We were very enthusiastic about the release of the Sound Devices MixPre-3 and MixPre-6 in 2017. The superior sound quality of these recorders, combined with their (relatively) low cost, was reason enough for excitement, but their flexibility has turned out to be equally impressive. They can:
- Mix multiple inputs to a stereo track and output that mix to a camera or other device
- Record individual inputs to discrete tracks, or record the stereo mix, or both
- Operate as USB interfaces for getting audio in and out of a computer
- Sync with video cameras and other time-code-enabled equipment
But this flexibility has a downside: setting up and operating these machines takes a bit more effort than is required by most other audio recorders. Although we gave a MixPre6 a good shakedown in our review, and tried to give a sense of how it worked, it has taken a bit more real-world use to truly get familiar with the pros and cons of its various operating modes. We’ve also gotten many questions about how to perform some specific recording tasks with these machines. After sending out multiple emails, we decided it would be better to publicly share some MixPre techniques that we’ve found to be useful for collecting audio for a typical radio or podcast environment.
Additionally, since our initial review, more MixPre models have been added. The MixPre-10T offers eight XLR/quarter-inch inputs in addition to a stereo mini input. This model adds several new capabilities including:
- A time-code generator
- A slate mic
- Balanced line-outputs — which are very helpful if you’re feeding a live mix to a professional video camera, and/or are feeding a stereo output down long cable runs.
Even more recently, the MixPre-10M has been released, which is almost identical to the MixPre-10T, but without any time-code capabilities, or HDMI video sync, for about $300 less than the 10T. The 10M also adds a few musician-specific capabilities, such as overdubbing, a metronome, some basic effects, like reverb, and the ability to render a stereo mixdown file from a multitrack recording. Additionally, Sound Devices will soon offer a “Musician Plug-In” option for $99, which can add those music-centric features to the MixPre-3,6 and 10T.
The 10T and 10M also have a Hirose power connector, like most other Sound Devices gear uses, but which is not included on the MixPre-3 or 6. The 10-series cannot be powered via 4-AA batteries or USB, as the 3 and 6 can, but they can use the same 8-AA and V-Mount batteries as the MixPre-3 and 6 use.
But perhaps the biggest change is a seemingly small thing: the USB-A connector — which can be used to attach a keyboard or to transfer data to a computer — can also be used to create backups on a USB thumb drive. All audio files (and metadata) that are recorded to a MixPre-10’s SD memory card will automatically be copied to the USB drive in the background. This is NOT a concurrent backup for the SD card — data must first be recorded to the SD card and then copied to the USB drive. So, the USB thumb drive cannot serve as overflow for a full SD card, or as a backup for a defective SD card, and it takes some time to copy the files (the progress can be shown on the display). But even with those caveats, it’s very nice to have a second copy of your recordings in (almost) real-time.
The MixPre-3 and 6 do not currently have this ability, and there’s no indication that Sound Devices can add it via a firmware update, so for now, this feature is exclusive to the MixPre-10T and 10M.
It may take time to get used to the MixPre signal flow: all the models can work in three different modes, none of which are quite the same as the portable audio recorders most radio and podcast producers are familiar with.
The biggest difference is that the initial input gain for each input is not always controlled by the big front-panel knobs. In Advanced Mode, gain is set on a page of a menu, using the headphone volume knob as an encoder. Then the knobs on the front panel are used to control the level of each channel that will be sent to a stereo mix. That stereo mix can be recorded by the MixPre, or sent to an external device, or both. In this way, a MixPre is actually a hybrid field mixer and recorder all in the same box. If you think of the MixPre as a mixer, rather than a recorder, many of the modes make more sense. The input level to a mixer is usually set with a gain control at the top of each channel strip, and then the fader at the bottom of the strip is used to set a mix level. On a MixPre, in the front panel volume knobs are often used like faders on a mixer, sending different levels to the stereo out.
In Basic Mode, the recorder is set up like a field mixer with a stereo recorder hanging off it: you can mix multiple audio inputs, but you can only record the stereo bus, not individual tracks. Each input can be assigned to Left, Right or Center, not to any intermediate positions. This is pretty straightforward if you’re doing a one or two mic recording. With one mic, simply assign it to the center. In Basic Mode, the input gain is set by the gain knob on the front panel, so watch your meters and set your gain with the front panel knob.
