Audio input ports

You can connect external audio devices like mixers (and microphones for Pearl Nexus) directly to the dedicated audio input ports on Pearl Nexus. Each Pearl Nexus has a unique set of audio input ports.

Pearl Nexus

Two XLR/TRS combo jacks (Mic/Line 1 and Mic/Line 2). These two ports are configured as a left/right stereo pair by default.
XLR mic-level inputs (balanced)
TRS 1/4" line-level inputs, + 4.0 dBu (balanced/unbalanced)
One 3.5 mm stereo mic-level for electret microphones
One RCA stereo pair consumer line-level input (-10 dBV)

The two XLR/TRS combo jacks on Pearl Nexus are configured as a stereo pair by default. You can configure the two combo jacks as two separate mono audio inputs using the Admin panel. You can also enable or disable phantom power for the two XLR ports.

The RCA and 3.5 mm audio sources share the same resource and appear under the label RCA/3.5 mm Audio. You can assign one or both audio sources to the RCA/3.5 mm Audio input.

Enable or disable phantom power on Pearl Nexus

Phantom power is not enabled on the XLR audio input ports by default on Pearl Nexus. You can enable 48 V Phantom power for the two XLR ports using the Admin panel.

When phantom power is enabled:

48 V phantom power is applied to both XLR port 1 and XLR port 2.
The phantom power LED beside the XLR/TRS combo jacks on the rear panel of Pearl Nexus is solid on.

Connecting devices that are not designed for phantom power when phantom power is enabled for the two XLR ports can seriously damage those devices. Always check the phantom power LED before connecting devices to the XLR ports. A direct box can be used to provide the correct mic-level signal to the XLR port and offers some isolation protection in case of accidental exposure to 48 V phantom power.

Enable or disable phantom power using the Admin panel

Log in to the Admin panel as admin
From the Inputs menu, click XLR/TRS Audio. The XLR/TRS Audio page opens.
Check Phantom power 48V, then click Apply.

Configure audio ports for stereo or mono

Using the Admin panel, you can configure ports to function as a stereo pair (left/right) or as separate mono ports.

Pearl Nexus

The two combo XLR/TRS audio input ports are configured to work together as a stereo pair by default.

XLR/TRS 1 = left
XLR/TRS 2 = right

Configure audio ports as stereo or mono using the Admin panel

Log in to the Admin panel as admin
Open the configuration page from the Inputs menu:
Pearl Nexus: click XLR/TRS Audio. The XLR/TRS Audio configuration page opens.
Do one of the following.
To make the ports function as a stereo pair, check Stereo pair and click Apply.
To make the ports function as separate mono ports, uncheck Stereo pair and click Apply.

When mono is selected, two sets of parameters and two audio VU meters appear in the interface - one for each audio input port on the Pearl Nexus. Parameters that are listed only once apply to both ports.

Assign audio sources to an input

Some audio input ports share internal audio processing resources in the Pearl Nexus. These shared audio sources appear in the same configuration menus in the Admin panel and appear under the same audio input label in the user interfaces.

The audio sources that share resources are:

RCA (left and right ports)
3.5 mm (stereo port)

Both the RCA and 3.5 mm audio sources appear under the label RCA/3.5 mm Audio. You can assign one or both audio sources to RCA/3.5 mm Audio. Choosing one audio source for the shared input disables the other audio source. This means that when you select RCA/3.5 mm Audio as the audio source for a layout using the custom layout editor, only the audio source you assign to RCA/3.5 mm Audio is used. Both audio sources are assigned by default.

To avoid unwanted signal noise on the RCA ports, we recommend adding no more than 12dB of gain when RCA

Assign the audio source to an input using the Admin panel

Log in to the Admin panel as admin.
From the Inputs menu, select the shared audio source. The audio configuration page opens.
From the Input menu, select the audio source and click Apply.

Adjust audio gain and delay

Pearl Nexus do not introduce audio delay and have near-zero latency when capturing. However, other external factors can cause audio to become de-synchronized, such as the length of audio cables or the configuration of your equipment. The audio delay feature helps you adjust audio coming from external sources so that your video and audio sources are synchronized when captured, streamed, and recorded.

