If you can get the easy feeling buzz on the lead pipe then transfer this same relaxed open feeling embouchure to your instrument. The chances are you will get a note lower than low C. This shows that you indeed have that relaxed embouchure. All you have to do to get the low C sounding great is engage the aperture corners a little more and probably raise the tongue a little. I’m guessing this will feel completely opposite to what you are used too. I’m lucky because I’m a relative beginner so don’t have engrained habits.

The funny thing about all of this is I wasted about 6 months trying to play with my lips touching and forcing the air. Just could not do it. As hard as tried my top space E was a squeak and bloody hard work. Now having discovered that pitch change is all about shape I can play from low F sharp to third space C with no effort. Third space C to G on top of the staff is coming along nicely and I have actually managed to ascend chromatically up to high C. OK at the moment the notes above the staff are not playable but they are starting to speak. For me I think I need to get better control of the aperture corners and tongue arch.

The other thing I have noticed is that the singing C exercises do wear out the muscles that control the aperture corners. I don’t feel at all tired but all of a sudden my brain sends the command to tighten the corners but nothing happens. At this point I rest or practise my appalling tonguing.