Suggestions for where to purchase concert tickets in advance online for Sept. in Vienna and Salzburg? Vienna concerts.com?
I would just go to the website of the venue, e.g. Vienna Staats Oper or Salzburg Festival.
Buy direct from the venues, not a reseller like Vienna Concerts.com. They will overcharge you at the very least.
What concerts are you planning to go see?
We want to see a concert at the Mirabell Palace on Sept. 16 but I can't get the web site the RS guidebook recommends to work. We wanted to see an opera or operetta on sept. 12 in Vienna but can't find one we want to see. The Magic Flute is on Sept 13 but we want to go to Melk and cruise on the Danube that day.
This site handles ticket sales for all Vienna state theaters, including the Staatsoper and the Volksoper.
https://www.culturall.com/docs/1310
The problem with resellers is you will not know exactly where your seats are until after you forked over the money. Some venues are using resellers exclusively because it saves them the expense of maintaining an on-line ticket shop. So check out the venues direct. You will probably need to register with them and set up an account. Just added typing to get into their system and find out what the real scoop is.
Edit- Use this site for Mirabell Palace concerts. http://www.classictic.com/en/special/mirabell_palace/1031/
For the Mirabell go direct to the venue:
https://www.salzburger-schlosskonzerte.at/en/index.htm
Since you will not be there for Die Zauberflote why not go to a real classic of Johann Strauss Eine Nacht In Venedig ( A Night In Venice).
It should be truly wonderful and will be performed on the 11th September. Again, go direct to the venue:
https://www.culturall.com/ticket/ivop/performance_schedule.mc?language=2