I've got the jeff berlin mark bass combo, I use 15" speakers about 5 years ago never liked the sound, but my god I asked my local music shop to get one in for me to try out they had other markbass stuff in but I don't like tweeters and never had, then I got the call about this little baby shocked I could lift it with one arm and then the sound sweet Jesus !!! Never heard anything like it even the guys in the shop were shocked !!! And still I turn the treble down because its a tad too bright for me but man awesome combo. It's has the little mark II head installed.