Hi guys, I've been thinking about setting up a new bass for my band. It'll be a four string with tuning Ab, Db, Ab, Db (low to high). The low Ab is a minor third down from the B string on a 5 string bass. I need some recommendations on some basses I could use for this project. I don't want to pay a huge amount of money (~$800 US) and i'm prepared to buy a used instrument. I play in a metal band so I really need a bass that will allow the low Ab to pump. I've noticed that because the Ab is a minor third lower than the low B on a 5 string, sometimes the Ab sounds muddy and lacks definition. I really want to avoid this but I understand this could also be an amp issue. Any recommendations would be greatly appreciated, such as string guages, active/passive pickups, anything that might help me get a great sounding bass. Thanks in advance for your help.