Audio Notes: Tim Carroll

Tim Carroll is a consultant based in New York City. In his copious spare time, he enjoys answering e-mail sent to him at: tjcarroll@ieee.org.

A Look at AC-3 Enhancements

by Tim Carroll, 1.19.2005

This month, I'll take a look at an enhanced version of AC-3 (Dolby Digital), the coding standard developed primarily to support the new enhanced version of the ATSC digital television standard.

Of Dolby, DVRs and Distant Signals

by Tim Carroll, 9.22.2004

I am happy to report that in August, Dolby Laboratories was informed that the company had won a technical Emmy award for its LM100 Broadcast Loudness Meter. This is a definite sign that the rest of the world is noticing that there is a real problem here, and that the first step toward solving it is being able to measure it.

Learning About 5.1 From Grade No. 9

by Tim Carroll, 8.18.2004

This fall season also brings with it the promise of 5.1-channel audio from all the major terrestrial television networks. This month, we will do a quick, high-level review of each network's capabilities thus far

Progress on Loudness And Sync Issues

by Tim Carroll, 7.21.2004

The two major themes of broadcast these days, programming aside, seem to be either loudness or lip sync.

Transport Stream Distribution Models

by Tim Carroll, 6.23.2004

As we prepare to enter into nice summer weather, I thought that it would be a perfect time to warm up to more details about transport stream distribution models.

Digital Audio: Getting From Here to There

by Tim Carroll, 4.21.2004

This month we will describe how each of the major terrestrial networks has chosen to distribute multichannel audio to their affiliate stations.

Dolby, The Chipmunks And NAB2004

by Tim Carroll, 3.26.2004

This time we will briefly wrap up our somewhat detailed look at audio compression by covering areas that some readers have submitted questions about.

Examining Audio Bitstreams

by Tim Carroll, 2.18.2004

Welcome to the next installment of our investigation into how Dolby Digital (AC-3), AAC, MP3, PAC, WMA and other audio data compression schemes get all that audio into such a small package and keep it sounding good.

The Skinny on Audio Coding

by Tim Carroll, 1.21.2004

To start the new year off on a solid foundation, we will begin a multi-part series of articles on audio data reduction, a.k.a. audio compression, a.k.a. audio coding.

Following Digital Audio To the Home

by Tim Carroll, 11.26.2003

We will wrap up our look at how to monitor almost every type of audio signal in a DTV plant by briefly exploring how to deal with baseband audio and separate metadata.

Preparing Audio for Distribution

by Tim Carroll, 10.29.2003

We return to the final stretch of our journey from post production to the consumer.

Audio Advances Rapidly Since 1983

by Tim Carroll, 9.17.2003

From BTSC to Surround Sound, audio changed with the times

Giving Dynamic Range Control to Consumers

by Tim Carroll, 8.20.2003

Last time we wrapped up our investigation of audio distribution. This time we are going to sidetrack just a little bit and take a look at a different approach to controlling dynamic range.

Alternatives to Dolby E

by Tim Carroll, 7.23.2003

Last time we discussed the details of how Dolby E works. This time we will investigate some other techniques as well as give a brief overview of the SMPTE standards that help to organize all this data.

What Is Dolby E?

by Tim Carroll, 6.25.2003

With the brief introduction to Dolby E last time, I figured it would be a good idea to leave an entire column to focus on the technology plus some of the difficulties in making it work in a typical plant, if such a thing as a typical plant exists.

Keeping MultiChannel Audio Under Control

by Tim Carroll, 4.23.2003

If you were able to attend, I hope your NAB experience was a good one and that you didn't get too many blank stares when you asked manufacturers about multichannel audio and/or metadata.

Using Metadata to Mix Multichannel Audio

by Tim Carroll, 3.19.2003

Last time I left you with a question: What is the problem with sending six channels of audio via three two-channel MPEG streams?

Following Audio Through The Delivery Chain

by Tim Carroll, 2.19.2003

Last time we started our trip following a program from origination all the way to the consumer. We got as far as getting the program on tape with audio metadata. This time we will deliver it to the front door of the network operation center and follow it to the start of distribution to the affiliate.

Audio for DTV: The Beginning of a Journey

by Tim Carroll, 1.22.2003

This month we will start our journey exploring audio for digital television from end to end.

A/V Sync: No Simple Solutions

by Tim Carroll, 11.27.2002

Last time we discussed A/V sync and how to measure it accurately using commonly available tools that directly analyze the encoded audio and video streams thereby removing measurement errors due to differing decoder implementations. This time we will take a look at another approach to solving the problem. By the miracle of modern digital electronics, this one does it automatically.

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