AcourateDRC

AcourateDRC is the next generation of AcouratePRO software from Dr Ulrich Brüggemann. Designed with simplicity in mind, AcourateDRC exports filters who can be directly imported in the OpenDRC.
An easy to use interface for an efficient result at correcting for the listening environment but also the weakness of a given speaker set. The soundstage becomes more stable and deep by improving the coherence of left and right side speakers. The boom factor caused by standing waves and room modes is removed. The end result is clean sound with a controlled bass. 

What you will need

  • A miniDSP OpenDRC-DI or OpenDRC-AN
  • AcourateDRC to generate the correction filters. A demo version is currently available at the following link. Purchase of the license to extract the filter is available via Paypal through the software for 75EUR.
  • A measurement microphone such as UMIK-1

Note that AcourateDRC is a Windows-only program. If you are not sure if you will be able to use your soundcard with AcourateDRC, download the trial version and go through the measurement process described below. This program is a 3rd party program. All support questions should be directed to AudioVero.

System setup

You will first need to get the OpenDRC connected into your system.

OpenDRC-DI: your digital source or sources are connected to the OpenDRC inputs, and the OpenDRC output is connected to your DAC. Since the OpenDRC-DI has a volume control, you can use it as a digital preamp.

OpenDRC-AN: your preamp is connected to the OpenDRC inputs, and the OpenDRC outputs are connected to your power amp. Or, if you have only a single source, you can use the OpenDRC-AN as the preamp, as it has volume control on board. The connections are balanced, so you will need to use adapters if your components don't have balanced signal connections.

Measuring with AcourateDRC

There are four steps to the process:

  1. Measure the system in AcourateDRC, without any processing being performed in the OpenDRC
  2. Generate the correction filter in AcourateDRC
  3. Load the correction filters into the OpenDRC
  4. Play music through the system

Ideally, you will able to perform step 1 with the OpenDRC still connected in the system. This will enable you to verify the result after loading correction filters, and also to take advantage of the parametric EQ function of the OpenDRC. If using OpenDRC-AN, connect your soundcard output to the OpenDRC-AN inputs. If using OpenDRC-DI, and your soundcard has a digital output, connect its digital output to the OpenDRC-DI input. You can also use a USB-to-SPDIF convertor.

If you have OpenDRC-DI but no digital output from your computer, then disconnect the OpenDRC-DI for measurement and connect the soundcard outputs to your preamp or power amp inputs.

1. Measure system response

In AcourateDRC, first ensure that your soundcard is configured in the Setup screen.

Then, on the Measurement screen, check the signal levels with the white noise generator. Set the level low initially, then adjust the gains on your soundcard and preamp (if present) until you have the test signal playing at a comfortable level and AcourateDRC indicates an adequate input level.

Note: if you have an OpenDRC inserted in the system, ensure that the FIR filters are set to Bypass mode.

Then click on "Logsweep Recording." AcourateDRC will play a sweep tone, first through the left speaker and then the right speaker, and will display the measurement result as it proceeds:

AcourateDRCmeasurement screen

2. Generate correction filters

After completing the measurement, AcourateDRC switches to the Calculation screen. Here you can set the target response (the frequency response desired for the system after correction is applied). To get started, there are a number of predefined target responses that you can select from the Setup screen:

AcourateDRC predefined target settings

You can adjust the target response using the controls on the right of the window. Then click on the "Correction" button. AcourateDRC computes the correction filters and displays the predicted response after correction:

AcourateDRCmeasured response and predicted response after correction

3. Load correction filters

In the OpenDRC 2x2 plugin interface, enable the FIR filters (by deselecting the Bypass button). Click on "FIR - channel 1" and then on "Browse." Navigate to the location where AcourateDRC has stored the impulse response files (for example, Libraries > Documents > My Documents > AcourateDRC > My Project) and select FilterL.bin. Click on Open and the correction filter is loaded and then displayed:

FIR filter response in theOpenDRC 2x2 plugin

Before closing the FIR window, click on "Send to DSP". Then repeat the process for "FIR - channel 2" and load FilterR.bin.

4. Play music

If you have disconnected OpenDRC for measuring, reconnect it. You can now play music through your system.

You may wish to measure the system response with and without DRC enabled. Run a measurement sweep, and then disable FIR filtering in the OpenDRC plugin and run another. The following screenshot shows the example system measured with Room EQ Wizard, without DRC in red, and with DRC in blue:

Right channel response before andafterFIR filter correction with OpenDRC and AcourateDRC

Repeat the above process with different target curves, to find what is best for you and your system. (You can rename the filter files each time so they don't get overwritten.) You can store up to four different sets of correction curves in the OpenDRC, to make it easy to switch between target curves and compare them. Configurations can be selected using a remote control, the front panel control, or in the plugin interface.

Don't forget to post on the miniDSP forum if you have questions!

opendrc_stack

All Digital Room Correction with Squeezebox + OpenDRC + Sumoh Amps