Multi-Sub Optimizer Reference Manual (page 6)

Creating Configurations Using the Configuration Wizard

MSO works by evaluating many different combinations of filter parameter values, finding combinations that give the lowest error it can find. However, during the optimization it does not alter the number of filters or the types of the filters used for each sub. It only alters the parameter values of existing filters within the parameter limits that you specify. Therefore you must specify the number and type of filters used for each sub. Fortunately, the Parametric EQ (PEQ) filters are the only filter types you'll need to worry about most of the time. Their role is to counteract room mode effects. The other filter types are mostly used just for frequency response shaping.

To determine how many PEQs should be used per subwoofer channel, some experimentation is useful. For each experiment, you'll want to keep the results to compare with other experiments. This is one problem that configurations are intended to solve. Instead of having a separate project for each experiment, you create multiple configurations within a given project. This allows for comparing the results of multiple configurations in several ways. You can either put all the results to be compared on a single graph in the project, compare different graphs in the project with one another, or compare the various error values that MSO computes by using the Configuration Performance Metrics dialog.

The ability to choose the number of PEQs to be used per sub also accommodates personal preference. Some people don't like the idea of having too many PEQs per sub, and might wish to limit that number to two or so. Then, they let their room correction software take care of the remaining response flatness errors. An example of a commercial implementation of this idea is the Harman SFM system, which uses only one PEQ per sub.

Configuration Types

Depending on your application goals, two types of configurations are supported.

Subs+Mains Configurations

Subs+Mains configurations require that you have measurement data for both subs and main speakers. When you specify this type of configuration to be created, the Configuration Wizard will create a configuration for you that contains the required elements. The integration of mains and subs will then be a part of the optimization.

Sub-Only Configurations

Sub-only configurations do not require that main speaker measurements be imported The optimization does no integration of the subs with the main speakers, but only optimizes the subs as a group. This can be useful when you want to use another tool such as Dirac to EQ the low-frequency response of the system or integrate the main speakers and subs. When you use MSO in this way, it minimizes the seat-to-seat variation of the sub responses, while also flattening the sub response at the MLP as much as it can, given the number of PEQs that you choose. Other software, such as Dirac, can apply more powerful filter resources to flatten the overall response more than the simpler DSP hardware ordinarily used with MSO can do.

The Different Methods of Creating Configurations

Broadly speaking, there are four different methods you can use to create configurations.

The discussion here will be centered on creating your first configurations using the Configuration Wizard, then creating subsequent ones by cloning. Manual creation of configurations is only necessary for non-standard configurations, and is discussed in a separate topic.

Using the Tutorial Measurement Files as Sample Files to Import

In order to illustrate the measurement import and configuration creation techniques described on the next several pages, some sample measurement files are needed. These examples will use the sample measurement files from the tutorial.

Creating Your First Configuration With the Configuration Wizard

When you first open up MSO, you are presented with a blank project. In order to do any optimizations, you must add a configuration to it. To add a new configuration, you can invoke the Configuration Wizard. This is done by choosing Config, New From Wizard... from the main menu. If you run this command when no measurement data has been imported yet, MSO will inform you that data needs to be imported, and you'll be presented with a message box asking you if you want to launch the Measurement Import Wizard to import the data. That message box is shown below.

Prompt to Run the Measurement Import Wizard
Prompt to Run the Measurement Import Wizard

Choose Yes to launch the Measurement Import Wizard.

Importing Your Data With the Measurement Import Wizard

The other way of launching the Measurement Import Wizard is to choose File, Measurement Import Wizard... from the main menu. No matter which way you launch the Measurement Import Wizard, the last page of the wizard gives you the option (enabled by default) to launch the Configuration Wizard when it's done. Choosing this option is strongly recommended, as the creation of your first configuration then becomes a completely wizard-driven experience from start to finish. This provides much-needed structure to a process that can otherwise be confusing, especially to new users.

When you invoke the Measurement Import Wizard, you'll first see the following page.

