Trending Lyricist I

17 years on and still no solution to AV Amp delays!

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As a reasonably techie guy I’ve been helping my neighbour set up his domestic sound system. He has a Sonos driven output in 5 separate rooms. There is a mixture of Sonos 5 speakers, Ports feeding AV amplifiers and an Amp running a pair of speakers. All the rooms are very separate acoustically apart from the lounge, which has a large opening into the kitchen/dinner area. The lounge has a Port feeding a good Sony AV surround sound amplifier and the kitchen has an Amp driving a pair of passive speakers. And so he is suffering from the dreaded ‘stadium echo’ effect when playing music in both the kitchen and lounge. The mechanism is easy to understand; the Sonos kit is all synchronised together but the Sony AV system adds its own delays after the output from the Sonos Port. Because the Sony amp, along with many other AV systems, is designed such that the video output is always lip synced with the TV picture, changing from surround to direct modes does not affect the audio delay. So it is impossible to reduce the Sony Amp audio processing delay to zero to ‘solve’ the problem.

I’ve spent quite some time looking back through the Sonos Community blogs. The earliest reference I’ve found so far to the AV Amp delay problem was 17 years ago

There are many, many other threads along the same topic. The root cause of the problem is well understood and explained but there is always an excuse why a fix can’t be offered. Yes, it would be difficult to implement variable delays that would allow any combination of Sonos and AV amps to work together. But, from the blogs, for most installations you only need to delay a single Sonos output device relative to the one feeding the AV receiver. Following the 80:20 rule that would fix the problem for most people.
Technically it is possible. There might be RAM constraints to how much delay can be introduced. But RAM is cheap. So I do not understand why Sonos is still not offering even a partial fix :-(

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T

TheRealAdrianAuthor

Trending Lyricist I

I’m not sure you can really call doing DSP to covert stereo signals to 3 or more signals always, even when it causes syncing issues in multiroom audio, as practical.

I’m not sure why you think this isn’t practical? There are any number of AV amps out there, running in price from not very much up to many thousands of pounds, that that are all capable of doing the job.

As I already said, because it’s causing sync issue with your multiroom system. I get that DSP manipulation of stereo audio is common, regardless of whether that be converting to 3 channels, 5, or whatever. I don’t see it as practical to expect Sonos, or any other multiroom audio system really, to allow users to manually tweak delays in any or all speakers in the system to accommodate processing on external systems.

As an aside, I find it interesting that music in never produced in 3 channel audio. Two channel, 5.1 for a while, and now atmos music. With the amount of homes that now had LCR setups and/or soundbars, seems a little surprising. Also, many new cars come with a center channel for audio, even though they only have 2 channel sources. Granted, this is because the manufacturer can use cheaper speakers while giving the impression to customers that they are getting a better audio system worth paying more for.

“because it’s causing sync issue with your multiroom system”

I look at this the other way round; the Sonos system is causing sync problems with the AV system in my neighbour's house! He can’t use the best music settings on the AV amp without the Sonos introducing horrible effects.

“practical to expect Sonos, or any other multiroom audio system to….”

As already mentioned, I use ROON for my home system and it does allow user programable delays that would solve this problem. But I don’t have the problem as my rooms are acoustically pretty much separate and I use Meridian surround controllers in each one. They presumably have very similar processing times.

“music in never produced in 3 channel audio”

The point about ‘stereo’ encoded audio is that both channels contain amplitude, frequency and phase information for each source on the sound stage. Therefore by throwing enough processing power at the problem, you can work out exactly where on the sound stage each source is located. So in theory you could have as many channels as you like driving individual speakers across the sound stage. Obviously there are practical limits; resolution, bit rate, digital noise and phase accuracy etc. And the quantity and hence cost of the electronics to drive so many speakers. Today’s present ‘practical’ solution is 3 channels; Left, Right and Center.

But because the signal also includes phase information a really decent ‘stereo’ system can also give the reproduced sound stage a sense of depth as well as simple left/right positioning. And an AV amp can use that to provide rear sounds as well; just listen to the X fighters on Star Wars flying over your head from behind you. And using the rear speakers to play music helps with the depth of the sound stage. Listening to music while writing this, I have my office system set to ‘Music’. Makes you feel that you are there on stage with the band.

Is is an ‘accurate’ reproduction? I have no idea as I don’t know what effects the original artist/mixer was trying to create. But it sounds more convincing to me. Is it worth the extra kit and costs? I think so. But then I have listened to the same music played in the same room with the different decoding options provided by the Meridian surround controller. If you haven’t listened to such a system and are happy with what you have then fine.

The new Dolby Atmos coding apparently includes height information as well. But I haven’t heard that yet.

