Question

Single sonos one working as stereo?

  • 5 December 2019
  • 41 replies
  • 511 views

Im with a problem with my Sonos one. 
 

Turns out I discovered a tune at work the other day and when I arrived home I wanted to listen to it on my Sonos. 
 

the song is wastelands-Bedouin. 

On minute 3:00 there’s an arpeggiator (it’s an electronic sound that gives the song a lot of character, and It’s the reason it caught my attention and made me want it to listen at home). 
Turns out when I played it on the Sonos that sound doesn’t come out! I didn’t understand why so I asked a friend. He tried it on his speakers and made me realize that the song is recorded in stereo and that sound comes out from the left speaker. 
is it possible that my Sonos is working as a right stereo speaker only? I’ve read it works as mono on its own, but I can’t find another explanation, the sound does not come out at all. It’s not that I hear it a little bit low, it’s not there. It sound ok on my phone, my computer, my headphones, but not no Sonos. 
this means that I might be losing music because of this. 
 

Helppp!


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41 replies

Likely the instrument in question is out of phase on the two channels. When summed for mono, the result is zero. If you place the two stereo configured speakers close to each other, there will be a partial cancellation and a “comb filter” effect.

You can experiment with this stereo cancellation if you place two full range speakers face to face and touching or nearly touching. The bass will be partially cancelled. If you have a “single point” ceiling or wall mounted speaker (one hole, both channels connected), wire the channels out of phase. Here you will have full or partial cancellation.

Edit: In my single point experiment above this out of phase instrument will increase in level while the normal music will decrease or disappear.

Sometimes a single instrument (usually a lead instrument) is deliberately processed out-of-phase to give it a floaty/ethereal sound. It’s very easy to do during the mixing process. The problem comes, as you’ve discovered, when you listen in mono - the instrument disappears.

Just for fun, I’ve taken this song and flipped the phase of the right channel, then added the left and right channels together (same as a mono speaker will do), and saved the result as a stereo file with this mono signal in both left and right channels (I’ve saved it this way so it sounds the same whether you listen in mono or stereo). You can hear the result by downloading the file from here.

You will notice the absence of the kick drum at the start, because it was recorded to be the same in both channels (often bass instruments are recorded the same in each channel because the ear is not very good at stereo locating low frequencies). Hence flipping the phase cancels it out. Vocals also are often recorded the same in both channels, but vocal reverb is generally a stereo effect, so can be different in each channel.

At 3:00 minutes, the synth is very much audible. It was definitely recorded out-of-phase as many people in this thread surmised.

At 3:31 you can just hear the vocals - this is mainly the vocal reverb. The dry (original non-reverbed) vocal part has been cancelled by the phase flip.

 

Cheers, Peter.

There is clearly a lot more to audio than meets the eye.

I am aware of this phenomenon, but I somehow can’t square it with what we are seeing here with one instrument that is playing music getting dropped out of the mix while all else seems to sound ok. And also, this seems to be the first time someone has noticed something like this so this is not at all common - kudos to the OP for picking it up, even if accidentally!

Curious as to why this is sad? They identified an issue in your submission, which might cause issues, even if not this particular one, and suggested a method for you to potentially resolve that issue. That’s what I would expect from a support line. Even if they’re unable to address my exact issue, due to the nature of the discussion above, they’ve identified another issue that I haven’t yet, and helped me address it before it becomes a problem. 

Hopefully, one of the community moderators will have time to look at it in the next 24 hours, and respond here. If you’d prefer, you could contact Sonos Support directly to discuss it.

I usually suggest the phone folks, they have more tools available because they're on the phone with you, but they are only available Monday through Friday during business hours. Both the Twitter and Facebook support folks are available 24/7.

if you do contact Sonos support directly, with that diagnostic number, I’d certainly would appreciate it if you’d come back and post what you find out. It’s likely to be another week or two before I get that PLAY;1 back, and it will have to be reset before I can add it to my own system, which might “fix” the problem, or not…

Good luck!

Now this is seriously weird.  I have just done a few experiments.  Here are the results:

  1. The ‘arpeggiator’ is audible on my stereo pair of Play:5s and my single Play:5 (which of course is a stereo speaker)
  2. It has, as the OP suggests, completely disappeared when the track is played on my Play:1 (mono)
  3. But I don’t believe it has anything to do with left and right stereo channels, because that arpeggiator is on both L and R channels (established this using the stereo pair of P:5s - seems to contradict OP’s experiment) 
  4. I also established that the P:1 is generally playing both channels.  The opening of ‘Beautiful Girl’ by INXS is a good test here - guitar on R channel, piano on L.

I must admit I wasn’t expecting this.  So what is going on?  My best guess is a frequency ‘hole’ on the Play:1 that this part of the music is dropping into - but that would be rather disturbing.

Further experiments.  Arpeggiator also audible on the Playbar, Beam…..and the Play:1 surround speakers bonded to the Beam.  It is just my single Play:1 that it completely vanishes on.  (And note that the OP’s problem was on a Sonos One)

Curiouser and curiouser……...

I am aware of this phenomenon, but I somehow can’t square it with what we are seeing here with one instrument that is playing music getting dropped out of the mix while all else seems to sound ok. And also, this seems to be the first time someone has noticed something like this so this is not at all common - kudos to the OP for picking it up, even if accidentally!

