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Would you like to get an early start on our industry’s biggest annual trade show? Come along for a free webinar from Radio World, hosted by Editor in Chief Paul McLane, on March 26 at noon Eastern time.

Paul will provide a peek at new products that he expects to create buzz; explore the newest, most promising radio sessions for radio technologists and managers; and share what he’s hearing from our industry’s leaders about important tech developments and standards.

The NAB Show is a huge and fabulous event, but it can also be daunting. With more than 90,000 attendees expected and more than 1,700 exhibits covering a million square feet, the job of getting the most out of the NAB Show requires a lot of planning. Radio World will help you learn about key pieces and products at the show, chosen with the radio reader in mind.

Sponsored by Broadcast Bionics, Comrex, ENCO, GatesAir, Inovonics, Logitek, NPRSS, RCS, Streamguys, MusicMaster and Wheatstone

Speakers

Paul McLane
Content Director
Radio World

 

Paul is a veteran industry technology journalist and former broadcast news anchor.

Click here to Watch.

 

The post Radio World Presents: NAB Show 2019 15 Things You Don’t Want to Miss appeared first on Radio World.

What was exciting on the NAB Show floor? Which new products and technologies got the top buzz? Maybe you couldn’t get to the show or didn’t have time to see it all.

Radio World did the walking for you to prepare our 2019 NAB Show Product Report, featuring:

• Dozens of new products
• Features, prices, and availability dates
• Cloud technologies for radio, hybrid radio platforms, MPX, digital radio monitoring, remote site management, new processors and much more
• Observations by Radio World’s veteran editors and engineering contributors

Speakers

Paul McLane
Content Director
Radio World

 

Paul is a veteran industry technology journalist and former broadcast news anchor.

Dan Slentz
Chief Video Engineer
New World Symphony

 

Dan Slentz,Chief Video Engineer for New World Symphony on Miami Beach, has over 40 years of radio & TV broadcast operations and engineering experience.

Marguerite Clark
Content Director
Radio World International

 

Born in the U.S. and based in Paris, Marguerite is a veteran industry technology journalist who has been covering issues impacting the global media sector for more than 20 years from both Italy and France.

Click here to Watch.

The post 2019 NAB Show Product Report appeared first on Radio World.

Network and local monitoring company Media Monitors is adding “regular podcasting metrics” this year. To highlight its latest offering, the company has released information about the “Top 25 Podcasts” as determined by a recall survey in January. 

In a press release announcing the information, Media Monitors President and CEO Philippe Generali addresses a question that has long plagued podcasters: Are downloads or subscriptions truly equivalent to listening? 

Why does this matter? Advertisers are used to metrics like views, impressions, etc., and they want to know that an ad will actually be heard by a consumer, not just stored on their iPhone.

“Opt-in redirects or server-based download measurements services …. might be an indication of who subscribes to a show, but here, this survey asked respondents to name the shows they actually listen to,” Generali said. 

Take “The Joe Rogan Experience,” for example. It’s consistently listed on top downloads lists, and it also dominated the recall survey, ranking “number one among men and women, in every income bracket, among listeners of any education level and in every region.” However, it is only second in the the 35-44 age bracket, perhaps its one area to improve outreach. 

Media Monitors said its survey, conducted by Macromill Group company Precision Sample, also confirmed the conventional wisdom that women are true crime obsessives. Two advice programs also made the cut.  

Their top five were:

1. “The Joe Rogan Experience” 
2. “Phil in the Blanks” 
3. “Crime Junkie” 
4. “My Favorite Murder with Karen Kilgariff and Georgia Hardstark”
5. “The Dave Ramsey Show” 

Men’s podcast listening habits also play to type, with representation from sports, news and comedy programming in their top five:

1. “The Joe Rogan Experience” 
2. “ESPN” 
3. “The Daily” 
4. “Conan O’Brien Needs a Friend”
5. “Rush Limbaugh Morning Update”

It’s interesting to note that the overall Top 25 Podcasts list is dominated by programming favored by women. The number one show overall (Joe Rogan) is a favorite among both men and women, but the remaining four are those named by listeners who identified as female. Check out the chart (above) to see the full list.

