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Playing Audio

The miniDSP Flex HT has a range of input sources and output connections. This page provides an overview so you can quickly get started with playing audio.

Warning

Ensure all equipment is powered off when making audio connections.

Connecting sources

The diagram below illustrates the audio sources that can be connected to the miniDSP Flex HT. The USB and HDMI eARC inputs accept multichannel linear PCM audio (8 channels), while the SPDIF and TOSLINK inputs accept stereo audio only. For more about HDMI and eARC, see the HDMI audio page.

Connecting audio sources to the miniDSP Flex HT

Connecting audio sources to the miniDSP Flex HT (click for larger)

Info

The SPDIF and TOSLINK inputs accept stereo PCM audio only. They will not decode bitstream audio.

Connecting an amplifier, speakers and subwoofer

The diagram below illustrates a basic connection of a multichannel amplifier, speakers and subwoofer to the miniDSP Flex HT. The default settings of the Flex HT route the input channels to the output channels with no bass management or crossovers active.

Connecting an amplifier, speakers and subwoofer to the miniDSP Flex HT

Connecting an amplifier, speakers and subwoofer to the miniDSP Flex HT

For a typical home theater system, bass management will need to be set up.

Warning

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

Advanced configuration

In addition to bass management, the miniDSP Flex HT provides a host of sophisticated DSP functions for routing, mixing, and equalization of the audio passing through it.

For example, if less than 7 speaker channels are used, the "spare" outputs can be used for additional subwoofers. Other applications such as active crossovers are also easily supported.

To configure the Flex HT, you will need to use miniDSP Device Console to set up its audio processing. We recommend that you take the time to read through the remaining sections of this manual and familiarize yourself with its capabilities.

In particular, see the Channel routing examples and Matrix mixer examples to find examples close to your desired application and for links to tutorial-style application notes.

LFE channel gain

The LFE channel of movie soundtracks is recorded 10 dB lower than the speaker channels, so that the higher signal levels required do not overload the recording medium. This 10 dB must be regained in the playback chain.

There are several elements to accomplishing this effectively with the Flex HT:

  1. Higher playback gain in the LFE/Sub channel
  2. Calibration for 10 dB higher Sub output
  3. 10 dB adjustment when mixing channels in bass management
  4. Adjusting the Sub channel gain before and after Dirac Live calibration

Info

"LFE" refers to the source (input) channel containing low-frequency effects. "Sub" or "Subwoofer" refers to the output channel that drives the subwoofer. When there is no bass management, they are used interchangeably. However when bass management is used, the Sub (output) channel includes both the LFE channel and low-frequency content from the speaker channels.

For a worked example, see the application note Bass management with miniDSP multichannel processors.

Sufficient Sub channel gain

Set the gain on your subwoofer to maximum to ensure that there is sufficient analog gain on this channel. (Note: this refers to your actual subwoofer, not the Sub output channel of the Flex HT). Otherwise, you run the risk of digital clipping on the Sub channel output.

Calibration

Use REW to run measurement sweeps on each channel. Adjust the output channel level or subwoofer gain so that the LFE channel measures 10 dB higher, as shown here:

REW measurement showing levels of subwoofer and speakers

Bass management

When the low frequencies of a speaker channel are mixed to the LFE channel, the speaker channel must be reduced 10 dB for the relative levels to be correct. The Flex HT provides this with the LFE mix level parameter on the Bass Management tab.

After bass management is set up, the channels should look like this:

REW measurement showing subwoofer and speakers after bass management

Dirac Live gain adjustments

When Dirac Live calibrates, it will lower the level of the Sub channel to match the speakers. This is not desired. Therefore, we recommend this procedure:

  1. Reduce the output level of the Sub channel by 10 dB.
  2. Run the Dirac Live calibration.
  3. Raise the output level of the Sub channel by 10 dB.

Confirm that the levels are as expected by running a measurement with REW.

About USB Audio

This content has moved to USB audio.