Using Multiple Instances Of a Plugin

Any device description with a single connector can only connect to one rack module at a time. So if you want to use multiple instances of the same plugin on a single rack, you need to add new connectors, or duplicate the device description.

Adding Connectors vs. Duplicating Device

Adding connectors is recommended, if your synth listens to a single MIDI channel and additional instances of the plug-in are all identical. From Synfire 1.7.14 build 8 and later, adding connectors is automated for convenience (see below).

Duplicating a device descripion (DD) is only recommended, if Synfire can not add a connector automatically. Only 'Synth'-style devices with a single MIDI channel and multiple programs (patches) to select from can be extended automatically. This is the case for most synthesizer type plug-ins on the market.

If a DD uses a customized MIDI channel layout, possibly a mix of dynamic and fixed channels, duplication needs to be done manually. In this case, you need to re-create the same channel layout on the new connector. Fortunately, this kind of heavily customized devices are rarely used with multiple instances anyway.

First off however, it is important to understand what connectors are:

Connectors, Instances

The purpose of a device description's connectors A, B, C, D is to connect it with one or more a rack modules, so Synfire knows what sounds are available on these modules.

It is very important to know that connectors typically do NOT represent multiple MIDI ports on a synth/sampler (it's possible, but rare). Most synths/samplers only have a single MIDI port, while their DD can still offer multiple connectors.

Admittedly, the term 'connector' is a bit misleading. To avoid confusion, connectors should probably better be named 'Instances', as each connector A, B, C, D represents a different instance of the same synth/sampler. These instances can be equal (multiple uses of an identical plug-in), or different (different collections of sounds loaded). A few examples:

EWQL Orchestra:A  Strings
EWQL Orchestra:B  Woodwinds
EWQL Orchestra:C  Brass
EWQL Orchestra:D  Percussion

This device description EWQL Orchestra offers 4 connectors (instances), each representing a different collection of sounds assigned to the 16 MIDI channels of the sampler. All instances share a common custom CC setup. Instead of maintaining 4 individual DDs, this one includes them all.


YAMAHA Tyros 4:A
YAMAHA Tyros 4:B

The connectors of this device description do in fact each represent a physical MIDI connector at the hardware synth (it has two of them). This is a situation where the name 'connector' really makes sense. You'll see this most likely with external hardware, as plug-ins can only address a single MIDI port anyway.


NI Reaktor 5 PRISM:A
NI Reaktor 5 PRISM:B

This device description NI Reaktor 5 PRISM is for a synth with 400 factory patches. Both instances A and B represent exactly the same plug-in and their sole purpose is to allow the DD to be used with two rack modules at the same time. 

Adding Connectors (Instances) Automatically

Manually adding connectors can be a pain, if you are frequently using multiple instances of a synth and haven't supplied your DD with multiple connectors in advance. With Synfire update 1.7.14 build 8 and later, a new connector (instance) will be added to an existing DD automatically when you select it on another rack module, or when you load the same rack module preset on multiple rack modules:


Note that you can still only use 4 instances of the same DD in any one rack. If you need more of them, you'll need to duplicate the DD, which will give you another 4 instances to use. We recommend you do so only on an arrangement's private rack and avoid the duplication of DDs on your global rack, as that would clutter your global device list with confusing duplicates.


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housekeeper's picture
Last seen 5 months 5 days ago

Updated for 1.7.14 build 8

janamdo's picture
Last seen 5 hours 10 min ago

Ok, no problem with HALion 5 with 4 connectors

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