Disabling/Changing the EQ on the 2011+ Head Unit

xluben · Apr 29, 2013

For anyone with a 2011+ (as far as I know) with the stock head unit, I found this info to be very useful. Originally was told about this by lkv, but then I found more info online. Here is a link to the original NASIOC thread:

http://forums.nasioc.com/forums/showthread.php?t=2317060

What does all this info mean? Here's my quick summary:

Factory EQ:
Sedan and Wagon mode are basically the same. Slight EQ tweaks on the front channels and basically zero bass from the rear speakers. Setting it to through mode will get full range (flat EQ) to all of the speakers.

Loudness Setting:
Normally on. Your basic pop music/consumer audio EQ. Really pumped up bass and treble with reduced mids. Gets closer to flat as you crank up the volume. Depending on what music you like you might like this on.

Bass/Mid/Treble Adjustments:
Basic adjustments that work as expected. Log based adjustment. Changes are less apparent at higher volumes.

My Overall Thoughts:
Turning the EQ to Through mode will get you more bass out of the rear (may have to fade towards the front if it causes rattling). Turning Loudness off will give you less bass/treble, but will make the midrange much more noticeable. I turned mine to Through mode with the Loudness off and it's a lot easier to actually hear vocals. I like it!

And here are the relevant items from the NASIOC thread:

wondras;38435221 said:

To disable factory EQ:
With the unit OFF, press one of these combinations of buttons:

1 + 2 + TUNE (right knob) for SEDAN
1 + 3 + TUNE (right knob) for WAGON
1 + 4 + TUNE (right knob) for THROUGH MODE (or a flat output)

Click to expand...

wondras;38435221 said:

To turn loudness on or off:

With the unit ON, press and hold 1, 6, and TUNE (right knob.) The display shows LOUD OFF or LOUD ON.

Click to expand...

wondras;38493230 said:

Excellent news -- Through Mode is indeed flat in both the front and rear channels!

I did some initial testing with a CZ624U1, using a makeshift line-out converter. Here is a frequency response comparison between the Sedan and Through Mode settings:

With loudness turned off, the response stays the same regardless of volume level.

Through Mode is flat to within 1 dB from 40 Hz to 20 KHz. The actual low-end response is slightly better than what's shown here; the capacitor in my LOC was on the small side, which caused some extra rolloff.

Looks like Sedan gives the fronts a +3 dB boost at 80 Hz, and a -7 dB cut at 250 Hz. The rears have a -9 dB slope from 1 KHz down to 125 Hz, then a quick rolloff below that.

Results for Wagon mode were identical to Sedan, so they are not shown here. (I'm guessing that both settings are there to be consistent with what they've done for other models, even though there are no differences in this case. The DSP chip in this unit can actually be programmed to do time alignment, dynamics compression, etc., but it seems highly unlikely they'd use them.)

Note that you will have quite a bit more bass going to the rears in Through Mode, so you may want to make sure you're not overdriving them, and fade more to the front if necessary.
Click to expand...

wondras;38493230 said:

As for the loudness function, here's what happens at various volume levels when it is enabled:

With the volume set to 12, there is an 11 dB boost to the low bass, and an 8 dB boost to the high treble. The boost decreases as you turn it up, until it is flat by a volume setting of 35. The decrease is slow until you turn it pretty far up, where it falls off more rapidly. This explains why at medium volumes it has so much "boom and sizzle."

The loudness and fixed EQ are both rather heavy-handed, but it's really the combination of the two that makes it so awful. Hopefully these results will be helpful when deciding what adjustments to make.
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wondras;38538763 said:

To help a bit more with system tuning, I measured the effects of the bass/midrange/treble controls. It uses the typical frequencies of 100 Hz / 1 KHz / 10 KHz, with a +-12 dB range, as shown here:

One interesting quirk is that the change is not constant throughout the 0-8 range:

Lower settings are closer together, which is actually pretty nice. A lot of decks go in 2 dB steps, and I often wish that I could make a smaller change.

Another thing to note is that boosted frequencies are limited above a volume setting of 34. For example, at a volume of 35, moving the bass from +7 to +8 makes no difference. At 40, there is no boosting at all. Cuts still apply, though.
Click to expand...

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Disabling/Changing the EQ on the 2011+ Head Unit

xluben Well-Known Member