RTA

Ignore all of the rest of them because this one is actually calibrated for your iOS device. I tried other apps setting up my vehicle and this one is obviously accurate. After about 10 minutes of tweaking the EQ on my head unit my new speakers sound 1 million times better. If you have a hard time setting your EQ to sound good this one will get you there.

How accurate is this compare to a calibrated measuring mic? My goal is to EQ my room to have a flat response. I have an iPhone XS Max.

I use this app at least 8 days a week! When the new iOS update came out the app was having problems fitting the screen. Everything still worked as expected, just smaller. I emailed the developer about the issue and had a response in 5 minutes! That is customer support if over seen it. In the response I was assured the new update is awaiting approval from Apple. Thanks Andrew for keeping us all afloat.