Before I get too deep into my review, thanks to Sound Devices for loaning me this MixPre-6! I didn’t pay for this, but I also don’t get to keep it. However, I like the MixPre-6 so much that if my disappointments were resolved—which is a real possibility—I would immediately buy my own MixPre-6.
The MixPre-3 and MixPre-6 are very similar with their core features. They both contain high-quality preamps, both record to multiple isolated tracks, both interface with computers and mobile devices as a multitrack input and output, and both the MixPre-3 and MixPre-6 have great mixing capabilities.
For the rest of my review, I’ll focus on the MixPre-6, but most of the information applies to the MixPre-3 as well, with the main difference being fewer inputs and outputs on the MixPre-3.
The MixPre-6 offers 4 combo locking XLR/TRS inputs, two on each side. The Kashmir preamps offer up to 96 dB of clean gain. That’s enough to support a directly connected dynamic studio microphones and record with little to no hiss.
On the right side, there’s also a 3.5 mm stereo (TRS) auxiliary input that makes it easy to bring in sound effects or a podcast guest or cohost from a consumer-level device, such as a PC, smartphone, or tablet.
For outputs, the MixPre-6 offers a stereo headphone out with its own volume control, and on the left side, a 3.5 mm stereo (TRS) line out with a really cool feature I’ll tell you about in a bit.
MixPre-3/6 is more versatile than Zoom H6 and others
Thus far, the MixPre-6 may not seem all that different from devices like the Zoom H6. But here are the amazing features that raise the MixPre-6 above other recorders, and mean it could replace several pieces of audio gear in your podcast studio.
Noticeably first is the higher build quality of the MixPre-6. It has a durable metal shell and corner grips that would protect the MixPre-6 from an impact.
The MixPre-6 can connect with computers and mobile devices as a multitrack audio interface via USB. While other devices may offer similar functionality, the MixPre-6 can interface while also functioning as a standalone recorder. Compare that to the Zoom H6, which can be only a recorder or an interface, but not be both simultaneously.
Multitrack USB interface
The USB interface itself is also quite amazing. When connected to your PC, the MixPre-6 can offer up to 4 audio outputs from your PC to the MixPre-6 and up to 8 audio inputs from the MixPre-6 to your PC. In full 8-track mode, input tracks 1 and 2 contain a stereo mix of everything going into the MixPre-6, and then tracks 3–8 are isolated tracks from the MixPre-6’s own input channels 1–6.
This is extremely handy for podcasting because it means you could connect everything to the MixPre-6 and use the stereo mix channels for live-streaming through your computer or mobile device.
The four USB output tracks can be assigned to any of the 6 channels on the MixPre-6, and you can even monitor all the inputs (yes, even the USB) through headphones connected to the MixPre-6 and see the isolated input levels for all 8 tracks (6 isos and 2 mix) on the touchscreen with a quick tap.
With a little bit of tweaking through software (such as Rogue Amoeba's Loopback on macOS or VoiceMeeter on Windows), you could achieve multiple mix-minus setups for VoIP calls all through USB!
Versatile analog audio output
The stereo line out is also impressive because it doesn’t have to be a simple mix of all channels. You can choose exactly what channels will route to the left or right tracks of the stereo line out.
For example, if I connect four microphones and a 3.5 mm auxiliary input from a smartphone for a Skype caller, I can set the stereo line out to include only those four microphones but omit the auxiliary input! I can even mix the left and right tracks separately, such as putting mics 1 and 2 on the left, and then mics 3 and 4 on the right!
In other words, the stereo line out is similar to the customizable auxiliary outputs of a mixer. This provides enough versatility that you could probably completely replace a mixer with the MixPre-6!
Another way the MixPre-6 stands out is in its analog limiter, which prevents audio peaks from clipping and distorting. Many other devices offer built-in digital limiters, but because of their position in the audio chain, digital limiters are often quite worthless because they still allow distortions. The MixPre-6’s analog limiter, however, was so fast and distortion-free that I could set the gain way too high for recording, but still never clip the audio.
Menus and settings
The MixPre-6 offers basic controls and text entry via USB keyboard or with the Wingman app on a Bluetooth-connected iOS or Android device. You can also use the app to monitor the track levels. The small touchscreen is surprisingly easy to use for navigating menus and adjusting settings. You can even switch the interface mode of the MixPre-6 between Basic, Advanced, or make you own mix of both in the Custom mode.
And if you have settings you use in different scenarios, you can save them to named presets for easy recall.
For powering the MixPre-6, you can use 4 AA batteries with the included adapter; or power via USB through your computer, a hub, a portable battery, or an AC power adapter; or you can purchase additional accessories to use Sony NP-style batteries or adapter for 8 AA batteries.