If you’re using two mics, and you’d like to keep the signals separate so you can mix them more accurately later, assign one channel left and the other right — you’ll end up with a stereo recording with each mic panned to its own channel. You could assign them both the the center, but you’ll have to live with the mix balance that you got live.
You can also mix multiple inputs live to stereo, how many depends on which MixPre you’re using. Remember, in Basic Mode, you’re only recording the stereo mix, so you have to get the balance right as you’re recording. The limiters are on by default, but despite the very good analog limiters, it’s possible to set the gain too high, which triggers the limiters and can make things sound weird, even if they’re not distorting. You can be a little conservative with a MixPre, and set levels a little on the low side. These recorders are SO quiet that even if you record a low signal, you can boost it later in your editor, and there will be no noticeable system noise from the recorder.
Switch the MixPre to Advanced Mode, and the initial input gains are now set in a set-up page in a menu; the value is set by twisting the headphone level knob, or by incrementing or decrementing with arrows on the touch screen. Just press in on any track’s knob, and the Set-Up page will display. After the initial gain is set for each channel on that page, the front panel knobs determine how much signal from each channel gets sent to the stereo bus. In Advanced Mode you can record each input to its own track (what they call ISOs — for isolated tracks) AND the stereo output too. Or you could choose to not record the stereo mix, and just record the ISO tracks. The front panel volume knobs determine what is sent out the main line outs, and what gets recorded as the stereo bus, if you choose to record that — but the front panel knobs do NOT affect the levels of the ISO tracks. Those individual track levels are set in the menu, with the headphone encoder. So you need to get your levels set twice: once with the gain setting, and again with the front panel knob. It’s safest to be a little conservative when setting the gain in the menu – it’s OK if it’s a little lower than you’re used-to. As mentioned above, the MixPre’s electronics add virtually no noise to the recording.
This is pretty great, actually, because you can track multiple inputs, and just send some of them to a camera, or to the stereo mix. But, for achieving a more precise mix later, you still have all the individual inputs recorded without their having been affected by any knob twiddling.
By default, the headphones are set to monitor the main Left-Right stereo output, but that can be changed in the headphone setup menu. So keep in mind that if you choose to record only the ISO tracks, and turn off the sends to the Left-Right mix, you may initially hear nothing in the headphones, and you will have to go into the headphone set-up menu and choose which inputs you DO want to monitor.
In advanced mode, you can use 44.1, 48, 96 kHz, or 192 kHz sample rates (96kHz is the limit on the MixPre-3 — you can go as high as 192 kHz on the 6 and 10). You can turn limiters on and off for individual tracks, and you have several more options than are available in Basic Mode.
Where it gets REALLY interesting is Custom Mode. We largely ignored that mode in our initial review, thinking that this mode was only for very specific nudgey situations, but it’s actually more useful than that. One of the customizations you can make is for the front-panel knobs to control the input gain, while still recording each ISO input to its own track. So, if you’re primarily interested in the ISO tracks, not a live stereo mix, and your sonic environment is variable enough that you’d want to be able to ride the input gain settings quickly, you CAN make those front-panel knobs work like the input gain on a basic recorder.
It entails putting the recorder into Custom Mode, then choosing Custom Set-Up and setting both the Channel and Record panes to Advanced. With those settings enabled, the MixPre will operate more like most recorders, with the knobs on the front controlling both how much signal is getting recorded to each ISO channel and how much is being sent to a stereo mix. You can choose to record that stereo mix, or not, but it’s often handy to mix the ISOs to the main Left-Right mix, just for ease of monitoring. Here’s a short video tutorial from Sound Devices showing this set-up.
Details, Details, Details
Obviously, there’s a lot more to think about than with most field recorders! But that’s what is ultimately one of the impressive things that Sound Devices achieved with these models: they can be simple recorders, or really complicated ones, or something in between.
For most recordings, the quick and easy Basic Mode is totally fine, and you don’t have to think about all those other capabilities. The one big problem is that it only runs at 48 Khz in this mode, which I’m sure is indicative of what Sound Devices thinks the largest market for these is — semi-pro video shooters. Many radio people will just want to stay in the simple Basic mode, but will have to keep in mind that they’ll be recording at 48 kHz, and may need to sample-rate-convert their recordings later. I’ve submitted a feature request asking to allow recording in Basic Mode at 44.1 kHz, but I’m not sure whether they’ll implement that . . .
