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Auto Time Alignment is not accurate for my setup

6K views 23 replies 9 participants last post by  tohdj 
#1 ·
When I used the auto time alignment on my Pioneer DEH-8650, the sound feels hollow or poor in bass. The distances calculated are
  • driver side front speakers is 220cm
  • passenger side front speakers is 280cm
  • driver side rear speakers is 250cm
  • passenger side rear speakers is 340+cm
  • subwoofer is 400cm

However, when I switch off time alignment or I use the headunit's factory settings for time alignment, the sound feels solid and bassy although there's some alignment issues.

Anybody knows the reason for this?

My setup:

My car is a compact MPV.
Headunit - Pioneer DEH-8650
Front Speakers - Rainbow Audio DL-C6.2 components running passive with tweeters on A-pillar pointing to the middle of the cabin at face level.
Rear Speakers - Rainbow Audio KX165 coaxials at rear doors.
Amp - Soundstream Rub4.600
Subwoofer - Mac Audio 10" in a sealed enclosure in car's rear boot facing upwards. Powered by an Alpine class D amp.
 
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#6 ·
UPDATE:

I found that one of my rear speakers was connected in reverse polarity. I tested it by switching off the front speakers and the subwoofers, and then i used the fader/balance to shift the 'focus' point from left to right and back. When the focus point was at the center of the rear seats, the sound didn't sound 'synchronised'.

So i switched the polarity of one of them and tested used the auto T/A and the settings for the rear speakers went to 300mm and 400mm for left and right rear.

Front Left - 220mm ...... Front Right - 160mm
Rear Left - 300mm ...... Rear Right - 400mm
Subwoofer - 260mm (Crossed at 50Hz. -12 levels. Normal)

So I switched both of them, and the current settings are as follow...

Front Left - 220mm ...... Front Right - 160mm
Rear Left - 160mm ...... Rear Right - 220mm
Subwoofer - 400mm (Crossed at 50Hz. -15 levels. Reversed)

Any advise on whether this is correct? How about the subwoofer? Should I switch the polarity, or just toggle it in the headunit?
 
#7 ·
I'd try one of the "setting TA by Ear" methods that are on here. I'd have to confess I never tried that with front and back component sets...
I think you would get a "stage" in your head like headphones :eek:
 
#12 ·
Fade all the way to the front (forget the rears for a bit) and measure distance to your front mid bass and the sub. Enter these and listen to it. You have a 13 band eq, that should help in dialing in nice tonality.
 
#13 ·
You could also try switching polarity between every mid and tweeter...

Listen to each channel with the rest muted with tweets "in and out" polarity... When it sounds like the sound comes out of the spot between the drivers then it is mostly ok.. When you hear both drivers from their own location it's mostly not ok...
 
#20 ·
UPDATE #2:

So I reversed the polarity of the subwoofer wiring, and the current Auto TA settings are as follow...

Front Left - 220mm ...... Front Right - 152.5mm
Rear Left - 180mm ...... Rear Right - 260mm
Subwoofer - 262.5mm (Crossed at 50Hz. -13 levels. Normal)

Previously, it was...

Front Left - 220mm ...... Front Right - 160mm
Rear Left - 160mm ...... Rear Right - 220mm
Subwoofer - 400mm (Crossed at 50Hz. -15 levels. Reversed)
 
#23 ·
Since Singapore is RHD, how can the rear left be closer than rear right? These aren't actual distances right? Based on your entered values, you have a 2.75" or 0.2ms delay between front L and R. Way too little. Typically the delay between front L/R would run 0.7ms ~ 1+ms, depending on width of the cabin. This is why I had recommended using actual measurements.

Did you try fading forward and then TA? Can you post your measured distance to near and far, mid bass and mid range?

I hope you are not expecting TA alone to dial in the staging and tonality, cause it won't. A big chunk of issues are resolved via your eq. A combination of TA and eq will get you better results than just TA alone.

Strongly suggest fading forward, setting distances based on measured distances and lets get on with setting the eq.
 
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