TechComm Labs

The tour bus, which took 100 hours of design time and 300 hours of installation time to complete, has seven miles of of cabling from Liberty Cable, five miles of Cat5 wiring and 3,000 feet of CresNET. The pre-wiring was done before the walls on the tour bus went up, requiring large bulks of wiring in channels and luggage bays that run the length of the vehicle.

7 miles is more than 800 bus lengths. BB King obviously has a few gadgets in his motorhome! This is just for travel and office work because the coach is not used for sleeping,

There are some folks who prefer listening to vinyl records run through a tube amplifier rather than a CD with a modern amp. There is a similar situation with video that is starting to show up with high definition fast refresh displays. Help Key: Why 120Hz looks “weird” at Crunch Gear takes a look and, in the process, provides a good rundown on telecine and the problems inherent in the display of frame by frame video.

The problem is that video captures a time series of images. When these are displayed in sequence, your brain interpolates between them to help you see a continuous scene with motion. The display technologies do what they can to help your brain in its process of smoothing the transition from one image to the next. What is happening now is that there is a technology from 24 images per second movies to displays that can show 120 or more images every second.

TV was a step in this technology. It provided 60 images per second by each image was only half of a full image. That is where interlace technology was used.

A modern 120 Hz LCD TV can show five images in the time its source puts up one. What should it do? Show the same image five times and then switch to the next? Fade out one image and fade in the next? Insert a black image or two between successive images (like movie projectors do)? Use the new technologies inherent computing power to make a series of interpolations from one image to the next to smooth the transition?

This last option may smooth things out but it is different from what people are used to like vinyl records and tubes are different from modern sound systems. The smooth interpolation technique produces what is called a ‘soap opera’ effect. Things look just too good to be true.

The comments to the blog post have some other good thoughts about how media is changing. Going from film to electronic media gets into changes in film grain, gamma, depth of field, and all sorts of other things. That, in turn, requires media producers to think about things differently. That kind of different thinking is starting to show up in subtle ways that will influence viewers in different ways.

The news headlines say Digitally remastered Beatles coming in September. This effort took four years and paid a lot of attention to preserving the original sound with few exceptions. Those exceptions were such things as obviously unintended artifacts such as electrical clicks, and mic pops and hisses (excess sibilance).

Prior to this effort, the Beatles digital media was created from rather straighforward ripping of published sources – the media masters were about as far upstream as the effort went. This effort gets back to the original mixing tapes and equipment then applies modern processing techniques that replicate some of the tricks applied to the original recordings that was unique to the equipment and media of the time.

Of course, this is also major media hype. There will be special packages and provenance add-ons and other stuff to try to sell more. Whatever. It will be interesting to just what 4 years of effort using modern tools will do to create a recording to sound just like it should have forty years ago.

Tech Notes has a good 63 page PDF answering the common questions about the DTV Transition coming up in the US. Tech-Note – 141. Dec 17, 2008. It says it was written for the broadcast engineer and technician who will be dealing with the transition first hand. That means it answers some questions you don’t often find elsewhere. It does not get technical and is easy to read evwn if you are not an engineer or technician. There are also many good links to websites that can provide additional information.

What kind of audio connection do you have in your AV system? It will determine what you can get out of your audio experience.

There are three ways of hooking up your PS3 for audio: using RCA cables (red and white), using optical out, and using HDMI. I guess you could consider using a RF cable as a fourth choice, …

RCA cables only allow for Dolby Pro Logic, … It “simulates” having surround sound without actually providing true tracks for each speaker. …

Optical out can carry DD5.1 and DTS tracks to your receiver, providing a much clearer, enjoyable sound. I highly recommend using optical cable, as the results are VERY noticeable. Optical only has enough bandwidth for PCM 2.0 uncompressed, resulting in uncompressed stereo sound (stereo? Meh!). To get the full PCM 7.1 experience, you’ll need…

HDMI. This can carry the next gen audio formats such as DTS-HD MA, Dolby True-HD and uncompressed PCM 5.1-7.1 audio at a full bitrate. The only other method of getting these codecs is through analog out, which is not supported by any console on the market today (but is supported by stand alone HD-DVD and Blu-Ray players). [HOW TO: Get uncompressed PCM 5.1/7.1 audio from your PS3!]

The issues involve the basic fidelity of the recording, signal compression, signal packaging, and the number of channels. The fidelity in modern audio is a digital measure of both how many bits per sample and the frequency of sampling. Signal compression is used to minimize storage space and connection bandwidth.

The latest and greatest audio is 7.1 or 8 channel audio where one is an LFE or low frequency effects channel that doesn’t have the fidelity requirements of the other 7. The latest HDMI standard: “supports 8-channel, 192kHz, uncompressed digital audio and all currently-available compressed formats (such as Dolby Digital and DTS), HDMI 1.3 adds additional support for new lossless digital audio formats Dolby® TrueHD and DTS-HD Master Audio™ with bandwidth to spare to accommodate future enhancements and requirements.” [HDMI FAQ]. This is the latest HD resource such as is available on some Blue-Ray recordings.

The previous generation, standard DVD, used 5.1 audio in a compressed form that used S/PDIF connections (see Wikipedia).

Before that was the 2 channel stereo connection that uses techniques like Dolby Pro Logic to get surround sound.

The acceptance of MP3 audio players and the near equal quality of Dolby and DTS on DVD presentations indicates that 5.1 channel compressed audio is near the knee of the curve and improvements such as the 7.1 uncompressed extra depth audio are down in the noise of equipment choice and environment for most folks.

See also Swedish Radio What is multichannel sound and how does it work? – see the multichannel check for samples to test your system. -|- Spanner Works Dolby Digital, DTS and DVD: A History -|- Practical Home Dolby vs DTS – Which is Better? for more information about the history, the techniques, and what it is all about.

John C. Dvorak has a point with his essay It’s the TV Killing the Computer, Not Vice Versa. TV’s are the big ticket items at places like Costco but PC’s can be had for about the same price – and many of us spend more time with the PC than the TV. Then there is point about what you look at on the screen.

TV is designed for small screens. Through trial and error over the decades, the camera angles, shot selections, framing, and everything else about a TV show have evolved to maximize the impact on a 21-inch view space. This is not a lot of real estate. And blowing it up to a 42-to-60-inch image in a 16-by-9 widescreen format often ruins the impact.

There is change in the wind, though. The producers are beginning to find out what you can do with widescreen aspect ratios and HD. The audio part should also not be ignored as the trend is towards surround sound with significant detail there as well. The CSI shows are good examples of the experiments with high definition digital presentations.

In other words, it is not just the technology but how it is used.