Sweep vs pink noise

[JoachimStrobel]

I recently came across the question, if a room analyses should be done with a sweep (which I always thought to be the default) or with pink noises which makes it easier to move the mike while doing an RTA. For a sweeps one would have to record in defined multiple positions.
Which method is better.
Is there a minimum time needed, like 100 ms or so, to trigger a room mode? Are room modes time dependent and would a sweep and even better, a long sweep therefore be beneficial, or would it amplify modes that music would never trigger?

 

[Socket]

pink noise only provides a RTA. Sweeps provide RTA and a range of other useful data like IR etc

 

[John Mulcahy]

Is there a minimum time needed, like 100 ms or so, to trigger a room mode? Are room modes time dependent and would a sweep and even better, a long sweep therefore be beneficial, or would it amplify modes that music would never trigger?

The sweep is used to measure the system's transfer function, which captures its behaviour in time and frequency. Longer sweeps have lower noise floors but the response they capture is the same.