Monthly Archives: January 2012

Reinventing the FM Audio Proof – Part Five

Jeff Keith

Jeff Keith

When does ‘Cranked Up!’ become ‘Over the Top’?

In part four, I touched on the importance of using good quality source material and how a little extra attention in that area can turn so-so sound into awesome sound. A few wrote and questioned my inference that codec-compressed audio was bad, but if your station has the opportunity to use uncompressed material, then why not? It’s another step towards your station sounding better than your competition.

This issue is about FM loudness wars. To get the ball rolling I’d like to refer to some research I did a few years ago on “loudness” from the point of view of listeners radios and how the average radio behaves when tuned to a station that’s modulating above 100%.

Rewind to 1994. Our $$$$ modulation monitor sounded good if we overmodulated, but I was wondering about the radios in the hands of listeners … what happened inside their radios?  I felt, and with a high degree of confidence, that consumer radios had nowhere near the demodulator performance of our station’s modulation monitor. But how bad were they? I wanted to find out.

I’m fortunate to have a nicely equipped lab at home so making some measurements on a collection of different consumer FM radios gave me a great excuse to stay inside on a cold and snowy weekend. The staff of the station graciously loaned me around two dozen radios for my project, and in return I promised that I would try not to break them.

My research had one goal; discover how run-of-the-mill radios behaved as FM modulation levels increased above 100%. I wasn’t interested in measuring the radios’ baseline distortion performance – I intuitively knew those numbers would be all over the map anyway and therefore meaningless, at least for this project.

What line of thinking led to this project? Tradeoffs were probably made in the design of consumer radios to minimize their cost and maximize the signal to noise performance with the components used. Using the regulations on FM modulation as a guide, designers would naturally believe that if the radio’s design had sufficient IF bandwidth and audio headroom to accommodate FM signals modulated at the legal limit, they would be home free.

The upside of that assumption was that radios could deliver decent audio performance at legal modulation levels, and in fact most do.

The downside (and this is where I was going with my thinking): designers would likely leave little if any headroom for accommodating FM modulation above 100% simply because they didn’t need to. To me, this hinted that higher modulation levels had the potential to generate significant and audible distortion in a listener’s receiver.

The data I collected during my experiment represents the comparison of two signals; the modulation percentage for the very linear FM signal generator I used, and the resulting audio level out of each receiver’s demodulator. I was not surprised that most radios had significant nonlinearity above 100% modulation.

In all, 27 radios were measured. To keep this article at a reasonable length I’ve selected five of the most revealing plots to share. The first one, at left, is for the receiver that best tolerated modulation above 100%; it’s my 1960’s vintage, tube type McIntosh MX-110 which just started to become nonlinear at 150% modulation!

The remaining four plots show what each radio’s audio output level did as the modulation levels went up. The associated graphs are easy to interpret; the straightness of the diagonal line going from lower left to upper right shows how well the radio’s audio output follows increasing modulation levels. A perfect receiver would plot as a perfectly straight line. Unfortunately such a receiver is quite expensive to build and could not be sold at ‘consumer’ prices. It’s also unfortunate that that’s what we’d like to believe our station’s listeners have.

The vertical line in the center of each plot represents 100% modulation. The left-hand scale is ‘relative’ because each radio had a different audio output level and since standardizing the radio’s actual output levels wasn’t relevant to my measurements, I simply chose to not calibrate that axis.

At left are four plots, beginning with Radio #1. Radio #1 was actually pretty good and its detector and audio sections didn’t become nonlinear until 135% FM modulation. I suppose this might be expected in a ‘higher-end’ consumer model that has sold for around $400 since the 1990’s.

Next is the plot for Radio #2. This radio was a ‘better’ model that formerly sold for around $75 at Radio Shack and it’s admired by broadcast professionals for its ‘nice’ AM sound.  Note however that on FM it becomes very nonlinear at around 118% modulation.

Next is the plot for Radio #3, a ‘mid-grade’ and popular table model. This radio was fairly linear up to 110% modulation but abruptly became very nonlinear above 115%.

The last plot is for Radio #4, a common consumer grade portable radio. Its output level exhibited a very strange behavior at 110% modulation where it suddenly stopped increasing, and once above 110% the output actually started decreasing as the modulation increased further.

