Sync Pulse of Horror

Copied from where I wrote about it on Facebook…

Let me take a moment to tell a tale of horror. Sorry, I missed Halloween with this one….

The Evertz 7700ADA7: A wonderful piece of hardware. Truly wonderful, I have nothing but glowing things to say aboutAAAAHH HELL IT’S A PIECE OF CRAP.

https://evertz.com/products/7700ADA7

Look in its manual and you’ll see a big contradiction. The block diagram says it has buffers on every output. The text says it has three output buffers. In reality, best I can tell from physically inspecting the card, it has ONE and all the outputs are just paralleled… maybe in pairs or something? Look closely and you can see the ICs at the right where the outputs come off. Everything to the left of center or so on the card is the power conversion and fault detection circuitry.

The input can be set with 75 ohm termination onboard or hi-z. This is like the inputs on the old Grass Valley Group analog video DAs, except that those had a far more convenient setup with two BNC spigots on the back – you used it either as a loop thru (short BNC jumper to the next DA card in the frame if you needed more ouptuts) or popped a terminator on the unused one.

Evertz says you can use BNC tees to do the same thing on theirs, except… there’s no physical space for the tee to fit back there… and if you do somehow manage to physically connect the cards up this way it’s obvious their idea of “hi-Z” loads the line down BADLY after connecting two or three cards.

So, someone who came to that facility before me wired the cards with the black burst coming from the Evertz GPS locked sync generator and switch unit of HORRORS (more on this later!) to the input on the first of like six 7700ADA7’s, then a short jumper from output #7 to the input of the next… and so on…!!!

I mean, luckily, by some grace of Farnsworth’s ghost himself, this still managed to work… HOWEVER…

Please note that I said the outputs are not individually buffered.

The DA outputs were all full up when I had to connect a long cable to a new video playout system, except for one output on the first in the chain that went to some long abandoned weirdness halfway across the building.

I will state the following now that the statute of limitations is over and I am several thousand miles from anyone who would want to throw things at me for what happened.

We were in a newscast and a break was rolling at the time. I disconnected the mystery cable and there was no excitement. I connected the cable that went about 100′ over to the new playout system, and I heard screaming.

Apparently when I connected the new cable, a glitch occurred on the output of that DA, and since it had no buffers, it propagated down to all the others and effectively to every other piece of equipment in the plant. The people in the control room were treated to the sight of every source suddenly melting down and laaaazily reclocking and coming back one at a time.

At the same time, this lit the FU Cracker on each of our Ericsson satellite receivers. See, this model.. I think it was RX8400? … if you paid for a ton of extra option codes you got an internal frame sync/converter. This was EXTREMELY FRAGILE, though– if you caused any problem with the black burst sync, the FU Cracker’s 45 second fuse was now lit and there was not a thing you could do about it. Once the fuse burned down, BANG!!!! The video and audio were gone. It’d sometimes come back after an agonizing 15 seconds or so, but if it did, this would keep recurring until you rebooted the receiver.

You could practically hear the hissing.

Fortunately no sat feeds were used in the remainder of this newscast and I was able to go around and do the mass reboots once it ended.

So, as for that Evertz failover switch unit that fed the stack of DAs with blackburst… boyy that thing had a … failure mode… about it.

So the way that unit worked was it took the output of two independent GPS locked timecode generators that I think put out SMPTE timecode and trilevel sync. This fed into the failover box which would “seamlessly” take over if one of those went invalid or failed, I guess, and it also generated blackburst with VITC, had a small DA for the trilevel sync (4 ports or something), and also generated a 10 mhz reference signal and some other stuff I’ve long since forgotten.

The chief engineer needed trilevel sync for something near it, so he removed the terminator from one of the taps on that DA.

“Tick tick tick tick tick tick”, responded the failover unit.
Cue MASSIVE screaming from every corner of the facility. Bad sync hit HARD, all the satellite receivers puked their guts up instantly, just about the only thing that survived it was the Omneon playout boxes and the Kahuna switcher. No more live shots as the receivers decoding their ASI streams died. Yes, we were in a newscast. Recorded packages were frantically bumped up the schedule as the Omneons, Grass Valley K2 playout and cameras were the only thing left alive.

The Omneons and K2’s were really good about sync loss, if the sync went invalid they just switched to free running without any further ado. Everything else was just a fecking drama queen.

A broadcast engineer’s nightmare.

