AVR auto cal vs DVE

[WxMan]

Recently I bought the Blu-ray version of DVE for calibrating my HDTV. I also checked the speaker levels using the audio test tones. The DVE disk has lossless DD-TruHD, dial norm = 0 db. I used a Radio Shack analog SPL meter to make the measurements set to C weighting and slow response. I let my AVR decode DD-TruHD. I positioned the SPL meter at the exact same location where I placed the AVR's auto calibration microphone. The levels of the front LCR speakers agreed within +/- 0.5 db with those set by the AVR autocalibration setup. However, DVE required setting the surrounds +3.0 db hotter than the AVR's auto setup did. Both DVE and my AVR use filtered pink noise for the test tones. Both sound quite similar to my ears too.

The surrounds are not bass shy satellites. They are rated at +/- 3 db from 55 Hz to 22K HZ, while the front LR are 35 Hz to 22K Hz and center from 45 Hz to 22K Hz. The cross over is set at 80 Hz. The front's have mediocre efficiency at 90 db at 1 m / 1 watt while the surrounds are 88 db. The surrounds are 6 ft each from the SPL meter position while the front LCR are 10 ft away.

Why do the surround levels differ so much between the two? Which one is more reliable, the AVR's or DVE's? I do distinctly hear a bit more surround action with the DVE setting but how do I know that is what the movie is supposed to have?

 

[Adam]

Hi. The difference might be due to how you had the microphone oriented when you did your measurements. Dolby at least used to recommend holding the SPL meter facing the center channel at a 45 degree angle to ground (so, not pointing at the speakers or at the ceiling).

This thread contains some information on that in post six. The original link doesn't work to the Dolby website, but the document might still be out there. That's consistent with what I'd read years ago when I started doing those measurements.

 

[jonnythan]

Recently I bought the Blu-ray version of DVE for calibrating my HDTV. I also checked the speaker levels using the audio test tones. The DVE disk has lossless DD-TruHD, dial norm = 0 db. I used a Radio Shack analog SPL meter to make the measurements set to C weighting and slow response. I let my AVR decode DD-TruHD. I positioned the SPL meter at the exact same location where I placed the AVR's auto calibration microphone. The levels of the front LCR speakers agreed within +/- 0.5 db with those set by the AVR autocalibration setup. However, DVE required setting the surrounds +3.0 db hotter than the AVR's auto setup did. Both DVE and my AVR use filtered pink noise for the test tones. Both sound quite similar to my ears too.

The surrounds are not bass shy satellites. They are rated at +/- 3 db from 55 Hz to 22K HZ, while the front LR are 35 Hz to 22K Hz and center from 45 Hz to 22K Hz. The cross over is set at 80 Hz. The front's have mediocre efficiency at 90 db at 1 m / 1 watt while the surrounds are 88 db. The surrounds are 6 ft each from the SPL meter position while the front LCR are 10 ft away.

Why do the surround levels differ so much between the two? Which one is more reliable, the AVR's or DVE's? I do distinctly hear a bit more surround action with the DVE setting but how do I know that is what the movie is supposed to have?

Did you completely disable all the audio processing by the AVR before using DVE?

 

[WxMan]

Hi. The difference might be due to how you had the microphone oriented when you did your measurements. Dolby at least used to recommend holding the SPL meter facing the center channel at a 45 degree angle to ground (so, not pointing at the speakers or at the ceiling).

This thread contains some information on that in post six. The original link doesn't work to the Dolby website, but the document might still be out there. That's consistent with what I'd read years ago when I started doing those measurements.

The SPL meter was pointed straight up just like the AVR calibration mike was as per the manual. I realize that could be flawed logic but that's where I started.

Thanks for the link. It looks like according to Dolby Labs the SPL meter should be tilted 45 deg. toward the front speakers on line with the center speaker. I'll try that later on tonight after our guests leave. Just thinking though that orientation could cause me to increase the surround levels even more. Then that means my AVR's autocal sets the surrounds far too low.
My wife often complains that she doesn't hear much from the surrounds even during a lot action scenes. Well, if YPAO doesn't get that right, I wonder how accurately it's setting the EQ!

Just another thought. Most of my Blu-rays are 5.1 DTS-HD MA. Does DTS follow the Dolby Labs standard or do they have their own?

 

[WxMan]

Did you completely disable all the audio processing by the AVR before using DVE?

Yes indeed I did. I have a Yamaha AVR. I always bypass DSP by choosing STRAIGHT mode. In fact, since I set the AVR to decode DVE's Dolby TruHD, it would automatically lock it into STRAIGHT mode thus disabling all audio processing.

 

[Adam]

Btw, it's great to see someone else from Tucson here.

 

[WxMan]

Btw, it's great to see someone else from Tucson here.

I'm in Arizona, but moved to Flagstaff. I need to update my location status box. Anyway it's great that we're still in the same state though.

Thus I'm back to getting my HT setup again. I did try the setup with the SPL meter tilted 45 deg toward the center speaker. It didn't make much difference at all for the front three speakers. However, the surrounds were boosted quite a bit, around +3 db. During movie action scenes, I found it too overwhelming. The highs from the surrounds eventually gets to your ears. My wife ran out of the room when I tried it out on Iron Man which is one of the BDs I use for listening tests. The surrounds are wall mounted 5.5 ft off the floor and 7 ft to the side of the sweet spot on each side at about 110 deg angle wrt the center line thus pretty much following the DDL room layout specifications.

For some reason YPAO EQs the surrounds by applying +5 db to +6 db boost in the 6.3 K to 8 K Hz range. It made no difference either whether set to NATURAL or FLAT. Why, I don't know. It could be due to comb filtering effects I suppose. Room treatments are out of the question though. However, YPAO's level for the surrounds does effectively keep the highs at bay. I will just leave it where YPAO says it should be instead of having DVE and my SPL meter set the surround levels.

Someday, when I get upgraditis, I am going to switch from Yamaha AVRs to Denon mainly to get a better, more advanced auto-calibration setup like Audyssey's multi-EQ. It really makes sense to me to use multiple spots instead of relying on just one static location.