I'm personally skeptical that there is any useful response in these regions, at least not in the front door speakers on my LX. They rolloff well before 40.Well I've been installing Rattletrap by Fatmat (anti-vibration material, similar to dynamat) in all my doors and tailgate (another story in itself) and decided to finally get a bead on the system specs for the JBL system using my multimeter. I've been thinking about replacing the stock speakers...www.toyotanation.com
This is specs for a Highlander JBL system. Different but you can extrapolate. Like i wrote above, JBL wattage is PEAK. RMS/continuous rating is probably around half.
The 6x9s can go down to around 28 Hz…but probably only useful to about 30-40 Hz. The cargo subwoofer and front door 6x9 speakers represent the BASS of the system.
Still think the stock ML stereo sounded good, if a bit bass light. And I didn't know it was bass light until I added the bass, if that makes any sense.
I'll go look at the DSP software and see if it'll output a xover report.