Online radio listenership has grown over 515 percent since January
2001, according to MeasureCast. Arbitron reports that 35 percent of all
Americans 12 and older have used streaming media. Why? Webcasting lets
loyal listeners continue to enjoy your content while traveling away
from home. It allows you to reach your audience at times you may not
have reached them before. Borders and transmitter coverage patterns no
longer limit your audience size, so you can reach listeners the next
city, next state, or next country over. Most importantly, it lets you
continue to reach loyal listeners who are "trapped" in an otherwise
impenetrable office building during the day.
Webcasting, or Internet broadcasting, is the process of transmitting
your station's signal over the Internet. The technology used in
webcasting is called streaming. Streaming multimedia allows
listeners to hear your station live, just as if they were listening
over the air. One more buzzword: rich media is an umbrella term
referring to streaming combined with web-delivered text, graphics,
animation and other content.
Figure 1. The basic transmission model for
over-the-air broadcasts is similar to the transmission model for
Far from being complex and difficult, the process of webcasting is
similar to traditional broadcasting models. To demystify the webcast
process, let's first review basic radio theory. In traditional radio
broadcasting, the station signal is delivered to the transmitter. Next,
the transmitter distributes the signal over the air. Finally, listeners
tune a radio set to the appropriate frequency to listen to the station
When a station's signal is webcast, only one step is added to the
transmission process. First, the station signal is delivered to an
encoder — a piece of equipment that converts the analog sound to
a digital signal. Now, the steps are exactly the same as those you
already know: the encoded signal is delivered to a server, a computer
that acts as a transmitter, which then delivers the digital signal as a
stream of packets over the Internet. Finally, listeners tune a computer
to the appropriate location to listen to your signal, by typing in the
address of your server on the Web, using media player software in place
of a radio tuner. (Figure 2).
Figure 2. The Internet radio model has building
blocks similar to the terrestrial radio model, but with a few
There is one critical difference between over-the-air terestrial
radio and Internet radio: bandwidth. When you distribute a signal over
the air, the signal is one-to-many. In other words, the radio signal is
hanging there in the air and any number of listeners (users) can
passively receive it. In webcasting, the signal transmitted over the
Internet is usually unicast, or one-to-one. This means that each
listener (user) connects individually to the server providing the
When you set up your webcast, you choose the quality level and size
of your stream's bandwidth. Internet broadcasts of audio programs are
usually delivered at bandwidths for dial-up modems, such as 14kb/s,
28kb/s or 56kb/s.
Some stations offer additional streams that are suitable only for
broadband users; these streams simply won't flow through a dial-up
connection. Broadband bandwidth is considered to be 100kb/s and
The smaller the bandwidth number, the more compressed the signal
will be. Higher bandwidth means the signal is less compressed and of
higher quality. Normally, an unmodified 14kb/s audio signal sounds like
a rural telephone connection, complete with static. A 28kb/s signal
sounds similar to AM radio. At 56kb/s, an unmodified stream is similar
to CD quality audio played from a basic stereo system. Audio processing
can improve the clarity, depth and perceived audio quality, allowing
some stations to be streamed at very low bandwidth.
Fortunately for the new webcaster, most users cannot tell the
difference between a 56kb/s streamed radio signal and one streamed at
broadband speeds. In fact, depending on your content, most radio
stations will find that a 28kb/s or 56kb/s stream will suit their
webcast needs quite well.
The next concern in webcasting is choosing the size of your
audience. The size of the Internet connection to your server and the
bandwidth that you use to encode your signal directly determine the
maximum number of simultaneous listeners that can access your webcast.
For example: if you stream your signal at 28kb/s, then every user
connecting to your server needs a continuous 28kb/s of network
bandwidth through your Internet connection. So, if two users are
connected at the same time, you'll need a minimum of a 56kb/s
connection to the Internet (2 × 28 = 56). If ten users are
connected simultaneously, you'll need a minimum connection of 280kb/s
(10 × 28 = 280), and so on.
Processing an online audio stream can
improve its overall sound. Some manufacturers offer processors designed
for the online medium.
Webcasting can consume bandwidth at a voracious rate. Many stations
choose to hire an Internet service provider (ISP) or specialist webcast
service provider, called a Content Delivery Network (CDN) to handle
their bandwidth needs.
But how do you put your station on the Net? Just as in traditional
radio, there are several ways to manage and modify the webcast audio
signal. There is also a staggering array of choices on hardware and
services that can be used for Internet broadcasting. For the beginner,
these choices can be broken down into three different categories:
do-it-yourself, hardware solutions, and full-service providers.
