Multi-Sub Optimizer Reference Manual (page 19)

Adding Filters, Delays and Gains to Filter Channels

Once you add filter channels, you can add filters, delays and gains to them. To do so, right-click on the Filters category node under the newly-created channel. This presents a context menu allowing the addition of various filter types as shown below.

Adding Filters Using the Context Menu
Adding Filters Using the Context Menu

Delays, gains and polarity inversions are considered "filters" for the purpose of adding these items to filter channels.

Adding Multiple Filters Using Copy and Paste

When setting up a configuration with multiple subs, you'll almost always want to add a number of parametric EQ filters to each sub channel. If you have four subs and you want to add, say, six parametric EQ filters to each of the four sub channels, that would mean invoking the context menu described above twenty-four times. Fortunately, there is a better way. Once you have added one filter via the context menu shown above, you can copy it and then paste it as many times as you need to. This is illustrated below.

Copying Filters
Copying Filters

When a filter is selected, you can copy it as illustrated above, both by the context menu and the Copy toolbar button being enabled (shown in color). But by far the quickest way to copy the filter is to just select it and press Ctrl+C, rather than using the context menu. This context menu is only shown above to illustrate the alternatives. To paste the filter, select the Filters node of the channel. This is shown below.

Pasting Filters
Pasting Filters

Although you could paste the filter using the above context menu, it's much easier to just press Ctrl+V to paste the filter as many times as needed while the Filters node of the channel is selected. The purpose of showing the context menu is just to illustrate the other options available.

Notice that not only is the Paste command enabled above, but also the Copy command. That is because when the Filters node of a channel is selected, you can copy either all the filters in the channel using Ctrl+C, or selected filters using Ctrl+Shift+C. The latter case will launch a dialog that allows you to select which filters in the channel you wish to copy.

Given our hypothetical case of a manually-created configuration for which we want six PEQs per channel, we can use this procedure to minimize the needed keystrokes.

Restrictions on Delays and Gains

The filters available to add via the context menu depend on whether the chosen channel is a main or sub channel, as well as what filters have already been added to that channel in certain specific cases. For instance, once a delay has been added to an individual subwoofer channel, another cannot be added to that same channel, as this would cause problems for the optimizer. If a delay or gain cannot be added, MSO shows the menu item as grayed out. For example, attempting to create the configuration of delays shown in Figure 1 or gains shown in Figure 2 below is disallowed.

Example of Disallowed Delay Configuration
Figure 1. Example of Disallowed Delay Configuration
Example of Disallowed Gain Configuration
Figure 2. Example of Disallowed Gain Configuration

This can be remedied in several ways. One way is shown in Figure 3 below.

An Alternative to the Configuration of Figure 1
Figure 3. An Alternative to the Configuration of Figure 1

The configuration above is only allowed for subs+mains configurations. For sub-only configurations, shared delay blocks are disallowed.

A corresponding fix for the disallowed gain configuration of Figure 2 is shown in Figure 4 below.

An Alternative to the Configuration of Figure 2
Figure 4. An Alternative to the Configuration of Figure 2

The leftmost delay in Figure 3 above represents a delay added to the Shared Filters node under Subwoofer Channels in the Config View. If you try to add a fifth delay to the configuration of Figure 3 in an attempt to obtain the configuration of Figure 1, you will find that MSO has disabled the menu option to add the delay. Of course, any of the four channels in Figure 3 can be chosen as the one without a delay block. A similar set of restrictions applies to adding gain blocks.

Another permitted delay configuration (for subs+mains configurations only) is shown in Figure 5 below.

Another Alternative to the Configuration of Figure 1
Figure 5. Another Alternative to the Configuration of Figure 1

This configuration has no delay block under the Shared Filters node of Subwoofer Channels in the Config View. Allowing negative delays is permitted, and can be a useful technique if the delay implied by the AVR subwoofer distance setting used when the measurements were performed is larger than the optimum value.

An exactly analogous situation exists with gains as well. MSO prevents configurations that will cause the optimizer trouble, and the preferred configurations for sub gains are shown in Figure 4 above and Figure 6 below.

Another Alternative to the Configuration of Figure 2
Figure 6. Another Alternative to the Configuration of Figure 2

Additional Delay Restrictions for Sub-Only Configurations

For sub-only configurations, only the relative delays between subs are meaningful. Any delay configuration such as Figure 3 above implies a shared or common delay among all subs. But such a shared delay does not affect integration of the subs with one another at all. A shared delay is only useful for integration of subs with main speakers. With subs+mains configurations, such a shared delay models the sub distance setting of the AVR or pre-pro. Allowing such a shared delay for sub-only configurations would cause convergence problems for the optimizer, so they are disallowed. Therefore, for sub-only configurations containing N individually controlled subs, only N - 1 delays are permitted, as shown in Figure 7 below.

Legal Delays for Sub-Only Configurations
Figure 7. Legal Delays for Sub-Only Configurations

For sub-only configurations, it's necessary to figure out which sub channel should end up with no delay block. Instructions for doing this can be found in "Normalizing Gains and Delays" in the "Tips and Tricks" section.

Delays and Gains Not Allowed in Main Channels

Delays and gains cannot be added to main channels. It's assumed that mains distance and level trims have been set correctly prior to performing measurements. Relative gain and delay are accomplished using adjustments to subwoofer channels only. Reductions in delay of the sub channels relative to the as-measured condition are accomplished by allowing negative delay values. A negative delay means that the delay should be reduced relative to the as-measured condition, which corresponds to increasing the subwoofer distance setting in your AVR from what it was when the measurements were performed. These distance changes will be shown at the end of the filter report, which you can view after the optimization is run. To enable the display of these distance changes, make sure System uses AVR or pre-pro with sub out is checked in the Hardware, Filter Reports property sheet of the Application Options dialog. See Supplying Information About Your AVR in this reference manual.

Delay and Gain Restrictions When Pasting Filters

If you copy a filter or filters, then try to paste the filters into another channel, there are certain situations when pasting one or more of the filters would violate one or more of the restrictions above. If none of the filters in the clipboard are legal to paste into a given channel (like trying to paste a single low-pass filter into a main speaker channel), pasting into that channel will be disabled entirely. If some of the filters in the clipboard are legal to paste into the destination channel and others not, MSO will paste all the legal filters into the destination channel, then display a tabbed text window showing what filters were not pasted and why. An example is shown below.

Message When Pasting Illegal Filter
Message When Pasting Illegal Filter