There has also been significant debate about how advertisers should take advantage of this medium. Many listeners of what Media Monitors classified as “niche podcasts” were unable to independently recall brands advertising on their favorite shows. With an assisted recall, respondents listed Geico, Squarespace, ZipRecruiter and Quip as podcast advertisers they remembered. Media Monitors suggests this means many podcasts still do not have advertisers/sponsors, which they say represents an “untapped opportunity.”

The post Top 25 Podcasts People Actually Listen to in 2020 appeared first on Radio World.

The National Association of Broadcasters will recognize Entercom Chief Digital Officer J.D. Crowley with its  Digital Leadership Award at this year’s NAB Show.

NAB says its Digital Leadership Award honors an individual “who has had a significant role in transforming a traditional broadcast business to succeed on digital media platforms.” The award was created in 2015.

At Entercom, Crowley heads the strategy and operations for the broadcaster’s digital portfolio and oversees its brand modernization efforts, emphasizing “premiere content, next-gen storytelling and digital distribution,” according to the announcement. For example, he has expanded Entercom’s podcasting efforts by acquiring podcast publishers  Cadence13 and Pineapple Street Studios. Crowley also focuses on “content-driven listening” via Entercom’s streaming service Radio.com.

Crowley’s previous digital and content leadership positions include stints as executive vice president of digital for CBS Radio, senior vice president of CBS Brand Studio, and senior vice president and general manager of digital for CBS Television Distribution.

Crowley will receive the award at the the Achievement in Broadcasting Dinner, scheduled for Monday, April 20, at the Encore in Las Vegas. NAB Broadcasting Hall of Fame inductees will be recognized at the same dinner.

Prior NAB Digital Leadership Award recipients include Wendy McMahon, Roger Keating and Catherine Badalamente.

The post Entercom’s J.D. Crowley Honored With NAB Digital Leadership Award appeared first on Radio World.

The National Religious Broadcasters will convene this month in Nashville for NRB 2020, the annual Christian media convention and exhibition.

This year’s theme is “Look Forward.” According to the event website, NRB 2020 offers networking opportunities, workshops, keynotes, panels and an exhibit hall. 

The schedule emphasizes practical skills for the digital age, tailored to religious communicators. Advice and insights will be offered by industry speakers such as Fletcher, Heald & Hildreth partner Karyn Ablin, Borrell Associates CEO Gordon Borrell, Moody Radio Director of Digital Strategy and UX Yvonne Carlson, Edison Research VP of Music & Research Sean Ross, Finney Media President Chuck Finney, Salem Media Group Senior Vice President Russell R. Hauth and others.

Additionally, several NRB 2020 policy sessions will be headlined by names familiar to news junkies and politicos. U.S. Secretary of Education Betsy DeVos and Attorney General Bill Barr are slated to speak at the event, as are Sen. Marsha Blackburn, R-Tenn., and TBN host and former Arkansas Gov. Mike Huckabee, who have each addressed prior NRB conventions. 

IF YOU GO

Who: Christian media and ministry professionals

When: Feb. 25–28

Where: Gaylord Opryland Resort and Convention Center, Nashville, Tenn.

How: https://nrbconvention.org/ 

How much: Full convention pass — $750 or $550 for NRB members; Expo Plus pass — $600 or $350; Expo only pass — $50

SAMPLE SESSIONS

Find the full schedule online at https://tinyurl.com/nrb2020schedule. It’s searchable by registration type and includes information on session locations. 

Feb. 25

7– 9 p.m. Opening Session 

Feb. 26

7–8:30 a.m. NRB Breakfast to Honor Israel 

9:30–10:45 a.m. Morning Forum — Policy featuring U.S. Secretary of Education Betsy DeVos and American Center for Law and Justice Chief Counsel Jay Sekulow

12–12:30 p.m. NRB Talks — Music Licensing: Keeping Up with Key Developments in the Ever-Changing World 

12–12:30 p.m.  Workshop — Demystifying Facebook Audiences 

12:45–1:15 p.m. NRB Talks — Podcasting

1:30–2 p.m. NRB Talks — Emerging Trends for Digital Fundraising Growth 

1:30–2 p.m. Workshop — Music Royalties — Broadcast and Digital 

3–3:30 p.m. NRB Talks — Five Fresh Digital Fundraising Approaches 

4–5:30 p.m. Afternoon Forum featuring U.S. Attorney General William P. Barr

Feb. 27

12–12:30 p.m. NRB Talks — Creating the Right Content for the Right Audience 

12–12:30 pm Workshop — From College to Career: Breaking into Christian Media 

1–3 p.m. iNRB Student Feedback & Standing Committee Meeting 

3–3:30 p.m. NRB Talks — Bringing Young Talent into the Industry 

4–4:30 p.m. Afternoon Forum — Public Policy Update from NRB General Counsel Craig Parshall

