Stuffed A and B in upper register of baritone

Check the upper 8ve vent key is opening sufficiently and the vent hole isn't blocked or occluded.

I can't remember if the upper 8ve vent is on the crook (like an X-bar or Buescher bari) or just below the socket (as on Selmer, Yamaha, Yanagisawa, Keilwerth, etc. baris) on Dolnet baris - I've a feeling it may be just below the socket.

But check that first.

http://saxpics.com/?v=img&img=/cpg1..._tone/6260x_jean-cartier_jd/db062i.jpg#imgTop So it is - it's been years since I last saw a Dolnet bari. The placement of the upper vent is pretty high on this bari compared to many others, even ones such as Conn X-bar, King Super 20 and Bueschers with a crook key have the upper 8ve vent much further down.

Take the crook key off and have a look in the vent tube to see if it's blocked with anything it shouldn't be - the vent should be clear of any built-up matter.

Don't use anything metal (eg. drill bit, scraper, needle, etc.) to dislodge anything that could be blocking it, so use a toothpick or coctail stick as that won't do any harm.

Check the key opens up enough when you play high A and also make sure the 8ve key on the body closes at the same time.

Hold the 8ve key down and play G-A repeated and watch both of the 8ve keys as they open and close. If both stay open at the same time or both remain closed at the same time while the 8ve key is pressed (and you're playing G-A slowly), then there's something wrong with the 8ve mechanism.