Playing Audio

The miniDSP Flex (DL) has a range of input sources and output connections. This section provides an overview of the basics so you can quickly get started with playing audio.

Connecting sources

The diagram below shows the audio sources that can be connected to the miniDSP Flex (DL).

Connecting audio sources to the miniDSP Flex (DL)

Connecting an amplifier and speakers

The diagram below illustrates a basic connection of a stereo amplifier and a pair of speakers to the miniDSP Flex (DL). Since the default settings of the Flex route the input channels to output channels 1 and 2 with no crossovers active, you can make this connection for initial testing and listening.

Connecting a stereo amplifier and speakers to the miniDSP Flex (DL)

Of course, more complex connections are possible using the additional outputs. In that case, the internal processing will need to be set up using the miniDSP Device Console. Refer to the Signal Flow and DSP Reference sections for details.

Warning

Ensure all equipment is powered off when making audio connections.

Warning

Before playing audio for the first time, turn the volume down using the front panel encoder. Increase it gradually after audio playback starts.

Bluetooth audio

The miniDSP Flex (DL) includes the LDAC™ and aptX™ HD Bluetooth codecs for high-fidelity Bluetooth™ audio.

Info

LDAC is an audio coding technology developed by Sony that enables the transmission of High-Resolution (Hi-Res) Audio content, even over a Bluetooth connection. Unlike other Bluetooth compatible coding technologies such as SBC, it operates without any down-conversion of the Hi-Res Audio content[^3], and allows approximately three times more data[^4] than those other technologies to be transmitted over a Bluetooth wireless network with unprecedented sound quality, by means of efficient coding and optimized packetization.

LDAC is supported on recent Android devices. If your device does not support LDAC, you can still pair it with the miniDSP Flex (DL), but Bluetooth audio will use a lower bitrate codec.

aptX™ HD is designed to deliver high definition (HD) audio over Bluetooth, to help you get the very most from your music.

Pairing your mobile device with the miniDSP Flex (DL) is essentially the same as pairing it with other Bluetooth audio devices such as headphones or your car.

To put the miniDSP Flex (DL) into pairing mode:

1. Press the encoder button on the miniDSP Flex (DL) twice and rotate it until the display shows "Bluetooth."

2. Press and hold the encoder and the display will change to "BTPairing." The miniDSP Flex (DL) is now in pairing mode.

3. Open the Bluetooth Settings on your mobile device to pair with the miniDSP Flex (DL). The exact appearance will vary depending on your specific device, but this series of screenshots illustrates a typical sequence:

1. If your device supports LDAC, enable it by using the gear icon:

When Bluetooth audio is selected as the source, the usual front panel display will display the source (lower right corner) as one of:

BT(C)

The miniDSP Flex (DL) is paired over Bluetooth.

BT(NC)

No Bluetooth device is paired.

BT(P)

The miniDSP Flex (DL) is in pairing mode.

Once paired, the miniDSP Flex (DL) will receive and play the audio stream from the paired device. If the Bluetooth input is not selected when you start audio playback, the miniDSP Flex (DL) will automatically switch to the Bluetooth input source when audio is Bluetooth detected.

About USB Audio

The miniDSP Flex (DL) accepts stereo PCM audio at sample rates of 44.1, 48, 88.2, 96, 176.4, and 192 kHz over USB. The same USB connector is used for playing USB Audio as well as for configuration and Dirac Live calibration.

To play USB Audio from a computer, use the supplied cable to connect the USB 2.0 (Type B) port of the miniDSP Flex (DL) to a free USB port on your computer. Alternatively, connect a network streamer to the USB port. For an example using the Raspberry Pi, see this application note on our website:

• Streaming to a miniDSP 2x4HD or DDRC-24 with a Raspberry Pi 3A+

macOS

The miniDSP Flex (DL) is USB Audio compliant, so no drivers need to be installed to play audio on macOS. Open Audio MIDI Setup (in Applications->Utilities) and click on its name in the list on the left-hand side.

Set sample rate

Click on the selector next to Format to bring up the sample rate and bit depth selector. Sample rates up to 192 kHz can be selected:

Default audio device

To set the miniDSP Flex (DL) as the default audio output device, right-click and select "Use this device for sound output":

Note that individual audio playback apps may allow the miniDSP Flex (DL) to be selected for audio output independently of the system default. They may also control sample rate automatically.

USB Audio from Flex to computer

The miniDSP Flex (DL) sends its four output channels to the computer over USB. Click on the Input button in Audio MIDI Setup to see them. These can be used to monitor or record the output channels of the miniDSP Flex (DL):

For an example application using this feature, see the app note Analog recording with miniDSP and ocenaudio on our website.

Tip

To avoid having macOS resample the outputs from the Flex, set the sample rate here to the DSP's internal sample rate: 48 kHz.

Windows 11

Note: to play USB audio from Windows, the miniDSP UAC2 driver package must be installed first.

Default audio device

To set the miniDSP Flex (DL) as the default audio output device, open the Settings app and navigate to the System -> Sound page. Select the Flex with the radio button:

Set sample rate

To change the bit depth and sample rate, click on the rightward angle symbol >. Click the selector next to Format to pop up the sample rate menu. Sample rates up to 192 kHz can be selected:

USB Audio from Flex to computer

The miniDSP Flex (DL) sends its four output channels to the computer over USB. These can be used to monitor or record the output channels after DSP processing:

To avoid Windows resampling the outputs from the Flex, set the sample rate here to the DSP's internal sample rate: 48 kHz.

For an example application using this feature, see the app note Analog recording with miniDSP and ocenaudio on our website.

ASIO

If your audio application supports ASIO® audio drivers, we recommend selecting the miniDSP ASIO Driver in its settings. This typically allows the application to automatically change sample rate. For example, in JRiver Media Center:

miniDSP UAC2 control panel

The current settings of the miniDSP Flex (DL) can be viewed by opening the miniDSP UAC2 Control Panel from the Windows Start menu (under the miniDSP Ltd folder). This control panel allows you to view current settings. In addition, it can be used to set buffer size, although we recommend that you leave this setting at the default. If you are having an issue with inadequate output volume over USB playback, check the Volume tab.

To see the installed version of the UAC2 driver, use the About tab: