Since this has been active in other forums, it's time for us bassoonists to unite and share what our highest note is. Surprisingly, and without any practice, on a Meason reed, I can get a high "E" two octaves above "middle C". I've tried to get out a really low "G-flat" which is just like low "D" without the first index finger on the boot joint.







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The website, "A Few Easy Multiphonics for Bassoon" has some cool and interesting things to try, like "impossible notes". With the last fingering for a "screecher" note (At the bottom of the page) I was able to hit that note, and a semi-tone above it.

I have only been able to reach an out of tune high c sharp (one semitone less than required for the rite solo) and my lowest note has been the low A with the cardboard tube in the bell. How can you possible go lower? It's not like you can make your bassoon get longer on command.

If you go the website "A Few Easy Multiphonics for Bassoon" (or something like that) it will give you fingerings for "impossible notes", which may need to be "reinforced by another instrument". They will not sound like they are lower, but they are.
P.S. - I tried extending the range by using a rolled up poster, but it only took out the "growling" sound of the lower notes.

I got up to a high E one octave above middle C.
Weissenborn goes up to G two octaves above middle C if I remember correctly.

Someone should alter the reed, because vox Humana is one of the best parts of the bassoon

It depends on the reed. I usually can hit a high f# (top line of the treble clef)

Can you high-noted people please give your fingerings for the notes C above middle C, and subsequent notes Csharp,D, Eflat, E, and any higher ones that you can reach.

The website, "A Few Easy Multiphonics for Bassoon" has fingering for what is called a 'screecher note', which I believe is a "c" above the treble staff (two octaves above middle "c").