The OBP-3 is Aguilar's most flexible onboard preamp design, providing +/-18dB of cut and boost at 40Hz, +/- 16dB of cut and boost at either 400Hz or 800Hz and +/- 16dB of treble cut and boost at 6.5 kHz. The OBP-3 has multiple wiring options, and can be wired with either a push/pull pot, mini-toggle or internal dip-switch for midrange frequency selection. Aguilar preamps have high headroom, low distortion and reproduce the full dynamic range of your instrument. The OBP-3 is the Aguilar Sound in an affordable, easy to install package. A great upgrade for any bass! I own 30 basses and I have the OBP-3 in about 20 of them. That s because the other ones are passive! LOL. Low end is big but not muddy. Mids are fat and not nasally. The Treble is perfect. Love this preamp! -Bryant Siono - Bassist for Jennifer LopezGet yours today; with the security of our many decades of experience and Sam Ash Direct efficient order processing, your satisfaction is guaranteed!