Rest In Peace Jeff Bagby

John Frum

Secret Society Member
Jeff Bagby passed away this morning after a long illness.

You may not know Jeff’s name, but he was a leading light in the DIY speaker community. Jeff’s free Passive Crossover Designer software brought professional-grade crossover design into the hands of amateurs. His data-driven approach to speaker building, based on successive rounds of measurement, modeling, building, and listening define the state of the hobby today, and many of the people that he mentored have gone on to careers in the industry. He patiently and graciously spent a great deal of time helping people build better speakers.

His designs won him a ton of competitions, and have been available as kits at Parts Express, Madisound, and DIY Sound Group.

If you go to a speaker design competition, you’ll be struck by how very good most of the speakers sound. That’s as much due to Jeff as anyone else. You’ll also find that most of these speakers sound surprisingly similar and, to be honest, kind of boring. Too many builders are leaving their ears out of the equation, pursuing the same set of checkmarks indicating technical excellence. It’s worth noting that Jeff started with technical excellence and tweaked after listening, sometimes ad nauseam. His superb ear for music is part of what set his designs apart from those of many of his students and peers.

He was a master of his craft, and a gentleman.
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Staff member
He was one of my friends on FB as well which is where I saw the news today. Rest in Peace Jeff.


Junior Member
Oh man. Such a shame and such a loss for us. He always patiently and politely answered any and all dumb questions I asked him. Great guy. Damn.