Sound Quality Connect vs. Port

  • 14 October 2020
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34 replies

ratty

I’m was in the same boat so I bought a Sonos amp to replace a zp90. Seems it is bit perfect to the source too. It sounded good even with my B&Ws from 1999. 

I’m not sure I understand. The Sonos Amp cannot be ‘bit perfect’ as such. It contains a DAC, and EQ, and drives analog passive speakers. 

 

However, just got a new iPhone and casting via iPhone / AirPlay 2 sounds stellar; way better than the Amp as a source.

Are you using AirPlay2 to stream from the iPhone to the Amp? If so, it’s clearly part of the chain, and is doing decode and DA conversion much as before. Perhaps the source you’re comparing with AirPlay2 was in some way compromised? 

X
Userlevel 1
Badge +3

I’m was in the same boat so I bought a Sonos amp to replace a zp90. Seems it is bit perfect to the source too. It sounded good even with my B&Ws from 1999. 
However, just got a new iPhone and casting via iPhone / AirPlay 2 sounds stellar; way better than the Amp as a source.
How is this possible? Is there a default setting messing up the sound from the Amp alone? 

ratty

Although I’ve never analysed its effect, one would logically expect a volume limit below 100% to simply scale the digital samples down linearly. They would obviously no longer be bit-perfect to the source, but I can see no reason why the soft-knee protective limiter in the DSP would be engaged. It’s there to stop samples being scaled up over Full Scale and clipping on the output. That can’t happen if there’s no EQ. 

M

Sorry to reopen this can of worms….

To clarify the use of Fixed Volume to obtain “bit perfect” output. Does this also require the volume limit to be set to 100%?

A quick test shows the volume limit reduces the analog and digital outputs together so i’d assume it’s doing some processing via DSP. If so, would expect that the limiter should be reset to 100% to avoid this.

If the volume variation is applied at the digital signal level (pre-DAC) I can’t see how the use of the analog outputs would bypass the problem (if there is actually a problem to bypass, i’m not sure there is anything audible) as some reviewers have suggested. Surely the only difference is that the signal is going via an internal rather external DAC.

I like the use of a fixed volume with a 66% limit to give a less sensitive dial on the external amp. However, analog attenuation might be “superior”, technically speaking.

:vulcan:

ratty

Use of Variable Volume on the digital output always involves some processing, whether on Connect or Port. Simple volume adjustment of course changes the samples from their original input values, never mind using EQ.

Along with most such devices, Connect had some dynamic range limiting on its digital output to avoid clipping. Port does too, but for some reason it’s evidently more aggressive.

Fixed Volume bypasses all such processing.

Reviewers have remarked that Port’s analog output is also a suitable way of avoiding the effects of Variable Volume on the digital out. Port’s DAC is based on the AK4490, which is a well regarded “premium” chip.

 

W
Userlevel 2
Badge +1

Thanks

jgatie

Can you confirm that if the output is set for fixed volume there is no digital processing by either unit?

 

Fixed output is bit-perfect to the source. 

W
Userlevel 2
Badge +1

Can you confirm that if the output is set for fixed volume there is no digital processing by either unit?

K

Best try based on a listening test, people here claim to hear differences even using the digital out that is measured bit perfect. Which does not imply that they are right or wrong, people hear what they want to hear.

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