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Show HN: Beatsync – perfect audio sync across multiple devices

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Re: Show HN: Beatsync – perfect audio sync across multiple devices

#111

Post by freemanjiang »

chaosprint wrote: post #108

have you considered using webtransport? When I was developing Glicol ( https://glicol.org/ ) sync, the main challenge is network jitter. Had to give it up eventually. Furthermore, have you factored in the synchronization as perceived by the listener? Also, it seems system-level differences, particularly in audio output latency across various OS and hardware setups, would need to be considered. What I mean is, the var…

Practically, the network jitter is averaged out in the clock synchronization calculations, and even output latency is remarkably well-behaved. Have you tried it on different devices? It is only noticeable when there's an external device connected to the computer.

Re: Show HN: Beatsync – perfect audio sync across multiple devices

#113

Post by freemanjiang »

withinboredom wrote: post #98

Works pretty good. There is noticeable desync when one device is plugged into speakers though (at least on windows). It'd be great if you had some way to get a specific device's audio lag or at least let us edit that aspect.

Yeah, at one point I had manual controls to adjust the delay to debug. I'll add that back.

Re: Show HN: Beatsync – perfect audio sync across multiple devices

#114

Post by freemanjiang »

_joel wrote: post #95
xnickb wrote: post #88

Earlier quoted context omitted.

if it's behind nginx, check client_max_body_size. Set it to something big

Yea could be, this was using their .gg hosted version, I'll try locally

Thanks for bringing this up! Made an issue to look into this.

Re: Show HN: Beatsync – perfect audio sync across multiple devices

#116

Post by dspillett »

entropie wrote: post #110
KayEss wrote: post #92

Earlier quoted context omitted.

And by a happy coincidence it turns out that audio does about one foot in one millisecond making light six orders of magnitude faster

About one foot sounds very american.

The original comment used imperial measures, following comments kept to that for consistency.

To put things into proper units: speed of light in vacuum is approx 1.8 terafurlongs per fortnight, and electricity in wires has a pace of similar magnitude, and sound in normal atmospheric conditions shuffles along at approx 2.1 megafurlongs per fortnight.

Re: Show HN: Beatsync – perfect audio sync across multiple devices

#117

Post by pmontra »

nsteel wrote: post #97
cypherpunks01 wrote: post #61

Earlier quoted context omitted.

Absolutely! Silent disco still requires impractically expensive rental hardware to work well as far as I know. A lot of them run off FM radio, since it's the simplest way to go, but nobody owns portable radios anymore. An OSS app with the ability to sync everyone up over mobile or wifi, on Android or iOS with BYO headphones, would be incredible. This should be a thing :)

Snapcast has a webapp and a native android client. Although I'm not sure how well it handles many, many clients. In theory, if all on the same WiFi they should all play in sync like a silent disco (at least for those not using Bluetooth headphones where the playback latency is too high/not available).

Web radios handle many clients. The first problem could be if the Wi-Fi hot spot can handle that many clients. The second one is that web radios and their protocols usually don't care if two clients are not in sync. They are usually in different places, maybe different continents.

I'm self hosting a web radio for my LAN at home. I set it up years ago, I'm not there so I can't check the details but I think it is: Icecast2 on an ARM small server with DeeFuzzer (sp?) to send my mp3s to the Icecast2 server. MPV or VLC to play music on my Linux laptop and Transistor from F-Droid (I believe)

Re: Show HN: Beatsync – perfect audio sync across multiple devices

#118

Post by bjackman »

hatthew wrote: post #26
bjackman wrote: post #24

Very cool! As someone who doesn't know much about the topic, I'm surprised that "millisecond-level accuracy" is enough. I would have imagined that you need to be accurate down to some fairly small multiple of the sample rate to avoid phasing effects. Do you have any interesting insight into that question?

Sound travels at a speed of ~1 foot/millisecond

Wow it's insane how slow that is!

But also, I don't really have an intuition for why the speed of travel is relevant here?

It's funny that I have a natural intuition that sound is slow over long distances, yet 1 ft/s still feels astonishingly slow. And yet while I know light travels 1ft/ns, it's still astonishing that it takes 30ms to travel from London to Sydney at that speed.

Re: Show HN: Beatsync – perfect audio sync across multiple devices

#119

Post by superjan »

entropie wrote: post #110
KayEss wrote: post #92

Earlier quoted context omitted.

And by a happy coincidence it turns out that audio does about one foot in one millisecond making light six orders of magnitude faster

About one foot sounds very american.

I’m in europe so I am all in on the metric system. But “about a foot” per nanosecond is so easy to remember, understand and reason about that it is worth the exception. If you prefer something European, think of a sheet of A4 printer paper: the long side is 29.7 cm. “One length of A4 per nanosecond” is within 1% of the actual value of the speed of light.

Re: Show HN: Beatsync – perfect audio sync across multiple devices

#120

Post by jpc0 »

cypherpunks01 wrote: post #61
hgomersall wrote: post #11

Earlier quoted context omitted.

Silent disco in which everyone brings their own source and headphones.

Absolutely! Silent disco still requires impractically expensive rental hardware to work well as far as I know. A lot of them run off FM radio, since it's the simplest way to go, but nobody owns portable radios anymore. An OSS app with the ability to sync everyone up over mobile or wifi, on Android or iOS with BYO headphones, would be incredible. This should be a thing :)

I think wifi + WebRTC would take be too hard for this honestly, maybe add wifi6 as a requirement because it can theoretically have lower latency.
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