On the HAT which will have it’s own clock.
Most probably a dual 44.1/48kHz clock circuit, which will also support exact multiples of those frequencies.
Assuming you are really hearing a difference, and only some hard data or a blind A/B test would confirm this, as we are all (myself included) susceptible to sighted biases.
My guess it that the two protocols are being treated differently, either after the data has been deserialised by your DAC, or before the data has been serialised and sent by your source device.
As I mention above, the two protocols themselves don’t deal with audio (in the analog sense) they deal with transmitting data, which doesn’t have the subtle sound characteristics you describe, only pops, clicks and dropouts if data is lost.
If you are sure you can hear a difference. I’d be inclined to route the analog output of your DAC back though an ADC interface on a PC and record the response in say REW or a DAW for both scenarios, then overlay the plots, if you see a difference then that will give you an indication of where they differ and maybe why ie. do they just differ in amplitude? Otherwise we are just speculating.
Personally I’d want to know why they were different, as they shouldn’t be and it would make me worry something wasn’t setup correctly in one or other case. So I’d do the above and plot both outputs so I had something concrete to visually compare (and share).
Mainly just a name difference, Roon Bridge is the software package anyone can download and install themselves on a PC, Mac, Linux or a Raspberry Pi.
Roon Ready refers to a Roon certification program that ensures a commercial hardware device works with Roon. These devices use a special ‘commercial’ version of Roon Bridge called the Roon SDK that is only available to vendors who have had their devices tested by Roon.
The main difference is you get a nice custom icon when you use a ‘Roon Ready’ device. Roon may also be able to control the devices volume and other settings. this is particular useful for say an amp where you want Roon to control the devices volume. It also lets Roon read and display the settings of the device. This is also why USB is useful as a protocol, as being two-way Roon can read the status and other settings of the upstream DAC.
Sound wide there is zero difference between either Roon Bridge vs SDK (Roon Ready).
–
In terms of common RPi Operating Systems.
Ropieee uses Roon Bridge behind the scenes. On first launch I believe it downloads and installs the Roon Bridge package. This approach allows it to work with a range of HAT and USB DAC without each needing to be certified by Roon.
HiFiBerry develop their own Raspberry Pi OS (HiFiBerryOS), similar to Ropieee. But it only works with their HATs. But because it only works with their HATS they have been certified by Roon and use the commercial Roon SDK (behind the scenes) and their devices are labeled Roon Ready.
But audio wise the HiFiBerry HATs sound exactly the same regardless of whether you use Ropieee or HiFiBerryOS as the operating system. The main difference is Roon can control the device volume of the HiFiBerry Digi+ Hats when using HiFiBerryOS as it used the lower level Roon SDK, something you can’t do with this HATs when using Ropieee, which uses the more general Roon Bridge package. If your using a fixed volume level or adjust volume in Roon via DSP it makes no difference.
