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Comment Re:Passed data with a ton of noise? (Score 1) 377

I can't even get people to stop using those Morley Volume Wah pedals from the 70s. They needed two internal voltages (well, 3) so they used dual half bridge rectifiers with different outputs, and so the different parts of the load each only pull their power off one direction of the AC. Creates huge amounts of hum. People just wave their hands, "oh you can filter that out." Yeah, in theory, but then, why do I spend so much time listening to it coming out of the speaker until somebody bitches?

It isn't usually the old wiring, it is the old crap that people plug in. Most old equipment was well designed and doesn't introduce much hum. Some does.

Yeah, in a private vanity audio room you can just move stuff around. But in a pro audio situation, that is lost money, and the equipment changes all the time as you bring in different musicians. Having directional cables and planning where the noise goes prevents problems when somebody plugs in their precious POS pedal. It is almost always analog effects or old cheapo digital effects and not the preamps or instrument. Modern cheapo digital is no problem, because these days you just use an off-the-shelf switch-mode power supply. And even if they do build in their own power supply, 2 more rectifier diodes is cheaper than doubling the capacitance. Once upon a time though, diodes were expensive and power supplies were noisy. Yeah, everybody tried to blame the house wiring. But no.

On the road, ground loops are serious business because stage wiring is hell.

I know a guy with over $20k in audio cables, most of them are Klotz. He says the same thing, "they don't tangle."

Comment Re:Passed data with a ton of noise? (Score 1) 377

Just walk into the studio and pop the fucking box open and look at it if you want to see if it is an ASIC.

http://yamahacommercialaudiosy...

Not a very good angle. I don't have any at home to take a pic.

You can forget about "these days" they've been making these for years. And yes, it is a huge market. BTW, FPGA is great for short runs, but when you're a major audio company selling large numbers of expensive units then ASIC is way cheaper. It isn't close.

And there are multiple companies with proprietary protocols in this space. They all use ASICs because microcontrollers are too slow, general purpose computing isn't responsive enough.

As to why, because incompatibility is brand lock. If it just pretends to be different but actually isn't, then plugging other machines in will work. Well, that is my cynical assumption. Also, in the case of Aviom (the one that is in almost every pro audio studio in the country) they use the ethernet physical protocol, and a proprietary daisy-chained network layer with redundancy. This allows for fairly robust behavior without any network administration required. You just plug the stuff in the same way you would with any other digital audio connection. And it shows up on the mixer in the intuitive place. Also, it stuffs a bunch of flags and crap into the packets. You can buy various controllers to remote manage stuff without learning networking, just how to stab buttons and spin rotary encoders. And there is a special switch that is also like a receiver and provides n digital audio outputs that can be selected from the 64 ethernet channels. So a standard studio setup you have maybe 8 individual monitor devices with ethernet, instrument in, headphones out with EQ, then a 16 port switch, then a 16 output receiver, which plugs into the mixing board. So you've actually got a dozen or so of those ASICs in each setup. And if you want to understand the network topology, just look at the cables. That is the topology.

In the end, why? Because you have one wire from each instrument position to the switch, and then only one wire from the switch to the sound shack. Then it goes back to one wire per track. That is actually a huge gain. If it required a network admin, or some kind of "computer guy," it would not be a gain.

http://www.prosoundweb.com/ima...
These things are ubiquitous. Sad but true. I preach standards at these guys all the time, and they laugh at me, "I already spent $10k on the Avioms, too late for that" ("Plus, everybody knows how to use them already")

Comment Re:Efficiency (Score 1) 889

AC/DC and DC/DC are way over 90% for the whole conversion from input AC voltage to output DC voltage. The actual AC/DC step is 98%+ efficient.

Just converting the AC to DC, the efficiency is higher the higher the voltage, using a simple diode bridge rectifier. You lose about a volt from the diodes. And now you have pulsed DC. If you use a capacitor to smooth that out, there is little loss. But actually there will be a high frequency switch-mode flyback converter that will take the pulsed DC and convert it to the load voltage with low ripple. This will be way over 90% for any fixed application where you know the input and output voltages at design time. If you need input below ~ 85V then efficiency will be lower. Car battery chargers will always have a known load voltage, so the efficiency will be high.

OTOH converting the 6V AC output of a bicycle bottle generator to AC, the efficiency drops to about 80% because of the fixed voltage drop of the diodes. And if you pedal slowly and that generator only puts out 4V, you're down under 75%, depending on the diodes.

Comment Re:Mod parent up. (Score 2) 377

Keep in mind that the "directional" cables are grounded at only one end, and you can't guarantee that digital and analog will have separate ground paths. They won't be separate, actually. So the noise from the digital system really does leak into the analog side. Most of that can be filtered out, but it isn't always easy to filter it just enough but not too much, in varying conditions that are only partially under control of the sound team.