I’m referring to a literal nightmare here, not a figurative one. I had a pretty frighteningly vivid one last night. I blame being a bit tired out after having subjected myself to transistor horror.

In this dream I had been invited to visit an engineer at a local TV station. In reality, up here in the northern Sacramento Valley, there’s pretty much just one TV station that produces the news for most of the cities north of Sac.. anyway…

I walked into the facility which was in some nondescript warehouse bay, past a row of dusty screaming servers, and into a dark, cold little control room that had unpainted drywall walls and a window looking out on the news set.

Photo by Tiia Monto

There was just one guy there. He sat in front of some kind of really REALLY dummied down console that had a few faders and buttons on it which apparently did next to nothing as they were covered in dust. A small cheap netbook computer with the power lead duct taped into the side sat in the middle of this console. The only button that did anything was an illuminated and quite worn TAKE button on the lower right corner. Above this console was some kind of weird rackmount unit with two 16:9 CRT monitors and a satellite receiver. One was on program out, one was showing the output of a waveform rasterizer somewhere which revealed the same thing that the program monitor did: the cameras which were on robotic pedestals out in the studio, which were set on auto white balance and auto iris, were shaded very very badly. No controls were present to correct this.

Nobody else was present.

The news show opened and the talent began reading from their teleprompters. The prompters were fed from who the hell knows where (the engineer didn’t even know!) and there were really messed up lower thirds and captions that appeared and disappeared pretty much whenever they felt like it – the guy was reading the show rundown on the netbook screen and calling the scenes, as he pressed the worn old take button to transition between them, but only the people on set actually ever seemed to listen. The cameras often didn’t move when they were supposed to, or pointed at the ceiling or something, and nobody was here to fix it— he’d just smash the take button again and skip the scene where they were supposed to be used.

Of course, the Sinclair group ‘must read’ propaganda piece on fake news was read by the talent. (In reality, this one local news station we have up here is a Shitclair property, but they have never read this that I’m aware of— instead they just have this weird pretentious sounding statement about accuracy.)

The weather was then run, supposedly from a local meterologist, but in reality it came from a satellite feed from who the hell knows where. A low Eb/N0 warning flashed on the receiver display and it glitched out. The engineer just hit TAKE again and the commercial break began.

I just felt this horrible sense of terror and started running. The shitty little warehouse bay suddenly became an endless maze of alternately insanely dense or empty racks of nonsense equipment and cabling. At some point I saw a display showing the transmitter readings, the VSWR was high as hell, the signal was (miraculously) in mask, but the 8VSB eye diagram showed two entire levels smashed flat and missing… I thought to myself “well, at least that means nobody is able to watch this shitty trainwreck over the air!”…

Then I was suddenly back home in my bedroom watching this shit on the television. There was a badly corrupted picture on screen as they started talking about a farmer’s market up in Shingletown. I saw one of my enormous Yaesu satellite base radios sitting on the nightstand, which was actually a useful detail later in convincing myself I dreamed all this shit.

Then I woke up, but I was stuck in that horrible state of having to convince myself that this incredibly vivid dream was NOT real.

WHAT THE FUCK WAS ANY OF THAT, BRAIN?! What’s scary is, depending on who you ask, this is the grim future of television news. It was truly horrifying at the time.

Here, enjoy these ridiculous-ass 90s game commercials.

THE SAME VOICE IS USED IN THE NEXT ONE— which made me loudly exclaim “ohhhh hell nope”.

As a palate cleanser, here’s a Gak ad. (GAK FARTS INTENSIFY.)

Pop Team Epic is amazing.

I’ve never seen anything so wonderfully deconstruct every possible trope in the world of anime, the very medium of anime itself, and even the nature of humor itself as what I’ve seen out of Pop Team Epic, but then this gem appeared in episode #8—

This is actually still animation, technically. In fact, they’ve also used puppetry which can be classified as animation. I’ve just never seen a performance anything like this before and it totally blew me away. I watched it twice and the second time I was looking for anywhere they could have cut it between takes— I only noticed one cut in the last few seconds when they cut to zoom in.

Some years ago I had a dream where I had found an episode of “Dave Barry TV” on the tube late at night. The sort of situations and pacing in Pop Team Epic reminds me of what I saw in that dream— except, in that dream, the episode of Dave Barry TV lasted about four minutes after which Dave didn’t know what to do past that point so he spent the rest of the episode massacring low-flow toilets.

The Maddening Tale of Mr. Ramko.

Note: This is not about anyone named Mr. Ramko. It is about a real person though, whose identity I have replaced with the name of a manufacturer of really shitty audio gear.

