Sony Mi Shoe Digital Audio and Terrible Noise Problems

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Modern Sony mirrorless cameras and some of their video cameras such as the FS-6 and FS-9 come with what’s called a Mi shoe. It stands for Multi-Interface shoe, and essentially it’s a hot shoe with several additional electronic contacts that allow for digital audio signals to flow into the camera from one of several compatible devices.

One of the Mi-compatible products is Sony’s UWP-D wireless lavalier system when paired with the SMAD-P5 Mi shoe adapter (older UWP-Ds use the SMAD-P3). This shoe adapter allows the wireless receiver to be powered by the camera, and it allows received audio to enter the camera through the digital contacts in the shoe, instead of needing a 3.5mm audio cable running into the mic input.

All of this looks good on paper, but when I put it into practice, I discovered the entire system is floored to the point of uselessness. The problem is that when you connect a microphone to the Mi shoe, you no longer have the ability to control the mic input level on the camera. You’ll see that the option becomes immediately greyed out.

At first, I gave it the benefit of the doubt. After all, Sony was singing the praises of an all-digital audio pipeline when the selector switch on the SMAD-P5 is set to digital. Would the audio signal bypass the AD converter in the camera and deliver a nice clean audio track?

The answer is no, not even close. What I heard coming out of the camera when recording audio with the UWP system and the SMAD-P5 was unbelievably noisy. There is nothing clever going on here with Sony’s digital audio input over the Mi shoe. In fact, it’s utter garbage.

The camera goes into auto gain mode and therefore calls heavily upon the terrible and noisy in-camera pre-amps. Amplifying a low-level signal with these cameras is a bad idea at the best of times, but because it is in auto gain mode, as soon as there is a quiet period, or worse, silence on your audio track, the gain is cranked way up and all you hear is noise. Terrible, terrible noise.

And it doesn’t get any better if you skip the digital mode and flip the switch on the SMAD-P5 back to analogue. It doesn’t matter which mode you are in, you are still stuck in auto gain mode and your audio will sound awful.

What’s the Solution?

The solution is simple enough. Never use the SMAD-P5 and Sony’s floored digital audio input system if you want to get clean audio in the camera. If you have to record sound in the camera, by far the best solution is to set a high analogue output level on the UWP-D receiver so that you can set the input level as low as possible on the camera, and of course, just go back to using a 3.5mm input and skip the pointless Mi shoe. The UWP-D wireless system is truly excellent when used in this way. Don’t cripple it with the junky Mi shoe adapter.

How Sony think that this system is acceptable is absolutely beyond me. They are essentially selling an add-on accessory to make your microphones sound worse. The SMAD-P5 (and older P3) are a complete waste of money, and as far as I can tell, the other Sony digital audio accessories work similarly, all forcing the cameras into the terrible, niosy auto gain mode. What is the point in having a digital audio pipeline if it sounds worse than the pre-existing analogue one?

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Professional photographer based in Yukon, Canada, and founder of Shutter Muse. His editorial work has been featured in publications all over the world, and his commercial clients include brands such as Nike, Apple, Adobe and Red Bull.

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8 thoughts on “Sony Mi Shoe Digital Audio and Terrible Noise Problems”

  1. Thanks for confirming this. Was really excited to get audio via from my sony URX-PO3 via the SMAD-P3 receiver -no cables! But crazy noise came through and I was sure it was user error. Adjusted to -3 db on receiver and still same awful noise. This is a disappointment. What on-camera 3.5mm input mic do you recommend? I’ve had bad experience with earlier rode on-camera mics, maybe they’re better now.

  2. In defence of the Mi shoe system, let me just point out that using my Sony PXW-X70 camcorder and the XLR handle that came with it poses no problem at all. Very crisp and clean audio. Well, at least with shotgun microphones that are sortof immune to phantom power noise such as the Sennheiser MKE 600. The Sennheiser XSWD wireless lavalier system also works like a charm.

    Complete failure though with the Rode NTG-2 in phantom powered mode where it obviously picked up considerable noise on the 48V rail. The issue completely disappeared once I was using the internal battery. As this generally decreases sensitivity on almost any microphone (the Sennheiser too) and I hate being forced to use AA primary cells when they are not strictly necessary, I opted for the Sennheiser.

    So, long story short: Sony Mi shoe devices might have some issues with noise introduced via the power supply rail. Perhaps some step up converter or switching regulator/too small capacitor thing. Keep an eye on those. Why you are forced to use automatic gain control with the SMAD-P5 Mi shoe adapter is completely beyond me. No one wants AGC as the only option. I get why people record dual channels as a backup though, where one channel is fully manual and the other automatic, just in case things get louder as expected.

  3. Thanks for writing this up, but I have some opposing anecdotal data.

    I’m using a URX-P40 and UTX-B40 with AA batteries in running through an SMAD-P5 on a Sony A7R V. I can manually control the level on the URX-P40 (not in camera) and it is great. The sound floor is too low to hear, my lav doesn’t peak. It works well.

    I had the previous version of the system running through a SMAD-P3 and found the sound floor to be too high to be usable.

    Now, I’m considering getting the dual mic version, and running the receiver output through a Zoom F2-BT, just to capture a wider range of noise so I can rest a little easier.

    • I’ve read elsewhere this issue of auto gain with the SMAD-P5 only affects the alpha series, maybe Sony listened (!) and fixed this issue on the A7R5 which is (I think) the most recent Alpha?

      I have an A74 and would have been interested in the D27 / SMAD-P5 system but seems not possible with this auto gain FU.

      Dan, am currently using a JuicedLink Riggy RM333 preamp with Sony D11’s on my A74. I love it because if I am only filming one speaker I can split my channels and have a -16db safety channel (ch.1 my set volume, ch.2 lower safety).

      I dislike it because it’s a massive PITA: awkward and heavy with bits hanging all over the place. If I have a second speaker, that adds another receiver to the already large pile of things hanging off the camera!

      The new Sony ECM-W3 has *exactly* the same issue with the MI shoe meaning you are forced into auto gain (!). Plus latency is around the 6-10m/s *and* it’s the 2.4ghz band. I would have risked being on that band if they could have reduced latency and allowed manual audio / gain controls.

      C’mon, Sony! So damn frustrating.


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