I want more bass…

The frequency balance is very important in an hi-end audio system. Even slightly more high freq, the sound becomes bright. The listener feels dark and gloomy if the low and mid freq are even slightly more. The best reference is to match freq balance with the original sound or music. Therefore, the audio sound is natural and balanced and one can listen to the audio system for the long time without the listener’s fatigue.

One of big reasons for craving more bass is the strong distortion in an audio system. The audio distortion is mostly felt in the higher freq and is playing like high freq which makes there is more high freq. Then the more bass and mid are needed to balance out. The audio distortion is major irritation to human ears and our ears will not tolerate even little distortion sound. Even the strongest bass is not enough to balance out to this harsh high freq like audio distortion.

One way to reducing the audio distortion easily is using good properly made audio power cords.

Alex/Wavetouch

Turn down the treble?? :D

The room may be too bright, and needs damping.  Speaker placement may be less than ideal.

I know it's not a big audiophile thing to do, but every speaker will benefit from dual subs, regardless of how low the speakers go. 

@baylinor I respectfully disagree. I'm sitting here right now listening to Afrocelt Sound System on my Legacy Focus SE's and the bass is shaking the room. They play down to 18hz, no sub required!

I didn’t think 300B’s were a great bass performer but I’m not a tube expert. I would try an amp that you could roll with KT120’s. You may give up a little midrange sweetness but they can drive your low end. Or, you could try a hybrid tube amp such as a VAC or Rogue Audio.