Jul. 25th, 2016

solarbird: (molly-oooooh)

In yesterday’s post, I posed a question: do USB chipsets matter in the 2.0 environment? I had reason to suspect they might.

The answer is holy crap yes they matter they matter so much it is unbelievable.

First, let me talk about what prompted this research, so you’ll know why this matters.

On my old sound interfaces I had live monitoring in hardware, so I didn’t have a lot of need to care about latency. Since that won’t mean much to most people, I’ll explain; when recording, it’s good if you can hear yourself, in headphones. If you’re multitracking, it’s critical.

My old audio interfaces did this with direct connections in the hardware. Whatever came in the microphones also went out the headset. There are advantages to this method, but also disadvantages, in that you aren’t actually hearing what’s being recorded, just what’s being sent in the microphone jack.

But now, I have this shiny new 1818vsl, which doesn’t do hardware monitoring under Linux. Higher-level kit generally doesn’t provide that; they’re assuming you have enough computer that your computer can send back what is actually being recorded, effects and all, and that you’ll do that instead.

This means I now have to care about latency in my system. Latency is basically delay, between mic and computer, and computer and headset. And if the computer is feeding my monitor headphones, that delay matters. You want to hear yourself live, or close to it, not with, oh, a quarter second of delay or something horrible like that.

Now, the good news was that straight out of the box on Ubuntu 16.04 (the latest long-term support version), I had better, lower latency numbers on my new 1818vsl than on my old hardware, when I was using that on 12.04. I could get down to a buffer size of 256 samples, and three frames, which gave me about 30ms basic latency – roughly half what I had with my old hardware and old install. I could use it as-was.

But I couldn’t go any lower on those buffers. One more setting down, and even playback would lag. It’d be okay until the system had to do anything else, then you’d get a playback pause, or a skip, or if recording – presumably, I didn’t bother trying – lost sound. That’s unacceptable, so 30ms was the lower limit, and I wasn’t sure it was a safe lower limit.

And that’s what got me doing all that chipset research I talked about yesterday, and I ordered a new USB card (plugs into PCI sockets) based on that research. I was hoping for a couple fewer milliseconds of latency, that I wouldn’t actually even use; I just wanted a safety margin.

So that new card arrived on Sunday, with its OHCI-compliant chipset made by NEC, and I popped it into the machine and started things up with normal settings.

At first, I was disappointed, because I only saw about half a millisecond less lag, instead of the 1-2ms drop I’d hoped to see. But across tests, it was more consistent – it was always at that same number, which meant I could rely on that 30ms latency in ways I wasn’t sure I could before.

They I decided to see what would happen moving the sample buffer setting one level lower, into what had been failure mode. And the result was 1) it actually worked just fine, where it hadn’t before, and 2) when running analysis, tests showed much lower latency at that setting than with the previous USB ports.

That was an ‘oh ho‘ moment, because it implied that the 256-sample run rate was basically the spot at which the on-motherboard USB could just keep up, and trying to run faster wouldn’t actually produce any actual processing improvement. It’d try, but fail, and time out.

So I did a couple of recordings on that, and they all worked. Then I dropped it another level, until finally, I just said hell with it, let’s just set it as far down as the software will allow and see how hilariously we explode.

I just successfully recorded test tracks four times with these settings, on the new card:

0.7 milliseconds isn’t even something you think about on USB 2.0. 2.8ms, maybe, okay. I’ve seen that managed a few times before, and that’s genuinely indistinguishable from realtime/hardware monitoring. But 0.7ms?

Seriously, this is well into “…is that actually possible?” territory. I’ve never even heard of someone running over USB 2.0 at latencies this low.

So, I guess it looks like the chipset matters a whole lot. Maybe not for most applications, and maybe not in the same way as in USB 3.0 or in FireWire, were there are serious compatibility issues. But in the 2.0 world, in realtime audio, it appears that the chipset makes all the difference in the world.

