If you find a big enough graphic eq you should be able to smoothly blend the low freqs in. Audiocontrol bijou is also nice. I'm not sure how much they cost. My favorite eq of all time is SoundCraftsman. They can be found used and they are very good IMO.

M80's VP150 QS8's Earthquake SuperNova MKV-15
Integra DTR-7.4 Outlaw 755 Outlaw M200's Outlaw ICBM