HomeAll VideosSerious sound & audio problems with Yi 4K+ noise distortion issues external and internal microphone
January 8, 2018
Serious sound & audio problems with Yi 4K+ noise distortion issues external and internal microphone
This video was meant to be a positive endorsement for the Yi 4K+ action camera. Or at least that was my intention when I set out to compare its external microphone capabilities against those of the GoPro Hero 5 Black, and by extension the GoPro Hero 6 Black as it has the exact same audio capabilities as the 5.
As you can hear, during the test I made some positive comments about the Yi and it’s price coupled with good cheap microphone options. At that point I was completely unaware as to how bad the audio quality with external microphones was on the Yi, I only found this out after I got back home to do the edit. To say that I was disappointed would be a massive understatement.
Because I thought the Yi had a great picture quality that I personally think to be better than the GoPro 5 and 6, and still do. I was really looking forward to pairing the Yi with my various microphones, to have the ultimate small, portable high quality vlogging and interview rig.
Anyway, enough about my disappointment, here are some technical details about the issues the Yi 4K+ has with external microphones.
The Yi distorts the microphone signals. It sounds like either the Yi’s preamp or it’s analogue to digital convertor, or maybe a combination of both. This happens even on the low gain setting in the Yi’s menu system.
As the actual recorded signal doesn’t even clip internally after it’s been converted from the analogue domain to the Yi’s internal digital audio system. This is a clear indication that the distortion is happening during the Yi’s pre-amplification or it’s digital to analogue conversion, or more likely both.
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Another indicator that it’s the Yi 4K+ distorting the audio signal, is the fact that it happens to varying degrees with all five microphones. The microphones themselves, or their capsules, are not being driven into distortion either. This is evident in the GoPro recordings, and the fact that I’m very familiar with all the microphones and use them on other devices without issue.
A bad preamp can result in distortion and/or a limited dynamic range.
Bad analogue conversion can also impact massively on the tone of the sound. This could explain why all the microphones had a very similar sound and did not exhibit their own sonic characteristics. They simply didn’t have enough digital audio recording resolution to reproduce their natural sound.
The Yi has a very low bitrate of 48kbps, compared to the GoPro’s 128kbps. Such a low bitrate can also have an adverse effect on the tone, dynamic range, sensitivity and perceived noise level of any mic being recorded.
The Yi recordings are very noisy.
Although the Yi has a two channel stereo internal microphone recording system, which also doesn’t sound too good. It will only record one side of a stereo source and duplicate that to its two recording tracks, but not as stereo. This wouldn’t be so bad for a mono source, such as any of the mics that I tested. But it would have been better to make a single channel recording that used all 48kbps of the bit rate rather than simply splitting that bitrate in half and applying it to two tracks of the same thing.
In any event. Only having a bitrate of 48kbps across two tracks, is no way to achieve anything close to a satisfactory audio recording. Bearing in mind that most recorded audio, along with the video, is going to be further processed and edited, so therefore needs as much information recorded at the point of acquisition.
What’s even more perplexing about this whole audio scenario, is that on the video side the Yi 4K+ actually records up to 135Mbps for the video encoding. That bitrate, although only applied to HFR settings, is higher than my Sony AX100 camcorder in 4K UHD mode at 25FPS. Which really begs the question, why does Xiaomi and the Yi 4K+ use such a low and inferior audio specification with a camera that has the ability to create beautiful video and pictures?
On a practical and worrying level. I’ve obviously got to return all the kit back to Amazon where I bought it all from. The worry is that Amazon may ban or impede my account for returning so many items in one go, even though this wasn’t my fault. I will be getting in touch with Yi to see if they will be good enough to accept the Amazon return without Amazon looking at me unfavourably and banning or negatively effecting my account.
I’ll post a video about my returns experience with Yi and Amazon. Hopefully that video will be all about their great customer service.
Anyway, to finish off.
The Yi 4K plus is an awesome camera for pictures but is terrible for external mic recording, with it’s internal audio also being quite bad. If external microphone recording is important to you, I’d totally avoid the Yi 4K+ action camera.
I hope this video will help people to avoid the mistake I made, or at least forewarn people to let them know what they are getting themselves into.