The important detail in each plot is at what modulation level the plot diverges from being a straight line because when it bends, it shows that the radio is no longer following the station’s modulation and is then generating its own distortion. The sharper the bend is at a particular modulation level, the more distorted the radio will be at that modulation level and above.

These plots ignore any influence from the station’s audio processing because it’s not relevant except for one thing; when a station is overmodulating, the denser the audio processing is, the more distorted the audio will be for listeners with those imperfect radios because the audio spends more time up in the nonlinear part of the radio’s level vs. distortion curve.

Do the plots provide other useful clues? Yes, and there’s one that I’m loath to admit; our country’s FCC somehow managed to get it right in 1984 when they decided to raise the FM modulation limit, but only to 110% (see FCC BC Docket #82-536 to amend parts 2 and 73 of the FCC rules…). As well as the interference concerns, the new ruling took into consideration how the radios of the day, and the anticipated radios of the future, would behave at 110% modulation.

I haven’t measured a group of newer FM radios yet. But the trend towards lower quality consumer AM radios suggests that the quality of today’s FM radios is probably inferior to those in 1984 when the 110% modulation limit went into effect. It also infers that the trend should be for the radios of today to be inferior to those I measured in 1994. Now that we know that our 130%-plus FM modulation probably isn’t doing many consumer radios any favors, what can we do?

As a sanity check, I plotted the ability of each of the 27 receivers to accept higher modulation percentages and put this data into the pie chart at left. What the chart shows is the percentage of receivers tested that are able to accept a certain level of modulation without becoming distorted. There are two numbers associated with each pie chart segment; the number inside the parenthesis is the percentage of radios tested that were able to accept a certain modulation level, and that modulation level is shown outside the parenthesis. For example, 100% of the receivers tested could demodulate 105% modulation without distortion, while only 44.4% could do so at 130% modulation.

Based on the data it’s tempting to suggest that modulating above 115% should be approached with caution because we can’t control what radios listeners are using to hear our station.  With the radio’s own ‘self-distortion’ exposed it’s also tempting to suggest that the distortion heard by listeners on their radios is probably being blamed on the station, and not on the radio (with everyone in a market modulating well over 110% listener’s have no point of reference, yes?). Could this mean that some of the erosion of time spent listening has much less to do with the stations programming, and more to do with the inability of consumer radios to handle the extremely competitive modulation levels we’re seeing today? In other words, is high modulation annoying our listener’s radios which then annoy the listener to the point that they tune out? It’s food for thought…

I decided to write an article on this particular subject in order to share the observations I’d made about how some not-too-carefully-selected consumer FM radios behaved at elevated modulation levels.  The fact that we as broadcasters have no control over what radio a listener might use perhaps leads to a very pertinent question:

What benefit, other than embarrassing the competition (which is just another form of inside joke that listeners will never get) are we getting from pushing FM modulation levels through the roof? 

I love reader feedback and welcome all comments. Please shoot me an email at jakeith@wheatstone.com and tell me what your observations have been in your market!


Wheatstone Delivers for CRC Broadcasting

KFNN D-75When you make a purchase from Wheatstone, not only do you get great equipment, you also receive customer support that is second to none. And you don’t need to be one of the large groups to receive this special treatment. Just ask Brian DuBose, VP of Programming and Operations for CRC Broadcasting, located in Phoenix AZ. CRC operates KFNN, Money Radio 1510.

“As we were planning a move to new facilities, we made the decision to purchase an Audioarts D-75 console. This was largely due to a sales call by Jay Tyler, Director of Sales, recalls DuBose. “We’re a small station, and we don’t make purchases all that often, so this attention was a welcome surprise.” The console was delivered to CRC two years ago.

DuBose appreciated the D-75’s four stereo output busses, direct digital VU-plus-peak LED metering displays, and the opto-isolated control ports on all of the input modules. Although CRC’s installation is all analog, inputs can be changed to digital in the future by installing new daughter cards.

A sagging economy and various logistical delays led CRC to postpone the move until recently. Then it was discovered that the station had mistakenly purchased input boards for the D-75N networked digital radio console, rather than the needed IN-75 boards for the non-network version. “Even though the purchased was made two years ago, Jay exchanged the network cards for the ones we needed,” adds DuBose.

