# Define a symbol already on stage (spectrum analyzer)

**URL:** <https://forum.kirupa.com/t/define-a-symbol-already-on-stage-spectrum-analyzer/216917>\
**Category:** Uncategorized\
**Created:** [February 21, 2007, 5:48pm UTC](https://forum.kirupa.com/t/define-a-symbol-already-on-stage-spectrum-analyzer/216917 "2007-02-21T17:48:01Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![raredesign](https://avatars.discourse-cdn.com/v4/letter/r/ea5d25/32.png) [@raredesign](https://forum.kirupa.com/u/raredesign)\
**Post date:** [February 21, 2007, 5:48pm UTC](https://forum.kirupa.com/t/define-a-symbol-already-on-stage-spectrum-analyzer/216917/1 "2007-02-21T17:48:01Z")

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Please see the attachment. I am using an opensource spectrum analyzer to try to learn, but I would like to start by making the stage symbol pulse in the same fashion. Thanks,

NOTE that I have inserted the below text at the bottom of the .as file so that you can see how it is not referencing.

//test to see if the MC can be referenced.  
\_root.mc\_ball.scaleX = 100;

I want to control a movie with the instance name mc\_ball that I already have on stage.  
If I reference it in the .as file via \_root.mc\_ball.scaleX or whatever I need to do, it says it is not defined…obviously.  
So what do I need to do, to define a movie ALREADY created?

I was informed on a different forum that \_root is no longer valid, so I am not sure where to go from here. Does anyone know of a tutorial that I could learn about this feature of referencing library/stage symbols? Thanks