And yet, I can find this nowhere online. I’m beginning to think nobody bothered until now. Certainly when I’ve asked about it, the response has “why are you on USB get firewire” or “why are you on USB get PCI” because sure I want to throw out all this hardware and start over THANKS NO.

I think USB users have been trained just to accept it and deal. But surprise! You don’t have to! You can actually get a better USB card, if your system allows it, and it’s $30 instead of $1300!

So, HELLO, OTHER SMALL-STUDIO MUSICIANS! You want a chipset that uses OHCI on the USB 1.1 level even if it’s a USB 2.0 card or later because the 1.1 layer still matters, and still gets invoked by the higher-order drivers for card management. See previous post for why that’s important.

This means avoid Intel and VIA chipsets, and look for NEC or SiS – or anything else that loads OHCI drivers and not UHCI. If you’re on Linux, you want to:

cat /proc/interrupts | grep usb

If you see “uhci_hcd” in there, you have a UHCI chipset running your USB port and getting a new USB card with an OHCI-compatible chipset (and disabling whatever’s already installed) might help you with your latency issues.

Good luck!

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solarbird: (korra-on-the-air)
Upright Republicans - ones to whom any of the supposed small-government principles ever mattered at all, or, for that matter, one to whom any of the claimed GOP principles ever mattered at all - need to understand that the GOP is no longer their party.

And if they want to take their party back, they need to cause the GOP to lose in 2016. There are times, no matter how much you don't like it, that you need to lose an election to win the future, and when you do that, you need to do it in a clear and visible way.

Fortunately, there is a clear and visible way to do that, and the way to do that in 2016 is to vote for Gary Johnson. Gary gets 5%, and it will be an extremely clear message: you can't win without us.

Because right now, at this moment, the GOP is an unrestrained horde of overt racism, anti-semitism, misogyny, and absolutism, it is a party of chaos and strong-man leadership, the opposite of law, the inverse of order. A GOP victory in this condition would be a tremendous loss for all the principles of small and hands-off government. Both parties will be mass rule, and the one least historically aligned against that will have won with that as their standard, and will not turn away for decades, if ever.

The GOP must lose this election, and it must be clear why.

Gary Johnson won't win; the Libertarian party is a joke. I say that as someone who has voted big-L more than not. A lot of people will say, therefore, that you are "throwing away your vote."

That's horseshit. This election, if you're on the small-government side, it's the only way not to throw away your vote, and it's the only shot at not losing the GOP to the mob.

The GOP must lose 2016. Badly. And it must be clear why. Responsible, upright Republicans must vote Gary Johnson in 2016. He won't win - but you will.
solarbird: (korra-excited)
During the 1990s, between episodes of Doctor Who, KBTC would air various shorts, plus Jack Horkheimer: Star Hustler (or Star Gazer, depending upon the year).

My favourite of these interstitial shorts was something called Computer-Home - or as we called it, Spider Chip 68000 - a bit of French computer animation that came out of nowhere, as far as we were concerned. And it wasn't ever online that I could find, until my housemate found it on one of his old VHS tapes!

So of course I ripped it and put it on YouTube:


But! I did that a year ago. The NEW surprise is that somebody else has posted the original French version!


And it's a much better transfer, even if you don't speak French. :D

So now you can relive your 1990s Doctor Who on KBTC fandom. Enjoy!
solarbird: (gun good job)
Yahoo! will be combined with AOL? Wow, it's Sears and K-Mart all over again, two more drunks clinging to each other desperately hoping to manage a straight line.

Tho' I guess in this case Verizon is in there too, lashing them together.

Fuck, this means Verizon will now own Tumblr. ノಠ益ಠ)ノ彡┻━┻

"US internet firm Yahoo is being acquired by American telecoms giant Verizon Communications for nearly $5bn (£3.8bn) in cash.

Yahoo will be combined with AOL, another faded internet star, which Verizon bought last year."


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