StruckBy99 said:
fourthmeal said:
FYI, rear taps will work but the factory HU is severely EQ contoured on the rear speakers, and only mildly on the front speakers.
Please explain how are the front and rear contours different? Do you have any specifics on what frequencies and how many db's they're cut or gained?
Thanks,
Jason
Sure.
I measured the outputs on my '08 Mazda Tribute on all channels before I settled on pulling from the front channels when I first installed my 3sixty.2 processor in-line with the factory HU. This was the first iteration of my system design. The 3sixty.2 takes outputs from the deck, digitizes it in 24bit, and then applies 31 bands of EQ to smooth out the response back to a somewhat flat level. The amount of EQ done on the rear speakers was bad enough that the processor ran out of EQ bandwidth before it ran flat. The fronts were a little off but not unbearable. This contour changes with volume, much like "loudness" buttons do. You can hear it in the output from front to back, as well. Those speakers are identical from what I remember, but the sound is completely different, even near-field.
In the end, I put the factory rear speaker wire back to stock, and tapped off the front speakers and sub output only. the Sub btw is shielded twisted pair, not speaker level. The processor had to compensate for that with major boost, but it was able to make it just barely.
The actual contour was not recorded. I gave up when I received error after error in attempting to flatten it out. Doing the fronts got me there so I kept it at that. To give you an idea though, the rear looked like a plateau, with heavy LF cuts and heavy HF cuts. Also the response was quite ragged overall, indicating distortion. The fronts definitely have the same plateau but it is more like a foothill than a mountain. It is fixable.
A note on this, the clipping lights indicated that the head unit was capable of semi-clean output up to about 1/2 volume. So when I set up my system, my volume knob's "clicks" on the on-screen display never could exceed 1/2 the available amount before severe distortion set in. Because of this I had to deal with the stock HU's volume changes in huge jumps. Meaning, one single bump of volume on the knob made roughly 3dB difference. Quite drastic, and hard to find the ideal listening volume. Changing to the Pioneer F900BT head unit made it much easier to find the sweet spot. Amongst many other advantages.