 

If that one instrument was purposefully recorded out of phase (which seems to be the case here), and the rest is recorded normally (i.e. in phase) across the two channels, this is the expected effect.  

In the LP mastering process the lowest frequencies are customarily cut in mono because this uses somewhat less “space” on the record surface.

By the way, modern LP mastering cutters digitize the signal. It is very difficult to find a recently cut LP that has not been digitized in any step of the process. In the digital domain it is easy to adjust the groove “pitch” (spacing) such that a loud bass note will not cut through to the adjacent groove. Otherwise the recording engineer must manually ride the groove pitch control. Dynamically changing the pitch allows stuffing more music on a side, but if the adjustment is a little late, the master is ruined because there is a “Y” in the spiral. In the digital domain, one can set the minimum groove wall thickness, then sit back and watch the process. If the groove wall is too thick, maximum time on the side is reduced, too thin results in “pre echo” and “post echo” because cutting will slightly deform the wall of adjacent grooves. (Think of the cutter as a hot knife melting wax) (There is also a pre or post echo associated with storage of an analog master tape)

It shouldn’t be. But having said that, I recently added a PLAY:1 to a friend’s system temporarily, and thought perhaps I was experiencing a similar issue…although I passed it off as my imagination. I’d recommend that you play the track, and then submit a system diagnostic within 10 minutes, and either post the number here, or contact Sonos Support to discuss it.

I usually suggest the phone folks, they have more tools available, but are only available Monday through Friday during business hours. Both the Twitter and Facebook support folks are available 24/7.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

I have to wonder if it’s an issue with speakers added under a more recent software update? For instance, I have just returned home, and am not noticing the issue with a previously set up “single” speaker. How long ago did you set up your speaker? I could be shooting in the dark here, and completely wrong...and not actually experiencing the same issue that you are. And that speaker I *think* I was experiencing the potential issue on is being shipped to me soon, so I can’t actually do any testing myself with that particular speaker.

I’ll follow this thread to see what you find out. I’d be fascinated to hear if you’re confirming what I thought was completely my imagination / bad ears.

 

In this case only the the instrument in question is out of phase. The other instruments are normal.

Now this is seriously weird.  I have just done a few experiments.  Here are the results:

  1. The ‘arpeggiator’ is audible on my stereo pair of Play:5s and my single Play:5 (which of course is a stereo speaker)
  2. It has, as the OP suggests, completely disappeared when the track is played on my Play:1 (mono)
  3. But I don’t believe it has anything to do with left and right stereo channels, because that arpeggiator is on both L and R channels (established this using the stereo pair of P:5s - seems to contradict OP’s experiment) 
  4. I also established that the P:1 is generally playing both channels.  The opening of ‘Beautiful Girl’ by INXS is a good test here - guitar on R channel, piano on L.

I must admit I wasn’t expecting this.  So what is going on?  My best guess is a frequency ‘hole’ on the Play:1 that this part of the music is dropping into - but that would be rather disturbing.

 

you’re right about INXS-beautiful girl. Works fine on my Sonos one. 
This just makes it even weirder. 
 

I don’t think that makes it weirder - I don’t think this is a L/R channel thing.

It’s plenty weird enough already though.

Curious as to why this is sad? They identified an issue in your submission, which might cause issues, even if not this particular one, and suggested a method for you to potentially resolve that issue. That’s what I would expect from a support line. Even if they’re unable to address my exact issue, due to the nature of the discussion above, they’ve identified another issue that I haven’t yet, and helped me address it before it becomes a problem. 

Agrreed. That was a harsh and unfair comment by the OP. The Support person is looking for problems that affect Sonos and that is what he found. The true explanation was nothing to do with Sonos, extremely unusual, and took a bunch of us geeks a fair while and lots of testing and discussion to get to the bottom of it. The Support person had no chance of coming up with the actual explanation here.

I grouped a Connect Amp and a Play 1 in two different rooms. For the first time ever, I find they play different music when grouped - very weird indeed. And not subtly so. One instrument, and just that, is missing in the play 1.

The first anomaly I have come across in all my Sonos experience that isn't related to Wifi issues and similar.

And easy to locate because it starts almost exactly at 3 minutes.

Yes I did the tests with speakers grouped too, to ensure the source was identical.  

that arpeggiator is on both L and R channels (established this using the stereo pair of P:5s - seems to contradict OP’s experiment) 

Ditto with Connect Amp, it is on both channels there as well.

More: plays on 1 pair, does not play on single 1 + Sub. 

More: plays on 1 pair, does not play on single 1 + Sub. 

I guess that is consistent with it playing on my P:1 surround speakers.  Unfortunately still inconsistent with sanity.

More weird stuff or insight to be found perhaps? An Echo also does not play the instrument, while the bluetooth source iPhone plays it when not paired to the Echo.

So best guess would be that something in the processing of a stereo signal into a mono loses a bit of frequency range.

More weird stuff or insight to be found perhaps? An Echo also does not play the instrument, while the bluetooth source iPhone plays it when not paired to the Echo.

I think that might blow a hole in my theory, which I would have attributed to Sonos software until this discovery!

Maybe this suggests some weird feature in the encoding of this one track.  Maybe the conclusion is: this track is not suitable for mono listening!

More: iPhones have a mono mode, meant for hearing impaired. The instrument vanishes in that mode. But mono modes, as far as I know, are summed up left and right, so this is still not fully explained.