KFNN hired three contract engineers to build the new facilities, but one had to drop out at the eleventh hour. “Jay got us connected with Jim Hibbard at Pacific Mobile Recorders, and their work saved the day for us,” recalls Du Bose.

Pacific Mobile, located in Sacramento CA,  is a systems integration company that has done installs for all of the major networks, many of them with Wheatstone gear. For CRC Broadcasting, they created a custom  wiring harness to connect the D-75 to the rest of their studio gear.

After two years of waiting, the D-75 install was completed. CRC’s experience with Wheatstone on the project made them decide to continue the relationship by purchasing several Audioarts Air-3 radio consoles for the next phase of the project.


App Gives iPhone a Retro Sound

Do you long for the days when AM top 40 radio ruled the airwaves?  How about the ‘sound’ of AM radio? Over processed, low fidelity, static, noise and adjacent-channel interference were all the norm. Well, there’s an app for that.

ONYX Apps of Sofia, Bulgaria recently announced its release of  Retro-Fi 1.0 for iOS. As reported in prMac, this app transforms music through real-time DSP, adding variable amounts of vintage AM radio effects. Retro-Fi works its magic on online radio stations, Podcasts or your oldies collection to change that pristine digital audio into into something that sounds like it came from the radio in your 1966 Chevy Nomad.

Retro-Fi’s developers advise that this is not an audiophile app that returns the warmth of high-fidelity vacuum tube amplifiers to harsh digital audio, but one that adds the many characteristics of AM radio sound. On startup, the app displays a 1940s-vintage AM-shortwave receiver. Frequency response is immediately reduced to 300-3,000 Hz. Dynamic range is reduced to 40 dB. Even on the iPhone’s tiny speaker, the difference is dramatic.

Users control the amount of AM with two continuously variable sliders, Ambience and Static Noise. Ambience adds a quasi-reverb effect as intermodulation distortion and the sound of other stations on nearby frequencies come in an out randomly. Static adds the crisp, intermittent sound of raw electricity, AM’s rendering of lightning, compressors, and car ignitions. The process is non-destructive, and once the app is closed, audio returns to its normal high quality mode.

“Retro-Fi is an fun little nostalgic iPhone app,” adds Eugene Klein of ONYX Apps, “that transforms a user’s music collection, or any other audio source that can be played on the iPhone, into a Low Fidelity, retro-sounding stream.”

Retro-Fi costs just 99 cents, and is available worldwide exclusively through the App Store in the Music category.


BBG Member Advocates to Save VOA Greenville

With the recent closing of the transmitting site in Bethany Ohio, and the earlier shuttering  of the Delano California facilities, the Edward R. Murrow Transmitting Station in Greenville, NC is the only remaining VOA transmitter site on American soil. If members of the Obama administration and the Broadcasting Board of Governors (BBG) have their way, it too will soon go dark. At least one member of the Board thinks that’s a very bad idea.

In a story reported in BBGWorld.com, BBG member Victor Ashe has called for keeping open the remaining broadcasting facility on U.S. territory that is capable of transmitting shortwave radio programs to China.

Citing the fragility of Internet connections during times of political turmoil, as well as the vulnerability of shortwave transmitting stations on foreign soil, Ashe has stood alone in the BBG as an advocate for retaining global shortwave broadcasting facilities for future emergencies. He adds that the closing of VOA stations in Kavala Greece and Morocco only add to the urgency of the situation.

Ashe also called for urgent reforms in the way the federal agency in charge of U.S. international broadcasting operates. He has become an outspoken critic of the permanent BBG bureaucracy in charge of planning and day-to-day operations of U.S. international broadcasting.

He has also spoken out about the way of some of the BBG top managers treat their subordinates, and by the second-class status of the agency’s full-time contract employees. In his statement, Ashe refers to the government-wide employee surveys conducted by the Office of Personnel Management, in which the BBG has been consistently rated as being among the worst-managed federal agencies.

His comments to the media, released as a personal wish list for 2012,  are  unprecedented.  BBG officials are  presidentially-appointed, and usually do not publicly express their opinions about how their agency is being managed.

