I strongly recommend Toneboosters EQ, or Fabfilter Pro-Q3
Both are excellent EQs that include spectrum analysers so you can monitor the freq spectrum of your audio both before and after applying EQ adjustments.
If you just want a spectrum analyser, I think there are a few cheaper options on the appstore that can be loaded as AUv3.
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I strongly recommend Toneboosters EQ, or Fabfilter Pro-Q3
Both are excellent EQs that include spectrum analysers so you can monitor the freq spectrum of your audio both before and after applying EQ adjustments.
If you just want a spectrum analyser, I think there are a few cheaper options on the appstore that can be loaded as AUv3.