I personally tend to use Advanced Mode — because I want to record ISO tracks for editing and mixing later. I don’t care so much about the stereo mix; I’m rarely feeding audio to a camera, or have a need to get a mix right in real time. But I often record the Left-Right stereo mix anyway, partly because it makes getting a headphone mix a little quicker, and who knows, maybe I’ll get the mix right on-the-fly. I also use Advanced Mode so I can record at 44.1 kHz, which is the default sample rate for all of my productions. Advanced Mode isn’t really much harder to use, it just presents lots more options, so there are a few more screens to scroll through to make sure that you’re set up exactly the way you want.
But I’ve more recently begun using the Custom Mode setup described above. This gives quick access to input gain via the front panel knobs, while recording ISO tracks. I was running into too many circumstances where the sound levels were so varied that I needed to ride the input gains. One of the major appeals of these new MixPres is that the mic preamps are SO quiet that you can record at a lower level than you might be comfortable with when using other recorders. When the recording is boosted up later, when you’re mixing, you won’t get any unwanted hiss or other noise created by the recorder. That said, recording too low can add some labor later, in the editing and mixing process. So it’s still good practice to still set your input gains so that you see healthy levels on the input meters, perhaps peaking between -15 and -12 dBFS. And therefore, it is handy to have quick access to the input gain via a front-panel knob, if things suddenly get very loud, or quiet.
If you happen to have your levels set too high, the MixPre limiters are transparent enough that they can handle the occasional spike, without creating distortion. They’re high-quality analog limiters that tame the levels before the signal hits the digital converters, unlike the limiters on some cheaper recorders. But like any limiters, they’ll sound bad if you push them TOO far. They do an admirable job controlling stray unexpected peaks, but you still need to set your levels carefully, so having quick access to the input gain via the front-panel knobs is very helpful.
If you’ve found a Custom Mode set-up that works for you, be sure to save it as a Preset — that way you can call that configuration back up without having to go through multiple menu pages to adjust everything again. This is true when working in other modes too: if you find an array of settings that seem to work, or are at least good starting points, save them as a preset. You can store four presets internally on the MixPre. You can save as many as you like onto an SD card, but remember that it’s good practice to re-format the SD card with some regularity, and that will erase everything on that card, so be sure to make copies of those presets if you choose to store any on the SD card.
If you’re using a MixPre primarily for its size and sound quality, and are usually using only one mic, there are two ways to go. The quick and simple thing is to use Basic Mode, set that one input channel to center, and record the resulting 48 kHz stereo file.
But if you’d prefer to record only a mono file (to save space on the SD card) and/or you want to record at 44.1 kHz (or 96 kHz) you’ll need to use Advanced or Custom mode. You can turn off the function to record to the Left-Right mix, so you’ll only record a single mono track. But if you switch off the feed to the Left-Right mix, you’ll lose audio in the default headphone configurations. You’ll then also need to set up a custom headphone monitoring preset.
Tap the headphone icon on the home screen and a few more taps will take you to a screen where you can define a new headphone preset, choosing the specific signal flow that you’d like to have in your headphones. You can create a Preset that monitors Input 1 in both ears (as shown), or one that monitors channel 1 in the left ear and channel 2 in the right ear, if you’re recording in stereo and want to monitor the ISOs. You can also set the headphones to follow the volume set on the front panel knobs (Postfade) or to ignore where you set those knobs (Prefade). Name your custom presets something memorable and you’ll be quickly set for all circumstances. (This image is from the MixPre-10T — the MixPre-3 and MixPre-6 will offer a simpler display with fewer options.)
Sound Devices has been regularly releasing firmware upgrades that sometimes add new features, or streamline the menu system, or repair bugs. So they may add new capabilities in the future.
Ultimately, the bottom line is that these MixPres sound great and only take a LITTLE getting used to. All recorders have a learning curve, and although the many pages of menus, and multiple operational modes may be initially confusing, they’re actually fairly easy to navigate with a little practice!