Hello, I own a professional straight tenor saxophone made by LaSax, however I believe that the qualities are very similar to a straight alto. What brands make a professional straight alto that are high quality and can take the usual wear and tear? LaSax makes an excellent straight tenor, however I am not sure about their straight altos. I have heard mixed reviews on the LaSax straight altos, however I have only heard good things about the Keilwerth straight altos. Is it comfortable to play while sitting down for concert or standing up and even marching? As for playing sitting down... it is a little uncomfortable on a standard chair, however I play sitting on a stool which is very comfortable. Standing and walking is easy as well. How is the sound compared to the traditional curved alto? The sound is a little different than the curved counterpart... My straight tenor has a much more broad range of sound and tone qualities than my 1940s Conn 10m tenor. My straight tenor can also play much louder or much softer than my 10m. Hope I was helpful ~Blaise~