Ugoos AM6+ downmixing


I have CE (nightlies) installed and I’m very happy, I’m playing UHD BD remuxes over USB HDD atm.

My TV is a Sony A95K, audio through the TV is cool but I would like more bass.

So I don’t want all the hassle of a surround setup, I have a 2CH USB DAC that I use mainly for music.

I connected the AM6+ over USB to my DAC and it works but I’m not happy with it, I’m guessing that it could be struggling to cope with downmixing as I had the audio cutting in/out on Heat. I also couldn’t seem to get the centre channel downmix to go louder and I was seeing a slight audio delay.

So I guess my post is to ask if CE downmixing on the AM6+ is a good idea?

Has anyone found an external downmixing solution that allows you to incorporate the LFE channel and change the centre channel volume?

Thinking about the audio dropouts, it could be an issue on the USB bus, CPU usage, a bug or something else and I’m thinking that an external solution might be best.



I’m in a somewhat similar situation: Sony A95L, Ugoos AM6B+ and a 2.1 audio system with a non-hdmi amplifier. So far I ended up downmixing on the Ugoos, outputting PCM 2.0 via HDMI to the TV, and then through the optical S/PDIF to the amplifier, with a Camilla DSP in the middle.

I haven’t fully worked out the lipsync issues yet: the delay is different depending on the file, and so far I’m gathering data and trying to find a pattern. When I’m done, I’m planning to automate the delay reconfiguration on the Camilla DSP, depending on what is currently being played.

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Thanks, thinking out loud, your delay changing depending on the content might be compounded by different sample rates and bit depths going into CamillaDSP taking more/less time to process, I know my MiniDSP converts everything to a fixed rate and depth before the DSP so the delay is consistent.

With the AM6+ running CE how does it actually handle Dolby and DTS, obviously it doesn’t have to do much for passthrough but for downmixing, can it struggle with decoding and combining the LFE and centre?

Everything is set up to use a constant 48khz sample rate. I’ve also configured CamillaDSP to use a more or less constant buffer size, the delay deviation is usually within 1-2ms.

I’ve experimented with plugging RPi with CamillaDSP directly into AM6B+ as a USB gadget, and I like the result better: there are no audible clicks when switching video modes anymore, and the delay between different files is not as all over the place, although not constant either. I believe most of the difference in the delay was introduced by the TV.

I don’t think so, because there were quite different delays for the files with the same codec. Besides, downmixing does not seem like a heavy operation, but I’ll take a look at the CPU load tonight. If that turns out to be a problem, then using the USB Gadget configuration it should be possible to route PCM 7.1 to CamillaDSP and perform the downmixing there.

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Checked the CPU usage while downmixing truehd, don’t see any concerning increase comparing to passthrough.

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Some things that may help (with help from Google):

You could try using “nice ” to give CDSP a lower scheduling priority.

Perhaps up the priority of CDSP in the kernel.

What CPU frequency governor do you use? I would suggest to try a frequency governor with fixed frequency.