Latency issue with the Lumin U1

Audio Gear Talk Lumin
1

I have been using a Lumin U1 in my main system for a while now. When I use it by itself, it sounds lovely. But when I use it with the Roon multi-room grouping, it does not behave properly. I probably have a half a dozen Roon end point around the house from multiple vendors. They all behave perfectly. But, with the U1, first of all, it is around 350ms slower than all the others. That much I can compensate for with the Zone grouping delay. Unfortunately, the latency through the streamer is not consistent and seems to depend on external factors. One, for certain, is the source of the track. Tracks from Qobuz have a slightly different latency than tracks from my NAS. Enough that if you are standing where you can hear both zones, the ‘echo’ makes you crazy (and your wife to throw things).

To test to make sure it isn’t from another part of that system, I swapped the U1 for a couple of other end point. They all worked perfectly. Somehow all the fingers seem to point to the U1.

I contacted Lumin customer support and was told that I must be wrong because they are Roon Certified. Putting aside whether a customer support person should respond that way, it does make me question what ‘Roon Certified’ actually means. I get the fact that Lumin has their own multi-room protocol, but could they not do both?

2

One of the things it means is that sync should work:

  • Multi-room synchronization of devices from different manufacturers For more information on the design goals and philosophy behind RAAT, see here.
3

To further the discussion here now. Is the U1 doing any extra processing? IE) upsampling, volume leveling, Lumin’s special volume control?

Have you tried resetting the U1 and setting it to Roon Ready only and see if it behaves differently?

4

Good questions, but no. First, of course, I made sure the firmware was up to date. The DAC is from Audio Note, so I have Roon set the max rate to 96kHz. Volume is fixed. No MQA. I guess there could be something I don’t know about.

I guess the extra 350ms of latency is somewhat explainable (e.g. they just don’t send that info to the Core), but the inconsistent latency sounds more like a different implementation philosophy, or maybe even an under powered processor. But that is just a guess.
I haven’t found someone with a U2, which might give me more data.

5

Roon certification tests are calibrated using USB audio path.

6

Peter,

Thanks for the honest, if carefully worded response. Should I assume that the firmware architecture for the U2 and U2x are basically the same? That is, that the Roon multi-room sync may have issues when played through the Coax output?

An interesting business decision to have an advertised capability only perform properly through half the outputs.

Again, thank you for solving the mystery.

\bob