WheatNews May 2022

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WHEAT:NEWS MAY 2022  Volume 13, Number 5

HOW TO TALK TO YOUR IT DEPARTMENT

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In March, Bill Jackson talked to us about Air1/K-LOVE’s new media center and hypervisors, thin clients and VoxPro. This month, he has a few suggestions for how to talk to your IT department. 

When someone from IT says they will be doing routine Windows® updates, what most broadcasters hear is that they’ll need to be back at the station around midnight to manually update and test each machine. 

BillJacksonBut that’s not what Bill Jackson hears. 

“In most enterprises, they have scripts and utilities that will update 400 computers with Windows all at once,” explained the principal studio engineer for Educational Media Foundation (EMF), a multiplatform media company that originates Air1 and K-LOVE radio network from two media centers in Nashville and Rocklin, Calif. 

He knows that the long nights could come much later. EMF lost a few touchscreens and audio drivers to a crucial Windows update before Jackson could explain to his IT counterparts why staggering updates is a tried-and-true method used in broadcasting. Now when Patch Day comes around, he works closely with IT to make sure that updates have been verified by vendors and are tested on auxiliary or backup systems first before moving on to critical machines. (Your IT department will be happy to know that Wheatstone is now offering Linux audio drivers for WheatNet-IP audio networks. Contact our customer support team at techsupport@wheatstone.com for information.)

This is just one example of how he has found common language – and ground – with EMF’s IT department. In fact, the two departments recently engineered a new media center combining enterprise IT and broadcast tools that is virtualizing what once took 172 rack units into 12 RUs at a cost savings of $300,000 (read Hypervisors, Thin Clients and VoxPro in the March issue of Wheat News). 

Learning to talk IT was one of the more important skills he’s developed as a broadcast engineer. “It was hard for me personally to put my trust in our server team because there is this perceived battle between enterprise and broadcast,” said Jackson.  But slowly, over the past three years, he’s learned to trust his IT counterparts as they contributed to the media center project in ways that broadcasters alone can’t. Their understanding of key technologies such as hypervisors and server farms was critical to the success of the project, just as Jackson’s understanding of the requirements for the use of those technologies was also critical to the success of the project. 

Mutual understanding is an important first step in the IT/broadcast relationship, according to Jackson. “You have to realize that they have no concept of what StudioHub is and if I say I need a certain specification of wire, it seems overkill to them. An IT guy thinks, ‘Well, it’s CAT5, it’s transferring data.’ But in reality, I have upward of 12 different signal types and using one color of wire doesn’t work.” 

What started out as apprehension has now turned into appreciation, even admiration, for his IT counterparts. “My goal for the ministry is to build everything foundationally on IP because everything is going to be delivered on IP eventually,” he said.  EMF’s overarching goal is to be able to be faster, more efficient and on more platforms going forward. To do that, he needs IT expertise.

“A lot of it is just education. They live in one box, and we live in another. Let’s create a bigger box around that,” commented Jackson. 

Note: Bill Jackson sat down with us for a YouTube discussion on hypervisors, thin clients and VoxPro as part of the Hypervisors, Thin Clients and VoxPro article that ran in the March issue of Wheat News.   

OUTING SONGS THAT ORIGINATED AS MP3s

By Steve Walker, Wheatstone Technical Support 

Walker Steve 2022Although most of the songs in your playout system are stored as uncompressed WAV files, at least some had originated as MP3 files. How can you identify those songs so they can be replaced with pristine, uncompressed audio files? Certain clues visible in the spectrogram of an audio file can help identify these.

The most obvious one is the cutoff frequency used by the encoder.

When a file is compressed to MP3 format, the algorithm removes parts of the audio that the designers of the standard felt wouldn’t be missed by the human ear in an attempt to reduce file size.

Part of this is the cutoff of all audio content above a certain frequency. That frequency varies according to the bitrate of the MP3 compression scheme.

From my tests, it seems that a bitrate of 192 kbps results in a cutoff of audio above about 18 kHz. A rate of 128 kbps cuts off above 16–17 kHz. This is easy to see when looking at the spectrogram of an MP3 song.

See Fig. 1. Notice that at 17 kHz, the audio levels of this file are already in the noise floor.

CrystalBallMP3

Fig. 1: Spectrogram of “Crystal Ball” by Styx as MP3.

Looking at the uncompressed version of the same song in Fig. 2, we don’t get to the –67 dB level until we reach the 21 kHz frequency range.

CrystalBallWAVFig. 2: The same song, linear uncompressed.

