rowuk

I have tried various weights and other things and can say the trumpet sounds and plays best the way it was originally designed. Adding weight can make the trumpet slot better, generally at the cost of poorer intonation and evenness of blow - which leads to a bigger mouthpiece with a drilled out throat to make the horn slot less and allow us to bend the intonation back to where it belongs. Placebos are available everywhere. If you believe in that stuff go for it, it is not my money that you are spending!
My take is, if you want a heavy trumpet, then buy one that was designed to be heavy. If you want something that makes a REAL and generally POSITIVE difference, spend the money to get your horn overhauled with a valve and gap alignment.

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Whenever I feel blue, I start breathing again.