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Audio routing and multi-channel audio Multi-channel audio output is only relevant if your computer has an audio interface that has multiple physical audio outputs which can be accessed independently (often not the case with surround-sound sound cards), and multiple amplifiers and speakers to drive from them. In such cases, you can route different ranks to different speakers, or groups of speakers, and thus provide a three-dimensional effect, at the same time optimising the load on the speakers and minimising distortions within the amplification system. With 'dry' sample sets (no room acoustic recorded into samples) the use of many separate speakers also makes the virtual pipes interact in a much more natural way with the acoustic of the listening room, helping the brain to identify them as separate sound sources and giving much greater perceived clarity. Multi-channel audio output is also only available in the Advanced Edition of Hauptwerk. The relevant screens are accessible in the Hauptwerk Basic Edition but it is not possible to insert additional outputs via the screens, so only a single stereo or mono output can be used with the Basic Edition. We will use an example (by no means optimal) to illustrate how it is configured: Suppose you have an audio interface with eight physical (mono) analogue audio output channels, such as the Focusrite Saffire. Suppose that you want two of those channels to be used for Pedal ranks, with output to two separate mono amplifiers and bass speakers, and with the Pedal pipes distributed evenly amongst those two amplifiers. You also want the next four audio channels to drive two stereo amplifiers to which you will route the main pipework, with the pipes being distributed evenly between those two stereo amplifiers. Finally, the remaining two channels will be used for high-pitch ranks, with standard stereo output. You would need to have three audio output groups in the General settings | Audio output groups screen:
The Output allocation algorithm within group setting determines how Hauptwerk will allocate each individual pipe amongst the available logical outputs within the group. For example, if a group contains three mono outputs and the the selected algorithm is 'Cyclic within octave, octaves constant', the a C-note pipe will be assigned to the first logical output, a C#-note pipe to the second, a D-note pipe to the third, a D#-note pipe back to the first, and so forth. Other algorithms can give a C/C# split, minimise the chance of any two pipes sounding through the same channel at the same time, minimise speaker intermodulation distortion, and other options. After clicking OK on the screen you will receive a warning message that some groups do not have any logical audio outputs within them. This is to be expected because they have not been created at this stage. You would then need to use the General settings | Audio outputs screen to configure five logical (primary) audio outputs:
Still on the General settings | Audio outputs screen, make sure that the correct audio driver is selected for all entries (the Focusrite Saffire's native driver in this example) and select the audio interface's physical analogue audio output channels for each of the logical audio output channels:
You are now ready to load the organ. Load the organ with Organ | Load organ, adjusting rank audio output routing so that the routing screen appears. For each of the Pedal ranks set the Destination output group to Pedal so that its pipes will be distributed evenly amongst the two available mono logical audio outputs, thus sounding in mono. For the high-pitched ranks, select Upperwork for the output group so that all of their pipes will be routed to the (only) stereo logical audio output within that group. Finally, select Main as the group for all remaining ranks. Because there are two stereo logical audio outputs within the group, the pipes will be distributed evenly between those two outputs, but each pipe will still produce stereo output because the logical audio output is stereo:
To summarise some of the key points:
It is also possible to route the lower and upper parts of a rank separately so that, for example, you could route the bottom octave of a rank to an audio output group containing high-powered mono bass amplifiers, and the remainder of the rank to standard full-range stereo amplifiers and speakers. To do so, on the Rank Bass Routing tab of the Rank Audio Output Routing screen, change the Main/bass split point note number from 0 (no split) to 48. 36 is the note number of the bottom C on a 61-note keyboard or a pedalboard, so 48 is the note number of the C one octave above it. You can then use the remaining settings on the tab to select a different audio output group for the bass part, and also to adjust the maximum channel format and resolution, as with the main part. You can also create additional logical audio outputs which are used to mix down the audio from other logical outputs, forming a virtual mixing desk. This enables you to drive separate mixed-down outputs to be sent to external reverb processors, monitor speakers, headphones, and for recording a mixed-down stereo output from a multi-channel audio system, for example. To do this, simply create a logical audio output for each such mixed-down output required, and set its Output type to 'Aux mix-down output':
Now for each of the other (primary; non mix-down) logical audio outputs, specify the new mix-down output as an aux send destination on the Routing tab:
You can also adjust the level for the send, thus providing different mix balances to different mix-down outputs. As with all of Hauptwerk's setting screens, click on the pointer/question-mark icon immediately to the left of a screen's OK button:
... then click onto the screen background or a specific setting for a detailed explanation of its function. This section in the user guide is only intended to give a very brief overview of the use of the audio screens, and must be used in conjunction with the pointer/question-mark. |
