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Mismatch in Port Line-Out to HiFi input

  • 11 June 2021
  • 9 replies
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Exactly the same problem as mentioned in the ‘Port Line-Out very low volume’ topic but alas unanswered there - there appears to be confusion between using the Port to drive the HiFi or the Hifi to feed into Sonos… I guess the latter is more common, and I am unusual (but not unique) in using Sonos to drive the HiFi.

I have a TEAC series 300 component HiFi and a Play:5 in the same room. If I group both to expand the sound stage (not exactly surround sound but...) there is a great disparity between the Sonos Setting for the Play and the (much greater) volume setting for the Port. The HiFi volume is set to a normal listening level for the other Hifi components - CD, cassette, DAB, and switching between them requires no volume adjustment. Switching to Sonos requires either the the Port Sonos volume to be set near max, or the HiFi volume greatly increased, which causes consternation if you switch to another source without readjusting… Also if you increase the group volume, the Play volume overtakes the Port/Hifi volume fairly swiftly, necessitating more adjustment. (the volumes increase disproportionally). If the HiFi volume is set to ‘normal’ the Sonos Port volume maxes out swiftly and the HiFi is drowned out by the Play:5 with its additional volume headroom/freeboard.

The Port has an input sensitivity adjustment. Why can it not have a similar output matching adjustment to augment or attentuate?

It looks like the only option that I have is to fit an additional preamplifier between the Port and the aux input on the HiFi to augment the Port output to match that of the other HifI components (2V RMS apparently). The expensive work around I had with my old Connect was to use a matching TEAC DAC whose output was on a par with the rest of my TEAC Series 300 components. Alas the Port does not have the digital output that I used… The Connect is now obsolete for S2 purposes and has been upgraded to the Port.

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Best answer by keiths 11 June 2021, 17:11

Thanks Ratty - I am ignorant of the coax digital which you have now brought to my attention, and that seems a no-brainer! To make this a slam-dunk there is already a coax input on the Teac DAC! One cable on order... I likewise see mileage in GuitarSuperstar’s suggestion, and will report back. There still was some disparity when using the Teac DAC, but less.

Regarding Kumar’s comment, it would appear that the output of the Port is attenuated compared to my other Teac components, and I am already using variable mode... I explained the problems encountered with this in my post.

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Userlevel 7

Have you tried lowering the Volume Limit on the Play:5 in the Sonos app to decrease the disparity between the two volume sliders?

Or simply insert a coax/optical converter between the Port and the existing TEAC DAC. Such converters are inexpensive items. 

 

The Port has an input sensitivity adjustment. Why can it not have a similar output matching adjustment to augment or attentuate?

 

Because it puts out roughly the same signal voltage of about 2 volts that a typical CD player does.

PS: oops...it does have the output matching thing you ask for, when set to variable mode: via the volume level sliders.

Thanks Ratty - I am ignorant of the coax digital which you have now brought to my attention, and that seems a no-brainer! To make this a slam-dunk there is already a coax input on the Teac DAC! One cable on order... I likewise see mileage in GuitarSuperstar’s suggestion, and will report back. There still was some disparity when using the Teac DAC, but less.

Regarding Kumar’s comment, it would appear that the output of the Port is attenuated compared to my other Teac components, and I am already using variable mode... I explained the problems encountered with this in my post.

Userlevel 6
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Hi @keiths 

Much like any other HiFi component, your Port’s output should always be at maximum (to reduce the signal-to-noise ratio), but especially if you want it’s volume to match that of your other HiFi inputs.

To do this, please set the Port’s output to Fixed, as described in our Set up your Sonos Port help page. This will disable the volume control on the Port, but that’s technically what you want if you want all sources on your HiFi to sound at the same level.

A difference in audio cable linking the Port to your HiFi could also cause a difference in volume, which your intended use of digital audio out would prevent. Note that you do not need a special digital coaxial cable to link the Port to your DAC. One side of the RCA cable you are using for analogue connection will do fine.

Hi Corry,

You’ve hit the nail on the head - the Sonos Port on max would match the hifi components output levels, but I wouldn’t be able to adjust the volume in sync with the grouped Play:5.

I guess I’m trying to do the impossible as the output of the hifi components is 2V, and amplified/adusted by the amp volume, where as the output of the Port is 2V max, but attenuated by the Sonos Controller, and will therefore always be quieter than a hifi component (with worse s/n, although that’s not a problem for background music).

If I amplified the Port output so that the normal listening level output was 2V, then momentarily turned up the wick on the Sonos controller (as in - I like this track), would probably overload the hifi :-). That’s what the Sonos Amp is for…

Thanks for all the help/suggestions, guys!

If you stuck with an outboard DAC then using variable volume wouldn’t have any effect on SNR, at least until the volume goes down below -48dB. The 16-bit information effectively gets shifted into the lowest 8 bits on the 24-bit S/PDIF as the volume reduces, so it’s not until -48dB (or thereabouts) that information starts to get truncated.

Hi Ratty - agreed! I’m now back to where I was with the Connect, using the coax cable which was an acceptable half-way house, and I will also add the max vol tweak to see what effect that has on volume slider sync. Most of my listening is done at low volume (except when the neighbours are away…!).

 

If I amplified the Port output so that the normal listening level output was 2V, then momentarily turned up the wick on the Sonos controller (as in - I like this track), would probably overload the hifi 🙂.

How? If you use the Port in fixed level mode, it will be like any other 2V input component, and there would be no “wick” for it on the Sonos controller.

And since I have never tried this out: my guess is that if the play 5 and the Port are then grouped, the Sonos controller volume control will work only on the 5 unit, allowing it to be matched to the sound levels from the speakers wired to the hifi.

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