The First Page of the Measurement Import Wizard
The First Page of the Measurement Import Wizard

What happens next depends on the option you choose. If you choose Only sub data, then click Next, the next wizard page will ask you to choose the data files for the measured subwoofer data. If you choose Both sub and main speaker data, you'll be presented with two consecutive wizard pages. The first will ask you to choose the subwoofer data files to import, and the second will do the same for the main speaker data. A representative page for the subwoofer data import is shown below.

The File Import Wizard Page
The File Import Wizard Page

When you click Add files..., you'll be presented with a standard Windows File Open dialog as shown below. Select the files you wish to import, then click Open to add them.

Windows File Open Dialog
Windows File Open Dialog

When you choose Open, the files won't be imported yet, just added to the File Import wizard page as shown below.

Getting a List of Measurement Files
Getting a List of Measurement Files

Since the files haven't been imported yet, you can add files you may have missed using the Add files... button, or remove files you may have accidentally added by selecting the files to remove, then using the Remove files button.

If you chose Both sub and main speaker data on the first page of the wizard, you'll be presented with a second File Import wizard page for importing main speaker data. Repeat the steps above to import the main speaker data.

After clicking the Next button on the final File Import wizard page, you'll be presented with the following wizard page.

Choose Whether to Run the Configuration Wizard
Choose to Run the Configuration Wizard

Choose the option to run the Configuration Wizard. When you click the Finish button, the files will be imported. You'll see a progress dialog as shown below.

Measurement Import Progress Dialog
Measurement Import Progress Dialog

Running the Configuration Wizard

When the progress dialog completes, the Configuration Wizard will start. If you imported both sub and main speaker data in the Measurement Import Wizard, the wizard page below will appear.

Choose the Type of Configuration to Create
Choose the Type of Configuration to Create

This wizard page gives you the opportunity to create a sub-only configuration if you wish, even though you imported both sub and main speaker data. If you only imported sub data, this page will not appear, as the only logical choice is to create a sub-only configuration in that case.

In the following discussion, the wizard pages that appear when you've chosen a subs+mains configuration on the first Configuration Wizard page will be shown. Some of these pages will not show up when you've chosen a sub-only configuration. It should be clear which wizard pages do not apply in that case. Showing the pages that appear when a subs+mains configuration is chosen allows for the most complete discussion.

When you press Next on the above wizard page, the following wizard page appears.

Pick the Number of Subs You've Independently Measured
Pick the Number of Subs You've Independently Measured

The next wizard page is shown below.

Pick the Number of Main Speakers You've Independently Measured
Pick the Number of Main Speakers You've Independently Measured

After entering the number of main speakers you've measured, you're presented with the following page.

Pick the Number of Listening Positions You've Measured
Pick the Number of Listening Positions You've Measured

MSO automatically calculates this number as the number of sub measurements imported divided by the number of subs. You can change it to a number less than that if you wish.

Below is the next wizard page.

Edit the Subwoofer Names
Edit the Subwoofer Names

MSO automatically generates subwoofer names for you. If these are similar enough to the subwoofer names you chose earlier when exporting the measurements from REW, you can leave them as-is. Otherwise, you can edit the names in place to get them to match the names you chose in the exported files. To edit a subwoofer name, click on the name and press F2.

The next wizard page is shown below.

Edit the Main Speaker Names
Edit the Main Speaker Names

An analogous situation to the one above with subwoofer names occurs with the main speaker names. Change them if needed.

Pressing Next causes the next wizard page to appear.

Edit the Names of the Listening Positions
Edit the Names of the Listening Positions

Just as with the subwoofer and main speaker names, the names of the listening positions can be changed to match the names you used when exporting the measurements.

Pressing Next on this wizard page causes the Measurement Associations page to appear.

Measurement Association Wizard Page
Measurement Association Wizard Page

You assign a measurement to each combination of listening position and sub/speaker by using the combo box associated with each item in the right-hand column. This is arguably the most important page in the wizard, as it brings together file names, listening position names and sub/speaker names to enable MSO to perform its calculations correctly. After all the associations are made, this page will look as below.