The Broadcasting Board of Governors encompasses all U.S. civilian international broadcasting, including the Voice of America (VOA), Radio Free Europe/Radio Liberty (RFE/RL), Radio Free Asia (RFA), Radio and TV Martí, and the Middle East Broadcasting Networks (MBN)—Radio Sawa and Alhurra Television. The Broadcasting Board of Governors is a bipartisan board comprised of nine members. Eight, no more than four from one party, are appointed by the President and confirmed by the U.S. Senate; the ninth is the Secretary of State, who serves ex officio.


Vinyl Resurfaces on Wake Island

Locked away for about 40 years in a small room on Wake Island is a vinyl treasure. A collection that now totals around 9,000 albums was started in the 1960s. That’s when KEAD, a low-power AM station, was set up by the Armed Forces Radio and Television Service (AFRTS) to entertain military personnel on the isolated island. The exact dates and history of the station are uncertain, as Colin Bradley, the communications superintendent with Chugach Federal Solutions, Inc. (CFSI) explains. “I would guess that KEAD started in the 60s due to the dates on the records,” he said. “Also, the FAA controlled Wake Island until the mid-60s, so an armed forces radio station wouldn’t have been here. I would guess it wrapped up maybe in the 70s or with the advent of satellite radio.”

What makes the collection especially valuable is the type of material preserved. It includes a variety of vinyl albums and records specially made for military audiences and distributed monthly by the American Forces Radio and Television Network . The records were copyrighted and only to be used for their official purpose of entertaining the troops overseas, and then returned to AFRTS. There are also a number of commercially available recordings.

Due to the condition, organization and uniqueness of the material, experts estimate its cash value between $90,000 and $250,000. “Because of the completeness of the collection, I assumed it was quite valuable,” notes Bradley. “I have not run across a collection that well preserved or that intact in my career. It’s a little time capsule.”  Some of the radio productions are original, like GI Jill and Command Performance, and have significant value.

For the past 40-odd years, the record collection remained all but forgotten,  cataloged and neatly organized on shelves in a small room on the second floor of the Wake Island Airfield base operations building. Efforts are now underway to return  the vinyl library to its rightful owner, the American Forces Radio and Television Network, located in Alexandria, Va.

Since Wake Island Airfield is a tiny 1,821-acre atoll located about 2,000 miles west of Hawaii and 2,000 miles east of Japan, it is possible that the cost and logistics of returning the records to the mainland were prohibitive at the time the radio station was shut down, officials said. It won’t be an inexpensive proposition to bring the records to their new home.

Bradley has estimated that it will take approximately 75 16-inch-by-16-inch boxes, and a total of about $10,000 worth of specialized material to properly pack up the records. AFRTS is providing the materials and the 611th Air Support Group’s Detachment 1 will do the packing, he said.

Once the collection is shipped to Alexandria, the records will be used to fill any gaps in the American Forces Network local museum,  and the remainder will be entered into either the Library of Congress or the National Archives to become a permanent piece of U.S. history, accessible to all.


Links from WHEAT:NEWS Volume 3, No. 2

WHEAT:NEWS

WHEAT:NEWS, Wheatstone’s twice-monthly newsletter, publishes a list of links of general interest in each issue. If you don’t receive WHEAT:NEWS and would like to, simply click the banner above and you’ll be led to a page where you can subscribe. We don’t sell or give away your contact info and we don’t SPAM, and we make it easy to unsubscribe at any time.

Volume 3, No. 2 published the following links:

  • The annual Consumer Electronics Show in Las Vegas is the largest convention in the Americas. But is it really the best place to debut new gadgets? PhysOrg examines the ‘CES Curse’.
  • Use your GPS to avoid bad neighborhoods. Microsoft has patented software that uses crime statistics to keep you out of the ghetto. CBS Seattle has the details.
  • An app note from Z Technology explains how to create meaningful DTV signal coverage maps.
  • Despite the bleak economy, there’s venture capital available for music startups. Audio4cast has the rundown of last year’s winners and losers in the Internet audio soundscape.
  • In an effort to wield greater cultural influence, China is launching a 24 hour TV channel in New York starting this quarter. Bloomberg News has the scoop.
  • For over 70 years, the BBC World Service broadcast from Bush House in London. That tradition ended on December 26, 2011. Listen to a 2-part documentary on the BBC about the organization’s historic headquarters.

AirAura 2.0: Making the Best Even Better

AirAura is the newest and most powerful Vorsis audio processor for FM and FM-HD. It’s won industry awards and accolades from broadcasters around the globe. Are Vorsis engineers content to bask in their success? No. Since its release, they have been devising ways to make the best audio processor even better. The result is the AirAura 2.0 upgrade.

