Sound Devices MixPre-3 II offers 32-bit float recording, -130dB noise floor and more

Sound Devices’ MixPre-3 II is a 32-bits floating-point 192KHz capable mixer-recorder that uses Sound Devices’ perfectly silent Kashmir microphone pre-amplifiers. The unit has faster, more advanced hardware, supports internal LTC Timecode generation and output and has adjustable limiters.

When the MixPre range of products was released, several years back, I was among the first to be allowed a shot at the small field mixer/recorders and I was immediately smitten with the quality and character of sound they are able to produce. Like the original MixPre-3, MixPre-6, and MixPre-10T recorders, the MixPre II Series features discrete, custom-designed class-A Kashmir microphone preamps with an exceptionally low noise floor of -130 dBV.

I tested the MixPre-3 II both indoors and outdoors with several microphones, including an sE Electronics V7 dynamic mic with and without the sE Electronics Dynamite preamp, a Deity S-Mic 2 and S-Mic 2S and a Sennheiser MKH 416. All of them were hooked up with a Vovox Sonorus Direct S microphone cable or – when interference could be a problem – a Mogami Gold Studio cable.

The new version of the MixPre range has several interesting new features and improvements. The first and most obvious, of course, is the ability to record 32-bit floating-point audio files. The 32-bit float recording is based on a patented ultra-wide dynamic range A-to-D conversion.

Because I’m not all that familiar with 32-bit float recording, I checked the next two paragraphs with a chair of AES and he confirmed my findings.

32-bit floating-point files have a huge dynamic range. A 24-bit recording “only” covers a range of 144dB. The question is whether you need that kind of brute force. Well, you do if you want to have the much higher SNR (Signal-to-Noise Ratio) compared to a 16-bit integer system and the headroom to spare for when you’re going to apply filters or EQ the results.

Recording in 32-bit floating-point has important benefits for when you record a pin dropping — which is a very low signal — and suddenly a jet flies over low. Even when that doesn’t occur, but you’ve inadvertently set a totally incorrect and very high gain setting that shows much clipping, you can still save the day when it’s been captured in 32-bit float by reducing the gain in post. The clipping will disappear and the sound distortion gone. With 24-bit files, the distortion remains, only less loud.

There is always a price to pay and that is that 32-bit files are 33% bigger than 24-bit files, but that’s nothing to worry about with today’s memory card prices and the added peace of mind and quality assurance you get from a 32-bit recording.

In other areas, the new models have improvements too. All models in the MixPre II Series now include a full-featured internal timecode generator and are accurate to better than 0.2 ppm (0.5 frames per 24 hours) and when the unit is off, the MixPre II will maintain accurate timecode for up to four hours, even without batteries or external power.

Even the MixPre-3 II, the smallest model in the range, and the one I was testing also includes adjustable limiters that let you set a release time of 50 to 10,000ms in 10ms increments and a threshold of -2 to -12dBFS in 1dB steps. Furthermore, the pre-roll buffer got increased to 10 seconds, although the exact buffer depends on your sampling setting; it’s two seconds at 192KHz.

The unit can also be controlled remotely with an iOS app, called Wingman, but a wired USB keyboard can be used as a controller as well. Even a MIDI USB controller can.

Recording is done to an SD-card or a USB thumb drive. When the latter is used, the unit automatically initiates a copy operation as soon as the stick or drive is connected.

Finally, the MixPre II series can be used as a USB audio interface as well. It can be set up for monitoring with zero-latency even. I tried this with Logic Pro X and it works like a charm.

Of course, nothing is perfect and that also goes for the MixPre II series. To begin with, the touch screen — as with the first generation — is a bit too small for my fingers. I regularly hit an icon that took me right back at the start screen instead of taking me to a feature that I wanted to change.

Secondly, the On/Off switch sits in a bit of an awkward location, certainly when a USB-C cable is inserted. And lastly, on my test unit at least, the XLR locks are difficult to reach — I had to use my fingernails to push them far enough down to unlock the cable.

Other than that, you really can’t go wrong with the MixPre-3 II. It’s small, lightweight, delivers outstanding quality and a lovely sound, no noise, extremely useful features and a price that is reasonable for even a somewhat successful Youtuber. It is a device that is suitable for professional sound people working as freelances and at radio stations. I assume many sound recordists in the TV and filmmaking industries will need either the more capable MixPre-10T II or the even pricier and highest-end Scorpio, but going by the sound quality alone I don’t believe for a minute that it is necessary.