The MixPre-6 records all channels as a polywave file (that is a single wave file with more than two tracks) and will split them into seamless 4 GB files. These are written to an SD, SDHC, or SDXC card. The position of the SD card slot behind the battery pack is a little strange and inconvenient, but considering that you would probably have this connected to your computer via USB anyway, data transfer is fast and supports USB-C.
Big value in a small form
It’s amazing that Sound Devices has packed so many high-quality features into such a small form. The MixPre-6 is small enough to be portable.
For videographers, the MixPre-6 has the necessary screw holes for mounting between a camera and tripod, and it supports HDMI timecode.
Before I tell you what I don’t like about the MixPre-6, you’re probably wondering about the price.
As of July 2017, the MixPre-6 retails for $899 while the MixPre-3 retails for $649. Those prices may seem high to you as a podcaster, but they’re a bargain for experienced audio professionals, especially with the MixPre-6 having such high build quality. Even for podcasters, it’s a great value, because matching these features would require a 6-channel mixer, a multitrack digital audio recorder, a multitrack USB interface, and a multichannel analog limiter. Add all those things together and you would pay about the same price as the MixPre-6, but you would still be missing some features and the physical footprint of all that gear would be much greater than the small and portable MixPre-6.
Seriously, your podcast studio could be as simple as the MixPre-6, your microphones, and cables to connect. That’s a whole lot better than several pieces of large audio equipment.
All these features in the MixPre-6 make it almost perfect, and I am so close to buying my own to replace my mixer, limiter, recorder, and interface. But in my opinion, there are only three things lacking, and these could even be resolved in a firmware update.
My first disappointment is the lack of a marker. I love that the Zoom recorders can place a mark inside my wave audio files while I’m recording. These show up in a professional digital audio workstation (DAW), such as Adobe Audition, but not in Audacity. I use these marks to indicate known edit points in my recordings, and that significantly speeds up the editing workflow.
On Zoom recorders, placing a mark while recording is a simple press on the record or scroll button, depending on the model. On the MixPre-6, a firmware update could offer this feature mapped to either the record or customizable star buttons.
I’ve come to rely on this feature so much that the MixPre-6’s lack of it is actually a deal-breaker for me.
My second disappointment is that the 8 USB input tracks (that is, input to the PC from the MixPre-6) can’t be custom-mixed like the stereo line out, which lets you assign any selection of channels to the left and right tracks. This could probably be implemented with a fairly simple firmware update. Such custom-mixing would make a digital mix-minus easier, but still not to its greatest potential.
And that leads to my third disappointment: the complication in routing audio to the multiple USB channels. Many recording, streaming, and VoIP apps will let you choose the audio input and output devices for that program, or you can set these at the system level. But most apps and operating systems won’t let you choose the channels on those input or output audio devices. DAWs like Adobe Audition or Audacity will let you do that for recording, but voice apps like Skype, Hangouts, and such won’t let you set a specific channel as the input or output for that app. Thus, input tracks 3–8 are useless for anything other than multitrack recording on a PC because most apps will pull only the first 1 or 2 channels from an audio input device. Skype, for example, gets audio from only channel 1 (the left side of stereo), so even if you could make USB input 3 a custom mix-minus, there isn’t a way for Skype to use it.
Sometimes, you can do this with extra software, such as Loopback or VoiceMeeter, but it’s still a complicated or almost impossible process in some setups.
I think the ideal solution would be to make the input and output channels appear as independent input and output devices instead of a single multitrack device. For example, connecting the MixPre-6 could appear as up to 4 separate audio output devices (mono or stereo) and up to 8 separate input audio devices (again, mono or stereo). This would allow you to target any input or output channel by selecting its corresponding audio device (such as “MixPre-6 mono channel 1”) within your programs.
Fully resolving this would probably require both a firmware update and special drivers, or maybe it would be easier to make a MixPre companion app for Windows and macOS that would create virtual audio devices for custom routing from apps. For example, I could set USB outputs 1 and 2 to be combined as a stereo output device, while outputs 3 and 4 would be separate mono output devices.
If all three of my disappointments could be resolved as I think would be possible and I hope Sound Devices will do, then I would consider the MixPre-6 to be the perfect modern mixing, recording, and interfacing device for podcasters. If that happens, then shut up and take my money!
Another potential annoyance is the position of the small power switch. Being next to the USB-C port, it can be a little difficult to reach the switch when a USB-C cable is connected.
I’m excited about the amazing abilities Sound Devices has packed into this small MixPre-6, and I hope to someday replace a bunch of my own audio gear with the MixPre-6 and then have greater recording and interfacing features than I have even now, and all in an extremely portable package for about the same price.