Viraj's Weblog

I just picked up a new Panasonic Viera TC-P50VT25 plasma TV (and sold my old one). This TV has 4 HDMI inputs, and I was able to convert completely from analog (component, vga, etc) to digital.

I have a couple of TV devices:

• Panasonic DMP-BDT100P Blu-ray and 3D player (came with the TV via a Best Buy special)
• Comcast/Motorolla HD Tuner/DVR
• Apple Mac Mini
• Sony Google TV

For audio I have a Bose 3 2 1 DVD system that has optical/SPDIF input for audio and component out for video, but I'm no longer using the video of it.

All of the 4 devices have HDMI and SPDIF/optical output. The TV has an optical output. So what I'm thinking, just plug in all of the devices via HDMI to the TV, then the TV optical output to the Bose for audio. That sounds like it should work, but woe is me. After much money spent on HDMI cables, I found that the new technology is not much of an improvement over old. You just need to spend more money.

First off, after hooking everything up, the picture was amazing. However instantly I noticed an echo effect in the sound output. It turns out both the TV speakers and the Bose system were outputting audio. What seemed strange is the delay/echo effect I could hear. But at this point I didn't pay much attention and went in the TV setup to disable the TV speakers.

Great, so first thing I notice is my Bose says "PCM" on it. This is usually displayed when there is no Dolby signal and it is just doing stereo. That seemed sucky and strange. The movie I was watching was on Comcast HD, and it definitely should be Dolby. I then switched to the Blu-ray player and played a DVD, which I know contains Dolby. Still the Bose said "PCM". Something was wrong.

The next thing I notice is the audio is a bit delayed, say 20-50ms later than the video. I'm very good at noticing this and it was hella annoying. This also explained the echo effect when turning on the TV speakers. The TV speakers were not delayed, but the optical audio was. WTF?

Next began my Google searching. What I found was a forum posting in 2007 indicating that the optical outs of most TVs that have HDMI convert HDMI audio to stereo. WHAT KIND OF GARBAGE IS THAT? If it's digital, why the hell is it doing any conversion on the signal?

At this point the thoughts in my head are all pointing to HDMI copy protection. This is likely the reason the TV doesn't pass through the signal as is, but I can't find any web pages explaining this. I see notes in the Panasonic manual about it doing this, and mention that many other TVs do it as well, but no mention of WHY!

So my next goal was to send the device audio signals directly to the Bose system. However, that system only has one optical input. Luckily, I had my Audio Authority Digital AV switcher. This accepts multiple component and optical inputs and simply lets you switch through them. It is a very simple device which I thought I could get rid of with my new TV. Not so. I kept HDMI for each device plugged into the TV for video, but for audio I connected optical cables for each device to the switcher. The output of the switcher is one optical cable to the Bose.

Voila, the Bose immediately said "Dolby ..." on it for all of my devices (Comcast, Blu-Ray, etc). The audio delay is pretty much gone (though there is still a small amount that is not noticeable).

Lesson learned? The HDMI gods really want you to buy a HDMI receiver, which would replace my switcher. The Audio Authority switcher is simply a bare-bones receiver. It unfortunately still requires me to press the switch whenever I want to change devices, but this for me is better than spending even more money for a receiver. Why doesn't Panasonic (and other TVs with multiple HDMI inputs and one optical out) do what my switcher does? It is sad.

Update: I came across this forum posting which states:

As far as I know, televisions are required by copyright law to disable Dolby Digital and other digital audio signal processing on the audio-out. They can only send 2-channel audio via Optical/Coaxial audio out.

Here are 2 new tracks I worked on in the past weeks:

• A Bit Reduction
• Desire Without End

The 2nd one is the first time I've ever recorded my voice . See if you can find it.

Here is a new track I worked on this weekend. I've found a new technique called midside eq which is a great method for getting tighter sounding bass.