5:30–7 p.m. Digital Media Advisory & Standing Committee Meetings 

7–8:30 p.m. Radio Advisory & Standing Committee Meetings 

Feb. 28

9:30–10:45 a.m. Morning Forum featuring Mike Huckabee and Sen. Marsha Blackburn of Tennessee

11:15–11:45 a.m.
NRB Talks — A 2020 Vision For Christian Radio 

12–12:30 p.m. NRB Talks — Video Did Not Kill the Radio Star: Moving Forward in a Digital World 

6–9 p.m. Closing Gala Dinner with Special Service Awards (ticket required) 

Feb. 25

7– 9 p.m. Opening Session 

Feb. 26

7–8:30 a.m. NRB Breakfast to Honor Israel 

9:30–10:45 a.m. Morning Forum — Policy featuring U.S. Secretary of Education Betsy DeVos and American Center for Law and Justice Chief Counsel Jay Sekulow

11:15–11:45 a.m. Workshop — How to Make an Internal/External Digital Media Communication Plan

12–12:30 p.m. NRB Talks — Music Licensing: Keeping Up with Key Developments in the Ever-Changing World 

12–12:30 p.m. Workshop — Demystifying Facebook Audiences 

12:45–1:15 p.m. NRB Talks — Podcasting

12:45– 1:15 p.m. Workshop — Subject Lines: 5 Mental Levers that Anyone Can Use to Get More Opens and Donations 

1:30–2 p.m. NRB Talks — Emerging Trends for Digital Fundraising Growth 

1:30–2 p.m. Workshop — Music Royalties — Broadcast and Digital 

3–3:30 pm NRB Talks — Five Fresh Digital Fundraising Approaches 

3–3:30 p.m. Workshop — The Importance of Knowing Your Audience 

4–5:30 p.m. Afternoon Forum featuring U.S. Attorney General William P. Barr

Feb. 27

11:15–11:45 a.m. Workshop — Taking Control of your Distribution Strategy in a World of Digital Disruption and VOD Streaming Wars 

12–12:30 p.m. NRB Talks — Creating the Right Content for the Right Audience 

12–12:30 pm Workshop — From College to Career: Breaking into Christian Media 

1–3 p.m. iNRB Student Feedback & Standing Committee Meeting 

1:30–2 p.m. Workshop — On Air Fundraising Done Internally 

3–3:30 p.m. NRB Talks — Bringing Young Talent into the Industry 

4–4:30 p.m. Afternoon Forum — Public Policy Update from NRB General Counsel Craig Parshall

5:30–7 p.m. Digital Media Advisory & Standing Committee Meetings 

7–8:30 p.m. Radio Advisory & Standing Committee Meetings 

Feb. 28

9:30–10:45 a.m. Morning Forum featuring Mike Huckabee and Sen. Marsha Blackburn of Tennessee

11:15–11:45 a.m. NRB Talks — A 2020 Vision For Christian Radio 

12–12:30 p.m. NRB Talks — Video Did Not Kill the Radio Star: Moving Forward in a Digital World 

12:45–1:15 p.m. Workshop — Next Gen TV / ATSC 3.0 — How the New Emerging Broadcast Standard Impacts Christian TV 

6–9 p.m. Closing Gala Dinner with Special Service Awards (ticket required) 

EXHIBITORS

A sampling of companies that will be represented on the show floor. The full list can be found at https://tinyurl.com/nrb2020exhibitors. 

[twelve:thirty] media

Aberdeen Broadcast Services

American Amplifier Technologies, LLC

AMS Agency

B&H B2B

Broadcast Concepts

Broadcast Depot

Broadcast Software International

Broadcasters General Store

Buoyancy Public Relations

Cars Inc.

CASTUS

CDR Communications

Christian Television Network

CNLTV

COICOM

Comrex

ComunicadoresUS

CrossMedia/Lightcast

CSN International

DJB Software Inc dba DJBRadio (Digital JukeBox)

DonorDirect

Encompass Digital Media

ENCO Systems

Faith Radio – WLBF/WSTF/WDYF

Galcom International

Grace And Truth Radio

Haivision

LBG Marketing Inc.