T

TheRealAdrianAuthor

Trending Lyricist I

Just been reviewing the specs for the Sonos Surround Sound implementation. The Arc Sound bar has 11 amplifiers and speakers built in. And it works with an additional sub-woofer and rear left and right speakers. It decodes all modern sound formats. Therefore there is a lot of software signal processing going on and hence the sound will be delayed. I wonder how Sonos are dealing with acoustically close rooms when you “add more speakers around your home for multiroom listening”?

jgatie

Just been reviewing the specs for the Sonos Surround Sound implementation. The Arc Sound bar has 11 amplifiers and speakers built in. And it works with an additional sub-woofer and rear left and right speakers. It decodes all modern sound formats. Therefore there is a lot of software signal processing going on and hence the sound will be delayed. I wonder how Sonos are dealing with acoustically close rooms when you “add more speakers around your home for multiroom listening”?

TV sources played in a grouped room are delayed, music sources are in sync.

melvimbe

“because it’s causing sync issue with your multiroom system”

I look at this the other way round; the Sonos system is causing sync problems with the AV system in my neighbour's house! He can’t use the best music settings on the AV amp without the Sonos introducing horrible effects.

Sonos is the source, and your neighbor’s AV system can’t sync with it with the setting you want to use.

“practical to expect Sonos, or any other multiroom audio system to….”

As already mentioned, I use ROON for my home system and it does allow user programable delays that would solve this problem. But I don’t have the problem as my rooms are acoustically pretty much separate and I use Meridian surround controllers in each one. They presumably have very similar processing times.

Roon may be the exception, don’t know, but not exactly a hardware speakers/amp multiroom audio system. It only takes streaming sources for one thing. Whatever...doesn’t really change that I don’t think it’s practical for Sonos to build in the ability in manually controlled delays to accommodate 3rd party/amp receivers dsp.

“music in never produced in 3 channel audio”

The point about ‘stereo’ encoded audio is that both channels contain amplitude, frequency and phase information for each source on the sound stage. Therefore by throwing enough processing power at the problem, you can work out exactly where on the sound stage each source is located. So in theory you could have as many channels as you like driving individual speakers across the sound stage. Obviously there are practical limits; resolution, bit rate, digital noise and phase accuracy etc. And the quantity and hence cost of the electronics to drive so many speakers. Today’s present ‘practical’ solution is 3 channels; Left, Right and Center.

My point is that if 3 channel audio is superiors for creating a sound stage for music sources, then I would expect there have been a movement to start selling recordings in 3 channel audio at some point, particularly when HTs with 3 front speakers has become very common. That would eliminate the need for any DSP and allow for it to play “as the artist intended”, and quite possible sell more experience in rooms/situations where TVs are not involved.

The new Dolby Atmos coding apparently includes height information as well. But I haven’t heard that yet.

Simulated atoms music, or music remastered (or whatever) to be atmos in haphazerd way sounds horrible to me. Music proberly produced for atmos sounds really good.

Danny

melvimbe

Just been reviewing the specs for the Sonos Surround Sound implementation. The Arc Sound bar has 11 amplifiers and speakers built in. And it works with an additional sub-woofer and rear left and right speakers. It decodes all modern sound formats. Therefore there is a lot of software signal processing going on and hence the sound will be delayed. I wonder how Sonos are dealing with acoustically close rooms when you “add more speakers around your home for multiroom listening”?

Number of speakers doesn’t equal number of audio channels. Sonos has separate woofers and tweeters for some of the channels. Side firing speaker do more work to bounce off walls and handle surround speaker duty, when no separate surround speakers are present. I’m not saying there isn’t any sound processing going on, but the Arc isn’t exactly creating a audio channel that doesn’t exist in the source.

But Sonos minimizes delay as much as possible to stay in sync with the video source. As already mentioned, delay happens when grouping with other Sonos rooms to minimize dropout for any network issues and allowing each grouped speaker to have a bit of a buffer.

Danny

buzz

Grand Maestro

We are moving toward object oriented audio where an instrument can be assigned an apparent location in three dimensions.

With respect to latencies (delays) it’s 30ms for the surround Room and 75ms for Grouped Rooms. If you Group TV audio in a surround Room, it will be about 45ms ahead of the Group. At the cost of some lip sync you can add some delay in the surround Room in order to better align it with other members of the Group.

K

Kumar

I am sure I can serve out the rest of my life with 2 channel stereo for music without hankering for more channels, but this has been interesting. Where does MQA fit into all this?

ratty

Where does MQA fit into all this?

Nowhere, I hope. It seems many have now written it off. Were you just casting around for all the music technologies you can safely ignore?

K

Kumar

Yes/no! Since I remembered it in the context of Meridian, I was wondering if that folds into this stuff in some manner.

melvimbe

We are moving toward object oriented audio where an instrument can be assigned an apparent location in three dimensions.

Yes, but in my opinion, it makes a big difference whether the audio was produced for object orient audio, or just two channel audio that a dsp passes through an algorithm to have audio come from locations that were never really intended during production.

Danny

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