Every once in a while, a product comes along that seems so obvious it makes you wonder why someone didn’t invent it a long time before. David Lichterman actually introduced me to the original D3 Optogate at the 1999 Winter NAMM Show. I would like to show you the PB-05.
The open mic problem in live sound is well known: One or more microphones must be turned on for something that’s about to happen, but until it happens, that open mic can add unwanted audio.
Noise gates and downward expanders have been used for years, but they often don’t act quickly enough, add noticeable artifacts, chatter, trigger falsely or not at all and sometimes do as much harm as good.
The PB-05 has actually been out for some time and is slim, the width of an in-line XLR barrel, protruding a mere half-inch above a microphone’s radius at its connector. On the edge facing the singer are three LEDs. A red LED illuminates to show when the mic is open, or un-attenuated. Two other LEDs are simply the infrared (IR) emitter and receiver, which cover a tight angle of about 15 degrees.
Phantom power operates the PB-05’s circuitry as well as most condenser mics, and it doesn’t even need a full 48 volts, as do true condensers. Unpowered, it simply acts as a wire. When powered, it turns on engaged, so when used with a dynamic mic, the engineer can simply operate it remotely by using the console’s phantom power switch.
The only adjustments are a recessed 12-turn pot, which adjusts sensitivity from less than an inch to several feet, and a bypass switch. At its shortest, it can be set so it only turns on when a hand is placed on the mic’s body right in front of the LEDs, even if a face is in front of the mic or lips are on its grill. About eight turns of the pot lengthens the distance to “lips on the mic” and a couple more turns increases the distance to a face about six inches from the grill. Once it’s in the ballpark, minor tweaks are all that’s ever needed.
The PB-05 latching bypass button opens the mic, and, of course, turns on the red LED. A second press of this small button re-engages the Optogate for normal operation. This is not only useful, but required for checking wedges and side-fills, especially on loud stages where monitor engineers must carefully ring out stage monitors for maximum gain before feedback, since, as with any engaged gate, it can be a ticking time bomb.
There are actually two versions of the Optogate PB-05. The standard version reduces the signal by 42 dB, which, for all practical purposes is “off.” The second version is the PB-05d (“D” as in ducking), reducing signals by 16 dB. This amount of ducking was arrived at from research with top monitor engineers who have suggested this amount of gain reduction allow IEM mixes to sound the most natural.
Another reason for using the Ducking model is that, on loud stages, the ducking allows the cleaning up of the sound without creating a big jump in balance between FOH and the monitors by ducking the mic instead of shutting it completely off.
The distance range of the Optogate can change slightly with ambient lighting and, like all infrared devices, they can’t work correctly when direct sunlight hits their IR sensor, in which case they simply remain open. This is typical of infrared technology due to the high power of sunlight’s IR spectrum. Bottom line, if you only occasionally perform with the direct sunlight shining into Optogate IR transceivers, these will definitely work all the other times.
Where would you use one? A traditional application is the vocal mic for a musician in front of a loud stack of amps that bleed into their vocal mic, especially when they step away from the mic. Anyone who has mixed loud rock or metal knows that part of the FOH job involves turning unused vocal mics on and off. A second application is singing drummers, particularly those who don’t sing on every song, and especially those who unpredictably make on-mic comments between songs. A third use is the dreaded festival announce mic than can and will be used at any moment without notice, usually while FOH is getting the next act organized.
Further applications are for the private on-stage communications mics used with IEMs that allow performers (and their techs) to communicate amongst themselves without taking to the audience. This is often done with footswitches, keeping that mic’s ambience out of the IEMs when not being used, but it’s easier with an Optogate.
We’ve used one with the Jacksonville Symphony for our off stage announcements: not the usual pre-show announcements to the audience, but the various pre-show and intermission lobby announcements. A separate Optogated mic patched to the lobby frees up the sound engineer to actually listen in the lobby and check levels instead of being stuck at the console operating it.
Years ago, I saw one being used on an Andreas Vollenweider show for a miked timpani on the drummer’s right, past the floor tom. An audio gate would have clicked when the drum’s transient opened it up, but the Optogate opened just before the stick hit the drum, allowing the entire transient through unscathed. Who knows, you may find a unique way to clean up your FOH mix.
More details at www.optogate.com.
