5 ms·

I went the other way. I tried laptops and raspis wirelessly, and then with audio over ethernet but the difference in timing caused by differences in signal deco

I went the other way. I tried laptops and raspis wirelessly, and then with audio over ethernet but the difference in timing caused by differences in signal decoding meant that you can couldn't sit in one room with the door open with the speakers in the next room also going because of microshift flanging (although I say micro, some rooms were over 100ms out of sync, which is unbearable). What I ended up doing instead of just running TRS cables along the ethernet cables that were already going to the various rooms I care to spend most of my time in, with some 4x4 audio interfaces that take care of sending the audio to the various speaker sets in those rooms (for rooms with more than one set). Any interface's output can route to any other interface, so if there's more than one thing playing you just press enable that input in the room you're in, and done. And of course, you can get the same done with some second hand professional audio routing rack units, but (a) those are rather inconveniently sized, and (b) you kinda need to have a hookup for those, or get lucky, whereas audio interfaces are a few clicks away and designed to at least look reasonably decent sat on a bookshelf =) More expensive? Probably. "Perfectly" synced audio across rooms? Very much so.

bombcar 4y ago
It's effectively impossible to "sync" audio across a large area (because if it is perfect in one area it will be imperfect in another) so often the best you can do is adjust it until it "sounds right". Some software and some hardware have built-in delays you can use to adjust as they do in a stadium, but often just getting everything "speed of light" in a house is good enough. The main thing is that you don't hear a delay when standing in the doorway between rooms.
- solardev 4y ago
  Don't Sonos, Ultimate Ears, Echo, Google Home etc solve this problem pretty effectively? I know there was a bit of a patent war between them for a while, but don't they still have this feature?
  - bombcar 4y ago
    They do - if you're using one kind for all. That's why starting a song can sometimes take a bit as it buffers/aligns. It's when you're mixing software systems that the fun can begin. (Also if you can route cables in your walls whole-home audio is way cheaper than you might expect: https://www.monoprice.com/product?p_id=10761 https://www.monoprice.com/product?p_id=10761 kicks ass)
  - creeble 4y ago
    FWIW, most of the patent war was about how Sonos syncs the volume controls so that changing a master volume level changes all the synced volumes. Seems obvious (and therefore unpatentable) but there is an ever-so-slightly-not-quite-obvious-at-first-glance aspect to it. I believe Google caved on this and doesn’t allow master level control with their devices. And of course they have been counter suing Sonos on other patents as a result.
    - solardev 4y ago
      What an interesting tibid! I didn't realize that. Thanks for sharing :) What is it about the volume controls that are anymore non-obvious than multi-room syncing to begin with?
      - bombcar 4y ago
        I suppose the argument would be that the "volume setting" is metadata or out-of-band compared to the audio itself.
      - creeble 4y ago
        It has to do with tracking the levels in the group. You want to be able to slide a master level up and down and have the levels maintain the "same" balance, even if one of the players ends up going to (effectively) zero level when you have turned it down. Takes a little bit of thinking about how you represent the range of the levels. I think the patent is actually quite a bit broader, and covers using a UI that has a master volume control across players whose individual volume levels are displayed as well. Google pulled all "master" level control in response.
- TheRealPomax 4y ago
  Unfortunately, decoding drift makes that seem initially fine, and then half an hour later you're going "w. t. f." so after several days of "why the f does this audio not STAY synced?" I gave up and went cables.
  - bombcar 4y ago
    Yeah, I really like physical cables myself, and if necessary you can buy analog audio delay units. For real fun, you can get into 70 volt speakers, which many people don't even know exist: https://www.parts-express.com/70-volt-systems-beginners https://www.parts-express.com/70-volt-systems-beginners
Melatonic 4y ago
Or just multiple chromecasts in the same group (chromecast audio ideally but theoretically I suppose you could use any chromecast with an HDMI converter to whatever audio format you need)
lowbloodsugar 4y ago
Roon actually does a really good job of matching timing between different devices if they are all using the same Roon transport, even when some are wifi and some are wired.

bombcar 4y ago

It's effectively impossible to "sync" audio across a large area (because if it is perfect in one area it will be imperfect in another) so often the best you can do is adjust it until it "sounds right". Some software and some hardware have built-in delays you can use to adjust as they do in a stadium, but often just getting everything "speed of light" in a house is good enough. The main thing is that you don't hear a delay when standing in the doorway between rooms.

solardev 4y ago
Don't Sonos, Ultimate Ears, Echo, Google Home etc solve this problem pretty effectively? I know there was a bit of a patent war between them for a while, but don't they still have this feature?
- bombcar 4y ago
  They do - if you're using one kind for all. That's why starting a song can sometimes take a bit as it buffers/aligns. It's when you're mixing software systems that the fun can begin. (Also if you can route cables in your walls whole-home audio is way cheaper than you might expect: https://www.monoprice.com/product?p_id=10761 https://www.monoprice.com/product?p_id=10761 kicks ass)
- creeble 4y ago
  FWIW, most of the patent war was about how Sonos syncs the volume controls so that changing a master volume level changes all the synced volumes. Seems obvious (and therefore unpatentable) but there is an ever-so-slightly-not-quite-obvious-at-first-glance aspect to it. I believe Google caved on this and doesn’t allow master level control with their devices. And of course they have been counter suing Sonos on other patents as a result.
  - solardev 4y ago
    What an interesting tibid! I didn't realize that. Thanks for sharing :) What is it about the volume controls that are anymore non-obvious than multi-room syncing to begin with?
    - bombcar 4y ago
      I suppose the argument would be that the "volume setting" is metadata or out-of-band compared to the audio itself.
    - creeble 4y ago
      It has to do with tracking the levels in the group. You want to be able to slide a master level up and down and have the levels maintain the "same" balance, even if one of the players ends up going to (effectively) zero level when you have turned it down. Takes a little bit of thinking about how you represent the range of the levels. I think the patent is actually quite a bit broader, and covers using a UI that has a master volume control across players whose individual volume levels are displayed as well. Google pulled all "master" level control in response.
TheRealPomax 4y ago
Unfortunately, decoding drift makes that seem initially fine, and then half an hour later you're going "w. t. f." so after several days of "why the f does this audio not STAY synced?" I gave up and went cables.
- bombcar 4y ago
  Yeah, I really like physical cables myself, and if necessary you can buy analog audio delay units. For real fun, you can get into 70 volt speakers, which many people don't even know exist: https://www.parts-express.com/70-volt-systems-beginners https://www.parts-express.com/70-volt-systems-beginners

Melatonic 4y ago

Or just multiple chromecasts in the same group (chromecast audio ideally but theoretically I suppose you could use any chromecast with an HDMI converter to whatever audio format you need)

lowbloodsugar 4y ago

Roon actually does a really good job of matching timing between different devices if they are all using the same Roon transport, even when some are wifi and some are wired.