depending on the song of course, but there’s a couple ways to go about it…
Playing as the only tenor sax and now adding an alto you can simply double his part to be the same as yours, but it’ll add a lot since it’ll sound higher. This method is even used when there are even more horns because unison can be pretty powerful.
Also, the two saxes can play simple harmony instead of unison. this would be a 3rd apart… so if the tenor line is C D E the alto would play E F G.
If the arrangement utilizes a bigger horn section, the other way is to give the alto the trumpet part and you play the lower part (whether that’s the same line with a harmony or a different moving part)
these are general ideas and only working with each individual songs would I make a decision on which way to go.
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