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      11-13-2012, 11:41 AM   #73
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Originally Posted by kaigoss69 View Post
OK, if your amp doesn't have a LP setting then you can't do it. The XD amps are not as flexible as I thought. Then your calibration procedure would be:
  • Set Ch1&2 filter to "off" (so the underseats get all frequencies between 20 and 200Hz)

  • Disconnect sub (so it doesn't interfere with calibration)

  • Correctly set the volume ( underseats are already level matched to fronts using MS8 test tones + JL App ) Do I have to re-do this since were changing amp settings?

  • Run sweeps

  • After calibration, make sure you have good tonality, stage width and midbass
  • If not, change amp gain and recalibrate
  • Set Ch1&2 filter to "HP" (keep at 80Hz)
  • Reconnect sub (set Ch3 filter to "24dB" at 80Hz and adjust gain to your liking)

Make sure your sweep volumes are all roughly the same level. Best to do this through the "secret menu", playing pink noise through each channel, and measuring with an iPhone app. Since you cannot use the LP trick to chop off frequencies above 200Hz from the underseats (MS-8 "design" flaw), you have to artificially lower the output of the underseats by around 4-6dB compared to the other channels. The reason for this is a bit complicated to explain but if you want to know, read this thread:

I take your word for it, I have read most of that thread but thanks I always love knowing exactly whats happening to learn.
I think I got this :
  • I put MS8 volume at -21 play test tones with the meter ear level and the front / centers ( app reads 68db )
  • Raise the volume of the underseats to match the 68db
  • Run sweeps in MS8
  • Lower amp gain 4-6db on midbass channel ( verified through jl app )
  • Turn X-over back on HP set at 80hz for mid bass and connect sub
  • Set sub gain to my liking
( ENJOY? )

Cant wait to do at lunch ( expecting better results ).
13 F30 328i Sport 6MT
95 E36 325i Vert 5MT
92 Sentra SE-R SR20DET DET Build Thread
08 E90 328i Sport [sold]
89 E30 325is [sold & missed]

Last edited by QUiKSR20; 11-13-2012 at 12:10 PM.