s.boot;

(
var bufferSize = s.sampleRate * 1; // Buffer size is fixed. s.sampleRate * seconds makes sense.

if( ~plotterIn == nil, { ~plotterIn = Bus.audio( s, 2 ) } ); // Declare a global channel for the plotter input, stereo

if( ~plotterBuffer != nil, { ~plotterBuffer.free } ); // Reset the buffer if existant
~plotterBuffer = Buffer.alloc( s, bufferSize, 2 ); // Create our buffer, stereo

SynthDef( \toBuffer, { // A simple routing synth
	| bufNum |
	var in = In.ar( ~plotterIn, 2 ); // Takes an input
	RecordBuf.ar( in, bufNum, loop: 0, doneAction: 2 ); // And outputs it in our buffer
} ).add;
)

( // Demo Synth
SynthDef( \demoSynth, {
	| out = 0, freq = 220 |

	var snd = SinOsc.ar( freq!2 );
	snd = snd * EnvGen.kr( Env.perc( 0.1, 0.9 ), doneAction: 2 );

	Out.ar( out, snd );
} ).add
)

(
Synth( \toBuffer, [ \bufNum, ~plotterBuffer ] ); // Trigger the buffer synth
Synth( \demoSynth, [ \out, ~plotterIn, \freq, 110 ] ); // Then our favorite synth
)

// You will need to wait the bufferSize length before plotting it !
~plotterBuffer.plot // Finally print the result

if( ~plotterBuffer != nil, { ~plotterBuffer.free } ); // Free the buffer if existant