Is this the case with all sources?

As a test, reverse the left and right assignments of your speakers. Does the loss of treble follow the L/R assignment or stay with the speaker?

Not as likely, there could be something odd with the room acoustics that is confusing the human. Physically swap the speakers to investigate this.

Hi.Yes tried different sources and swapped speakers around and trueplay done twice.vocals of song are far clearer than the other.More noticeable when moving balance left to right.

Is it corrected if you switch off Trueplay in the ‘room’ settings? If not and you’ve tried the things suggested by @buzz, then it maybe best to submit a system diagnostic and note, or post, it’s reference back here and then contact/chat with the Sonos Support Staff via this LINK and see if they can see any issues with the device.

Hi.Yes that seemed to correct it.Is this just what trueplay has set for my room.Seems strange.My speakers are well apart and on corner shelfs of my living room.They are about 8 metres apart.

I can suggest a few things in this instance. Maybe try these steps first..

• Unpair the Play:5’s and factory reset the right speaker only and setup the speaker back in the App, exactly the same as before.
• When happy that the above speaker is working then go onto factory reset the left speaker and set up that speaker again in the App, so all is the same as before.

Now try stereo pairing them again and test their sound balance (presumably all will be well at this point) and then Trueplay tune the speakers again.

Now test all again - In the very rare instances I’ve seen this reported here in the community, the above steps usually resolves the issue.

However, If the problems do persist, then my thoughts are it’s ‘possibly’ the iDevice you are using to Trueplay tune the ‘room’ and the next step will be to see if a different iOS device will work for you and if that’s no good too, then whilst playing the unbalanced audio, it maybe best to submit a system diagnostic and note, or post, it’s reference back here and then contact/chat with the Sonos Support Staff via this LINK and see if they can see any issues with the device.

Note, whatever you do, do not factory reset both speakers at the same time if they are your only Sonos products as you will lose the current setup, which is stored on both speakers, so only ever reset just one at a time and that way you will not lose your configuration. 

Hope the suggested steps above work for you.

Thanks.Did unpair them and after I trueplay tuned were the same.It could be my iOS device.Its not damaged in any way and is running latest 15.7 software.Ill speak to Sonos I think submit a diagnostic.Thans for your help.

15.7? - latest Apple release is iOS 16.1.2 - maybe you just need to update the O/S - if it’s an older device, maybe check mic aperture for dust/pocket-fluff too.

It is an ipad mini 4 so maybe it's getting a bit old.I wouldn't think that would affect what trueplay does.I think it's maybe a speaker fault or it's just the way trueplay has set up for the room.Thanks

As the 5-pair work without Trueplay, the worst case scenario is a ‘fixable’ software issue, in which case I think we would have seen more reports in the community here about the issue. If a reset doesn’t sort it, my thoughts are to certainly try another iDevice and re-Trueplay tune the room - I’m assuming though that your listening environment is not in anyway unique, or so unusual, to likely cause such strange tuning issues. Anyhow hope you get it resolved and that you will kindly report back the outcome here.

Thanks again for your help.Will try another iOS device.