer upgrade and multiple subwoofers. I have a single SB2000, but its low extension isnt the best, especially in my room and starts to roll off in the mid 20s(as measured in REW).
I have the option to trade it in for a dual PC2000 setup. But it would be cheaper to simply grab a second SB2000. I have no DSP currently and likely wont for some time. My system is dedicated 2.1(or .2)
I am curious, do multiple subwoofers aid in better extension?
Move your sub to the middle of the room and take a measurement of the sub "nearfield" with the mic 1" away from the driver. This will allow you to see the "native" response of the sub with little to no room influence. If you see the same roll-off as the in-room response, you'll know it's the sub. If the response rolls off differently than the in-room response, you'll know it's the room.
Adding a 2nd sub does not change the F3, (-3 dB point) of the subs. It will increase the amount of output at the F3, but the F3 itself will not change.
You only get FR smoothing, and more consistent response across multiple listening positions if you distribute the subs around the room. Placing them as far apart as possible is the most likely way to get the optimal amount of smoothing. Co-locating, (i.e., stacking them or placing them side by side or very close together), will provide the most output, (up to 6 dB more), but will provide little to no smoothing and/or increased consistency. When co-located, subs will "mutually couple" and the wavefronts will propagate as one, single, combined wavefront. Therefore, you'll only have one transfer function of the soundwaves to the LP. Distributing them will provide a variable amount of increased output, but it can provide the maximal amount of smoothing because you have two separate transfer functions to the listening position, and you are statistically more likely to have one transfer function fill in for the deficiencies of the other transfer function.
If the ultimate goal is deeper extension, and the lack of extension is definitely related to the subs and NOT the room, then subs with deeper extension are the only solution. OTOH, if the lack of extension is caused by the room and modal response, then additional distributed subs can *potentially* provide deeper extension by improving the modal response.
Is that as clear as mud???