Measurement Association Wizard Page After Associations
Measurement Association Wizard Page After Associations

Notice that careful choices of file names made filling out this wizard page easier. When the listening position is placed first in the file name (rather than putting the sub or speaker name first), the order of the file names in the combo box is the same as the order of the items on this wizard page. This approach speeds up filling out this wizard page and lessens the chance of error.

After clicking Next on the Measurement Associations page, the following wizard page will appear.

Create Configuration or Just a Template
Create Configuration or Just a Template

Choose the Create both a configuration and a template option. Configuration templates are an advenced subject that will be discussed in a separate topic.

Click Next to show the final wizard page.

Specifying the Properties of the New Configuration
Specifying the Properties of the New Configuration

Specifying the Properties of the New Configuration

An MSO configuration uses zero or more parametric EQ filters (PEQs) in each subwoofer DSP channel, along with zero or one gain blocks and zero or one delay blocks per subwoofer channel. This wizard page allows you to specify how many PEQs you wish to use per subwoofer channel in the newly-created configuration. The purpose of each PEQ is to counteract the effect of a room mode on the seat-to-seat variation of frequency response. You can think of it as one individual PEQ per sub channel per room mode, so that N PEQs per channel can counteract N room modes. Thus the number of PEQs per subwoofer channel that you choose roughly corresponds to the number of room modes that have a non-trivial effect on the sub responses over the frequency range of optimization (which defaults to the range 20 Hz to 150 Hz).

Gain blocks are used both to control the level of the subs relative to one another in order to minimize seat-to-seat response variation, and to establish a target SPL level that you'll specify later.

Delay blocks are used to control the interaction of the subs with one another, and provide a way to ameliorate or eliminate response "suckouts" without using a boost at the frequency of the suckout.

Specifying the Number of PEQs Per Sub

If you haven't done so yet, I highly recommend getting the third edition of Floyd Toole's Sound Reproduction book. Chapter 8 alone is worth the price of the book. His Figure 8.8 (d) and (e), which I can't reproduce here, nicely show the relationships between room mode frequencies and response peaks and dips at a given listening position. This insight, along with a room mode calculator, can help guide you in your choice of the number of PEQs per sub to use.

The spin button control illustrated allows you to pick the number of PEQs per sub to use.

Specifying Whether to Use RBJ or Legacy Q Definition for PEQs

Users of miniDSP hardware that will be exporting biquad text files from MSO to set up their filters need not be concerned about this option, as these differences in definition of Q all "come out in the wash" of the biquad coefficient calculations. Users of hardware requiring manual entry of PEQ Q values, such as Behringer DSP amps, need to take care with this option. The Behringer DSP amps use the RBJ Q convention, while the Behringer DCX2496 uses the legacy Q convention. More information can be found in the filter compatibility section. The most commonly used Q convention in modern hardware is the RBJ Q convention.

Specifying Whether to Add Gain and Delay Blocks

Gain blocks are necessary for establishing the response reference level that you specify in the Optimization Options dialog, while delay blocks are very useful to minimize response "suckouts" as mentioned earlier. The default checked option for both of these is recommended.

Specifying Whether to Launch the Graph Properties and Optimization Options Dialogs

Although this is the last page of the Configuration Wizard proper, you can get additional wizard-like behavior by choosing the Launch Graph Properties dialog when done and Launch Optimization Options dialog when done options. By selecting these options, you'll be able to set up your graphs and optimization options right away, speeding up the process. The default checked option for both of these is recommended.

Finishing Up

Press the Finish button to complete the wizard.

Although this completes the wizard-related topic of creating configurations, there are still other configuration-related topics to be discussed. These will be covered in the advanced configuration topics in a separate section.

Next Steps

The next topics to be discussed will follow the chronological order of the dialog boxes that are launched as a result of having chosen the Launch Graph Properties dialog when done and Launch Optimization Options dialog when done options on the last page of the Configuration Wizard above. This leads to a preliminary and very brief discussion of the Graph Properties dialog, followed by a full discussion of optimization options. Graph options will be discussed more fully in a later topic.