miniDSP makes easy-to-use digital audio processors. The technology we use is broadly called Digital Signal Processing, or DSP – hence the name of our company.

• Overview
• Applications
• Input and output selection
• Configuration software
  • Device Console
  • Plugins
• miniDSP introduction video
• Wrapping up
• Appendix: More about ins and outs

Overview[Top]

Figure 1 illustrates the overall product concept (*1). The square in the lower middle is the miniDSP processor itself, which is physical hardware with audio input and output connectors. Each processor includes one or more digital processor chips, which run the firmware (*2) that performs the audio processing. They also manage various elements of the processor such as USB communication, the front panel, and so on.

The input to the processor is an audio signal. This could be digital or analog, and could be received over the network or Bluetooth. It may be stereo or multichannel. Different processors differ in the number and types of input they support.

The output from the processor is also an audio signal. However, it has been altered compared to the input. A very simple example is volume control: the output signal is a "smaller" version of the input signal. However, there are many more interesting and useful things that can be done with audio signals, and we'll provide an overview in the Applications section below.

At the top of the diagram is the configuration software, which is what you use to tell the processor how to process the audio signals. This is an application that you run on a Windows PC or on an Apple Mac. The configuration software is not needed once configuration is complete – although you can still run it if you want to, to monitor signal levels and control volume, select the preset and so on.

Notes:
*1. miniDSP also makes products that don't fit this model, such as microphones. However, the bulk of the product line consists of audio processors.
*2. "Firmware" is software that is dedicated to run on a specific piece of hardware.

Applications[Top]

The first step in choosing a miniDSP processor is understanding the type of application. There is a lot of overlap here, but here are the main categories:

Digital room correction

Digital room correction is a general term that applies to using digital processing to counteract negative effects of the room. Any miniDSP processor can be used for room correction. There are essentially two types:

1. Basic manual correction with parametric EQ. Our Active crossovers are often used this way.

2. More automated correction with Dirac Live. This is available on the Streaming HD Series and the Dirac Live Series. In addition, all of our Active crossovers can be upgraded with Dirac Live (optional purchase).

For an overview of the two approaches, see the app note REW vs Dirac Live.

Subwoofer integration

Awesome bass! We all want it, but traditional methods of integrating subwoofers fall short. By using measurements and a miniDSP, you can achieve much better results, from integrating a single subwoofer into a stereo system (aka "2.1") to multiple subwoofers.

To learn more about subwoofer integration, see the Subwoofer Tuning application notes.

Active crossover

With an active crossover, each speaker driver (tweeter, midrange, woofer) has its own amplifier. The crossover between the drivers is done in the miniDSP processor.

To learn more about active crossovers, see the Digital Crossover Basics app note and the full set of Digital Crossover application notes.

Multichannel and home theater

Multichannel and home theater systems benefit greatly from DSP: to equalize and match each channel, to properly integrate the subwoofer (or even multiple subwoofers), and for room correction.

To learn more about home theater tuning, see the Home Theater and Subwoofer Tuning application notes.

Input and Output[Top]

The second step in choosing a miniDSP processor is deciding on what types of input and output that you need. Most processors have at least digital inputs and analog outputs. Then you can ask yourself:

• Are analog inputs needed? Analog inputs can be used for sources such as vinyl or tape. They can also be used if you are integrating a miniDSP processor into a system with an existing analog preamp that you wish to retain.

• Are digital outputs needed? Digital outputs can be used to connect to your own DAC or to active speakers with digital input.

• How many input channels are needed? All processors support stereo input, but only some support multichannel (e.g. 8 channels) input.

• How many output channels are needed? Most processors support at least four outputs – this is useful for stereo output with one or two subwoofers, for example, or for a two-way active speaker. For more complex active systems or for multichannel audio, choose a processor with more output channels.

The table below lists the key input-output specifications of a number of our processors.

Notes:
*1 - Flex has 4 analog output channels on RCA, Flex/balanced has 4 analog output channels on TRS, Flex/Digital has no analog outputs.
*2 - Flex and Flex/Balanced have no digital outputs, Flex/Digital has four digital output channels on SPDIF.

Some more detail on inputs and outputs is provided in the Appendix.

Configuration Software[Top]

The processor is configured with software running on a PC or Mac. When the configuration is finished, the PC or Mac is not needed for normal use in playing audio.

Device Console[Top]

miniDSP Device Console (DC) is our latest configuration program for use with our most recent processors. Device Console provides features such as a single software program to control all miniDSP processors (going forward), over-the-air (OTA) self-updates, detection and installation of firmware upgrades, and integrated Dirac Live upgrades (where applicable).

Plugins[Top]

A "plugin" is our older style of configuration software. The name originated from the concept that each hardware processor could be used in multiple ways, so there were multiple combinations of firmware and the configuration software that could be used with each processor hardware.

However our processors are more powerful now, so we've been able to build more flexible processing power into each one.

miniDSP introduction video[Top]

For more on our product concept, please view the introduction video:

Wrapping up[Top]

That's it for this app note! Have fun, and let us know about your thoughts in our forum.

Appendix: More about ins and outs[Top]

Figure 2 shows a little more detail on how the different input and output types are handled. Digital inputs are converted to the internal sample rate – 48, 96, or 192 kHz – while analog inputs are sampled at that rate by an analog-to-digital convertor (ADC). Digital outputs have a conversion from the internal I2S format used internally to SPDIF, TOSLINK (optical) or AES/EBU, while analog outputs are produced by a digital-to-analog convertor (DAC). This ensures that the processor performing the audio processing always has a consistent signal that it can work with.