Yes, putting a 12 in. 350 watt sub with a sub of 2400 watts and 15 or 18 in. is not a good ideal. But, mixing 12 and 15 in. subs is not a problem in most situation. Identical subs, one mid-wall and one corner loaded can be a very bad power match and easily stress the mid-wall sub. A lesser sub can be used nearfield. It is not a good ideal to make blanket statements. I have mixed subs from 8-18 inches and never bottomed out a sub. Subs just need to be somewhat similar in power and perfromance.
In my signature, a vented single driver sub is used with a sealed double driver sub. These subs play well together or alone in pairs. Adequate knowledge and proper setup are key to good HT bass.
Klipsch RF 7 based HT 7.4, Pioneer SC 35, Acurus 200 Five, Dayton 18 Ultimxa Dual Sub Cab(2), Dayton 18 Ultimax Large Vented Sub Cab (2), on Berhinger I Nuke DPS amps, Samsung BDP F 7500, Asus/My Book Live HPC 4 TB
Yaquin VK 2100 amp, McIntosh XR 5 speakers, Samsung BDP F 7500
Last edited by derrickdj1; 07-28-2014 at 08:13 PM.