Libsyn Pro

LinkUp Communications

Live365

LUMO Project

MegaVoice

Nimble Connect

NRBTV

PTZOptics

Quad Tape Transfer

RCS

SCMS Inc.

Shively Labs

Soliton Systems, Inc.

Stream Station

SuperChannel WACX-TV

Teradek

Trinet Internet Solutions, Inc.

Tulix Systems, Inc.

WATC-TV

WAVSTAR

WBNA TV 21

Wedel Software

WGGS-TV / KMCT-TV

Wheatstone Corp.

World News Group

The post NRB Show Seeks 2020 Vision appeared first on Radio World.

BRUSSELS — Telenet is shutting down its analog cable radio transmission service. Under the slogan “De Signaal Switch” (“The signal switch”) it began phasing out the service on Feb. 11.

The transmission provider, which serves 1.8 Million households in Flanders and Brussels, says the operation will be complete by the end of April. It also plans to end the transmission of analog television in 2021, leaving some 360,000 households to switch to alternatives.

MORE BANDWIDTH

“Our objective is to use the 88–108 FM MHz bandwidth for new projects like extra internet capacity — we simply need more room to speedup internet transmission and therefore we decided to stop our analog radio and television services,” said Bruno Bilic, entertainment product manager with Telenet Group.

“The fact is that we don’t have an idea how many people use analog cable radio,” admitted Bilic. “It has been part of our cable offer package since day one, and offers good analog audio quality, with excellent signal to noise ratio and 24/7 output. And although the service has existed for 30 years, many clients are not aware they use it — radio has always been there…”

After having tested a corporate communication campaign in two urban areas, Telenet launched a info-message on the 105.3 FM MHz. “We direct our customers to that specific frequency — when they hear a message saying they are connected to our analog cable network, they must take action,” explained Bilic.

[Belgium Holds National Digital Radio Week]

Telenet put in place various solutions, including a complimentary indoor radio antenna. “Replacing the coax-cable by the antenna allows the reception of some 30 FM stations but the signal is not always optimal,” Bilic said.

SIMPLIFY THE DIGITAL TRANSITION

“With most of our clients using the Telenet-Digicorder-device, the simplest and free access to radio, with 50 digital channels and 10 no-speech Stingray channels, is to connect the Digicorder’s output to the AUX-input of an amplifier. No need to switch on the TV set.”

In addition, Telenet’s web shop offers alternatives like a Vistron DVB-C VDR 210 radio -tuner, a Pure Elan BT3 DAB+ radio set or an LG WK7 smart speaker.

“The last thing we wanted was to leave our clients in the cold,” underlined Bilic. “The various solutions boost the number of stations from about 30 on the current analog dial to 40 with the cable tuner, and 60 with the Digicorder.”

Insiders are convinced the shutdown of analog cable radio will benefit listening overall and further facilitate the transition to digital radio.

In the South of Belgium, cable company VOO, serving some 800,000 households in Wallonia and Brussels, continues its analog signal transmission. “At this point, we have no plans or timetable to shut down our analog radio services,” commented VOO spokesman Patrick Blocry.

The post Telenet Closes Analog Radio Transmission Service appeared first on Radio World.

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Petition to add Titus County, TX to the local market of five stations is dismissed without prejudice due to an incomplete record. The Petitioner may supplement and refile

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The Commission Announces the Membership of the Diversity Advisory Committee's Working Groups

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Duluth, Minn., rock station KQDS(FM) hosts a Great Outdoors blog at https://95kqds.com/. It features “experiences, tips and discussion.”

I love to hike, bike and walk, especially on trails through the woods. Judging from the quantity of people I encounter on my excursions, I am not alone in my passion for the great outdoors. It’s one of the few remaining places in America where people actually openly smile and say hello to one another. I suppose we are all in a better mood when carefree and breathing fresh air. 

Radio stations are always searching for ways to project fun, tap into good feelings and show support for public institutions. By appointing one of your on-air personalities as your “outdoors person” — or hiring a freelancer — you can capture this feel-good attitude. And yes, there’s even a way to generate revenue by doing so.

