Audioparam (Signal) value stays ignored

[wictorsson]

Hi,
when I connect and then disconnect to a parameter, the parameter.value stays ignored. I tried to connect a LFO to both filter frequency and to Oscillator frequency. Once connected and then disconnected I cant change the value anymore unless I reconnect the same LFO. Here is my example code

 var filter = new Tone.Filter(1200, "lowpass");
 filter.frequency.value = 200;
 console.log(filter.frequency.value); //OUTPUTS 200
 var lfo = new Tone.LFO(4, 200, 1200);
 lfo.connect(filter.frequency);
 filter.frequency.cancelScheduledValues();
 lfo.disconnect(filter.frequency);
 filter.frequency.value = 200;
 console.log(filter.frequency.value); //OUTPUTS 0

[chrisguttandin]

As far as I can tell this seems to be a bug somewhere in Tone.js. I tried to replicate the test case with the native Web Audio API and with standardized-audio-context but couldn't reproduce the problem.

https://stackblitz.com/edit/js-jrh9jh?file=index.js

However the code is not entirely equivalent. There is a good chance that I missed something.

[chrisguttandin]

I guess this is the part of the code which is causing the problem.

Tone.js/Tone/signal/Signal.ts

Lines 203 to 226 in 08df7ad

	/**
	* When connecting from a signal, it's necessary to zero out the node destination
	* node if that node is also a signal. If the destination is not 0, then the values
	* will be summed. This method insures that the output of the destination signal will
	* be the same as the source signal, making the destination signal a pass through node.
	* @param signal The output signal to connect from
	* @param destination the destination to connect to
	* @param outputNum the optional output number
	* @param inputNum the input number
	*/
	export function connectSignal(signal: OutputNode, destination: InputNode, outputNum?: number, inputNum?: number): void {
	if (destination instanceof Param || isAudioParam(destination) ||
	(destination instanceof Signal && destination.override)) {
	// cancel changes
	destination.cancelScheduledValues(0);
	// reset the value
	destination.setValueAtTime(0, 0);
	// mark the value as overridden
	if (destination instanceof Signal) {
	destination.overridden = true;
	}
	}
	connect(signal, destination, outputNum, inputNum);
	}

[chrisguttandin]

It's possible to avoid this behavior by piping the audio through a raw GainNode from standardized-audio-context at first.

https://stackblitz.com/edit/js-vot4qi?file=index.js

[mikezaby]

I'm facing the same problem as well. I'm trying to build a modular system and dynamically connecting and disconnecting modules, so it's a significant issue for me.

[wictorsson]

I'm facing the same problem as well. I'm trying to build a modular system and dynamically connecting and disconnecting modules, so it's a significant issue for me.

I can confirm that chrisguttandins workaround above using a GainNode works. I’m also building a modular system.

[mikezaby]

overridden

Based on what you sent, I tried to changed to oscillator.frequency.overridden = false after the disconnect, and seems that works