Madrid to Barcelona to San Sebastian and back to Madrid in 10 days?

Great. San Sebastian has a great music Festival outside on the beach there in the evenings free this July 20-25
http://heinekenjazzaldia.eus/en/

Beware there is currently limited hotel space if you go during that span

Oh and if your family likes art history you may want to spend more time in Madrid. They have some of the most famous paintings you may have seen in text books in school.

Take some days away feom Barcelona and add them to Madrid.

I think much of Madrid's interest for teenagers comes down to their tolerance for the art museums. I liked the museums but was beyond bored by the Palacio Real. However, the palace was full of Spanish visitors, who were enjoying themselves. I happily spent 10 days in Barcelona.

I think the weather in July is a factor, too. It will probably be comfortable in the Basque Country (with some rain possible), warm to hot in Barcelona and quite a bit hotter in Madrid.

Thanks so much for this input.
Agree more time in Madrid makes sense but am also trying to balance my kids interests (would much rather be playing soccer/watching a game -unfortunately none that I can find during early July) then going to museums.
Given your recommendations - this may be our compromise - We arrive in Madrid on day 1 in the am (tired) but can see some things, Day 2 Madrid and leave on 8pm train. And then day 10 - if we haven't gotten enough Madrid leave San Sebastian early am and spend afternoon/evening in Madrid.

Day 1 - (am) arrive in Madrid. Evening train to Barcelona
Day 2 - Barcelona
Day 3 - Barcelona
Day 4 - Barcelona
Day 5 - Fly to San Sebastian
Day 6 - San Sebastián
Day 7 - San Sebastián (side trip to Bilbao)
Day 8 - Fly/drive from San Sebastian to Madrid
Day 9 - Madrid
Day 10 - Madrid (side trip to Toledo)
Day 11 - Fly home