Put on your SoX
This finding allows us an opportunity to examine our library programmatically. There is a command-line audio utility called “SoX” (for “sound exchange”) that we can use along with a scripting language to open files and examine their frequency content.

I decided to see if I could figure out how to use this utility to check out audio files. The hope was that it would identify the songs that may have once been compressed so that we could examine these more closely and replace them if necessary.

I ended up with a Python script that loops through a folder with the audio files, opening each and using SoX to create a temporary file from the song after applying a high-pass filter at, say, 17 kHz. Then a second process takes the RMS amplitude value from this temporary file and compares it to a value previously discovered by experimentation. If below this nominal value, the file is flagged as a potential candidate for replacement.

These files can be examined manually with a program such as Audacity or Adobe Audition that offers a spectrogram view. The spectrogram can be examined and the file can be played in a controlled studio environment so that a determination can be made as to the need for replacement of the audio.

The line that creates the temporary high-pass-filtered audio file (filtered at 17 kHz) looks like this:

sox [original_filename] [output_file_name] sinc 17k

The code that does rest of the heavy lifting (determining the RMS value of the high-pass-filtered audio file) is a little scary looking:

sox output.wav -n stat 2>&1 | sed -n 's|^RMS amplitude:[^0-9]*\([0-9.]*\)$|\\1|p' >>../rms.txt

All this really does is take a look at the temp file (output.wav) and call up the stats of the file. Then the sed program searches the resulting statistical output for the phrase “RMS amplitude” and writes the numerical value of that stat to a file called rms.txt. The rest of the code, not shown here, inserts the name of the song or audio file alongside the RMS value of that file. We end up with a list that looks something like Fig. 3, below.

WalkerInset

Fig. 3

In this case, any song with a value below 0.001 is suspect. Subsequent inspection of those songs’ spectrograms confirmed that they had a “flat top” at about 17 kHz, thus we know that, although they are WAV files now, they have likely been compressed at some point in the past. Those songs should be replaced with known linear audio.

It should be noted that at high bitrates such as 320 kbps, this method won’t work as well because the frequency cutoff is close to 20 kHz.

Steve Walker, previously the assistant CE for Radio One in Dallas, recently joined the Wheatstone technical support team. The above is an excerpt of his article What’s in Your Audio Library and was reprinted with permission from Radio World. For information on Steve’s Python script or for other questions, he can be reached at steve@wheatstone.com.

MIXING, PROCESSING AND STREAMING INSTANCES ON A DELL SERVER

In the video below, Wheatstone Engineering Manager Dominic Giambo demonstrates mixing, processing and streaming as instances on a Dell server in an all-virtual air chain. He also demonstrates our latest generation Blade 4 I/O access unit.

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In the video below, Wheatstone’s Senior Development Engineer Jeff Keith takes us through FM audio processing as an instance on a Dell server. Our new Wheatstone Layers server-based software was introduced at the recent NAB show. 

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STILL WHEATY AFTER ALL THESE YEARS

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CLICK ON THE IMAGE ABOVE FOR A PHOTO GALLERY

While in Vegas for the NAB show, Jay Tyler stopped in on an old friend. Beasley in Las Vegas has been a Wheat shop for more than 10 years. Our first-generation Blades and E-6 console surfaces work day in and day out for Las Vegas stations KCYE-FM, KKLZ-FM, KOAS-FM, KDWN-AM and KVGS-FM. It’s all here, and more, in these photos shot by Jay – including one rare find. 

LINEAR ALL THE WAY FOR CRAWFORD CHICAGO

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It’s linear audio all the way for Crawford in Chicago, which recently extended its studio WheatNet-IP to its transmitter site in Lansing, Illinois, using a Cambium 18GHz link. 

Cambium is a licensed-frequency Ethernet link that transfers almost 1Gbps within line of sight. 

Crawford is transferring uncompressed 44.1 kHz digital audio from a WheatNet-IP I/O Blade at the studio and across the Cambium link into a Blade at the transmitter site. “We noticed an immediate improvement in sound just by putting that 44.1 linear audio right there at the processor at the transmitter site,” commented Rick Sewell, Engineering Manager for Crawford, Chicago.

“The transmitter Blade just shows up in Navigator like it’s in the next room, but in reality, it’s four miles away.”

As a licensed IP wireless STL, the Cambium PTP820S has exclusive use of the band and therefore has consistent throughput and lower latency compared to unlicensed IP wireless options. “We’ve had this up for about three weeks and we haven’t heard any skipping or any indication of network congestion,” said Sewell.