This is a kind of long mess so I’ll use the “don’t make the main page ten miles long” tag as I did for The Scrolling Tray Of Horrors

Continue reading »

deep thoughts

I’ll always take “Sorry, we just don’t want to spend the money” over “Sorry, we won’t spend the money…. But here, enjoy this rococo piece of rushed to market garbage we bought sight unseen at the NAB show after the vendor bought us a fancy lunch and we’re expecting you to deploy in the facility.”

Random stolen transmitter meme related? I forget who I lifted it from but it’s so true

Oops, guess I should write a TV reception guide

Or buy and resell cheap rabbit ear antennas as a barely legal hack device to fellow millenials

 

Picture stolen from Phil Burks.

 

Yes in the actual article they interview people who can’t believe receiving free to air television is legal

you can’t handle our secrets

 

Acoustic Treatments and General Mayhem

Now that I have skin on my hands again and it doesn’t hurt to type this—
Proper acoustic treatment is vital in studio and performance spaces to avoid echoes that will prove destructive to audio quality. Sometimes it’s done right. Sometimes it’s done wrong. To me it’s utter black magic but I know what works for the most part.

The first thing you want to look out for is stray sound entering your studio space. This may be trickier to do unless you’re constructing a studio from scratch. The methods I’ve seen used to great success are either adding insulation batting inside walls as they’re being built, or using cinder block walls to enclose the space instead of hollow. Either way, avoiding the use of walls shared with noisy things like air conditioning units or bathroom plumbing are very good ideas. Don’t use the other side of the wall pictured here if you can avoid it 😉

The second stage in acoustic treatment is to manage reflections within the space. Any hard flat surface within the studio may cause echoes which can become unpleasant and generally make your recordings sound like you’re standing in the shower.

The typical method of dealing with this is to put up some kind of sound absorbing material on the walls. A number of criteria should be considered when selecting your sound absorbing material:

  • Cost
  • Durability
  • Acoustic performance
  • Fire retardant properties

Materials I’ve seen used:

  • Carpet. Can be obtained anywhere, extremely cheap and actually very durable, since it’s made to be walked on. Works pretty well, but double check that all materials you are using will meet fire code standards for use on a wall. (Carpets may only be rated for proper fire retardant action when installed on a floor, as the flame spread dynamics are a hell of a lot different. Consult the manufacturer and/or their documentation before use.)
    You can glue and/or staple it to the wall or even use the self adhesive carpet tiles that peel and stick.

    CAN BE CLEANED. This is a big advantage. Over time, airborne contaminants will settle on the wall material and should ideally be removable. I’ve found that in an old studio with textile walls, allergens will gather and cause some people to get sniffly if not removed. Your mileage may vary, but I’ve found that the ideal maintenance interval to vacuum the walls is about 2-6 months. That’s all it takes, actually – just use a vacuum cleaner with a hose and an upholstery attachment and suck the dust out. More major junk may be dealt with using carpet shampoo and a wet/dry vac.

  • Cloth and Fiberglass. I’ve seen this one in a couple of older studios and it works very well. Small wooden strips were attached to the wall followed by fiberglass batting being installed between them, with a fairly open weave upholstery cloth used to cover it all up. The cloth is finally secured by tacking a small wooden moulding to the wooden strips below it.

    Performance is very good. Flame resistance will be identical to that of the upholstery fabric used. Durability isn’t as good; wheeled chairs, furniture, irresponsibly sharp spiked leather gauntlets (of course I say this from experience), and other things can tear the fabric. Repair is easy though.

    You can also buy prefabricated panels using these materials, or build your own. How to Build Your Own Acoustic Panels

    DIY acoustic panels – from article on acousticsfreq.com

    Cleaning: Can be surface cleaned. I’ve always just used a vacuum – with a HEPA filter just in case glass fibres are released through the surface fabric as you’re sucking the schmutz off. When I’ve done it, I have never noticed glass fibers visible in the vacuum as I cleaned it out – just lots of fine dust and pollen!!

  • Foam. This is a very common acoustic treatment material and I kind of wish it wasn’t. Performance is good, yes, but durability is totally in the dumper. When it’s new, it’s easy to tear up, especially when…. SOMEONE… decides to get creative and try to hang decorations from it. By the way, don’t cover your acoustic treatments with posters, because the essentially airtight paper of the poster will just form a really nice REFLECTOR, completely defeating the treatment. Some materials have fire retardant ratings, check with the manufacturer.
    A really swank looking example of Auralex SonoFlat foam installation from their website, with corner diffusers and wall and ceiling panels.

