So I got the AIX and PentaTone discs, and I measured the difference between the Oppo outputing multichannel analog, the Oppo outputing multichannel LPCM, and the Oppo outputing a bitstream decoded by the Onkyo 805.
Audyssey was off, all speakers set to small/80hz on both the Oppo and Onkyo, Onkyo mode was multichannel/DSD/bitstream where appropriate, bass management on.
Secondary audio was off on the Oppo (which is necessary to get HD bitstream).
I had to use the channel idenfitication tracks on the AIX disc, since the speaker calibration tracks didn't have DTS versions.
The table below shows the level of the front left speaker/subwoofer level, with the volume adjusted to get 75db on the front most of the time:
So this data confirms the bug that I've reported: on DTS tracks, the Oppo applies about +5db extra on the subwoofer output, when it shouldn't, since neither its LPCM output nor the Onkyo decoding do it.
What surprises me is that it also reproes on plain old 5.1 DTS and also on the 7.1 track, which means that I was wrong when guessing that it is due to the 5.1->7.1 upmix (that the Oppo only does on the analog outputs).
Also, I still can't find more than a 1db difference between the analog, LPCM and Onkyo outputs on the LOTR "Fellowship of the Ring" BD, with is a DTS-HD MA 6.1 track that seems immune to this bug.
Audyssey was off, all speakers set to small/80hz on both the Oppo and Onkyo, Onkyo mode was multichannel/DSD/bitstream where appropriate, bass management on.
Secondary audio was off on the Oppo (which is necessary to get HD bitstream).
I had to use the channel idenfitication tracks on the AIX disc, since the speaker calibration tracks didn't have DTS versions.
The table below shows the level of the front left speaker/subwoofer level, with the volume adjusted to get 75db on the front most of the time:
| Track | Oppo analog | Oppo LPCM | Onkyo Bitstream |
|---|---|---|---|
| AIX 96/24/7.1 Dolby TrueHD | 70/77 (+7) | 69/76 (+7) | 74/80 (+6) |
| AIX 96/24/7.1 DTS HD MA | 75/85 (+10) | 74/80 (+6) | 75/81 (+6) |
| AIX 96/24/7.1 LPCM | 75/80 (+5) | 74/80 (+6) | 75/80 (+5) |
| AIX 96/24/5.1 LPCM | 75/80 (+5) | 74/80 (+6) | 75/80 (+5) |
| AIX 48/16/5.1 Dolby Digital | 75/80 (+5) | 74/80 (+6) | 78/84 (+6) |
| AIX 48/24/5.1 DTS | 75/85 (+10) | 74/79 (+5) | 75/80 (+5) |
| PentaTone DSD tracks 43/48 | 75/84 (+9) | 75/84 (+9) | 75/85 (+10) |
So this data confirms the bug that I've reported: on DTS tracks, the Oppo applies about +5db extra on the subwoofer output, when it shouldn't, since neither its LPCM output nor the Onkyo decoding do it.
What surprises me is that it also reproes on plain old 5.1 DTS and also on the 7.1 track, which means that I was wrong when guessing that it is due to the 5.1->7.1 upmix (that the Oppo only does on the analog outputs).
Also, I still can't find more than a 1db difference between the analog, LPCM and Onkyo outputs on the LOTR "Fellowship of the Ring" BD, with is a DTS-HD MA 6.1 track that seems immune to this bug.


























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I would love a phono input though
