Making a sound judgement

Dubai-based sound recordist Simon Charles recently tested the new Sound Devices MixPre-3 and MixPre-6. He gives us his verdict

As a long-time user of Sound Devices equipment, I’m always excited when new audio products are introduced. In April, Sound Devices announced an update to the MixPre series, the MixPre-3 and the MixPre-6.

While the MixPre has been around for a few years, this is a major redesign and a new way forward for this series. As well as being mixers, they now have built-in recorders and can be used as a USB audio interface.

After waiting a few weeks for them to become available, NMK Electronics let me know it had received one of each model. I picked up the first MixPre-6 in the region the next day.

I knew from the reviews I read that this was a small device, but until you have it in your hands you don’t realise how small it actually is. While compact, it packs in an enormous amount of functionality.

Both models are fundamentally the same and are built around Sound Devices’ new Kashmir microphone preamps. These preamps have a very low noise floor, analogue limiters and new 32-bit analogue to digital converters, to ensure the highest quality audio. The key difference between the models is the number of channels. The MixPre-3 has three XLR/TRS inputs and can record five tracks (3x ISO + LR); the MixPre-6 has four XLR/TRS inputs, an unbalanced 3.5mm input for channels 5 & 6 and can record eight tracks (6x ISO + LR). The MixPre-6 offers an extended sample rate up to 192kHz, compared to the MixPre-3’s maximum of 96kHz.

Both record to an SD card, but sadly there is only one slot for a card, which means there is no internal back-up. This is one of the few things about the MixPre that I’m not excited about.

While this is unlikely to be an issue for most users, SD cards do fail at times, so it would have been a nice addition.

The small capacitive touch screen is very usable, and the layout makes it very simple to change the functions and set up the device. I thought it was going to be hard to use when I first saw it, but the user interface (UI) is very good. I wouldn’t want to use the small on-screen keyboard to input anything more than a few characters, but with a USB socket for a physical keyboard or using the Wingman app, this is not needed for the most part. The only time you have to use the on-screen keyboard is to input the project name.

You have the option to have the units running in basic or advanced modes. Basic mode is a simpler interface with fewer options and is more suitable for recording interviews, podcasts or situations where you just need a couple of channels and basic monitoring. The Advanced mode

enables multi-channel recording along with options for metering, routing, timecode, stereo and mid-side (M-S), as well as a plethora of other settings.

I primarily bought this for my Ambisonics recording setup for use with my Sennheiser AMBEO microphone. For those who don’t know, Ambisonics is a surround sound recording method which uses a single microphone containing four capsules to record sound from all directions. The resulting recordings are primarily used for 360-degree and VR videos, as well as computer games. There aren’t any specific settings on the MixPre-6 for this set-up, but it is a very capable device and will work very well for this purpose. As well as Ambisonics recording, I will also be using this for general sound effects recording (mono, stereo and M-S), and also for a lightweight production recording bag for when I don’t need so many channels or need to be more stealthy.

These are fantastic recorders for sound effects capture. With the small size and light weight they can be carried easily and take up very little space, and with stereo linking options and settings for M-S recording and monitoring, they will fit into the workflow of many field recordists. As for the production recording set-up, these recorders certainly do not have the functionality of more expensive recorders but for basic use, perhaps a boom and a couple of radio mics, they are excellent.

There are various powering options and both models use the same size battery sled. Sound Devices includes a battery sled that takes four AA batteries and also offers an eight-battery option as well as a Sony L-series battery option. One option unavailable from Sound Devices is an external powering option for professional power supplies – most sound recordists use large batteries with a power distribution system outputting to HiRose connectors.

Thankfully, these are being developed by third parties. You can power the units using the USB-C connector, but for professional use in a bag, I would not recommend this, as it’s not a heavy-duty connection. To power the mixer fully using standard USB, you need to use the splitter cable included in the package. This uses two standard USB sockets to the USB-C connector on the mixer. This gives you the power to use all four channels with phantom power. If you use just one USB, you can use two channels with phantom power and line level on the other channels. USB-C gives you full power for all channels.

For videographers who purchase this to add high-quality sound to their videos, there are a few functions that make the workflow very easy. There is a tripod connector on the top which retracts into the device when not in use but pops up when you use the included Allen key to screw the MixPre into the base of a camera. On the bottom, there is a tripod socket to attach to a tripod.

You can also plug a micro HDMI cable from the camera into the MixPre. This will start and stop the recorder at the same time as the camera, and you can use the stereo output from the MixPre to send a feed into the camera. This will make syncing sound easy in post production.

While the MixPres don’t have a built-in timecode generator like all the higher-end recorders from Sound Devices, you can input Timecode by using the AUX and changing the function to Timecode in the menu. You can also bring a timecode into the MixPre via micro HDMI. If there is no timecode input detected, you can set the timecode function to Time of Day or Off, which starts all recordings at zero.

As there is no timecode clock, there is no option to select the frame rate of the recordings. The default setting seems to be 30fps. However, if you have a timecode input

from the micro HDMI or AUX, the correct frame rate will be automatically set.

The Wingman app for IOS and Android works out of the box on the MixPres; the higher-end six-series recorders require an additional dongle, so you can download the application and use with the MixPre immediately.

I would highly recommend using the app, as it gives you a larger display and makes inputting notes, changing track and scene names, and arming and disarming tracks much easier. You can’t change levels or monitor through the application, which is a shame. Depending on which device you are using, you should get approximately 10m of range. For VR and 360 applications this is very useful, as you can leave the recorder with the mic and hide out of view of the camera.

As well as being excellent standalone recorders and mixers, the MixPres are also USB audio interfaces with the ability to simultaneously record internally as well as stream multiple channels via USB to DAWs (digital audio workstations) such as ProTools, Nuendo, Logic X and many others. I have tested with ProTools and WaveLab, and the experience was great; the sound quality is fantastic and the unit’s headphone amplifier is a definite upgrade from the headphone socket on laptops.

One thing I found was that the headphone output of my MacBook Pro will only play sounds recorded at 48kHz or below. I recorded at a higher sample rate and it would not play if the headphones were plugged in, so using the MixPre as an interface means I can now use headphones to listen to sounds recorded up to 192kHz.

In conclusion, both versions of the MixPre are excellent and offer an incredible amount of functionality in a small and lightweight package. I would personally recommend the MixPre-6, as you get the extra channels and higher sample rate. These are also very reasonably priced for what you are getting: the MixPre-3 retails for $649 and the MixPre-6 is $899.

Simon Charles is a Dubai-based sound recordist.