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Ciciora’s Corner - Can You Hear Me?

Mon, 01/31/2011 - 7:25pm
Walt S. Ciciora, Expert on Cable and Consumer Electronics Issues

Where has TV sound appreciation gone?

Over Christmas, we went to church in the Chicago area with relatives in the old neighborhood. The church is an acoustic disaster. It’s a huge, usually empty echo chamber, making what is being said or sung all but impossible to understand. The pipe organ is in the back of the church, along with a trumpet player at Christmas. The leader of song is in front. The church is long enough for the propagation delay to be very noticeable, so the singing and the organ music are badly out of synchronism. What a mess. Quality sound seems to get insufficient attention in public places.

Walt CicioraLast night, we went to a movie with some friends in a local, older theater. The sound was truly awful. I got so frustrated, I left. Yes, it’s getting time to consider a hearing aid. (My friends with hearing aids aren’t that happy with them, either). But there’s more to this issue than just my aging ears.

Those recent experiences focused me on the issues of sound in cable television and consumer electronics. The problems there are pretty awful, too.

There are at least four sound issues with the cable television service and the broadcast and network signals that are carried. The first sound issue has motivated regulatory action (see “CALM promises less noise”). Sound levels during commercials appear to be louder to many, if not most, listeners. Or is it just that the ads are irritating and anything above “mute” would be perceived as too loud? In any case, the government has decided that this issue requires intervention. Perhaps they feel this is one thing they can do without raising the national debt, so why not! But it won’t be quite that easy.

The perception of the loudness of sound is very complex and difficult to put numbers on. It’s more than just measuring sound power; the power distribution over frequencies is critical. Two signals with the same total power can appear to have quite different loudness depending on the way the power is distributed over frequency. An instrument may say one thing, and the ear insists that the result is something else.

Another issue is that the sound level varies from channel to channel. Frequently, there is a noticeable difference in sound level. This may be enhanced if the move is from a channel with a commercial to another channel with programming. The commercial may indeed be louder. If the volume is adjusted, then the return to the original channel may include a painful blast.

Digital television has brought the scourge of “lip sync” errors. Video signals and aural signals require vastly different processing, which results in different amounts of processing time. Unless appropriate additional artificial delay is added, the sound and the video will end up out of synchronization. This difference can accumulate if multiple conversions take place in the path from the original source to the final display site. I’ve seen lip sync discrepancies that were so bad, it appeared that the characters were speaking another language and that the speech I was hearing was dubbed in. The problem is so pervasive that my sound system comes with a delay adjustment so that I can manually compensate at home. That would be a reasonable solution if the delay was constant from channel to channel, or even from program to program on the same channel. But it is not.

There are production issues with sound that cable can’t do anything to cure. Many of the programs we watch include mumbling actors. Thanks to TiVo, we can pause, back up, increase the loudness and repeat the mumbled segment. Sometimes we have to do it several times. That’s not my hearing problem, that’s poor sound production, and maybe bad acting technique. Sometimes, we even have to just give up, unable to make out what has been said. In some cases, even guessing from the context of the conversation fails.

What has happened to the appreciation of sound in television? In the analog broadcast world we have left behind, sound was considered so important that as distance from the transmitter increased, the video became more “snowy,” but the sound hung in. Eventually, at sufficient distance, the picture became almost unusable, but the sound still was there.

The consumer electronics industry shares some blame here. The smaller television we have in another room has tiny speakers that significantly add to the problem. The frustration of missing so much of the dialogue drove me to read instead of watch the television. I got my wife an infrared-linked headphone called “TV Ears.” It is wireless with a rechargeable battery and a volume and tone control. It makes a huge difference. It really improves the intelligibility of the dialogue. The main unit has five infrared light-emitting diodes and is connected to a booster unit with 10 infrared LEDs. Coverage is excellent. The product comes with two headphone sets, but I’d rather read!

E-Mail: wciciora@ieee.org

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