Many new features have been added to AirAura. Starting with the low end, VBMS Sub is a new DSP algorithm that analyzes bass material in the 20-100 Hz range.  It then uses it to synthesize spectrally-pure subharmonics. And it does this without affecting the clarity of the mid- and high-frequency content. The result is a virtual subwoofer in the 40-90 Hz range, and bass you can really feel. VBMS Sub gives a powerful competitive edge to stations with CHR and Urban formats.

Another part of the AurAura upgrade is Speech Smart™ Technology. It manages the multi-band AGC and compressor to keep voices sounding perfectly clean and natural at all times. Speech Smart™ ensures there will be no missing midrange presence, an issue  which is common on other processors.

With AirAura 2.0 you can expect incredibly smooth gain and spectral control with a wide range of input levels, thanks to the AGC/SST (Sweet Spot Technology). The AGC features separately adjustable low and high inter-band coupling for precision sonic tuning of your on-air signal.

Powerful processing demands powerful analysis tools. AirAura 2.0 has new graphic displays that provide a level of control and sophistication never seen before in the industry.  Included in the analysis tool box is a display of spectral dynamic range, which shows the relationship between the actual peak and RMS levels in each band. The shorter the line, the louder the audio.

The energy vs. frequency display shows the total relative loudness of various parts of the audio spectrum. The display may be switched to show the effects of processing for either the FM or HD signal paths.

The AirAura clipper activity display uses a color scheme similar to weather radar  to show how much work the AirAura clipper is doing to mask distortion, and where in the audio spectrum it is doing this work. Just as in weather radar, intensity is indicated with reds and oranges.  In audio processing, these colors indicate more active distortion management.

Finally, the AirAura 2.0 upgrade includes a newly-written and comprehensive user manual, all new factory presets, and the new ‘Audio Processing Guru’ software, which replaces the previous ‘GUI Lite’ interface. Vorsis users running software version 1.2.x will be able to upgrade to 2.0 by simply running the new software installer.


Wheatstone E-1 Digital Audio Console

Zach Morton, WIKY

Zach Morton, WIKY

Whether its in the foothills of Afghanistan or small towns in America, Wheatstone’s E-1 digital audio console makes a great impression. Zach Morton, Chief Engineer of South Central Media’s Evansville IL operations first encountered the E-1 while working as a contractor in Afghanistan. “It was used in a network operations control point to send IP audio to stations throughout the country,” recalls Morton. Back in the States, he recently installed a 12-input E-1 in the on-air studio of WIKY, a news-talk operation in Evansville.

Installation was simply a matter of plugging in a cat-5 cable and power connections. “IP audio means there’s no more rat’s nests under the console,” adds Morton. WIKY’s inputs are all digital except for the phone hybrid.

Once the E-1 was installed, Morton busied himself creating show presets. A morning preset allowed for four microphones, while the midday layout was more simplified. An afternoon drive and generic weekend preset enabled the station to customize their E-1 for every daypart. With four presets created, Morton could have created 95 more before reaching the system’s limit of 99.

The E-1 series offers powerful mix minus flexibility, with a mix minus output from every input channel that can use any console bus as its reference mix. Each channel also has direct to source talkback and auto-switching between On Air and Off Line mix minus. Morton used the mix minus to feed Tieline equipment for sports and remote broadcasts.

Wheatstone’s E-1 is also bulletproof, as Morton discovered. “Someone spilled a soda into the control surface. It never affected our on-air operations, and I was able to unplug it, disassemble the input panel, clean it up with vinegar and reassemble the control surface while we were on the air.” The E-1 was also unfazed by a recent  lightning strike to the WIKY studio building.

“Everyone from engineering to programming loves the E-1 console,” concludes Morton. “My only regret is that we purchased the 12-input mainframe instead of the 18-input version.”


Internet Radio That’s Out of This World

NASA Third Rock RadioSeeking to win the hearts and minds of a younger tech-savvy audience, NASA has launched it’s own Internet radio station. Third Rock – America’s Space Station recently began broadcasting 24/7 with a New Rock/Indie/Alternative format. The station may be reached through NASA’s home page, and will also be available through NASA iPhone and Android mobile applications.

