Field Mixing with the PSC AlphaMix

Shortly after the PSC AlphaMix became available on the market I had a chance to use one in an ENG application.

Quite coincidentally, I had recently demonstrated the unit in my Location Sound Production course at the University of New Orleans. The students and I had enjoyed an opportunity to do a side-by-side comparison of a wide range of mixers of varying price including the PSC AlphaMix, PSC M8, Shure FP-33, SQN-2S, and the Cooper CS-104.

The AlphaMix had shown itself to be much quieter than the others in this price range. With features such as variable input gain, support for 2 simultaneous cameras, an NP-1 battery compartment, AUX power supplies for wireless receivers and a good price point, it was head and shoulders above the competition.

Based upon this comparison I recommended the AlphaMix to one of my colleagues. He is a New Orleans based DP who does a lot of news magazine type programs like 20/20, GMA, Martha Stewart Living, etc. To meet networks specs, he needed to buy a 4-channel mixer but didn’t want to sell the farm. The AlphaMix offered several features he appreciated.

NP-1 support….and AA
The AlphaMix is powered from an internally housed NP-1. Many ENG/EFP professionals use the NP-1 to externally power other mixers. (And of course, many camera operators use NP-1 batteries to power their cameras as well.)

The difference with the AlphaMix from other mixers is that the battery inserts directly into the unit, rather than being carried outside in a special adapter. (See lower right, in the image below.) If no microphones are being powered, the AlphaMix consumes only 210mA of current which translates to a 10 – 15 hour battery life. In a pinch, you can also use 10x AA Alkaline batteries, which supply 4 – 7 hours of operating time.

Remote control for boom audio
Another milestone for PSC is featured just above input Channel 1, a remote control of the boom audio level. This affects Channel 1 only and offers the operator the capability of riding the level of the boom input via a remote that can be mounted on the boom pole. This feature is very useful when attempting to mix and boom simultaneously. Although not recommended, this scenario is a common occurrence with ENG. An LED on the front panel indicates that the remote control is engaged which overrides the channel gain trim pot while in use.

Microphone input and phantom power
Microphone powering switches are also located below the XLR connectors and provide standard Dynamic (D), Tornader 12-volt (T-series/AB) and 48-volt phantom powering. (See image above.) When using line level, dynamic mics or wireless receivers, the Dynamic (DYN) setting should be selected as no voltage is applied.

Input
The AlphaMix offers individual balanced outputs for each of the four channels. This feature, rare in ENG mixers, is extremely useful for isolating the output of each channel. Multiple microphone input mixing to mono or stereo output typically raises the noise floor to unacceptable levels.

In addition, mixing of signals renders absolute isolation of each signal in post-production impossible. PSC has overcome this obstacle by providing individual balanced outputs for each channel. With this flexibility, the operator can send isolated channel program content to dedicated inputs on a single camera/VTR or to multiple record units.

(Note the remote control for the boom audio level, above the Channel 1 input.)

Front panel controls
Retractable channel gain, pan pot and headphone level controls greatly improve operation; preventing unintended changes in the settings while in use. When needed, these controls will pop up for access. The chassis features shields on either side of the mixer protruding sufficiently to protect the mixer controls. The addition of retractable gain trims on each channel allows continuously variable control of the input gain over a 40dB range.

Other advanced features include a Slate Microphone button to momentarily reduce input, Releasing the button restores the previously set inputs. That means no manual volume adjustments that might destroy a previously-set mix. A Tone Oscillator, Battery Test button, and two separate Output Limiters, especially useful when using Betacam-family cameras.

At a suggested retail price of $1,895.00, the PSC AlphaMix offers tremendous flexibility for the money. To make the value even more enticing, PSC delivers AlphaMix with a Porta Brace™ Case to house the mixer (strap also included).

A final note about output: the AlphaMix supplies 3 balanced stereo outputs, 2 TRS stereo outputs and 1 mono output in addition to the 4 direct outputs on the Input Panel. ENG teams will also want to note that 2 separate transformers can feed 2 cameras without interference.

In the field
The two-camera output feature was quite appealing to my colleague. He already had NP-1 batteries and the charger so this quite literally was a fit. Finally, because the sound people he hired might not be familiar with the mixer, he needed it to be easy to operate.

I got to see all of this in action when I was the one he hired to run the mixer. I had to manage impedances and mixing for several wireless receivers and his boom mic. I was elated that all of these controls were now easy to see and access. We were able to quickly calibrate the peak reading dB meters of the AlphaMix to the VU meters of his Ikegami camera with a BetaSP back.

The shoot went off without a hitch. The NP-1 batteries were a breeze to change out, sound clarity was excellent for a mixer in its class and level monitoring was a snap due to the large display. By the end of the day, we were sold on the AlphaMix’s value.