I want to repeat my advice - make sure you are playing the "same way"
Yes - this is spot on good advice --
Consistency in mouth position, breath support, throat conformation, reed placement - everything I can think of - trying to do it "the same way".
I am trying to "isolate" the issue (as you said) and pay close attention.
I just wondered if other beginners had these issues.
Sometimes I practice with just the mouthpiece or just the mouthpiece and the neck and it seems that the pitch I get there can be quite variable.
Especially with mouthpiece plus neck alone.
So I was thinking that maybe the more "open hole" notes on the sax might be more sensitive to problems with intonation and timbre - just like when playing the neck alone.
Meanwhile - When doing scales I often throw in accidentals so I do wander outside of the strict major scale at times - sorry if I gave a wrong impression.
The idea of the drone tones giving a constant reference is very good as it could be the case that I slowly go a little sharp over the practice period until it becomes blatantly noticeable at some point and so I "hear" a bad note but really the notes have all been getting a wee bit bad all throughout the session.
Your suggestion on "Extending the scale" is also very good. I agree 100% -
Still working on those palm keys.
Also as regards specifics ---
Specifically - when I play chromatic scales starting on Low C on tenor and going not a full two octaves but up to around G - so octave and a fifth (i may need a fifth soon) - there is no problem ---But when I play a chromatic scale starting on the F up to the same G, then the D flat sounds weak and typically flat - like really flat. Which seems odd.
I thought that flat intonation was with a more relaxed embouchure.
But as a beginner plays (or so I have been instructed) and becomes fatigued, then the tendency for the tired beginner is to pinch and make intonation go sharp - ?
Now I don't know ---
Did the D flat really go flat or did the F through C all go sharp?
Driving me nuts - and by the way if I just keep playing that problem note, I can eventually fix it - but you can not do that in an ensemble or in a lyrical solo - sounds terrible.
So I am resolved to work with your drone tones, and expanded scales, and try to see what on earth I am doing to cause this - because if the notes sound fine on Monday but smelly on Tuesday stinky on Wednesday but great on Thursday - Then it is the player and not the machine.
Also I did a little internet search just asking: "What are the most difficult notes to play on a tenor sax?" >>>>> And the mid range B, C, and D flat did not make the list at all!!! And these are the buggers for me. So - focus - practice - isolate - drone tones - extended scales.
Thanks for the suggestions - truly - and hope my tone will become clearer than my questions - ;-)
PS you sound great on the drone tone example - nice!