A clever name or title for this al-fresco role will help you to build affection for the person presenting information on-air, online and via your social platforms. You are creating a subject matter expert — an influencer, in today’s parlance — who has the street cred to guide your audience into the great outdoors. 

No doubt, part of the appeal of communing with nature is that many outside activities are either inexpensive or even free. It’s important to communicate the financial facts and other details when talking about park entry fees, activities and events. 

Here’s an example of how this could play out on your station and then across your brand’s platforms: 

1. On-air pre-recorded piece: “Hey, it’s Smokey O, the Outdoors Guy. During this amazing spell of mild winter weather, have you considered hiking in the nearby George Washington National Forest? Parts of the forest are less than two hours from DC. One trail I particularly recommend is the Woodstock Tower Trail, a moderate 45-minute gradual climb. When you get to the top, you can climb the ranger tower where you can see for miles over the Shenandoah Valley. Entrance to the park is free. Get more details about how to plan your day at [station’s website], Facebook page or see pics at #SmokeyO.” 
2. Tag: “Smokey O, the Outdoors Guy, is brought to you by Smoot’s Outfitters, where all your climbing gear is now 20% off.” 
3. On Instagram, you’d post pics of the hike. 
4. Your host, Smokey O, could do a weekly five-minute podcast about his forays. 
5. Some of these clips could be recorded while Smoky O is actually hiking, a great way to inspire listeners to get up and go.

Ozarks Public Radio capitalized on June as Great Outdoors month at www.ksmu.org, branching out from its regular coverage of Missouri news and politics.

After you’ve established your Outdoors Person as an authentic, reliable personality and he or she has gained a following, you’re really ready to run. They can begin making appearances at nonprofit events and activities to strengthen your station’s community relations, then also serve as a personality doing live cut-ins from retail establishments and commercial exhibitions related to anything outdoors.

FINDING YOUR SMOKEY O

I’ve left the most challenging part of this plan for last. You’re likely wondering how in the world you are going to find the right person for this role. 

Aside from the normal job sites, like LinkedIn and Indeed, and getting recommendations from locals connected to the outdoor scene, have some fun! 

Run a contest and do “tryouts” for a month. You could feature contestants on your morning show, have them guest-post photos on your Instagram, and then let your audience vote. 

You could also check to see if there are any local influencers with an active lifestyle who are already big on YouTube or Instagram. Likely, they’d love to reach a new audience via radio and your social channels. 

Sowegalive.com features its own “The Great Outdoors Radio Show” and a podcast for Georgia outdoor enthusiasts.

Remember that this concept is not limited to hiking. Depending on your location, you can cover fishing, hunting, skiing, snowboarding, kayaking, sailing… virtually any outside activity that your audience enjoys in your area. 

More than 150 years ago, Massachusetts native Henry David Thoreau wrote in his journal, “What is Nature unless there is an eventful human life passing within her?” Encourage your listeners to experience the world outside, and who knows what they may discover.

Mark Lapidus is a multi-platform media, content and marketing executive and longtime Radio World contributor. Email mark.lapidus1@gmail.com.

The post The Great Outdoors for Fun and Profit  appeared first on Radio World.

The FCC is getting pressure to free up the entire 1,200 megahertz of the 6 GHz band for Wi-Fi, as broadcasters wave caution flags over potential interference to their signals should a sharing regime be instituted.

A continued call for all of the spectrum that stations now use for electronic newsgathering (ENG) came in a letter to the FCC from some of the biggest in Big Tech — Apple, Facebook, Google — as well as from consumer and free-market advocacy groups.

That was followed closely by a letter from a bipartisan pair of legislators calling for the same approach, including one whose Northern California district skirts Silicon Valley.

Broadcasters use the band for broadcast auxiliary services (BAS) operations such as sporting events, breaking news and special events. They said the FCC’s proposed interference protections — limited to lower-power, indoor operations — miss the mark, particularly as some camera transmitters used to relay footage to stations also operate indoors and at low power, so they would be in the interference line of fire even with those limitations on unlicensed devices.

Broadcasters have had to fight for ENG before as the FCC trolled for spectrum. They don’t want the agency to allow full use of the band without assurances — and not simply from the computer companies or cable operators hungrily eyeing the spectrum — that new uses won’t interfere with existing operations.

Cable operators, who are looking for more Wi-Fi spectrum, agree with the computer companies that there is a way to share and share alike.

