Motu 828es Phase Issues

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Joined: Fri Nov 06, 2009 4:54 pm

Motu 828es Phase Issues

Post by Bullone » Mon Feb 12, 2024 7:44 am

Dear fellow MOTU 828es users,

I am experiencing phase issues on my MOTU 828es: when I feed the same mono signal to inputs 1&2 (front) I should get two identical mono signals in both channels.
However, when I analyse them with MOTU Audio Tools Phase Analysis in rectangular view, it shows a line that tilts right very much like the example MOTU gives for the one-sample delay case in their MOTU Audio Tools user guide.
It looks like channel 2 has a delay of one sample.
On further inspection, I could verify that at 48Khz sample rate, there is one-sample delay between the channels. It does vary at different sample rates. In Ableton Live, as a workaround, I managed to compensate using either the AlignDelay plugin or a custom built max4live patch: by delaying channel number one of exactly one sample @ 48khz sr I can perfectly phase-align the two channels (straight line in Phase Analysis).
This happens with all input pairs 3-4, 5-6, 7-8, but curiously the delay for all rear inputs is reversed (line tilting to the left, showing a one-sample delay in channel 3, 5, 7). On the other hand, it does not happen if I pair the inputs this way: 1-3, 2-4, 5-7, 6-8.

My workaround allows me to fix my recordings, but I can’t do anything for live monitoring nor for standalone mixer use.

I contacted MOTU support in September 2023 and I sent them screenshots, audio clips and detailed description. They recognised the issue and told me they were going to check with their engineers. I have regularly asked for updates every 15 days or so, but my issue has been constantly postponed until yesterday, when I received a message stating “I do not want to get your hopes up for an update in the near future”. After waiting for more than 4 months, my hopes are very low indeed.I guess this is how it goes with out-of-warranty products (my 828es was 3 years old when I first contacted them).

Hence, I am asking the community: could you please check if you can reproduce the issue on your units?

Please let me know, that would be much appreciated.



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