[randywebb]

I understand what you are saying...

But that isn't really "sub" - the best description I can give is to listen to orchestral music with true, low frequencies -- around 20- 30 Hz.

Not to say that the item above and other similar things will not make your listening more enjoyable and/or make the sound more accurate.

FWIW, folks who want lower frequencies can search up posts by bell on using the smuggler's box for a sub - that would be my next choice after this -- more trouble to do tho.