The FCC on a mission to free up as much spectrum for 5G as possible (a Trump administration priority), including allowing shared use wherever it is feasible.

While some have argued for moving incumbents to a different band entirely, Apple and others have said that process could take a decade. Besides, sharing will work without jeopardizing incumbent service, tech companies told the FCC: “If the commission wants to bring more midband spectrum into use for next-generation wireless in the near term, while preventing disruption and interference to incumbents, the clear answer is to make 6 GHz available for shared unlicensed use.”

Lawmakers Join Push

In their letter, Reps. Jerry McNerney (D-Calif.) and H. Morgan Griffith (R-Va.) asked the FCC to free up the entire band ASAP. “We believe the 6 GHz band’s greatest potential would be realized by unlocking all 1,200 MHz of the band for unlicensed use,” they wrote. “This would foster innovation and greatly benefit American consumers and our nation’s economy.”

The legislators said they agree that protecting incumbents is crucial, but also argue that Wi-Fi has a track record of successful sharing and this should be no different, given the FCC’s expertise in protecting licensed users from interference.

The FCC voted unanimously back in October 2018 to propose opening up the band to unlicensed devices — everything from laptops to Fitbits to offloading wireless traffic — using automatic frequency control (AFC) devices to prevent interference with licensed users.

All the commissioners pointed to the need to relieve congestion in the wireless band, including under the direction of Congress in the MOBILE NOW Act, which charged the FCC with finding more spectrum for 5G.

The FCC is expected soon to vote on making that proposal a reality. But not if broadcasters have anything to do with it.

The National Association of Broadcasters argues the proponents of sharing in the band “assume away” the challenges of protecting those BAS operations. The trade group told the FCC earlier this month that hundreds of MHz can be opened for Wi-Fi and broadcasters are willing to work with the government and stakeholders on a solution to sharing. But nothing the computer companies have so far come up with fills the bill.

“[T]he Wi-Fi uses under consideration in this proceeding are simply incompatible with mobile broadcast operations used for electronic newsgathering — and no proposal advanced by any party to date will protect those mobile operations,” NAB says.

If those do ever materialize, the NAB said, the FCC can consider them then, and in a separate proceeding.

 

The post Big Tech, Broadcast Battle Over 6 GHz appeared first on Radio World.

David Mathew

The author is technical publications manager and a senior technical writer at Audio Precision in Beaverton, Ore.

When reduced to its basics, the process of audio test and measurement is concerned with a small number of performance benchmarks. At my company, we call these “the Big Six,” and they are as follows:

• Level
• Frequency Response
• THD+N (Total Harmonic Distortion plus Noise)
• Phase
• Crosstalk
• Signal-to-Noise Ratio (SNR)

Fig. 1 shows a typical test setup for the Big Six audio measurements.

Fig. 1: Test setup for the Big Six audio measurements of a device under test. LEVEL

Any Device Under Test (or DUT, as often referenced in the world of test and measurement) may have a number of level measurements that are of interest. You must choose which level you are seeking. Target levels include:

• an input level that produces a given output level, such as 1 volt, or 1 watt, or unity gain (see below for a discussion of DUT gain);
• an input level that produces a certain output distortion, such as 1% THD+N;
• a level that provides good noise performance with comfortable headroom, often called the operating level;
• an input or output level specified in a testing document.

Any of these levels may be used as a reference level on which we can base further measurements. Frequency response measurements, for example, are expressed relative to the level of a mid-band frequency; THD+N measurements are made at specified levels, which should be reported in the results.

The ratio of a DUT’s output voltage level to its input voltage level is the voltage gain of the DUT. For example, in a DUT with a gain of 2, an applied input of 2 volts will produce an output of 4 volts. A gain of 1, where the output voltage equals the input voltage, is called unity gain. Some DUTs offer no gain adjustments, and are said to have fixed gain. The gain may be fixed at unity, or at some other value.

A DUT with a volume control or other setting that affects gain is a variable gain device. When setting and measuring level, it is essential to consider whether or not the DUT gain is variable (not only volume controls, but tone controls and other settings can change gain), and, if it is, how to set the DUT controls for the desired test results.

