The miniDSP SHD Power implements stereo Dirac Live correction. That is, there are two channels of Dirac Live correction. After stereo Dirac Live correction, the audio signal is routed to the four output channels for processing such as parametric EQ and crossovers.
Dirac Live overview¶
Dirac Live uses from 9 to 17 measurements made at different locations in your listening room to calculate correction filters for your speakers (and integrated subwoofer if you have one). You will take these measurements using the miniDSP SHD Power, the Dirac Live application running on your computer, and a miniDSP UMIK-1 or UMIK-2 measurement microphone.
This software runs on Windows 10 or later and macOS 10.14 Mojave or later. Other versions of Windows or macOS/OS X are not supported.
Connections for Dirac Live calibration¶
The diagram below shows typical connections for acoustic measurement with the Dirac Live application. Usually, you do not need to change any of the audio connections, as the Dirac Live test signals are generated inside the miniDSP SHD Power.
Connect the supplied USB cable (type A to type B) from the miniDSP SHD Power to a USB port on the computer.
Connect the supplied USB cable (type A to mini type B or type C, depending on version) from the UMIK-1 or UMIK-2 to a USB port on the computer.
Place the UMIK-1 microphone into a microphone stand and position the computer and cabling so that there is enough freedom of movement to move the microphone into the needed locations. A small tripod stand is supplied with the UMIK-1, but a larger stand with boom arm can be used if desired. If necessary, a USB extension (up to a total USB cable length of 5 meters) can be used. In larger spaces, an active USB repeater may be needed.
- For stereo systems, we generally recommend that the microphone be pointed between the speakers and the "0 degree" calibration file used. However, many of our customers point the microphone at the ceiling and use the "90 degree" calibration file. Feel free to try it both ways.
Loudspeaker and microphone positioning¶
Prior to performing acoustic measurements, optimize your loudspeaker and listening positions. Start with the recommendations of the manufacturer of your loudspeakers. Loudspeakers designed for home hifi use typically perform best away from the walls, whereas speakers designed for studio use may be designed for use closer to walls or other surfaces. With Dirac Live, you have more freedom with loudspeaker placement, but the best result will still be achieved if optimal loudspeaker placement is used together with Dirac Live.
You should also experiment with toe-in – many loudspeakers benefit from pointing directly at the listening position or even slightly in front. The listening position should be away from the rear wall, as placing the listening chair or sofa right against the wall will result in increased early reflections and changes in timbre.
The first measurement must be taken at the exact center of the listening area, so that Dirac Live can set the levels and delays of each speaker. While this will usually place the microphone an equal distance from both speakers, Dirac Live will adjust in cases where it is not. Additional measurements are taken at other positions around the listening area and at different heights from the floor. All measurement positions should have acoustic "line of sight" – that is, the direct signal from the speaker to the microphone should not be obstructed by furniture or other objects.