For stations in smaller markets or those on a tight budget,
do-it-yourself (DIY) webcasting can be an inexpensive solution. In this
model, you trade-off the quality of the signal and the number of
listeners you can reach to gain the reduced cost.
To create your own DIY webcast, you will need a minimum of two
computers, one sound card and an Internet connection. The computers can
be somewhat older machines; PCs need to be at least a Pentium II
running Microsoft Windows. Macintoshs need to be at least a G3 running
MacOS X. The computers used for Internet broadcasting should not be
used for running other applications, such as word processors,
spreadsheets or browsing the Internet. No special hardware is needed,
and an off-the-shelf consumer sound card can be used, placed into the
machine that will be used as the encoder. Free encoding software
can be downloaded from Real (www.realnetworks.com/products), Microsoft (www.microsoft.com/windows/windowsmedia) and Apple
The second PC (the one without the sound card) will be your
server. Server software is also available from Real, Microsoft
and Apple, however not all versions of the server software are free, so
read the license agreements carefully. Real has a 12 month server
license that supports up to 25 users at no charge. Microsoft's Windows
Media server is included in Windows 2000 Server or can be downloaded
for no cost for machines running Windows NT Server. Apple's QuickTime
Streaming Server is a free service included with MacOS X Server.
The server needs to have a constant connection to the Internet. Many
do-it-yourselfers find it is best to place the server at their local
Internet Service Provider (ISP), so that they have the bandwidth to
support dozens or hundreds of users. It is possible, though, to support
a few users on a cable modem or ADSL line.
When quality and control of the signal are more important factors
than price, it's time to consider hardware solutions.
To simplify integration with existing broadcast equipment,
manufacturers have developed sturdy, rack-mounted devices with
professional-level analog and digital inputs. These devices generally
handle at least one of the streaming formats and offer a choice of
bandwidth and audio processing options. Some even have options to allow
you to run special commercial insertions, so you can run targeted spots
for your Internet listeners.
Most of these hardware solutions were created to handle the encoding
step of the webcast, so these units still need to be connected to an
external server or service provider to transmit your signal to the
listener. After investing in high-end hardware, don't skimp on the
server and Internet connection; it doesn't matter how good your source
audio sounds if no one can hear it.
When choosing your encoding hardware, the key things to ask are what
format and bandwidth does the unit support, how will the hardware
integrate with your existing systems, and how will the unit connect to
your server, ISP or CDN. Telos, for example, offers the Audioactive, an
MP3-based encoder that can offer streams in both Real and Windows Media
formats, as well as MP3 multicast for intranet networks. This sleek,
1RU unit starts at about $2,800.
Broadcast Electronics developed the WebVault, a combination hardware
and software solution. WebVault streams in both Real and Windows Media
formats and has proprietary audio processing systems through its
e-stream card. The WebVault can integrate with an existing AudioVault
system to filter ads for your stream.
Some hardware systems developed for video users may fit larger radio
webcasters, or those who wish to include a studio camera image with
their audio signal. Pinnacle's StreamFactory is a low profile, 1RU unit
that streams in both Real and Windows Media formats and starts at about
$9,995. Chyron, of television engineering fame, offers the Clari.Net, a
2RU system streaming in both Real and Windows Media.
If you expect to install a simple solution and leave it running for
months on end, a hardware solution may be right for you. Everything
comes in one integrated package with one manual and once source for
Service provider means
If you prefer a full-service streaming solution, or if you need to
reach a larger Internet audience than your ISP can accommodate, CDNs
are usually the answer. A Content Delivery Network is a special ISP
that offers a wide range of webcasting services, including encoding,
server hosting and bandwidth management. Stations managing their own
encoding process tend to purchase only servers and bandwidth from a
CDN. However, some stations choose to hand over the entire streaming
and encoding process to the service providers.
Some CDNs offer a turn-key solution, where they handle all the
details of your stream, from providing the equipment to setting it up
and monitoring it for you. This is attractive, as it frees you to focus
on what you do best: making good radio. One word of caution: be careful
to verify a CDN's offer against their actual capability before signing
a contract. The “Dot Com revolution” saw literally hundreds
of closet-sized CDNs spring up, each claiming to be “The World
Leader!” in some small niche in the streaming industry.
Turnkey approaches remove the burden of
webcasting from the station.
