Mix On the Run
For those occasions when the audio has to shine and the two channels on your camera just aren’t enough, enter the DV Promix 3 by Professional Sound Corp, a sleek little audio mixer that’s built like a rock and packed with the tools necessary to produce studio quality recordings in the field.
First Things First
The DV Promix 3 is a 3-XLR-in, 2-XLR-out mixer that can handle just about any audio source including line level signals, dynamic (non-powered) microphone signals and even professional quality, phantom-powered condenser microphones. Selector switches for the line type settings are located on the left panel next to each of the three XLR input connectors. The front panel features three rotary level controls, each with a dedicated left-center-right pan switch and 3-position low-cut filter switch for wind noise reduction. Continuing left to right, there’s the LED level meters and headphone volume control followed by a monitor switch, tone generator on/off switch and an internal/external power switch. Moving around to the right panel we find the two XLR outputs, each with a line/mic selector switch and, finally, three 3.5mm outputs — one each for headphones, tape return and mic out. Around the back are two slide-out doors for the 9-volt batteries that power the unit and an external DC power input.
Blinded by the Light
The first thing you notice when you switch the unit on is the twenty super bright LEDs that make up the level meter. They all flash on at power-up and, designed to be visible in bright daylight conditions, are absolutely blinding in a dimly lit edit bay. Once the retinal burn fades, you see that the Promix 3 is ruggedly built from .040" aircraft aluminum and the rotary controls have a smooth, high-quality feel similar to those found on Mackie studio mixers. With the included protective carrying bag and shoulder strap, the whole package weighs in at a light 1lb. 11oz.
Before heading outside, We plugged in a Shure KSM-44, a large diaphragm condenser microphone known for its warm, rich voice reproduction. Listening to our favorite voice-over woman through Sennheiser HD202s plugged directly into the Promix 3’s headphone jack, everything was clean and smooth. Just like our 36-channel studio Mackie mixer.
Out Standing in the Field
To put the Promix through its paces in the great outdoors, we loaded up a couple of our studio crew members, and several Samson UHF Series One wireless kits with Sony ECM-44 lavaliere mics, and drove out to our favorite little league field where we knew we could count on blustery wind conditions. Already knowing that the mixer passed clean sound, we were interested in testing the low-cut filters’ wind-noise suppression abilities. There are 3 settings on each of the three input channels low-cut filters: 20Hz for windless days, 80Hz for low wind conditions and 150Hz for recording in high winds.
Winds were light this day — probably 10-15 mph. Our crew spread out with their mics, holding them up like kite strings to intentionally catch some wind. The 150Hz setting did a great job of knocking down the wind noise when we were moving the mic in the air and eliminated it completely when the lavalieres were clipped to shirt fronts as they would be on a real shoot. The sound remained good and we couldn’t detect any significant loss in headroom..
So, once again, the mixer did what it was supposed to do. And remember that super-bright LED level meter? Even in direct sunlight, it’s incredibly easy to read.
One feature that’s invisible until you need it is the limiter circuit built in to the Promix 3. Set at a 2.7 to 1 reduction ratio, this feature compresses output spikes to reduce over-modulation in the signal going to your camera.
Another feature we found especially convenient was the tape return jack located on the output panel. Running a cable from this output back to the camera mic input allowed for confidence monitoring through the camera’s headphone jack.
Is 3 better than 2?
As good as the Promix 3 is, what occurred to us while we were putting it through its paces in the field, is that most of its features, balanced-in/out, channel pan, low-cut filtering, etc., duplicate what’s already on most prosumer DV cameras. The difference is three channels over two. Given the Promix 3’s $495 price point, you really have to ask yourself if that one extra channel is worth it. Over the years, I’ve found that when I had a shoot where more than two channels of audio were required, it usually meant that I was going to need a lot more, not just one more. PSC knows this, we think, because they’ll be shipping the Promix 6 by the time you read this.
Who Needs It?
Having given the Promix 3 all the kudos it deserves, we’re not sure who is actually going to absolutely, positively have to have it in their field equipment arsenal. If you’re shooting with any of the many DV cameras with balance inputs you’re probably not going to be able justify spending almost five-hundred bucks for one additional channel of mixing capability. However, if (1) you’re shooting with a camera that doesn’t have balanced I/O and (2) you need to field mix three audio channels and (3) you can afford to spend $495, the Promix 3 by Professional Sound Corp. won’t let you down.
Size: 9.950" X 6.675" X 1.500" (25 cm X 17 cm X 3.8 cm)
Weight: 1 lb., 11.5 oz (0.8 kg)
Distortion: 0.08% THD @ 1kHz
Power: 2x 9V Alkaline Batteries, 4 to 6 hours typical run time or external power of 7 to 18Vdc
Inputs: XLR Female, Electronically Balanced, 3K Ohm Impedance,3-Way Switchable, Line Level, Dynamic Mic, Condenser Mic
Mic Power: 48PH to DIN Specifications, individually switch able
Low Cut Filters: 6dB/Octave, -3dB at 80Hz, -3dB at 150Hz
Channel Pans: Individually Switch able Left, Center, Right
Frequency Response: 20Hz to 20kHz +/-0.5dB
Noise Level: -128dB EIN, 150 Ohms, "A" Weighted
Tape/Direct: Headphone Monitoring, Direct (mixer) or Tape (camera)
Limiters: Outputs, approximate 2.7 to 1 ratio above threshold
Meters: LED, Peak Reading, Sun Light Readable, -20dB to +3dB
Monitor Volume: Rotary Control, Off to Maximum Volume
Outputs: XLR male, Balanced, Line (0dBv) or Mic Level (-50dBv)
Auxiliary Outputs: 3.5mm Jack, Dedicated Microphone Level Output (-50dBv)
Headphone Out: 3.5mm Jack, will drive 25 to 600 Ohm Headphones
Warranty: One year limited
- Balanced XLR microphone input/output connectors
- Phantom power switchable on each input channel
- Low Frequency roll off filters on each input to reduce wind noise
- Dedicated Microphone level output jack for use with cameras not equipped with XLRs
- 3 inputs not enough for most field work
A solid well designed mixer for those needing a third mic or line input or need to remove the mixing controls from the camera body.
Richard Gray is the Production Manager for a network affiliate TV station.
Professional Sound Corp
28085 Smyth Dr.
Valencia, CA 91355