Interesting problem with Amp and turntable

Tinny sound with no bass is a sign of hearing the raw RIAA mastering applied to records to give them higher dynamic range.  In other words, you are hearing a phono output instead of a line output.  Phono output is made for phono inputs, where it is converted to standard line input.  Sonos only has line inputs. 

Does your turntable have a setting for Phono/Line output?  If it does, switch it to Line.  If not, you need what is called an external Phono Pre-Amp to go between the phono output on the turntable and the line input on the Sonos.  This will convert the RIAA mastering of the record to standard line-in.  You can get them for under $25 US on Amazon. 

Initially I thought this was the issue as I've never owned a TT and I've now tried it with two different phono pre-amps. The first one had a switch which was set to line. The second one doesn't have a switch, but the manual has assured me the output is line level.

It’s the issue.  Double check the wiring and configuration of the preamps, something is wrong in that area.  

@swisser,

If not done already, perhaps also raise the line-in source level in the Sonos App to level 10, (Settings/System/[Amp Room Name]’ that’s once you have the pre-amp/TT setup/working correctly. 

tbh I've tried all these settings in the app. I'll have to try again with wired speakers... I'm just being impatient. While scratching my head, I managed to recorded the entire A side of "Time out" onto my laptop from the exact same output and it sounds great... full sound. Not sure what my interface is doing that the Amp isn't.

The fact you mentioned earlier… "Used other line-in sources to the Amp... my phone, cd player... all sound great” seems to clearly suggest it’s the TT, Pre-Amp or the cables in between. I don’t see how adding the B&W passive speakers is going to be relevant, as that’s just a further means of outputting the line-audio. I’m guessing the cables haven’t changed, so maybe look closer at the TT and Pre-Amp products.

@Ken_Griffiths 

You're totally right. But after hours of going after the TT/preamp I'm just just convinced that's it's not the issue and I need some wired speakers to prove it. What are the chances two different phono pre-amps haven't worked? Especially after trying different cables and settings on each. The reason I came here was to determine whether it could realistically be an issue in my network? 

Okay, well I hope you sort it - if not, then just to say here’s a link to contact/speak with Sonos Support Staff if you find you need to go that route later…

https://support.sonos.com/s/contact

Let us know if you sort it. 👍

No, a network issue would cause missing, not distorted audio.

@buzz

Actually the audio I'm getting through the Arc is not distorted. It's clearly just missing some lower frequencies. The rest actually sounds okay... maybe a bit quieter than it should be, but no distortion, or extra humming/buzzing.

For example on "blue rondo a la turc" everything seems to be going well until the 5th bar when the bass player quite literally just doesn't come in...