Several options here...
Bud used several different midbass drivers. Do you have the C/3 or the C/3L aka C/4? The former are sealed, the latter are true transmission line. In the end, he disliked Focal most but liked Gefco (defunct, out of Chicago) best, and the last versions employed them.
I recommend contacting Bill Legall of Millersound at (215) 412-7700, whose rebuilt countless drivers over the years. He redid two sets of my Frieds (C/3L and Beta), among others. In fact, I have Bud's own personal pair, and Bill replaced a special hot rod voice coil Bud had Gefco do for himself with a part he'd only seen once previously in all his years, yet actually had on hand! That will also cost you less than most new replacements.
When we began producing new Frieds in the previous decade, we used Peerless / Vifa drivers. You can go that route, but I'd recommend considering Shanghai Silver Flute, which I used in some of mine. ScanSpeak also makes a great replacement in this application, albeit at a far higher cost. If you want to remain truest to Bud's philosophy, choose the model with the lowest Qts available, which actually goes against almost every other TL follower. Please feel free to reach out if you need any help
Bud used several different midbass drivers. Do you have the C/3 or the C/3L aka C/4? The former are sealed, the latter are true transmission line. In the end, he disliked Focal most but liked Gefco (defunct, out of Chicago) best, and the last versions employed them.
I recommend contacting Bill Legall of Millersound at (215) 412-7700, whose rebuilt countless drivers over the years. He redid two sets of my Frieds (C/3L and Beta), among others. In fact, I have Bud's own personal pair, and Bill replaced a special hot rod voice coil Bud had Gefco do for himself with a part he'd only seen once previously in all his years, yet actually had on hand! That will also cost you less than most new replacements.
When we began producing new Frieds in the previous decade, we used Peerless / Vifa drivers. You can go that route, but I'd recommend considering Shanghai Silver Flute, which I used in some of mine. ScanSpeak also makes a great replacement in this application, albeit at a far higher cost. If you want to remain truest to Bud's philosophy, choose the model with the lowest Qts available, which actually goes against almost every other TL follower. Please feel free to reach out if you need any help