WiiM Ultra as digital input switcher with (potential) room correction

oshogg

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Jul 12, 2024
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Hi All,

I have a 2-channel stereo system consisting of McIntosh C2700 Pre-amp + two McIntosh MC611s amp + GoldenEar Triton One speakers. I also have Apple TV 4k that is connected to a TV. My usage is roughly 50% music listening (Tidal) or 50% music videos (Youtube, Tidal Video etc.).

I am thinking of using the Ultra as purely a digital input switcher with potentially applying room correction to all the digital sources. I plan to connect Ultra to C2700 via USB.

My sources are going to be:
  1. Television eARC (or SPDIF digital out)
  2. Apple TV 4k. There are multiple ways to possibly connect it.
    1. Apple TV 4k HDMI -> HDMI audio extractor to SPDIF/coax digital out -> Ultra -> C2700 Pre-amp (via USB)
    2. Apple TV 4k HDMI -> TV HDMI -> TV eARC out -> Ultra -> C2700 Pre-amp (via USB)
    3. Apple TV 4k HDMI -> TV HDMI -> TV SPDIF digital out -> Ultra -> C2700 Pre-amp (via USB)
  3. Tidal Connect (within WiiM Ultra)
I would like to play with applying room correction to all three sources.

Few questions:
  1. If I disable volume, room correction etc., is Ultra 100% bitperfect for switching between these inputs?
  2. If I enable room correction, will it apply equally to whichever input is being used now?
  3. Not an Ultra related question, but a general question: are there any differences/advantages between different ways of connection Apple TV 4k?
Thoughts?

Thanks,
Osho
 
For starters, Ultra USB Out isn’t yet available but should be soon as it’s already available on beta on the Amp. With that in mind:
Q1. I believe so
Q2. As room correction is just a set of PEQ settings, and given you can set peq per source, you can choose which input it applies to or not
Q3. Re the three connections methods, I’ll skip the first as I have no experience of such connectors (nor of recent Apple TV models) but I’d expect the ARC connection in part 2 to be higher resolution than part 3 where the TV spdif connection might well be constrained to 16/48.
 
HDMI-ARC may also be limited to 16bit/48KHz.
It might, but it all depends on the TV. As far as I know the maximum allowed bandwidth of HDMI ARC is 1 Mbit/s, which is quite a lot. ;)
 
Thanks for the answers. Is there any difference in the room correction quality between WiiM Pro Plus and Ultra? As I won't be using the DAC and most likely even the screen, I may just go with Pro Plus if it's the same.

Re: ARC, I currently have a 2015 Sony Bravia - which supports ARC but not eARC. The ARC sound quality on that is atrocious to say the least. I have ordered a new TV - TCL 98QM851G, which is a 2024 model with eARC support. Hopefully it will do better.

Thanks,
Osho
 
Thanks for the answers. Is there any difference in the room correction quality between WiiM Pro Plus and Ultra? As I won't be using the DAC and most likely even the screen, I may just go with Pro Plus if it's the same.

Re: ARC, I currently have a 2015 Sony Bravia - which supports ARC but not eARC. The ARC sound quality on that is atrocious to say the least. I have ordered a new TV - TCL 98QM851G, which is a 2024 model with eARC support. Hopefully it will do better.

Thanks,
Osho
Sounds like a Pro might be all you need if you're always going to use an external dac.
Unless the improved adc on the pro plus interests you?
And then, the Ultra apparently has better again adc over the plus.
Note that the Ultra supports arc, not earc.

What dac might you use? I also note that some have had some issues with 192 sample rate locking with some dacs with the pros, but the ultra provides a 'cleaner' signal (better looking eye pattern).
See https://forum.wiimhome.com/threads/my-ultra-tests.3964/post-62840
 
Sounds like a Pro might be all you need if you're always going to use an external dac.
Unless the improved adc on the pro plus interests you?
And then, the Ultra apparently has better again adc over the plus.
I am not interested in ADC. I do listen to records and have a turntable but that is directly connected to the McIntosh C2700 pre-amp.
Note that the Ultra supports arc, not earc.
That's a shame. Why? I hope that for 2-channel sound, it probably will not matter.
What dac might you use? I also note that some have had some issues with 192 sample rate locking with some dacs with the pros, but the ultra provides a 'cleaner' signal (better looking eye pattern).
See https://forum.wiimhome.com/threads/my-ultra-tests.3964/post-62840
I currently have the McIntosh C2700 tube pre-amp (and potentially upgrading it to McIntosh c2800 tube pre-amp in a few weeks). If I go Ultra and then perhaps I can use USB to completely avoid the clarity of the signal issues with digital out?

Thanks,
Osho
 
... which is a 2024 model with eARC support. Hopefully it will do better.
As if now, the WiiM Amp and the WiiM Ultra support ARC, but not eARC. This is not indicative of sound quality, though, and your new TV will be backwards compatible with ARC.
 
It can be indicative of sound quality, eARC supports up to 24/192 but ARC does not.
That table from HDMI.org is nonsense. Optical and ARC can support 24/192. It claims that optical is limited to 384Kbits/sec, but 1.4Mbits/s is needed to play a CD and virtually all CD players have an optical out. Ironic, that you quote Sony who limit eARC to 48KHz on many TVs.
 
The data transmission rate for S/PDIF is 64 times the sampling rate. Sony should know that.
 
That table from HDMI.org is nonsense. Optical and ARC can support 24/192. It claims that optical is limited to 384Kbits/sec, but 1.4Mbits/s is needed to play a CD and virtually all CD players have an optical out. Ironic, that you quote Sony who limit eARC to 48KHz on many TVs.
Hmm.. hope you are right. So, if WiiM Ultra is fed a HDMI ARC signal with 24/192 stereo signal, it should have no problem extracting it and passing it to the output bitperfect?

Thanks,
Osho
 
It can be indicative of sound quality, eARC supports up to 24/192 but ARC does not.
Audible sound quality? My TV supports eARC, should I use this option vs ARC to connect to the Ultra?
I am asking the question because I do not understand how the non-stereo signals are decoded and where. eArc also support bitstream, a superior streaming feed?

In the end, I am curious, as the OP is, on what will make the Ultra shine best.
 
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