Originally Posted by barhoram
D2 ARC question....I've been doing some adjustments with a new sub. To speed thing up, I set ARC settings just to run tones for L, R and Sub. I found a position that seems good, and uploaded the settings to the unit. I tested and was very impressed with the sound. Bass slammed me in the chest when it should have. I did notice that instead of 5.1 + Dolby PLIIx on 5.1 input, I was just getting 5.1 with no PLIIx. I could not get it to switch PLIIx on....did the upload make it think I do not have a 7.1 setup?
I went ahead and ran a full calibration for all 7 speakers and sub in 5 positions. Uploaded the settings to the unit. Played same demo material, and PLIIx was back. However, bass wasn't quit as strong as it was before.
Is there some reason that bass output would be different between the two ARC uploads?
Yes, ARC Uploads the "speaker configuration" along with the solution. So if you built the solution as 2.1 speakers, then ARC will set 2.1 speakers as part of the Upload.
Now, when you play 5.1 content into a 2.1 speaker system several things happen. First you get a down-mix, which alters the sound. Second you can't enable surround sound processing like PLIIx because there's no work for it to do. I.e., it can't expand 5.1 to more speakers because you don't even have 5.1 configured.
When you play down-mixed audio, the volume is different. This may cause you to raise Main Volume. When you switch to your true, 7.1 configuration that may mean you are playing at a different volume which could account for the bass.
There are a couple things you can do to verify the 7.1 ARC solution is doing the right thing. First, play the LPCM test tracks from AIX Audio Calibration, Blu-ray, and verify matched speaker and Sub levels with an SPL meter. That will show you haven't somehow screwed up the levels after uploading the ARC solution. If the levels are wrong, before you do anything else, reset the "temporary" level adjustments that can be set using the buttons on the remote. These are remembered per input format and so you can easily confuse yourself into leaving some of them enabled. The fastest way to reset these is:
1) Save User Settings
2) Restore Factory Defaults
3) Load Saved User Settings
Since the "temporary" settings are not saved, this resets all of them. Also check that you have the Tone controls bypassed (button on the remote) and that you haven't added any EQ filtering to your Setup > Source Setup definition.
NOTE: Sub may measure a few dB hot in SPL due to the Room Gain built into the ARC solution. This is normal.
Once you find that levels are matched, then play the Crossover test from that AIX disc. That will send a bass sweep to the front speakers (only). At the high frequency end the sweep tone will all come out of the fronts. At the low frequency end it will all come out from the Sub due to Crossover processing set up by ARC. In between you get a mix. If things are working right, that sweep tone should be constant volume from end to end -- except for the lowest bass which is more felt than heard.
If the levels are matched and Crossover test sounds good, then you can feel confident ARC is doing the right thing, and the difference you heard earlier was likely due to the down-mix processing and how you reacted to that (e.g., volume adjustment).