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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

#91

Post by dsr_ »

pete1302 wrote: post #86

Great solution based on websocket!. My Vision: A web based VLC-type webplayer (capable of VLC level features) with support to distribute Audio channels over connect devices. Here me out: - Mac as display(Movies screen) - iPad as a Center channel - 4 iPhones as LR and rear channels, (and something for LFE). Is it Practical? sound cool in my head. What do you guys think??

It is not practical unless you already have all the devices.

Let's suppose that you are paying half the new price for the bottom-tier of each of these:

MBA: 500

iPad mini: 250

iPhone 16e: 300 * 4

Your budget is $1950. For that, you can get:

A 50" 4K TV, a Denon X1700H 7.2 receiver, 6 Klipsch R51M speakers, and a half-decent subwoofer, all new.

This will provide a far superior experience for you and a half-dozen friends, and each part will last longer, have no permanent battery to wear out, and be upgradable independently and without relying on a specific software product. I would estimate the lifetime of your proposal at about 3 years, and of my counter-proposal at 20 years.

Yours is much more portable.

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

#92

Post by KayEss »

superjan wrote: post #67
camtarn wrote: post #19

Earlier quoted context omitted.

> This speaker is 300 feet away from its output through X meters of copper; figure out my additional latency offset for me. 0.3 microseconds. The period of a wave at 20kHz (very roughly the highest pitch we can hear) is 50 microseconds. So - more or less insignificant. Cable latency is basically never an issue for audio. Latency due to speed of sound in air is what you see techs at stadiums and performance halls tuni…

For those wondering: The rule thumb here is that light travels at one foot per nanosecond. 300 ns =0,3 μsec. Electricity is a bit slower but the same order of magnitude.

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

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

#93

Post by urbandw311er »

mkishi wrote: post #39
freemanjiang wrote: post #27

Earlier quoted context omitted.

Yeah the threshold is pretty brutal, but it is enough. Experimentally, I'd say you need under 2-3ms but even at 1ms you can start to hear some phase differences. Most of the time, I think my synchronization algorithm is actually sub-1ms, but it can be worse depending on unstable network conditions.

How are you measuring this? I'm surprised the Web Audio API scheduling system has that much insight into the hardware latency.

I was wondering that too. It’s an impressive demo when used on devices with low latency audio drivers but I’m not convinced there’s any ability to detect drift beyond this. Might be interesting to have an option to use microphones to detect and calibrate this… …but then you have the same issue of an unknown delay on the microphone input too.

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

#95

Post by _joel »

xnickb wrote: post #88
_joel wrote: post #85

Really cool but issues for me when uploading mixes (MP3's about 90 mins long, 150MB). They never make it to the playlists

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

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

#96

Post by pete1302 »

dsr_ wrote: post #91
pete1302 wrote: post #86

Great solution based on websocket!. My Vision: A web based VLC-type webplayer (capable of VLC level features) with support to distribute Audio channels over connect devices. Here me out: - Mac as display(Movies screen) - iPad as a Center channel - 4 iPhones as LR and rear channels, (and something for LFE). Is it Practical? sound cool in my head. What do you guys think??

It is not practical unless you already have all the devices. Let's suppose that you are paying half the new price for the bottom-tier of each of these: MBA: 500 iPad mini: 250 iPhone 16e: 300 * 4 Your budget is $1950. For that, you can get: A 50" 4K TV, a Denon X1700H 7.2 receiver, 6 Klipsch R51M speakers, and a half-decent subwoofer, all new. This will provide a far superior experience for you and a half-dozen frien…

I was eagerly expecting such practical breakdown of the Vision. Thanks for the numbers.

But, the scenario is of a Open-Source solution for a Student living in a Hostel/ Home.

The Vision is tilted towards Hostel Dorms where you won't bother a Home Theater, but where every friend has Apple device( any robust device with good onboard audio).

My Friend himself has a MBPRO and 2 iPhones, Totalling to 6 Apple device( Audio Sinks).

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

#97

Post by nsteel »

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 :)

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).

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

#99

Post by iamsaitam »

freemanjiang wrote: post #41
hackncheese wrote: post #30

Any plans to integrate this with Apple Music or Spotify? I would assume your algorithm would work only with files uploaded to the site, but curious if you had plans to attempt something with Apple Music/Spotify

Yes! The very next step.

The challenge here is not technical but legal, good luck.

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

#100

Post by amluto »

moomin wrote: post #22
Ne02ptzero wrote: post #18

Earlier quoted context omitted.

> You can guarantee that you and someone else are listening to the same thing even across an ocean. How can you guarantee that? NTP fails to guarantee that all clocks are synced inside a datacenter, let alone across an ocean (Did not read the code yet) EDIT: The wording got me. "Guarantee" & "Perfect" in the post title, and "Millisecond-accurate synchronization" in the README. Cool project!

More, the speed of light puts a hard cap on how simultaneous you can be. Wolfram Alpha reckons New York to London is 19ms in a vacuum, more using fibre. Going off on a tangent: Back in the days of Live Aid, they tried doing a transatlantic duet. Turns out it’s literally physically impossible because if A songs when they hear B, then B hears A at least 38ms too late, which is too much for the human body to handle and…

> More, the speed of light puts a hard cap on how simultaneous you can be.

Special relativity does indeed have something to say about simultaneity.

> Wolfram Alpha reckons New York to London is 19ms in a vacuum, more using fibre.

And this is not, in any respect, a limit on simultaneity. If the endpoints are moving at very very very quickly relative to each other, then there are complications. Otherwise you measure that 19ms or so and deal with it.

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