Since the advent of small format DV and HDV cameras, those in the sound department have struggled with impedance mismatches between professional line-level mixer output and the pro/consumer line-level input of the DV family of cameras. As a result, this signal has frequently clipped at the camera inputs.
To overcome the limitations of impedance and voltage conflict, the solution has typically been to send audio at mic-level from the mixer to the camera sacrificing the benefits quality preamps and S/N ratio. But then, along comes the 3-input PSC DV ProMix 3; specifically designed for DV.
We had an opportunity to use the DV ProMix3 on several shoots recently and it proved to be an excellent choice for DV production. We were quite pleased to find calibrating the mixer output to the camera input yielded precise metering between the two devices.
Of course, one must appropriately match impedance between the two devices to ensure accurate level metering and clean sound. For example, the Panasonic DVX100A/B takes a 0dBu line-level input while the Sony PD150/175 requires a -10dBV line-level input. The DV ProMix3 offers both of these output settings (in addition to mic-level) so be sure to check the specs on your camera and adjust the mixer output impedance accordingly.
There was one thing that required attention during recording of bars and tone. Engaging tone does not defeat the inputs. It is imperative that the input levels be set to null when recording tone; otherwise, the tone could contain program content that would render the reference level unusable for calibration.
The down side to this is that you have to kill your mix in order to send tone. On the flip side, it is not too difficult to reset the mix when working with only 3 channels.
The DV ProMix3 has a great safeguard for the confines of DV audio. While not readily apparent, the mixer has automatic output limiters. These limiters are not optional; rather, they are constantly engaged. Set at a fixed threshold of +2 on the meters, the limiters compress the output signal at a 2.7:1 ratio. Compressing the output effectively protects the limited audio headroom of most DV cameras and significantly decreases the chances of distortion on the audio tracks.
Adjacent to the 2 XLR outputs are three mini jacks. These include Headphones, Tape Return and Mic Out. The Mic Out is of particular interest. Most consumer grade and many prosumer grade DV cameras offer only 3.5mm (mini-jack) inputs. In a pleasant surprise, PSC has supplied a 3.5mm output at mic-level (-50dBu) that complies with the mic-level input impedance of DV cameras. They also include a mini-to-mini cable with the mixer. Combined, these two features greatly facilitate most audio situations encountered while attempting to input audio into a DV camera.
The Tape Return jack is used for return feed from the headphone jack on any camera or alternative recording device. Use of this jack will enable the operator to confidence monitor the signal recorded to the camera via a switch on the front panel, just to the right of the headphone level pot. Matching levels between the mixer and camera is accomplished by simply adjusting the monitor amplifier levels with a small jeweler’s or “Greenie” screwdriver. The adjustment ports are located on the back of the mixer.
During our shoots, we used a Sennheiser 816, which required 48-volt phantom power. We engaged the “C” (condenser) input setting as instructed for any condenser microphone. The DV ProMix3 has a setting for phantom power which will power 48PH condenser microphones. In the event that your mic requires 12T voltage, you will need to insert an inline power converter between the mixer and mic cable. The mixer also features input settings for dynamic mics (D) and line-level (L) signal. All inputs are balanced XLR which is the standard for pro-audio.
This is definitely a hands-on mixer as you may experience dramatic level fluctuation in the metering. Since the faders attenuate the output gain rather than functioning as a continuous variable input gain control, caution is advised to protect against clipping distortion. At times, a pad might be advantageous on the input; particularly if you anticipate extreme input levels such as people shouting or otherwise loud sounds. Active attention to output levels on the meters and continuous auditioning; however, will ensure delivery of quality sound.
The DV ProMix3 is an excellent choice for DV audio. It is suitably transparent and offers many of the features necessary for professional sound. These include 48-volt phantom power, pan switches (L, C, R), HP filtering selectable at 80Hz, 150Hz or 20Hz, and confidence monitoring. The meter bridge is absolutely brilliant and easy to read in daylight.
The most valuable feature by far is the line-level output selection of 0dBu and -10dBV. At a suggested retail price of $495 (ENG style case and mini-to-mini cable included) one would be remiss to ignore the benefits of using a 3-channel mixer of this caliber in a DV production setting.