FREQUENCY RESPONSE

A frequency response measurement reports the output levels of a DUT when stimulated with different frequencies of known level. The simplest of all frequency response measurements consists of only two or three tones, the first near the middle of a DUT’s usable frequency range, and followed by a tone near the higher extreme of the range and sometimes a tone near the lower extreme. Assuming the tones are all generated at the same level, the DUT’s output levels describe its response to these different frequencies.

Fig. 2: An example of a frequency response sweep of a device.

Full-range frequency response measurements can be made by a number of different methods, the classic being a sweep of a sine wave from the lowest frequency in the range to the highest, with the results plotted on a graph. A “flat” response describes the shape of a graph where the DUT responds equally at all frequencies, producing a trace with a slope of 0 and with minimal variations. Fig. 2 shows a typical result.

THD+N

THD+N stands for Total Harmonic Distortion plus Noise. Harmonic distortion is the unwanted addition of new tones to the audio signal. These tones are harmonically related tones to the original signal: when the signal is one sine wave of frequency f1, harmonic tones are f2, f3 and so on, at integral multiples of the original tone. Total harmonic distortion is the sum of all of the harmonics measured in the DUT’s bandwidth.

Why THD+N? Why not just measure THD (the distortion) and N (the noise) individually? Well, in the pre-FFT days of audio measurement, it was difficult to measure the THD by itself, without the noise, but it was relatively simple to measure the THD and the N together. So the accepted techniques handed down from years past specify THD+N, because that’s what was practical. In addition, THD+N is a convenient and telling single-number mark of performance, widely understood and accepted.

The measured THD+N of a device will vary with the measurement bandwidth. You will almost always want to restrict the measurement bandwidth using high-pass and low-pass filters, and you must include the bandwidth used when you state the result. THD+N is typically measured and reported in a 20 Hz–20 kHz bandwidth.

Fig. 3: Screenshot of a THD+N measurement of a device at maximum operating level.

The measured THD+N of a device will also vary with level and the frequency of the applied signal. Audio THD+N is typically measured and reported at a mid-range frequency (1 kHz or so) at either the device’s nominal operating level or at its maximum output level (MOL). Fig. 3 shows a typical THD+N measurement result at MOL.

PHASE

In audio engineering, phase measurements are used to describe the positive or negative time offset in a cycle of a periodic waveform (such as a sine wave), measured from a reference waveform. The reference is usually the same signal at a different point in the system, or a related signal in a different channel in the system. This choice of references defines the two most common phase measurements: device input/output phase, and interchannel phase.

Phase shift varies with frequency, and it is not uncommon to make phase measurements at several frequencies or to plot the phase response of a frequency sweep. Phase is expressed in degrees.

CROSSTALK

In audio systems of more than one channel, it is undesirable for the signal in one channel to appear at a reduced level in the output of another channel. This signal leakage across channels is called crosstalk, and in practical devices it is very difficult to eliminate. It’s expressed as the ratio of the undesired signal in the unstimulated channel to the signal in the stimulated channel.

Crosstalk is largely the result of capacitive coupling between channel conductors in the device, and usually exhibits a rising characteristic with frequency. It’s often expressed in the form of a single-number result; however, a crosstalk versus frequency sweep will show how a DUT performs across its operating bandwidth.

SIGNAL-TO-NOISE RATIO

How much noise is too much? That depends on how loud your signal is. Signal-to-noise ratio (or SNR) is a measure of this difference, providing (like THD+N) a single-number mark of device performance. The signal is usually set to the nominal operating level or to the maximum operating level (MOL) of the DUT. When SNR is made using the MOL, the result can also be called the dynamic range, since it describes the two extremes of level possible in the DUT. (Dynamic range in digital devices has a somewhat different meaning). SNR is usually stated in decibels, often shown as negative. Fig. 4 shows a typical SNR measurement result.

Fig. 4: A typical SNR measurement result.

Using traditional methods, SNR requires two measurements and a bit of arithmetic. First you measure the signal level, then turn off the generator (and often, terminate the DUT inputs in a low impedance as well, to fully reduce the noise in the device). Then the noise level (often called the noise floor) is measured, using filters to restrict the measurement bandwidth. The ratio between the two is the SNR.

David Mathew has worked as both a mixing engineer and a technical engineer in the recording and filmmaking industries. He was awarded an Emmy for his sound work in 1988.           

The post Introduction to the Six Basic Audio Measurements appeared first on Radio World.