Non-JBL radio frequency response measurement

Has anyone seen an electronics person measure the frequency response of the Non-JBL radio in the TRD sport? This would be playing a white noise or frequency sweep MP3 and see what how the voltage at the speaker terminals change with frequency.

I know its not great but I want to see how bad it is. Same for the sound adjustment with speed setting. Does it act like a loudness button as well and add bass and treble at low volumes.

 

maybe hear https://www.tacomaworld.com/forums/audio-video.12/

 

wouldn't you rather use pink noise because of its flat frequency response?

 

either reference is fine. I just want to know when I put a frequency in at a certain amplitude, call it 0db, the output is the same RMS voltage (Amplifier are high current voltage sources). If there is strong equailzation even with the 3 band EQ is set for flat, I would like to know. If its "good enough" I will push back the urge to replace the entire system. If its not then I feel like Im not wasting money replacing the entire system.

I already replaced the door speakers with JBLs and the sound is much better for vocals. Pulled them more to the front instead hollow and echo-y.

I have an small 200 watt sub amp and 10" sub I'll be adding and "MAYBE" doing the rear speakers for some fill. Also MAYBE on the dash tweets since the JBLs so a pretty good job here.

Not looking to make a audiophile system of a concert hall. Just wall balanced full sound similar to my 20 year old BOSE sound canceling headphones.