You can apply from -300 ms to +300 ms of delay to any audio source using the Admin panel. By default, there's 0 ms of delay applied to audio sources.

Adjusting the Input Gain for an analog audio source affects the volume for that audio source in recordings, streamed output, video output ports, and in the headphone jack. Be aware that excessive amounts of gain can increase the perception of any noise that may be present in the audio signal.

If the gain of your analog audio signal needs adjustment, connect your headphones and use the VU meters to monitor the audio level while you add some gain. As a rule, each 10 dB of gain doubles the perceived loudness of the audio signal.

This table offers some guidelines for adjusting the gain at the audio input port of Pearl Nexus for common types of audio input devices. You should add the suggested gain to the audio input to get an average signal to register at a nominal level in the VU meter (i.e. where the green bars change to yellow). The actual amount of gain needed depends on the strength of the original audio signal.

Table 22 Audio input port gain guidelines

Audio source	Input port	Gain
Dynamic microphone	XLR	Add +50 to +60 dB gain to the audio input port.
Electret microphone	XLR	Add +18 to +40 dB gain to the audio input port.
	3.5 mm	Add +6 to +12 dB gain to the audio input port.
Wireless microphone receiver	XLR	Add +18 to +40 dB gain to the audio input port.
	3.5 mm	Add +6 to +12 dB gain to the audio input port.
Condenser microphone with phantom power	XLR	Add +40 to +60 dB gain to the audio input port.
Mobile phone or other consumer line level device	TRS	Add +6 to +12 dB gain to the audio input port.
	XLR	Add +6 to +12 dB gain to the audio input port.
	RCA1	Nominal
Professional mixer	TRS	Nominal
	XLR	Nominal
	RCA	Not recommended.

1 To avoid unwanted signal noise on the RCA ports, we recommend adding no more than 12dB of gain to the RCA ports or when RCA/3.5 mm is used

Ensure the audio input source is connected to an analog audio input port on Pearl Nexus before proceeding.

Adjust the gain and delay for an audio source using the Admin panel

Log in to the Admin panel as admin.
From the Inputs menu, select an audio source. The audio configuration page for the audio source opens.
In the Input Gain field, select the amount of gain to apply to the audio source.
In the Audio delay field, enter a value between 300 and -300 ms. A positive value adds delay to the audio signal. A negative value adjusts the audio to start earlier.
Click Apply.

Mute audio

You can mute any audio input port using the Admin panel. For analog audio ports that are configured as mono inputs, you can mute each port separately.

Some audio input ports share internal audio processing resources in the Pearl Nexus. Muting an audio input that shares internal resources mutes all the associated audio sources. The following table lists the audio input ports that share internal processing and the results of applying mute.

Table 23 Muting audio inputs that share resources

Device	Audio input (Admin panel)	Shared audio input resources	Results
Pearl Nexus	XLR/TRS Audio	XLR/TRS 1 (left) XLR/TRS 2 (right)	In stereo mode: Both XLR ports (left and right) are muted. Both TRS ports (left and right) are muted.
			In mono mode (XLR/TRS audio 1 muted): The XLR 1 (left) and TRS 1 (left) ports are muted. The XLR 2 (right) and TRS 2 (right) ports are not muted.
			In mono mode (XLR/TRS audio 2 muted):The XLR 2 (right) and TRS 2 (right) ports are muted. The XLR 1 (left) and TRS 1 (left) ports are not muted.
	RCA/3.5 mm Audio	RCA (left/right) 3.5 mm (left/right)	Both RCA ports (left and right) are muted. Both 3.5 mm ports (left and right) are muted.

Mute an audio source using the admin panel

Log in to the Admin panel as admin.
From the Inputs menu, select an audio source. The audio configuration page for the audio source opens.
Check Mute to mute the audio source or uncheck Mute if you no longer want the audio source muted, then click Apply.