With the vinyl water bladders bass sounds travel faster in water then in air. Since we are about 90% water the sound resonsates in us. Meaning that you feel the bass even before you hear it. So it can go down as low as 5 or 6 hz, you won't hear that tone since the human ear can't hear that low but you will still feel it. the bass is very defined, you can feel and hear the bass string as it is being picked. So the bass is much faster, more defined and you feel it alot more because of the water. I got the IBS-12 which cost me 1368.00 but that was a special deal because that is the one that goes in theaters and they normally do not make it, so I got a special deal. They make the IBS-8 for 595.00 and IBS-10 for 795.00. the phone # for them is 1-800-718-5716. thank John The best way I can describe it is that the bass feels "thick" and you feel about about Chest high.