The new look for BE Radio premiered with the March issue, and
your calls, letters and e-mails show that you like what you see. We
have reprinted some of your comments here. Thank you to everyone who
took the time to tell us what they thought of the new look and
- Chriss Scherer
The magazine looks absolutely fabulous. BE Radio continues to
be a leader.
Broadview Hts., OH
Nice new look for BE Radio. The larger type in the table of
contents is nice, too. Same with the bold headers at the top of the
pages. Makes it easy to flip through and find the section of
director of engineering
Vermont Public Radio
Great new look for a great title. Congratulations. I always study
BE Radio when it arrives, and there's not an issue where I don't
learn…and learn…and learn.
Robert E. Richer
Crossed Field Antennas Ltd.
I like the new graphic look of BE Radio a lot. And unlike
other mags that always claim their content will not change and then
does, yours hasn't.
broadcast sales manager
Technet Systems Group
In Reader Feedback in the March 2002 issue, there is a photo
of the KFBK Franklin tower. This is quite an unusual arrangement for
feeding the uppersection of that tower. It is fed by open wire
transmission line, suspended from the side of the tower. I know of no
other installation like this and wonder if any other readers know of
The KYW/WKYC/WWWE (now WTAM) Franklin tower, built in Cleveland in
1956, was fed by hardline running up the inside of the tower.
I wanted to send a note to say thanks for your publication. It's
good to know a magazine of your caliber still remembers those in the
Our little two-man operation services nearly 20 stations(maybe more)
in Missouri-a radio network in the KC area and we also help service
another network in Missouri that has a number of stations. Yep, we stay
Anyhow, I enjoy BE Radio and look forward to the next issue.
Keep up the good work. I appreciate the fact I don't have to work for
Clear Channel, Infinity, or the other big boys to get a free
subscription to your magazine.
Broadcast Communications Engineering
I enjoyed the article “Perceptual Audio Encoding” in the
February 2002 issue of BE Radio, but I have a few questions
about the content. First, while frequency masking and temporal masking
are certainly important factors in MPEG encoding, why was sub-audible
level masking not mentioned? In MPEG data reduction, one of the most
efficient ways to reduce irrelevant data is to remove signals that are
below the sensitivity of human hearing.
Second, I'm a bit surprised that 48kHz sampling was never once
mentioned in the article. Instead, the article states, “The most
common in broadcasting is the use of a 32kHz sampling rate as opposed
to 44.1.” I'd like to know where this information comes from. In
my experience, the most common codec sampling rate in broadcasting
might be 16kHz, as used in the G.722 algorithm. Another choice might be
48kHz, as used in most professional stereo MPEG 2 applications. With
48kHz MPEG 2, especially as used in our enhanced compatible MUSICAM
encoding, users benefit from a full 20kHz frequency response, as well
as short delay. This mode of operation has been and remains the choice
of golden ears worldwide.
Third, the article seems to suggest that 128kb/s transmission rates
are the only option. It might be helpful to remind BE Radio
readers that higher transmission rates are easily achievable with the
right equipment. Then, let's try another listening test.
VP, business development
Corporate Computer Systems Inc., d/b/a MUSICAM USA
Doug Irwin replies:
Of course I did mention that perceptual audio encoding algoriths
were in use in both radio broadcasting and production, but being a
radio person myself I've become accustomed to not giving any thought to
signals above 15kHz, except for 19kHz. A sampling rate of 32kHz is all
that is necessary to handle anything transmitted in the FM
With the advent of IBOC, the 44.1kHz sampling rate will become
commonplace, as will higher audio bandwidth. For over-the-air broadcast
applications, 48kHz sampling will not be necessary, at least for the
Thanks for reading the article and I'm glad you enjoyed it.
I read with interest the article “Perceptual Audio
Coding” in the February 2002 issue of BE Radio. I commend
Mr Irwin for such a clear and concise article about perceptual coding.
With coded audio being used so extensively in the broadcasting world
today, this is valuable information for your readers.
I would like to add the following that may also be of interest to
readers of BE Radio.
In 1997, the MPEG-2 standard included AAC (Advanced Audio Coding)
along with the existing Layer 1, Layer 2, and Layer 3 audio coding
standards, adding to the palette of options available to implementers.
This new standard truly represents the current state of the art &
science of audio coding. It was developed through the combined efforts
of a number of the top laboratories and developers in this area,
including Fraunhofer, Dolby, Sony, and AT&T. In fact, a number of
experts predict that major advancements beyond AAC, for general purpose
codecs, are unlikely in the near future.
At this time, AAC codecs for the broadcast market are available from
several manufacturers, including Telos Systems. AAC offers the first
coding technology to achieve the ITU-R's criteria for
“indistinguishable quality” at 128kb/s: To meet this
requirement, no test item, out of a battery of difficult items, is
permitted to score worse than the “Perceptible but not
annoying” rating in controlled tests. AAC is the only codec to
date to achieve this difficult criterion at 128kb/s stereo (12.5:1
AAC's biggest advantage to broadcasters is that it offers them
additional “coding headroom” in cases were perceptual
coding must be used before, or after, the AAC link. It can also achieve
fidelity equivalent to Layer 3 at 66 percent of the bit rate. AAC also
offers reduced delay compared to Layer 3.
Speaking of delay, the latest MPEG standard (MPEG-4) adds an
important AAC derivative; AAC-LD (Advanced Audio Coding Low Delay).
This offers Layer 3 quality with greatly reduced delay. This technology
is available now, and offers broadcasters the fidelity they want for
live end-to-end interaction, without the uncomfortable difficulties of
trying to converse with delay present.
Cleveland, OH 44114