I measured my system distortion with rew using impulse response, using lenght=1M as suggested in REW's docs. System is composed of a subwoofer, woofers in the doors, mids and tweeters in the a-pillars. Crossover are 75Hz - 400Hz - 3.5kHz.
These are the results (it is the same measurement but plotted differently, one for SPL and one for distortion % for easier visualization - white line is THD):
The spike at 200Hz (3% THD at 80dB) is volume-dependent and I'm not sure if it's the speaker itself or the plastic panel of the door vibrating. The spike at around 1.6kHz (1.7% THD) is not volume-dependent, it is always there and corresponds to a dip in the frequency response of the mid, I'm still trying to understand where it comes from. Anyway the overall THD is mostly below 1% but sometimes higher than 0.5%.
I'm not an expert in car audio at all, unfortunately I could never hear a proper setup and I couldn't find any similar graph on the internet (I can only find THD measurement of the amps, but not of the speakers) so I wonder if those distortion values are considered good for a medium-quality system.
Any suggestion for improvement... Thank you.
P.S. The subwoofer is turned off in this measurement
These are the results (it is the same measurement but plotted differently, one for SPL and one for distortion % for easier visualization - white line is THD):
The spike at 200Hz (3% THD at 80dB) is volume-dependent and I'm not sure if it's the speaker itself or the plastic panel of the door vibrating. The spike at around 1.6kHz (1.7% THD) is not volume-dependent, it is always there and corresponds to a dip in the frequency response of the mid, I'm still trying to understand where it comes from. Anyway the overall THD is mostly below 1% but sometimes higher than 0.5%.
I'm not an expert in car audio at all, unfortunately I could never hear a proper setup and I couldn't find any similar graph on the internet (I can only find THD measurement of the amps, but not of the speakers) so I wonder if those distortion values are considered good for a medium-quality system.
Any suggestion for improvement... Thank you.
P.S. The subwoofer is turned off in this measurement
I've never tried this but a distortion at a speaker level in a car would likely be at least 5%. Speakers and resonance of panels can cause a lot of distortion.