For home use, perfect filtering should be easy, and problems are limited to start with. But in pro audio this shit matters. It is not a pure digital system.

Comment Re:Passed data with a ton of noise? (Score 1) 377

I'm not sure about other systems, but most modern linux burners can set the flag. You can also flag them as audio masters, which is really useful for when you want to stick them into pro audio equipment.

IME if you set the flags right you can even get them to play in drives that attempt not to play any kind of CD-R. :)

Comment Re:Passed data with a ton of noise? (Score 0) 377

If you just snootily turn your nose up, though, you could fail to realize that there was a difference, just not the obvious one that you thought and that sounded wrong. If you keep trying until you find a plausible difference, then you're ready to understand that when the CD-Rs are tested, there are some number of units that almost pass the test, but have a higher likelihood of data loss. These can be sold as audio CDs, because audio data is more tolerant of data errors than computer software, or even other media types.

It is important to know the difference, because if you see the "audio CD" on sale for cheaper than the "data" CD, it might not actually be a good buy. Unless your use case is digital audio, then it might be worth the increased risk of a bad bit or two.

Comment Re:Passed data with a ton of noise? (Score 5, Informative) 377

Actually, in pro audio ethernet is used with proprietary protocols, handled by black box ASIC chips with special switches. I deal with this crap in the studio. Where I am they use it mostly for the personal mixers providing monitor outputs, but some places use it for inputs too.

Also, warning for those about to embarrass themselves making fun of "directional" cables, that means it is grounded at one end, and you put all the grounded ends in to the same device to avoid ground loops. If you don't know what it is, it must be brain-numbingly stupid... right? Ignorance is bliss.

We use normal cables, sure. But we do buy expensive ones with nice plug shielding, because musicians may or may not even be sober at work. Expensive cables isn't just for fancy looks, that build quality can make a real difference. Plus, it might be a lot easier to get the bean counters to agree to buy premium cables, than to get them to agree to replace equipment. They might tell you, "use the spares until they fail" in which case you'll regret not having spent their money on the "over"-priced ones.

Same with instrument cables. No, a brand new expensive guitar cable does not sound better than a cheap one. But after 300 shows, the cheap one craps out during a show or session, and the expensive "hifi" one didn't because it has premium long life rubber and better plug strength. So it does actually sound better once you factor in the way it sounds when equipment fails and you can't even hear the instrument. Most of that benefit is in the middle price range, of course. A $1000 guitar cord probably has metal mesh "shielding" that substantially increases cable strength, but the $300 one already has plastic mesh that will provide more than enough abrasion protection.

Also... some commenters don't know this, apparently, but a "placebo effect" is a real effect. It doesn't mean it is a scam, it means the people were successfully tricked into getting healthier faster, or in this case, to have more fun. If you "trick" them into thinking the artist is more artsy, they might enjoy it more too. Pretty snooty to claim they're not really enjoying the subjective aspect of their choices as much as they claim to... especially if you're also claiming that due to the placebo effect they really are enjoying it more!

Comment Re:Doubtful (Score 1) 889

Most cities in high density urban neighborhoods already provide charging stations at metered parking spots, and the parking time limit is only business hours. Also most urban municipality-owned parking garages have charging stations.

Those urban libraaals are already building this stuff and living in the future. Even in small cities.

Comment Re:AYFKM? (Score 1) 889

Most of driving is to get out of town, often up in the mountains way off the beaten path... I can't imagine needing more than 250 miles range. A fast charge just means I'd need a 30 minute meal break every 250 miles. For people who aren't professional drivers, that's a good idea anyways. But it is very unlikely I would go that far and not fly.

We are only a handful of years away from $6k EVs with 250 miles range. The future is coming. And those cars will be the dinosaurs of the self-driving age because they'll never lose the ability to home fuel.

Comment Re:Error 1 (Score 1) 889

What they need is to set it up like a carnival ride; a car elevator takes it up and puts it into a slot in a vertical machine. This is great for high traffic areas like tourist traps, where land space is expensive. Then you're out of the car, waiting in a boring lobby with a loud television, next to the convenience store/gift shop with soothing thematic music.

This is why (if it wasn't for the TSA) flying is so much more convenient.

Comment Re:Truck Stops, Gas Stations, etc (Score 1) 889

That's why we turned the lottery over to the State, and turned it into a Stupid Tax to support education.

My State did that with alcohol distribution, too. Organized crime can't penetrate the distribution layer that way. Too many bar codes and computerized inventory systems.

To iterate is human, to recurse, divine. -- Robert Heller

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