ableton, wifi and low latency

September 13, 2009 1:42 PM

If you're able to run Ableton with very low ASIO latency AND have a USB wifi dongle AND can run both simultaneously AND run Windows XP, please tell me what wifi dongle you have.

Wifi dongles and their drivers have a known habit of locking up, blocking up and cocking up the smooth flow of data required for low latency ASIO Ableton awesomeness.

My Zydas/Linkskey USB dongle is such a one.

I'd like to buy a different wifi USB dongle so I can stream Ableton awesomeness via wifi.

posted by Moistener to media & arts (8 comments total)

I don't use Windows, but I do low latency audio, and have suggestions that apply cross platform:

Make sure any USB devices are 2.0 for maximum throughput.

If the sound card and the wifi device are both USB, make sure they are on different busses, because two devices on the same bus are going to fight for the bus and hurt throughput and latency.

The better your signal from wifi device to base station, the better your throughput and latency, because fewer packets need to be resent.

If cat5 or cat6 is feasable the performance blows wifi out of the water, even if the cables are inconvenient. With general internet stuff the bottleneck is somewhere upstream, making any improvements on the wifi side unhelpful; but with streaming high quality audio, the bottleneck between you and your router becomes very important.
posted by idiopath at 2:32 PM on September 13

hust for the sake of clarity, if the low-level code of a driver says, "stall until i get response", it's going to create trouble for low-latency audio (blocking).

if that driver is talking on a wifi network with a crystal-clear signal and even has its own usb bus but decides to hang on to the processor while it does WHATEVER, there's gonna be trouble.
posted by Moistener at 3:17 PM on September 13

(btw, my existing rig follows all your advice)
posted by Moistener at 3:18 PM on September 13

Moistener: "if the low-level code of a driver says, "stall until i get response", it's going to create trouble for low-latency audio (blocking)"

OK. I am a bit spoiled in the land of pre-emptible kernel and driver code, I didn't even think about that being an issue. Some people use Windows in realtime wifi connected industrial equipment, it may be worth looking into what devices and drivers they are using? Best of luck, that is about where my ability to help ends.
posted by idiopath at 3:32 PM on September 13

In my experience, wireless USB dongles have some of the worst written drivers out there. That said, it seems like the bottleneck might actually be the shared IO bus. I've seen some pretty atrocious USB implementations, and it might be that a single root hub is handling all of the data transfers (over PCI, presumably), so try different physical ports.

Other than that, can you just disable the wireless while working with Ableton? Oftentimes they include services to handle the networking that you should be able to stop from running in the background. You'll have to Google how to get to the services page on whatever Windows you're running, since it varies -- however, you might have luck with Start -> Run -> msconfig. Post a response if you can't find this.
posted by spiderskull at 4:27 PM on September 13

I don't mean to start a derail/side argument, but I'm fairly certain that any modern Windows kernel is preemtable, so somehow the scheduler thinks the wireless is more important. Unfortunately, this doesn't help the situation much because I don't know of any way to permanently prioritize certain drivers...
posted by spiderskull at 4:29 PM on September 13

Disabling the wireless USB has always solved the issue, but I was hoping to find a way to stay net-connected and simultaneously enjoy MODERN HI-SPEED COMPUTING.without redoing my LAN situation to use wired ethernet.
posted by Moistener at 8:12 AM on September 14

Have you considered a PCMCIA/cardbus wireless adapter? They may have better drivers (although I have zero experience with them).
posted by spiderskull at 10:58 PM on September 19