I have a 10" sub and a 250 watt RMS amp in my prius. It does pretty well for most bass, but some tracks have some very low notes, and the output just isn't there. The woofer should go down to 28hz, but bass drops off pretty significantly right at 40hz. I've tested this with a frequency generator. This is actually the second sub that I've had in here, and both of them behaved the same way in terms of losing bass below exactly 40hz, which makes me think this low cut is built in to the head unit. Which makes me wonder: is it software or hardware that cuts the sub bass? If it's software, is there any kind of mod or hack that I can do? I'm guessing the real mod is to get a proper head unit, but I have few issues with the factory head unit, and I think it would be a decent chunk of change for what I think would be a small upgrade.
A reminder that some compressors do a bandpass before encode, a lot of good bass and sub bass is left behind this way. Depending on the audio source and pathway to the car, the portion of the signal you seek may not be making it into the car.
Good point. Most of the music I listen to is MP3 on a CD. However, my frequency generator test was using a phone over bluetooth. Maybe I need to generate a frequency sweep and burn it as an audio CD to see if it's much different.
Record your frequency generator into another device. Then encode that as an mp3 and play it back in the car and compare that to the direct playback from the generator. Really, every little choice made (bluetooth vs. wire... USB vs analog audio wire) comes with consequences in the resulting audio. Usually it's close enough, but if you have a specific interest (low frequencies) then you need to be more careful than the average music lover.