25-Seven PDM II User manual

PDM II
PDM II User Manual
Front Panel Overview
Figure 1 - Front panel controls
The Input Level Meter (A) monitors the signal going into PDM II’s processing circuit. As they follow the A/D
converter in the signal path, they will accurately monitor the input regardless of the Input Sensitivity setting.
Note that this is a peak meter to be used as a diagnostic tool for setting input levels; it does not display RMS
voltage or a time-integrated level and is not intended to be a replacement for a more sophisticated loudness
meter.
Four dark LEDs: The input signal is below -36 dBFS.
One Green LED: The input signal is above -24dBFS.
Two Green LEDs: The input signal is above -18dBFS.
Three Green LEDs: The input signal is above -12dBFS.
Four Green LEDs: The input signal is above -6dBFS.
Top LED is Yellow: The input signal is above -0.5dBFS.
Top LED is Red: The input signal is above +0.5dBFS.
All LEDs are Yellow: The unit is expecting a Livewire input but not seeing a valid signal, or there is an
internal error.

The LCD display (B) shows a variety of information about the current status of the PDM II and provides a
menu system for front-panel setup and configuration.
The navigation cluster (C) is made up of left, right, up, and down arrows plus a green "checkmark" button
(generally used as an "Enter" button to confirm choices) and a red "X" button (used as a "Cancel" button to
exit a menu without saving any changes).
The main color-coded operational buttons are grouped together and their use in actual operation is outlined
in greater detail in the and sections, but in short: Front Panel Overview Basic Operation
The green Build button (D) starts building a delay at the start of a program.
The yellow Exit button (E) starts the process of exiting the delay to return to real-time audio.
The blue Cough button (F) temporarily stops incoming audio from reaching the delay buffer
The red Dump button (G) dumps the buffered audio or plays a pre-recorded audio file when a guest,
caller. or even the talent (!) utters something objectionable that should not be aired.
The Bypass button (H) is used for emergencies or when you want to electrically remove PDM II from the
signal path. Pressing it connects its outputs directly to its inputs with no processing or delay, and also clears
the PDM II's delay memory.
Note: PDM II also goes into electrical bypass - connecting the analog and AES/EBU RJ45 inputs
to the corresponding RJ45 outputs - when power is removed. In this situation, the PDM II becomes
a completely passive device with no level adjustment or A/D conversion taking place.
Rear Panel Overview
Figure 1 - Rear panel connections
The rear panel of the PDM II contains the following connections and information:

Analog Input and Output via RJ45 connector (A)
AES3 Input and Output via RJ45 connector (B)
GPIO on a standard DB15 connector (C)
Model number (D)
Serial number (E)
Primary and Secondary MAC addresses (F)
Secondary Ethernet port via RJ45 connector (G)
Primary Ethernet port via RJ45 connector; PoE-ready (H)
Chassis ground lug (I)
IEC AC power inlet (J)
Front Panel Menus
While PDM II offers a comprehensive HTML5 browser-based user interface, most of the setup, configuration,
and operation of the unit can also be accomplished via the front panel controls.
The front panel navigation cluster is made up of five buttons:
Navigation cluster
Left, Right, Up, and Down buttons, for navigating through lists and adjusting values; holding down an
arrow will generally repeat the action
Checkmark button, for entering menus and confirming choices
X button, to "Cancel" and exit a menu without saving any changes
To begin, press the Checkmark button to enter the top-level menu.
Configuration Menu
Pressing the Checkmark button from the normal status screen brings up the Configuration menu with sub-
menus for Audio, Controls, System, Network, GPIO, and Information.
The Up/Down arrows scroll vertically through the current menu. The Right arrow is used to enter any

available sub menus
Figure 1 - Configuration menu
Many of the PDM II's menus contain more than four items, and so cannot be completely displayed on one
screen. In this case, the extra items above or below the visible items (as indicated by the word "More") can
be seen by scrolling with Up/Down arrows.
For illustration purposes throughout this user manual, the screens will be merged into a single image so that
all information can be displayed at once.
The full configuration menu is below; the sections that follow will describe each sub-menu.
Figure 2 - Complete Configuration menu
Audio Menu
The Audio Menu is used to select and configure various audio I/O parameters and values.
Note - Some of the options displayed in the Audio Menu are contextual and will change
depending upon the type of audio input selected. Therefore, the figures below may not exactly
match what is available on the front panel of your unit.
Figure 1 - Audio menu

Audio Input
Audio input options include Analog, AES67, Livewire, and AES3. The up/down arrows scroll through the
options. In this and in subsequent edit screens, the Checkmark button accepts and applies any changes
while the X button cancels without saving.
Figure 2 - Audio input screen
AES67 Receive Channel
When using an AES67 audio source, the multicast address of the receive channel is set here. The up/down
arrows change the number by a value of 1, and the left/right arrows navigate between fields.
Figure 3 - AES67 receive address
Livewire Receive Channel
When using a Livewire audio source, the receive channel is set here. The up/down arrows change the
number by a value of 1, and the left/right arrows change the channel number by a value of 100.
Figure 4 - Livewire receive channel screen
Input Sensitivity
When using an analog audio source, this value should be set to the absolute loudest level PDM II will see in
your installation. The up/down arrows change the value. The "L" and "R" values represent the resulting
digital levels for the incoming analog signal and can be used along with an externally generated test tone to
adjust the sensitivity settings.

