Having this extremely strange audio problem. At first I thought my subwoofer was failing but convinced it's something inside the Dolby Digtal audio track of the encoded HD signal.
Some Key A/V Info:
- Tivo HD Series 3 HDMI connected to receiver. Audio Setting on Tivo: Dolby Digital
- Onkyo NR-709 Receiver with 7.1 Surround speakers. Audio Setting: Dolby Digital Expanded
- Panamax 5400 filtering power and HFC cable TV Signal
With the local NBC Affiliate here outside Boston, I am receiving random audio LFE thumps from my subwoofer ONLY during Network broadcasts, NOT the local NBC affiliate broadcasts (WHDH in Boston). The problem ONLY happens during NBC Today show, NBC Nightly News, Presidential Election night. NEVER during any other local or network broadcast on any other HD Channel.
- Thumps can be heard in same scenario with HFC cable connected directly to clear QAM Tuner TV card in my PC. This tells me it's not the Tivo.
- Thumps occur in the same scenario with HFC cable connected directly to my Samsung LED TV using clear QAM tuner inside TV Set. This tells me it's NOT the Tivo.
- Random thumps ARE recorded on the Tivo. I can play them back to the cable company when they are here to diagnose the problem.
- Cable company came in and tested the QAM frequency (607) and it's clear and almost error free.
I contacted the NBC affiliate in Boston regarding this problem but they weren't aware of the problem. Had the local cable company out here and inquired if the "Network" broadcast feed was coming in via satellite and being re-encoded and spliced locally with the Boston affiliate station. Nope, they only have one signal off the satellite and they do no encoding or re-modulation.
What I DID find: Whatever is encoded in the original Audio track coming into my Tivo is "filtered out" when I set the Tivo to down convert to PCM. In this mode, I can't run Dolby Digital Expanded, audio sounds OK but I am stuck on THX Cinema.
This problem doesn't happen on ANY other HD channel that I might watch. FOX, CBS, ABC etc...ONLY NBC and ONLY during Network originating broadcasts.
Suggestions Anyone? Grasping at straws here.