I use my laptop with a program called REW to send a frequency sweep to my cars stereo head unit in order to tune the stereo with a calibrate mic. I do this by plugging in an aux from the laptop to the headunit. Recently, i've come to the realization that my aux out may not be sending out a flat signal due to internal eq and high pass/low pass filters.
Is there anyway to check for high/low pass filters built in, or bypass them all together? I am aware of the sound settings EQ that i can turn to flat.
On this subject, when i plug the aux in, i get a list of options such as speaker out, and dell speaker out. What are the differences in these options?