Linear audio from a studio Blade feeds directly into the Cambium IP radio through RJ-45 connectors. Little more than a RF unit with antenna is needed on each end, with a single WheatNet-IP digital Blade able to run eight stereo channels across and still have enough bandwidth left over for video surveillance, VoIP, remote control and other periphery functions.

“What’s coming out of the studio is exactly what’s going into the processor at the transmitter site four miles away,” explained Sewell, who recently began using the onboard processor built into the Blade to do minor pre-STL EQing and normalizing before the signal leaves the studio for the on-air processor at the transmitter site. 

The 18GHz link is now used as the main STL for Crawford station WSRB-FM, which broadcasts from a tower site in Lansing, Illinois. The Crawford Chicago cluster also uses a 5GHz unlicensed Ubiquiti as a backup STL. Sewell plans to add at least one more program stream to the 18GHz Cambium link as a backup for another station and possibly add programming for an HD channel. The group will be duplicating the system for other Crawford stations around the country. 

LAYERS WINS NAB BEST OF SHOW

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Our Layers broadcast software suite made NAB 2022 Best of Show! Thanks to the broadcast community for recognizing all our hard work and seeing the potential in this entirely virtual broadcast chain, from multitouch “glass” consoles to backend mixing, audio processing and streaming into the transmitter or CDN provider. 

NAB 2022 OUTTAKES

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Here is an assortment of videos and photos from NAB 2022. Great to spend time with our friends and colleagues for the first time in several years. 

Click to Wheatstone at NAB 2022

SCREENBUILDER SCRIPTER'S FORUM

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Are you a ScreenBuilder or ConsoleBuilder power user? Register and log onto our Scripters Forum. This is a new meeting place for anyone interested in developing new screens and workflows for our WheatNet-IP audio network. Share scripts, screen shots and ideas with others also developing virtual news desks, control panels, and signal monitors. You’ll find documents, starter scripts and a whole knowledge base available to you for making customized screens like those pictured.

Click to register for our Scripters Forum (it's free)

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The Wheatstone online store is now open! You can purchase demo units, spare cards, subassemblies, modules and other discontinued or out-of-production components for Wheatstone, Audioarts, PR&E and VoxPro products online, or call Wheatstone customer support at 252-638-7000 or contact the Wheatstone technical support team online as usual. 

The store is another convenience at wheatstone.com, where you can access product manuals, white papers and tutorials as well as technical and discussion forums such as our AoIP Scripters Forum

Compare All of Wheatstone's Remote Solutions

REMIXWe've got remote solutions for virtually every networkable console we've built in the last 20 years or so. For basic volume, on/off, bus assign, logic, it's as easy as running an app either locally with a good VPN, or back at the studio, using a remote-access app such as Teambuilder to run.

Remote Solutions Video Demonstrations

Jay Tyler recently completed a series of videos demonstrating the various solutions Wheatstone offers for remote broadcasting.

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Click for a Comparison Chart of All Wheatstone Remote Software Solutions

MAKING SENSE OF THE VIRTUAL STUDIO COVERMaking Sense of the Virtual Studio
SMART STRATEGIES AND VIRTUAL TOOLS FOR ADAPTING TO CHANGE

Curious about how the modern studio has evolved in an IP world? Virtualization of the studio is WAY more than tossing a control surface on a touch screen. With today's tools, you can virtualize control over almost ANYTHING you want to do with your audio network. This free e-book illustrates what real-world engineers and radio studios are doing. Pretty amazing stuff.

AdvancingAOIP E BookCoverAdvancing AOIP for Broadcast
TAKING ADVANTAGE OF EMERGING STANDARDS SUCH AS AES67 VIA AUDIO OVER IP TO GET THE MOST OUT OF YOUR BROADCAST FACILITY

Putting together a new studio? Updating an existing studio? This collection of articles, white papers, and brand new material can help you get the most out of your venture. Best of all, it's FREE to download!

IP TV EBOOK COVER

IP Audio for TV Production and Beyond

WHAT YOU NEED TO KNOW ABOUT MANAGING MORE CHANNELS, MORE MIXES, AND MORE REMOTE VENUES

For this FREE e-book download, we've put together this e-book with fresh info and some of the articles that we've authored for our website, white papers, and news that dives into some of the cool stuff you can do with a modern AoIP network like Wheatstone's WheatNet-IP. 

Got feedback or questions? Click my name below to send us an e-mail. You can also use the links at the top or bottom of the page to follow us on popular social networking sites and the tabs will take you to our most often visited pages.

-- Uncle Wheat, Editor

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