“NASA constantly is looking for new and innovative ways to engage the public and inspire the next generation of scientists and engineers,” added David Weaver, associate administrator for the Office of Communications at NASA Headquarters in Washington. “We have led the way in innovative uses of new media and this is another example of how the agency is taking advantage of these important communication tools.” The space agency adds Internet radio to its current offerings of on-demand videos, NASA television, interactive multimedia features and podcasts & vodcasts.

RFC Media, a Houston-based ISP, is partnering with NASA to host the station. Music is an eclectic mix of all flavors of rock, including new music that seems to go largely unexplored by commercial radio, along with some familiar favorites.

Third Rock will also feature short NASA programs and news items embedded throughout the day.  Programming will include greetings from celebrity artists and listings of high-tech job openings from NASA partner companies in the engineering, science and IT fields. Since NASA’s Internet radio station is supported by advertising, it operates at no expense to the taxpayers.

“No one knows more about discovering new rock than NASA,” said Cruze, RFC Media co-founder and president. “Exciting new music is being discovered online through specialty sites like Third Rock-America’s Space Station, where listeners will hear about great new artists way before their friends hear of them.”


Summit Eyes Challenges and Opportunities

Jacobs Media SummitSeeking to gain a broad perspective on the radio industry in 2011 and beyond, Jacobs Media Summit 16 tried a different format than used in previous years to gain a 360-degree view on the industry. “Over four hours, we heard from many thought leaders from a wide variety of backgrounds,” adds Jacobs Media’s President Fred Jacobs.

Hour-long sessions have seemed too long in the past, so this year’s nine presenters were each given 25-30 minutes. The event ended with a roundtable discussion featuring some of the industry’s best thinkers.

The summit began with a presentation by Jeff Pulver, founder of the 140 Characters Conference. He  discussed how Twitter and the real-time web impact station operations. He also described the power of one through the new media, where any individual can become a potent force. Pulver’s unconventional speaking style included having the 250 participants give each other hugs at the end of his presentation.

James Cridland, a radio futurologist from the UK, and a fan of American radio, spoke of the ‘power of one’. Stations in the UK have united and speak with a powerful voice. In the U.S., however, all broadcasters are in their own silos. Radio as a medium is therefore underrated. It needs to come together and speak with one voice.

The U.S. Census Bureau generates an enormous amount of data. Dr. Robert Groves, the agency’s director used a slide show to demonstrate the changing demography and ethnicity of the U.S., and explained how radio can use this data to enhance its decision-making in the future. “There have been many requests for Groves’ slide show,” adds Jacobs.

The star of MSNBC’s “The Ed Show” and his own syndicated radio talk show, Ed Schultz discussed radio’s ability to motivate its listeners, as well as the value of ‘retail radio’, which means getting out of the studio and interacting with listeners.

Jacobs Media set out to find the most outstanding social network strategist in radio. 43,000 votes later, Chris Petlak, Social Media Manager of WTMX Chicago, emerged as the winner. He shared his key factors for success with the audience.

Jim Farley, VP of News and Programming at WTOP told the audience how he and his team moved the nation’s top news station to FM and created a multi-platform phenomenon that has emerged as one of the most successful news media operations in the U.S.

As the co-host of NPR’s ‘On The Media’, Brooke Gladstone has some informed insights on the current state of media and the impact of technology on journalism and broadcasting. She was interviewed by Fred Jacobs about her observations regarding where the media is heading.

The final session was led by Sean Parker, Director and Social Solutions Provider for the NHL’s Washington Capitals. Parker talked about how the Capitals and other NHL teams locate core fans who are adept at social media, and use them to extend the brand and ignite other fans.

The summit wrapped up with a roundtable moderated by Kurt Hanson, founder of RAIN. Participants included KUT’s Hawk Mendenhall, Dial Global’s Beau Phillips, WMMR’s Bill Weston, WTOP’s Jim Farley, James Cridland and others. Summit attendees were able to provide a running commentary on the roundtable via Twitter.

This is the 16th year for the Jacobs Media Summit. “This year’s event was six months in the planning, and we’re already jotting down ideas for the 2012 summit,” adds Jacobs. The annual event is held in partnership with the Arbitron Client Conference, allowing attendees to participate in Arbitron’s presentations as well.