Help with which board and more

In completely new to this and I've been looking for about a year to figure it out and seen a video about the arduino spectrum analyzer.
I'm trying to duplicate what's in the video of the link it starts at 1:14. I have about the same amount of space and will also be using it for the same application. Green Cobra 29LTD 10-28 ''el brujo'' - YouTube

Do you mean that you want to be able to make LEDs flash depending on the frequency of sound?

I don't know the answer but maybe if your Title related to your problem someone who does would notice it. You can change the Title if you edit your Original Post.