# Load external synthdefs

``

    load_synthdefs  path (string)

Load all pre-compiled synth designs in the specified directory. The binary files containing synth designs need to have the extension `.scsyndef`. This is useful if you wish to use your own SuperCollider synthesiser designs within Sonic Pi.

## Important notes

You may not trigger external synthdefs unless you enable the following GUI preference:

`Studio -> Synths -> Enable external synths and FX`

Also, if you wish your synth to work with Sonic Pi’s automatic stereo sound infrastructure you need to ensure your synth outputs a stereo signal to an audio bus with an index specified by a synth arg named `out_bus`. For example, the following synth would work nicely:

    (
    SynthDef(\piTest,
             {|freq = 200, amp = 1, out_bus = 0 |
               Out.ar(out_bus,
                      SinOsc.ar([freq,freq],0,0.5)* Line.kr(1, 0, 5, amp, doneAction: 2))}
    ).writeDefFile("/Users/sam/Desktop/")
    )

Introduced in v2.0

## Example

# Example 1
``
    load_synthdefs "~/Desktop/my_noises"
| ``
    # Load all synthdefs in my_noises folder