Figure 5 - Input sensitivity screen
For most installations where 0 VU = +4 dBu, the recommended setting is +14 dBu = 0 dBFS.
Note: Don't confuse dBu with dBFS!
dBu - an analog measurement - is a comparison to an arbitrary voltage. When a console's VU
meter reads 0, the output is typically +4 dBu, or 1.228 volts when using a sine wave. However,
actual audio levels are typically much higher due to audio peaks in the waveform. Analog audio is
very forgiving of such peaks, but digital audio is not.
A digital level of 0 dBFS (decibels in reference to full scale) is an absolute ceiling, and audio that
exceeds that level will result in audible distortion. PDM II has a built-in limiter to prevent levels
from exceeding 0 dBFS, but the recommended setting of 14 dBU = 0 dBFS provides 10dB of
headroom while still maintaining an 84dB signal-to-noise ratio. Lower settings can be used when
dealing with heavily processed input content, while higher settings may be necessary for content
with very wide dynamic range.
Analog Output Level
The Analog Output Level screen displays how the analog output level reflects digital audio levels within
PDM II's processor. With the setting as shown below, 0 dBFS within PDM II will yield a +14 dBu analog
output. The output levels should generally be set to match the Input Sensitivity level, though levels can be
adjusted to create a gain or loss at the analog outputs. Note that in Bypass mode, any such gain changes
are also bypassed and the output levels will equal the input levels.
Figure 6 - Output level screen
AES3 Default Output Rate
The default sample rate of the AES3 output can be set to 32, 44.1, or 48kHz.
Figure 7 - AES output rate screen
AES3 Output Lock
The sample rate of the AES3 output can be locked to the sample rate of the AES3 input, even if the unit is
not configured for an AES3 input. If there is no valid clock at the AES3 input, the output will revert to the rate
set in the AES3 Default Output Rate screen above.

Figure 8 - AES output lock screen
AoIP TX Type
Audio over IP (AoIP) audio can be sent from PDM II as either a standard AES67 stream or as a Livewire
stream. It can also be disabled if desired.
Figure 9 - AoIP Tx mode screen
AES67 Tx Address
The multicast address of the AES67 transmit channel is set here. The up/down arrows change the number
by a value of 1, and the left/right arrows navigate between fields.
Figure 10 - AES67 Tx address
Livewire TX Channel
The Livewire channel number for PDM II's audio output is set here. The up/down arrows change the number
by a value of 1, and the left/right arrows change the channel number by a value of 100.
Figure 11 - Livewire Tx channel screen

Controls Menu
The Controls menu is used to configure parameters and settings that determine how a delay is built, what
happens when the delay is dumped, and what happens when you exit the delay and return to passing real-
time audio.
Figure 1 - Controls screen
Dump Size
The Dump Size screen sets the amount of audio deleted when the Dump button is pressed. The up/down
arrows set a value between 1.0 and 60.0 seconds in 0.1 second increments.
Figure 2 - Dump size screen
Note - The Dump Size and Delay Size screens are not visible when the Dump Mode is set to
"OverKill."
Delay Size
The Delay Size control determines how much delayed audio PDM II will store in its buffer. The up/down
arrows set a value between a minimum of 1.0 second and the maximum as determined by the setting of the
Max Delay menu below.

Figure 3 - Delay size screen
Note: The Delay Size can also be temporarily set from outside of the menu system any time PDM
II is in Delay mode by pressing the left/right arrow keys to decrease/increase the value.
Max Delay
The Max Delay setting determines the upper limit of the Delay Size range described above to help prevent
operators from accidentally setting unrealistic delays. The maximum value is 90 seconds.
Figure 4- Max delay screen
Build Speed
The Build Speed screen sets how quickly PDM II can build up to and exit from its delay memory. The default
value is 7. Higher values will build the delay more quickly but may cause audible artifacts depending on the
type of programming.
As a rule, content with more density (such as highly-produced music) will better tolerate higher speeds
without audibly compromising the audio. More sparse material (such as speech) will more easily reveal
artifacts.
We recommend starting with the default value, carefully listening to your on-air audio during the build and
exit process, and making adjustments that balance the need to build a delay buffer quickly with your
tolerance for any variation in the audio quality during that time.
Figure 5 - Build speed screen
Max Speed
The Max Speed screen sets a limit for how quickly PDM II can build or exit a delay. The Build Speed setting
cannot be set faster than the value set here.

Figure 6 - Maximum speed screen
Build Mode
Build Mode determines the method PDM II uses to build its delay.
Figure 7 - Build mode screen
Expand - 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.
Insert - PDM II will play a station jingle, ID, or other fill material from its internal memory.
Pre-roll - PDM II will mute its output while you play material from another source, or while it signals your
automation system to play audio.
Build File
The Build File menu allows you to choose which audio file will play out from PDM II's internal memory when
building a delay using the "Insert" mode.
Figure 8 - Build file screen
Note: PDM II can store multiple audio files in its internal library. Files can be uploaded and
managed on the page of the web-based user interface.Audio Files
Note: The audio files should be stereo (or 2-channel mono) 16-bit WAV files with a 48kHz sample
rate to match the sample rate of PDM II's internal clock and ensure proper speed and pitch during
playback.
Exit Mode
The Exit Mode determines how PDM II behaves when transitioning between delayed and real-time audio.