Audio Issues when Using Apple’s USB-C Digital AV Multiport Adapter

MJ1K2I record podcasts and screencasts, and usually do my audio recording on my iMac, but recently I’ve been using my MacBook Pro (2017, sans touch bar) a bit. Since it only has two ports, and I needed to record something with my iPhone connected to it, I attached the dongle you see on the left: it has three ports, one is USB-C, one USB-A, and one HDMI. I bought this a few years ago to use with the crippled single-port MacBook, and while I don’t use it often, now that I have 100% more ports on my MacBook Pro, there are times I need it. The battery was running low, and I needed to connect a microphone via USB, so I used one port for the iPhone, and the other for the power and microphone.

I recorded about two minutes of audio for a screencast using Audio Hijack, and, as I always do, opened it in Rogue Amoeba’s Fission to check it and edit it. This is what I saw:

Audio artifacts

As you can see, there are some very nasty audio artifacts on the recording. Interesting, they only show on one channel, but they are very loud diginoise. I don’t know why this happens, but when I plugged the microphone directly into a USB-C > USB-A adapter, then into the MacBook Pro, the problem went away. Also, when the power cable wasn’t connected to the mammoth dongle, it worked fine. I can only assume that there’s something wrong with the larger dongle when it’s sending both power and data. I don’t think there’s any way to fix this, and I don’t really need to use this configuration often, but it’s worth noting if you do plan to do audio recording and need another peripheral connected to a Mac via one of these dongles.

Fortunately, I didn’t discover this after recording a podcast…

10 thoughts on “Audio Issues when Using Apple’s USB-C Digital AV Multiport Adapter

  1. Just another example of “well, no one will notice” that Apple and others inject. The audio port is no longer important, no one will notice it gone. USB-C handles power and data, who cares if there is a conflict a a few bits get messed up. No one will notice. Until we do and by then it is too late.

  2. Just another example of “well, no one will notice” that Apple and others inject. The audio port is no longer important, no one will notice it gone. USB-C handles power and data, who cares if there is a conflict a a few bits get messed up. No one will notice. Until we do and by then it is too late.

    • Wow, I hadn’t seen that. I bought it when the 12″ MacBook was first released, so there were no reviews at the time as it was brand new.

    • Wow, I hadn’t seen that. I bought it when the 12″ MacBook was first released, so there were no reviews at the time as it was brand new.

  3. Mine seems to have destroyed a USB HD that had never had problematic elsewhere. HDMI still works but I wouldn’t use the USB with anything I care about.

  4. Mine seems to have destroyed a USB HD that had never had problematic elsewhere. HDMI still works but I wouldn’t use the USB with anything I care about.

  5. All the more reason I am still very satisfied with my 2012 non retina MacBook Pro. I truly do not understand why fewer ports were so desirable. The thinness thing – it has been carried to the point where style has interrupted function.But I am not the extraordinarily successful and wealthy Mr. Ive. It is obvious the overwhelming majority of the world wants thinner and thinner and does not value multiple ports or longer battery life or upgradability. The facts are the facts. This is not the only issue I feel like a dinosaur ..

  6. All the more reason I am still very satisfied with my 2012 non retina MacBook Pro. I truly do not understand why fewer ports were so desirable. The thinness thing – it has been carried to the point where style has interrupted function.But I am not the extraordinarily successful and wealthy Mr. Ive. It is obvious the overwhelming majority of the world wants thinner and thinner and does not value multiple ports or longer battery life or upgradability. The facts are the facts. This is not the only issue I feel like a dinosaur ..

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