Basic Operation
In short, the primary function of the PDM II is to create a buffer of delayed audio that ensures profanity or other objectionable audio doesn't make it to the air. Creating this buffer is called "building a delay."
When a guest or caller says something that shouldn't be aired, the audio is erased from the buffer. This is called "dumping the delay."
Depending upon the programming, a delay may not always be necessary and so some means of returning to real-time audio is required. This process is called "exiting the delay."
Initial Boot-up
When PDM II is first powered up, the Bypass button will flash. After about 10 seconds, the LCD will display a welcome screen:
This is followed by a status screen. The unit will be in Bypass mode by default but can be set up to boot in Real-time or Building mode in the web GUI by navigating to the Control menu on the Configuration page. If the unit has been set to boot in Real-time or Building mode and there is audio present in the selected input, the input level meters will show activity.
Pressing the Bypass button brings up the Ready screen. PDM II has no delay at this point, which makes the transition from Bypass mode seamless.
Pressing the Build button begins building a delay, and the length of the delay will increase as the buffer builds.
Building a Delay
Begin by pressing the green Build button, which will flash while the delay is building up. The talent should start talking immediately. Depending on how your system is set up, PDM II will either:
Build a delay by expanding. PDM II will send the incoming audio to the transmitter but at a subtly slowed-down rate, taking more time until the delay memory is filled.
Build a delay by inserting content. PDM II will play a station jingle, ID, or other fill material from its internal memory.
Build a delay by pre-rolling. PDM II will mute its output while you play material from another source, or while it signals your automation system to play audio.
Regardless of which method is used, PDM II will be recording its input to the buffer for eventual transmission.
While the delay is building, the LCD will look like the example in Figure 1 below. Note the arrow and checkmark icons, which indicate how PDM II can be controlled from the front panel:
The Up/Down arrows will temporarily adjust the build speed.
The Right/Left arrows will temporarily adjust the length of the target delay.
The Checkmark will take you to the Configuration menu.
The horizontal bar will fill and the Delay counter on the bottom line of the display will count how many seconds of audio are in PDM II’s delay memory. As soon as there’s enough audio in memory to dump programming smoothly, the Dump button will light.
The delay memory can hold more audio than is needed for a single dump event. When it reaches a limit you’ve previously set, the Build button stops flashing while the Dump button remains lit.
You can choose how long PDM II takes to build a delay. Choose a setting based on how quickly your talent talks, how subtle you want the time manipulations to be (slower speaking styles can work with higher speed settings), and how long you’re willing to wait for the delay memory to fill.
Dumping Objectionable Content
"Dumping" is the process of eliminating the last few seconds of audio heard in the control room before it can reach the transmitter or network feed and is activated by tapping the red Dump button. The number of seconds that get dumped depends upon how PDM II is set up, and on how much delay memory has been stored.
The size of each Dump event is determined when the unit is initially set up but can be changed at any time, even while you’re on the air.
When there is enough audio in memory to smoothly dump the full amount of time you’ve preset, the Dump button will light.
You can also press the Dump button when it’s not lit. While PDM II won’t have enough audio stored to dump all of the seconds you’ve designated for a dump event, it will dump whatever it has available.
As long as the Dump button is held down, incoming audio will be discarded, which can be useful if the buffer is empty but a guest or caller continues to generate objectionable material.
When the Dump button is released, PDM II will start rebuilding its memory with incoming audio using subtle time expansion so that programming is never disrupted.
You can also tap the Dump button again while PDM II is building. Each subsequent tap will add the preset dump size's seconds to the current dump event, assuming enough audio is available in the buffer. For example, if the dump size is 4 seconds, tapping twice will dump 8 seconds of audio (provided 8 seconds of audio is available in the buffer).
Overkill™ Mode
PDM II also lets you dump incoming material by playing an internal audio file instead of collapsing and rebuilding the delay. For example, a comedy show might want to cover objectionable comments with a string of cartoon sound effects. The normal delay doesn’t get depleted and therefore doesn’t have to be rebuilt. We call this "Overkill Mode".
The Controls Menu selects whether PDM II uses Normal or Overkill mode when you press the Dump button. You can change this setting as needed for different program formats.
The same menu also lets you select which stored audio file will play during Overkill.
PDM II's Dump Size and Delay Amount automatically adjust to the length of the selected Overkill file. For example, if you want an 8-second delay, create a replacement audio file that's 8-seconds long. After the file finishes playing, PDM’s output switches back to delayed audio.
When using Overkill Mode, tapping the Dump button while PDM II is dumping starts playing the specified audio file from the beginning. Note that this can create a “stutter” effect or longer dumps.
The COUGH Button
When the blue Cough button is pressed and held, PDM II will continue to send delayed audio from its buffer to the transmitter but won't store any new audio arriving at the input. Anything said will be heard only in the studio and control room and will not be aired. When the Cough button is released, PDM II starts to rebuild the delay.
The obvious use of the Cough button is to prevent coughs and sneezes from making it to air, but it can also be used to allow short comments between the talent and the producer or guests.
Panic Mode
Panic Mode is activated by pressing and holding the blue Cough button as described above, but for a length of time exceeding the available buffer. When the buffer is empty, PDM II will mute the output and flash the Cough button light to warn you of dead air.
When the Cough button is released, PDM II immediately begins to rebuild the delay.
Note: Panic Mode works only when PDM II is set to the Normal dump mode as is not needed for Overkill Mode where the buffer does not get depleted.
After a Dump Occurs
Whenever you press the Dump button, program audio gets dumped as you’d expect, but PDM II also does other things when you press that button.
PDM II starts writing a pair of audio files, one of that audio that was actually broadcast and another of the audio from the studio. This provides indisputable records of both what the listeners heard and what they didn’t hear because of the dump.
It then adds a few seconds of extra audio to these files that preceded and followed the dump event to make it easier to identify the context.
The files are stamped with the current date and time, then stored in non-volatile memory.
A notification that the files have been created or the complete files are sent to the e-mail addresses set up in your PD-Alert System. Instructions for setting up this list are provided in the PD-Alert section of the Configuration menu in the web GUI.
Exiting Delay
To exit the delay, press the yellow Exit button.
If the Exit Mode is set to "Compress", PDM II will play any remaining audio using time compression, subtly speeding up what’s in memory to rejoin real-time faster.
If the Exit Mode is set to "Roll Out", PDM II will stop storing new audio and play what’s in memory with no speed change. Some operators call this function "roll out" or "wait and exit".
Note: Even if you've set things up to exit by compression, you can access the "roll out" mode at any time by pressing and holding the Cough button and observing the LCD screen. When the delay is close to 1.0s, release the Cough button and resume programming. PDM II will smoothly transition to real-time mode.
Whichever method you choose, PDM II tells you where you are in the exit process as shown below in Figure 2.
When Delay equals 0 seconds, PDM II will return to Real-Time mode and feed the input signal directly to its output.
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