    When it gets old, some foams will just crumble and disintegrate horribly, especially if touched.

    Cleaning: …. maaaaaaybe. If you’re lucky.

    Shop-Vac 9018000 soft bristle brush. Horsehair vacuum brushes work fine too. BE GENTLE!!

    I’ve had okay luck with vacuuming the surface of Auralex StudioFoam products using a soft bristle brush. Work slowly and gently going along the ridges. In one studio I started doing this and the foam turned from dingy gray to its original burgundy red— I didn’t even know that was the color it was supposed to be! Yeeeechhhhh.

    I wouldn’t even try this at all on the type of sound insulation where it has alternating deep, thin vertical and horizontal ridges.

Now here’s where I talk about strange things.

A while back I was in the studio of The Jeff Adams Show and as soon as I walked in, I saw his wall panels and couldn’t believe my eyes. They’re wood! They did not contribute to any unpleasant echoes, yet had a little bit of a warm reverberation. You can see one in this picture:
I didn’t get a closeup picture of the panels when I was there, but they did not have a smooth planar surface. The different planks are overlapped forming a convoluted surface, which would contribute to diffusion instead of a clean surface reflection. Notice the mic he’s holding here – that’s a Heil PR 40 cardioid dynamic that is just INSANELY sensitive. You’d almost think it’s a condenser (I mean— it kind of even looks like one). The Heil PR 40 is NOT forgiving to bad room acoustics. It proves that these funky wooden wall panels work perfectly as an acoustic treatment!
In contrast, the Electro-Voice RE20 that’s used at close proximity by a lot of radio jocks couldn’t care less what your room acoustics are like as long as you aren’t in an all glass aquarium or something.

The same soft vacuum brush cleaning I mentioned above will work if they ever start to gather dust. Since he’s doing video on the same set, avoiding lighting glare is definitely a plus – they’re not shiny in any way.

Now, you may have a sick curiosity and wonder what the first sentence of this post is all about. Well…. I had to displace some very old carpet on a wall at work to hide a cable behind it, and I don’t know if it was the 20+ years of old crud built up in the carpet, the glue that held it to the wall, or a likely combination of both, but something caused a very bad reaction on the skin on my hands that caused it to blister, crack, and weep as if it had been severely burned.

If you’re really curious, I have a picture of the results here. Content warning: extremely gross. There’s good reason I put /nope/ in the URL. It’s mostly healed now and all that remains is a little redness. That week sucked, man.

Tilt-A-Whirl Video Heads.

I was digging around in the… uh… museum… here at work and found a whole box of worn out video head drums. Some of them had a very interesting feature to them— piezoelectric tracking.

The head can be shifted up and down on a piezo bender.

Why is this here, you may ask? Well, here’s the reason—

Normally, when you play a tape in a helical scan transport like this, the video heads trace an arc across the tape as the drum spins. This arc more or less perfectly matches the way the video frames/fields are recorded across the tape *as it moves* at normal operating speed.

Purpose of the fixed heads and other gribbles on this drum will be read out of a dusty old service manual some day when I’m not fighting the migraine from hell.

But what about when you are NOT at normal operating speed? The tracking angle will not be correct, and the picture “tears” as the head runs across the boundaries between fields.

Enter the piezoelectric tracking mechanism. By applying a sawtooth waveform synchronized with the head drum’s rotation, Sony was able to cause the head to perfectly track a video field beyond angle differences caused by different tape speeds. Thus, when you grab the jog/shuttle dial on one of the decks employing this system and start moving around, or settle down on a still frame (don’t do this too long!), the picture remains clear.

The Sony J-1 Betacam/SX compact player I use at my desk doesn’t have this, and the picture tears when you mess with the speed or pause on Betacam SP (analog) tapes. On BetaSeX tapes, as my coworker calls them, the digitized frame data seems to land in a RAM buffer somewhere and you can still frame or slow down. The tape transport speed and drum rotation speed in Betacam SX mode are much different, and the angle error doesn’t cause as much of an impairment.

I recall seeing a high voltage warning on or near the head drum inside these decks. Not just for show. It’s about 200 volts!
A much more thoughtful description of the dynamic tracking system and better view of the heads and benders may be found here:

http://dexterslab2013.blogspot.com/2016/05/sony-betacam-dynamic-tracking.html

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