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Elk OS – Audio Operating System

elk.audio

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Re: Elk OS – Audio Operating System

#51

Post by zamadatix »

PaulDavisThe1st wrote: post #19
matheusmoreira wrote: post #10

Earlier quoted context omitted.

So the real time kernel patches have been mainlined? How comprehensive are the real time features of Linux now?

Almost all of the original PREEMPT_RT patchset are mainlined now, but the features are not (all) enabled by default. Low latency will always present a tradeoff with bandwidth, and Linux is used for so many different purposes that one is not clearly more important than the other. For more than 10 years, Linux with the PREEMPT_RT patch has been capable of more-or-less hard real time, with latencies in the 10's of usecs…

Dumb question inbound are those features boot/runtime toggable or compile time options?

Re: Elk OS – Audio Operating System

#52

Post by cmiller1 »

PaulDavisThe1st wrote: post #47
cmiller1 wrote: post #43

Earlier quoted context omitted.

192 khz/24 bit

Just put a hifiberry card in there. Done.

I already have a DAC that can do it, but I was hesitant about trying to use the pi after seeing this forum thread https://www.raspberrypi.org/forums/viewtopic.php?t=25810

Re: Elk OS – Audio Operating System

#53

Post by Scramblejams »

tigeba wrote: post #37
hsbauauvhabzb wrote: post #29

Earlier quoted context omitted.

I’ve never understood the latency requirement for professional gear, are you able to articulate why there’s a need for lower latency than average consumer gear?

It only takes a small amount of latency (5 ms or so) to noticeably impact performances by musicians. Latency is also an issue when you want to monitor a live signal along with other recorded audio, like in a DAW. It is not as big a deal with a playback only device.

Interesting, I wouldn't have expected it to be that low, though in the aircraft space, control harmony can be disrupted with as little as 20ms of delay between control input and control surface movement[0].

Do you have any research you can suggest for that 5ms number?

[0] http://www.klabs.org/history/history_docs/reports/dfbw_tomay... (Keeping the delay at or under 10ms was the recommendation I got from the study P.I.)

Re: Elk OS – Audio Operating System

#54

Post by spicybright »

moonchild wrote: post #31
jancsika wrote: post #6

> 1ms round-trip Ooh, a rare latency claim that actually specifies which type of latency they mean! One millisecond round-trip latency, if true in practice, is quite impressive. I'm going to continue reading now... :)

That's necessarily going to be aspirational in at least some respects, though—it's limited by the hardware.

I wonder if there's a way for computers to self-measure round trip. Even if you have to plug an aux cord between the speaker + mic jacks.

Re: Elk OS – Audio Operating System

#55

Post by spicybright »

mwcampbell wrote: post #28
LeoPanthera wrote: post #20

Earlier quoted context omitted.

I started developing a blind computing system in the late 80s based on a BBC Micro and a very early speech synthesizer. It never went anywhere, and I'm no longer in contact with the blind friend who was helping me, but I often wonder if today's solutions such as Apple's Voiceover aren't the ideal solution. They seem to be trying to adapt the GUI for the blind, rather than trying to build a text/voice based system fro…

As a legally blind developer who has worked on accessibility for a while (see my HN profile for more), I'm inclined to agree with you. We use screen readers like VoiceOver because, practically, we often need to access mainstream applications. But I think we tend to get too dogmatic about going mainstream, to the point that some of us are disdainful toward systems designed specifically for blind people, particularly i…

I'm very curious about your thoughts. How would you make a shell designed for TTS?

Re: Elk OS – Audio Operating System

#56

Post by PaulDavisThe1st »

zamadatix wrote: post #51
PaulDavisThe1st wrote: post #19

Earlier quoted context omitted.

Almost all of the original PREEMPT_RT patchset are mainlined now, but the features are not (all) enabled by default. Low latency will always present a tradeoff with bandwidth, and Linux is used for so many different purposes that one is not clearly more important than the other. For more than 10 years, Linux with the PREEMPT_RT patch has been capable of more-or-less hard real time, with latencies in the 10's of usecs…

Dumb question inbound are those features boot/runtime toggable or compile time options?

Compile time.

Re: Elk OS – Audio Operating System

#57

Post by PaulDavisThe1st »

cmiller1 wrote: post #52
PaulDavisThe1st wrote: post #47

Earlier quoted context omitted.

Just put a hifiberry card in there. Done.

I already have a DAC that can do it, but I was hesitant about trying to use the pi after seeing this forum thread https://www.raspberrypi.org/forums/viewtopic.php?t=25810

That thread is rather old, and seems to be concerned with using HDMI, which I don't think anyone concerned about high resolution audio should be doing. The last comment confirms "working fine" back in 2013, more than 7 years ago.

Re: Elk OS – Audio Operating System

#58

Post by snvzz »

PaulDavisThe1st wrote: post #19
matheusmoreira wrote: post #10

Earlier quoted context omitted.

So the real time kernel patches have been mainlined? How comprehensive are the real time features of Linux now?

Almost all of the original PREEMPT_RT patchset are mainlined now, but the features are not (all) enabled by default. Low latency will always present a tradeoff with bandwidth, and Linux is used for so many different purposes that one is not clearly more important than the other. For more than 10 years, Linux with the PREEMPT_RT patch has been capable of more-or-less hard real time, with latencies in the 10's of usecs…

>more-or-less hard real time

Also known as soft realtime.

For hard realtime, you need guarantees. Linux is too complex and cannot possibly offer them; this is the territory of formal proof, with complexity growing exponentially with code size.

Look at seL4 for hard realtime.

Re: Elk OS – Audio Operating System

#59

Post by toast0 »

spicybright wrote: post #55
mwcampbell wrote: post #28

Earlier quoted context omitted.

As a legally blind developer who has worked on accessibility for a while (see my HN profile for more), I'm inclined to agree with you. We use screen readers like VoiceOver because, practically, we often need to access mainstream applications. But I think we tend to get too dogmatic about going mainstream, to the point that some of us are disdainful toward systems designed specifically for blind people, particularly i…

I'm very curious about your thoughts. How would you make a shell designed for TTS?

There's emacspeak.
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