so I’m sure you know beryllium is only toxic when being machined , sanded or otherwise being physically worked with creating dust or fumes.
@ronboco - Thanks for the complements but I was referring to Be tweeters being potentially toxic when damaged. I quote one of Focal’s own manuals:
If the beryllium dome is damaged in any way, it should be covered as soon as possible. We recommend that you contact the retailer to have the tweeter dismantled and replaced by trained personnel at the distributor.
If the dome is broken, any beryllium particles should be carefully collected and then placed in a hermetically sealed plastic bag. It should be sent back to the retailer at the same time as the speaker.
I’m unaware of ANY other speaker component or material having similar instructions. It is perfectly safe to be around adults who aren’t busy sticking their thumbs into it, but it IS more brittle than aluminum or titanium and, as you point out, the dust is toxic when inhaled. So long as you avoid damaging them they are fine.
This potential danger is also a reason why many manufacturers only sell Be tweeters with integrated screens.
Having said all that, with normal precautions no reason why you should avoid them. I only meant to say that if glass gave similar performance to Be without the sky high prices for Be today and had a better safety profile they’d make excellent replacements.
Your ears and wallets should judge, as always.