Signal routing¶
Overview¶
Each input channel can be sent, or routed, to any number of output channels. This is accomplished with the routing buttons at the top of the output channel strips. This is the default routing:
In addition to routing, the miniDSP SHD supports mixing, where input channels can be mixed at different levels to a single output channel. The complete set of routing controls along the top of the output channel strips is therefore also called the "matrix mixer."
Basic routing¶
To route an input channel to an output channel, click on the input channel's name. When routed, the button is green:
Note: if the input channel has been renamed, its name will appear instead of e.g. "Input 1".
Mixing¶
To mix both input channels to an output, select both of them:
By default, each input channel is mixed at "full strength" – that is, without any attenuation, as indicated by the "0 dB" label. To mix at different levels, click on the level button and either use the slider or enter the desired value directly. The gain of the signal being mixed can be set to a value between -72 and +12 dB.
In this example, both channels are mixed at half level (-6 dB):
Routing examples¶
This section illustrates a few examples of signal routing. In these examples, the input and output channels have been renamed by typing in the labels at the top of the channel strips. We recommend you do the same to help avoid errors.
Subwoofer integration¶
The diagram below shows the connections for a stereo pair of speakers plus a single powered subwoofer. This is the simplest type of active system, so is a good introduction to the advanced features of the miniDSP SHD. It is also known as a "2.1" system.
The stereo amplifier is connected to outputs 1 and 2, and the subwoofer is connected to output 3.
Info
The examples in the diagrams show a powered subwoofer. If using a passive subwoofer, a separate amplifier will be needed. Never connect an output of the SHD directly to a subwoofer driver or to a speaker or speaker driver.
Rename the input and output channels accordingly, then set up the routing matrix:
The left and right inputs are sent to outputs 1 and 2. Both inputs are summed and sent to output 3. Outputs 1 and 2 will need a high pass crossover filter to remove the sub frequencies, while output 3 will need a low pass crossover filter.
For a tutorial-style walkthrough, see these application notes on our website:
Dual subwoofers¶
The diagram below shows the connections for a stereo pair of speakers plus two powered subwoofers:
We will assume that the two subwoofers are driven as "mono" subs – that is, they both take the sum of the left and right channels at low frequencies. Rename the input and output channels accordingly, then set up the routing matrix:
Outputs 1 and 2 will need have a high pass crossover filter to remove the sub frequencies, while outputs 3 and 4 will have a low pass crossover filter.
To begin with, you may wish to simply set the time delay on both subwoofers and speakers to match the relative distances from the listening position. Then proceed as for the single-subwoofer case using one of these application notes:
For more advanced use, the two subwoofers can be treated as a "multisub" system. In this case, the processing on the subwoofer output channels is adjusted to obtain the least variation around the listening area. A walkthrough using the sophisticated MSO (multi-sub optimizer) program to optimize the subs and the speakers is given in this app note:
Alternatively, you can optimize the subs first, then integrate with the speakers as for the single-subwoofer case. For an introduction to methods of optimizing a group of subwoofers, see this application note:
Two-way active speaker¶
The diagram below shows the connections for a two-way active speaker. Amplification can be either a multichannel amplifier or a pair of stereo amplifiers.
Rename the input and output channels accordingly, then set up the routing matrix:
The left input is routed to outputs 1 and 3, and the right input is routed to outputs 2 and 4. Each output channel will need a low pass filter for the woofers or a high pass filter for the tweeter.
For a tutorial-style walkthrough, see this application note on our website: