Here's where I've gone so far trying to make the best of what I have. I'm looking for any tips or constructive criticism.
My system is passive 6.5" components up front & a 12" sub in the back of the car. It's powered by a 4-channel MTX amp with the rear channel bridged to drive the sub. My headunit is a
Kenwood that has all the tuning features of the midrange Kenwood & JVC units these days.
The main tools I use are:
13-band graphic EQ (range is +/- 9db per band)
Digital Time Alignment (distance & gain adjustment for each channel)
Crossovers ("Tweeter crossover" is actually an adjustable high pass shelf filter with frequency adjustment and seperate L & R gain)
I am not using any of the other adjustments like loudness, bass boost, subwoofer level control, "stage EQ", "sound realizer" and so on.
Install log is here:
http://www.diymobileaudio.com/forum...8690-2010-mazda-cx-9-touring-install-log.html
I'm using the
Dayton IMM-6 calibrated mic in my Android phone and the
Audio Tool app for measurements.
I'm generally following Andy W's approach he's been writing up on the AudioFrog Forum:
Time Alignment Part 5: Putting it all together
First, I set all my amp gains using an
o-scope to watch for clipping. I used -10db sine tones, 1KHz for the front and 40Hz for the sub channel.
The passive crossovers cross my mids & tweeters about
4.8kHz with a
12db slope. My mids are high-passed at
80Hz with a
24db slope. My subwoofer is low-passed at
70Hz, 24db.
Then I used Erin's site to set up my time alignment. Here are my measurements and the site's calculations:
Capture by
ben.garner, on Flickr
From there, I tweaked the left and right side values to move the image more to the center using pink noise pops.
My final time alignment settings are:
Front Left:
3.73ms
Front Right
2.8ms
Subwoofer:
0.0ms
Next I used uncorrelated pink noise & the Dayton mic to adjust the subwoofer gain down at the amplifier until it's volume at the driver's seat matched the front channels.
Setting the Audio Tool app to 1/3 Octave & playing the uncorrelated pink noise, here's my uncorrected response:
Screenshot_20180209-100710 by
ben.garner, on Flickr
Then I used the headunit EQ to raise the bass level back up using the "Bass Extend" function. This turns the bottom EQ band (63Hz) setting into a shelf filter that raises or lowers all the frequencies below 63Hz.
Again using the mic and uncorrelated pink noise, I adjusted the other EQ bands to minimize any peaks that I could. I also used the the head unit "tweeter crossover" to bring down everything above 4kHz just a tiny bit.
My EQ settings so far (all filters have a Q of 1.35):
20-63 Hz: +9
100 Hz: +4
160 Hz: -8
250 Hz: -7
400 Hz: +6
630 Hz: -3
1 kHz: 0
1.6 kHz: -6
2.5 kHz: -3
4 kHz: -2
6.3 kHz: -4
10 kHz: -2
16 kHz: +5
Here's the response I'm at so far with EQ:
Screenshot_20180209-101025 by
ben.garner, on Flickr
All that being said, the system definitely sounds better than it did before all this. I'm most impressed with the subwoofer integration using Andy's advice. It's blended into the front MUCH better than I was ever able to achieve trying to adjust the subwoofer's time delay to match its phase with the front.
So, thoughts from anyone?