# Short time energy or root mean square?

What is the difference between Short time energy(STE) or root mean square(RMS), Librosa library offers a function to calculate RMS but doesn't offer one to calculate STE, which gives the impression that STE isn't that useful and RMS is enough, While in researchers paper they use STE, so that I got confused a little bit.

What is the difference between them and can one behalf of the another ?

• Personally, I am not familiar with the Short Time Energy metric so I would really appreciate it if you could share the formula to calculate it. Nevertheless, I am not really an expert on the field so I may be just missing something important. Mar 31 at 18:45
• Mar 31 at 19:17

• RMS $$\sqrt{\frac{1}{N}\sum_{n_0}^{n_0+N}x^2[n]}$$
• STE $$\sum_{n_0}^{n_0+N}x^2[n]$$
As far as why use one over the other, I'm guessing if you're using a short time window ($$N$$ small), then it might make more sense not to take the average... but that's really grasping at straws, especially if you consider the fact that some references define STE with the $$1/N$$ factor as well.