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Problem: Cyrus soundkey intermittent distortion
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Posts: 2
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Joined: Apr 2021
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(03-07-2020, 03:51 PM)l eicray Wrote: Hi Kent,
Many thanks for the additional suggestions. After lots of test combinations, and rewriting of microSD cards, I conclude that the USB ports on a Pi-4B do not play nicely with some USB DAC-like devices.
I have previously reported that my Pi-4B causes a popping noise when connected to my Audiolab M-DAC, though the M-DAC works just fine when connected to a Pi-2B running exactly the same version of moOde. However, the Pi-4B does work fine with a simple USB audio adapter (Trond AC2-B). The adapter would have been a possible solution, but the volume is simply too low and that's why I bought the Cyrus soundKey which incorporates an amplifier.
I have now tested the soundKey connected to a Pi-2B and a Pi-1B, again running the same version of moOde, without any problems. This suggests that the Pi-4B is the culprit. For some reason it plays nicely with the Trond USB audio adapter, but not the M-DAC or the soundKey
My intended solution is to put the Pi-4B into safe storage for now and buy a second Pi-2B (very reasonably priced on eBay for a new unit) as I know that that will work.
There is at least one report of a kernel bug in Ubuntu causing problems with the 4 GB RAM version of the Pi-4B (as is mine), so perhaps a solution to my problem will arrive in some future kernel update for Raspian. Not holding my breath. however.
Again, many thanks.
Posts: 2
Threads: 0
Joined: Apr 2021
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(04-15-2021, 12:31 PM)Mfuggles I have a Cyrus CardKey i have used on two Pi4 one running Volumio and the other RoPieee and both exhibited the same distortion from the usb DAC. First i thought it was mains interference but it seemed to be at regular intervals like a fridge cycling. Now i think the device is polling trying to communicate with an apple device as part of the authentication process (Apple Certified Product etc) and for some reason you can hear this through the pi. I guess if the device does not submit the signal every (x period of time) the iphone cuts the output. I tried a good Chinese USB DAC off Ebay which would not work on the iphone but works fine on the pi 4 and the problem has gone. Definitely the USB and its a transmitting interference. Wrote: Kind of ironic really that the expensive DAC will not work seamlessly on the pi4.
These are my thoughts which may help someone. Its very annoying.I have a Cyrus CardKey i have used on two Pi4 one running Volumio and the other RoPieee and both exhibited the same distortion from the usb DAC. First i thought it was mains interference but it seemed to be at regular intervals like a fridge cycling. Now i think the device is polling trying to communicate with an apple device as part of the authentication process (Apple Certified Product etc) and for some reason you can hear this through the pi. I guess if the device does not submit the signal every (x period of time) the iphone cuts the output. I tried a good Chinese USB DAC off Ebay which would not work on the iphone but works fine on the pi 4 and the problem has gone. Definitely the USB and its a transmitting interference.
Kind of ironic really that the expensive DAC will not work seamlessly on the pi4.
These are my thoughts which may help someone. Its very annoying.
(03-07-2020, 03:51 PM)l eicray Wrote: Hi Kent,
Many thanks for the additional suggestions. After lots of test combinations, and rewriting of microSD cards, I conclude that the USB ports on a Pi-4B do not play nicely with some USB DAC-like devices.
I have previously reported that my Pi-4B causes a popping noise when connected to my Audiolab M-DAC, though the M-DAC works just fine when connected to a Pi-2B running exactly the same version of moOde. However, the Pi-4B does work fine with a simple USB audio adapter (Trond AC2-B). The adapter would have been a possible solution, but the volume is simply too low and that's why I bought the Cyrus soundKey which incorporates an amplifier.
I have now tested the soundKey connected to a Pi-2B and a Pi-1B, again running the same version of moOde, without any problems. This suggests that the Pi-4B is the culprit. For some reason it plays nicely with the Trond USB audio adapter, but not the M-DAC or the soundKey
My intended solution is to put the Pi-4B into safe storage for now and buy a second Pi-2B (very reasonably priced on eBay for a new unit) as I know that that will work.
There is at least one report of a kernel bug in Ubuntu causing problems with the 4 GB RAM version of the Pi-4B (as is mine), so perhaps a solution to my problem will arrive in some future kernel update for Raspian. Not holding my breath. however.
Again, many thanks.
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