Check the listing for details. Grace Design BiX Acoustic Preamp Pedal. Condition: New. Listed at 355.00 USD. Your Acoustic Guitar's Best Friend The Grace Design BiX is a compact version of the company's acclaimed FELiX and AliX acoustic instrument preamps. Pro touring and recording musicians here at Sweetwater — and worldwide — have embraced these ground-breaking devices for delivering a quality of amplified sound beyond what was thought possible. BiX, the new baby of the family, serves up the same level of audio performance as its big siblings, but in a more compact pedalboard-friendly format with a streamlined control set and a gentle price tag any performing musician can afford. Plug into BiX, and you'll hear your instrument with pristine clarity. Highs are silky and open, lows are strong and tight. Your playing dynamics come through, vibrant and true.