Even if you are doing your own encoding by a hardware or a
do-it-yourself method, it can still make sense to use a CDN for the
delivery of your webcast streams. Mature CDNs have access to larger
Internet connections and can help you reach a larger audience more cost
effectively, than you could manage by installing or running your own
Service providers are fee-for-service solutions. While some will
accept barter or trade to offset part of the cost, you should be
prepared to pay a monthly service fee based on the size of your
audience. Fees vary considerably, from a few hundred dollars a month to
several thousand depending on the amount of bandwidth you require. Most
CDNs also have setup fees and minimum-use contracts. If you are
planning to have the CDN provide you with all the hardware and
installation to start webcasting, these setup fees can run upwards of
Choosing a CDN is like making any other large purchase. Look at the
agreements carefully and make sure you understand all the options and
add-ons available to you.
Because you are probably choosing a CDN to give you more listeners
at less cost, the CDN's network is an important item to examine. To
save money, some ISPs and CDNs will oversell their connections to the
Internet backbone. They make the assumption that not all of their users
will be online at once. Because streaming is a continuous
service (meaning that once a stream starts, it needs the same amount of
bandwidth continuously until the stream ends), make sure that your ISP
or CDN can provide you enough guaranteed bandwidth at peak usage
times to reach your regular audience.
Some CDNs manage and control every server on their network, while
others distribute their servers among a variety of partners at
different locations. A distributed network model can give you greater
access to bandwidth, but the quality of service can be inconsistent in
some areas of the network as high-demand servers get saturated. In a
centralized network model, all of the servers are in one location, so
the location of the central site might impact quality of service for
remote listeners. Each model has its advantages and neither is truly
superior over the other.
Regardless of the CDN's server model, make sure to ask how your
signal will be acquired. Will the service provider be able to accept a
pre-encoded stream from you, or do you have to use special equipment
provided by the CDN? How does the encoded stream reach the servers?
Delivering your stream over a public Internet connection can be
inexpensive, but you may have buffering or degradation of your source
signal. Conversely, a private digital line from your studios to the
network costs a bit more, but can provide much more reliable
Redundancy and backup procedures are crucial when considering a CDN.
For example, how does the provider handle power outages, downed
telephone lines, and freak accidents? Some smaller service providers
have limited response times and minimal monitoring, while larger CDNs
maintain 24-hour operations and have a global support plan. Also, be
sure to ask how quickly known problems will be repaired.
Statistic reporting is a service offered as an incentive from many
CDNs. A variety of statistics on the listeners can be gathered from a
radio stream. Data can be accumulated on time spent listening and
number of users. Ask what other types of demographic or click through
statistics the CDN can provide, if such data is important to you.
Each CDN has a different set of special features they can offer to
differentiate themselves. These can include ad substitution, promotion,
music titling, or interactive images and slides. You may want to
experiment to determine which special features work best for your
When discussing standard agreements, be sure to understand any
exclusivity clauses that the CDNs require. A CDN is like any other
business partner; make sure that you're not committing yourself to a
relationship that you can't escape.
Many stations forget to consider the cost of success. Ask how your
monthly fees are determined (that is, are the monthly charges set in
advance or are they based on usage? Is it priced on monthly bandwidth
usage, peak bandwidth usage or on a set number of users?). If your
station is very popular and you go over your limit, what will happen to
your users? Some providers will give your listeners an error message;
others will just send you a bill for the extra usage. What will your
Despite all the best-laid plans, things change quickly in the
service provider market and many service providers have gone out of
business in the past year. The “Dot Com crash” of 2001
eliminated many CDNs. As in all Internet businesses, consider your
potential partner in terms of their leadership, business savvy and
market resilience as well as the allure of their promises.
Some CDNs who specialize in radio station streaming are BNet Radio,
Real Broadcast Network, StreamAudio, Broadcastport, Warp Radio and
Are you ready to start streaming? One last step to take before
putting your stream live is to check your legal rights. Your station's
legal counsel should be able to advise you on the details, but be aware
that not all syndicated programs, commercial spots or music programs
are allowed to be distributed over the Internet. In addition, the
Copyright Arbitration Royalty Panel (CARP), in February delivered a
report recommending rates and terms for transmission of webcast
performances. While this is only a recommendation, it may have effects
on webcasters legal obligations in the future.
Finally, weigh your staff's commitment to supporting both webcasting
and Internet-based services. Once you begin offering a service, your
customers begin to expect that the service will stay as fresh and
reliable as you initially make it. Keeping your station on the Internet
may require extra long-term commitments from computer and
communications specialists, and may even evolve into a full-time
requirement, so plan accordingly.
Snyder is an independent streaming media consultant based in