Darn good idea.
Your existing speakers may sound great, however they are bass limited, and inefficient as you know.
1. a stereo pair of self powered subs is a very good idea, don't over do it. two, located near the mains, so the low bass and the overtones from those notes are directional.
2. removing the need for your existing amp to handle the bass is going to allow it to do a better job with your inefficient mains.
3. easy independent volume control/balance with the mains is nice, if buying new, remote vol of sub would be very nice.
Your existing speakers may sound great, however they are bass limited, and inefficient as you know.
1. a stereo pair of self powered subs is a very good idea, don't over do it. two, located near the mains, so the low bass and the overtones from those notes are directional.
2. removing the need for your existing amp to handle the bass is going to allow it to do a better job with your inefficient mains.
3. easy independent volume control/balance with the mains is nice, if buying new, remote vol of sub would be very nice.