Sound Devices MixPre-3 II Multichannel Recorder Review

[DLS79]

Did you disable the limiters? I ask because these things have a bootload of options, and it can be confusing.

yep to the point that I've seen several professionals offer what's basically amounts to a how do i use this thing class.
for example. https://school.learnlightandsound.com/p/sound-devices-mixpre

might want to check the firmware is up to date.

Downloads - Sound Devices

www.sounddevices.com

And have a good look through the users manual.
https://cdn.sounddevices.com/wp-content/uploads/2023/10/MixPre-II-v9.00.pdf (75 pages actually seems short for sound devices)

I don't think headphone performance is important for this product, but low noise mic preamps, ADC and battery life are important, as is warranty support and durability.

Yea, generally speaking the headphones even professionals use are pretty cheap. I know people who are just listening to see if levels are in the ballpark and no weird issues are going on.

 

[Stokdoof]

Mixed feelings about this one

 

[BadAudioAdvice]

might want to check the firmware is up to date.

I sent it to Amir with firmware v8.0.

V9 came out while it was in the review queue. The new version doesn't seem to have any features or updates that would impact the suite of measurements.

 

[BadAudioAdvice]

but low noise mic preamps, ADC and battery life are important, as is warranty support and durability.

The unit that Amir reviewed is mine, and I've had it for 4 years (I just checked the receipt).

It has been very durable. While it is disappointing to see that it doesn't measure well, it sees constant use, and has been a rock-solid useful tool.

I use it to do a mix-minus to monitor a microphone via XLR and hear computer audio (via USB), and then feed the mic into an ATEM via the stereo out. A very good feature is that it allows me to adjust the audio delay with ms precision, to nicely sync up speech and video capture for videoconferencing.

 

[617]

The unit that Amir reviewed is mine, and I've had it for 4 years (I just checked the receipt).

It has been very durable. While it is disappointing to see that it doesn't measure well, it sees constant use, and has been a rock-solid useful tool.

I use it to do a mix-minus to monitor a microphone via XLR and hear computer audio (via USB), and then feed the mic into an ATEM via the stereo out. A very good feature is that it allows me to adjust the audio delay with ms precision, to nicely sync up speech and video capture for videoconferencing.

Noise in the real world almost always dwarfs electronics; one big exception of course is ambient recording, for which sound devices has always been favored.

I had one of those tascam units and although its noise performance was exceptional, if I was a professional I'd use sound devices 100%.

 

[SuicideSquid]

So - and I'm not baiting - there *are* differences in USB cables? Just not in data transfer, but maybe cable construction in getting the power supplied properly?

Yes. There are cheap cables that carry data but minimal power, don't support USB 3.2 transfer speeds or fast charging, etc.

But there's no difference in "sound quality". They either work or they don't. A cable certified for USB 3.2 data and fast charging will work just as well as any other cable certified for USB 3.2 and fast charging.

 

[amirm]

Folks, the dashboard with headphone out fully matches thd+n that company specifies so there is nothing wrong.

As to sharing settings, every test subsection required different settings so I can't share anything other than mic test.

 

[Ifrit]

Hmm. I have their USBPre2 and find the headphone output quite noisy, at least with the Sony MDR-7506. Probably should send that thing to Amir.

 

[dtaylo1066]

Meh! Need a panther with a Babyface on it.

 

[restorer-john]

Just not in data transfer, but maybe cable construction in getting the power supplied properly?

Absolutely. If your device pulls enough current to modulate or cause significant voltage drop in the USB cables, you can have problems. That and length/timing/shielding issues.

 

[AnalogSteph]

It is very strange to have a lower inverted EIN at max gain than at lower gain.

Indeed. This should never-ever be happening, and I don't even see how it could. Maybe the spectrum will give some clues, or there is some sort of math fail involved (such is incorrect calculation of effective gain).

 

[amirm]

It is very strange to have a lower inverted EIN at max gain than at lower gain.

As I explained, this unit has very strange behavior when it comes to gain settings. It for example keeps going up in gain as you turn the knob even though the output does not change! I did my best to stop when it did this and computed the results.

 

[BadAudioAdvice]

It for example keeps going up in gain as you turn the knob even though the output does not change!

I have a hunch - the output may be taken direct from the channel (with the channel gain set on the channel screen using the rotating control on the side of the unit), rather than the mix gain set using the front channel knob.

 

[SMJ]

I'm guessing there are some menu setting errors somewhere, especially if you're not getting the output levels you would expect. The odd headphone levels and the artefacts in the measurements suggest limiters operating somewhere too. There are analogue limiters on input, output and headphone limiters are in the digital domain accessible from the Advanced menu. Also output routing can be set up to be pre or post fader which will change things too. Worth mentioning that being in Advanced mode introduces a two stage gain path and you have to visit the channel screen to adjust the input gain with the control knobs also adjusting the output bus level.

The limiter On/Off switch is global so ALL limiters are switched together the threshold default value is -6 dBFS. The highest threshold setting is -2 dBFS which may explain some oddities if the limiter is still on.

I've used the MixPre 6 and the earlier 744T & 788T for location recording and all were utterly reliable, but the MixPre6 was the hardest to set up before use but it makes a great recorder for partnering an old AMS ST250 Surround mic for choral and organ or with a Neumann RSM191 for wildlife Fx.

I think the USB C issues can normally be resolved by powering with AA batteries and USB C simultaneously and choosing battery power when the low power USB C warning activates.

 

[Rja4000]

As I explained, this unit has very strange behavior when it comes to gain settings. It for example keeps going up in gain as you turn the knob even though the output does not change! I did my best to stop when it did this and computed the results.

Could you run some kind of level sweep ?
To check if some limiter is at play.

 

[amirm]

I have shipped it back already.

 

[Rja4000]

This device is, for sure, not the easiest to test.

 

[Bergante]

As I said I own a first generation MixPre-3. I remember that the manual is not very detailed.

Woth the release of the second generation they published a helpful block diagram. Still, with the block diagram beijg software defined, it’s worth checking it with new releases.

To make it even more confusing I found a routing bug or two back in the 2.0 or so releases.

 

[Rja4000]

Woth the release of the second generation they published a helpful block diagram

Where is it ?
I looked through the user manual, both PDF and on line but couldn't find any.

 

[Bergante]

Here, in the downloads section. I remember, before the release of the second generation units I had drawn a crude block diagram (none was available I think) and I was thinking about drawing a nice one and publishing it. They released these with the second generation (or maybe I hadn't noticed before!)

MixPre-3 II Block Diagram - Sound Devices

www.sounddevices.com

MixPre-6 II Block Diagram - Sound Devices

www.sounddevices.com

MixPre-10 II Block Diagram - Sound Devices

www.sounddevices.com

It's a bit crazy to pack such a functionality with a tiny screen!

And if you look closely at it you will notice, @amirm that indeed it has "limiters at all gain stages". So, not only a limiter in the analog inputs, but another one after the mixer fader *and* yet another assigned to the stereo out.

The safest way to make mesurements is to put the unit in advanced mode, disable the limiters (it's a global setting) and to configure the line/headphone outputs to a couple of input channels (say 1, 2) are assigned pre-fader. Input 1 to the left output/HP, input 2 to the right output/HP for example.

If you do that the faders won't affect the signal levels, so they won't disturb the gain staging.

If you ever borrow one MixPre (or one of the more advanced 8 series units) I would strongly advise to do a factory reset. There are quite a lot of not so obvious routing settings.