I'm building a visualiser with multiple graphic modes. For a few of them I need to calculate the beat of the track being played, and as I understand I then need to apply a lowpass filter like the following, to enhance frequencies that are most probable to hold drum sounds:
var filter = context.createBiquadFilter();
source.connect(filter);
filter.connect(context.destination);
filter.type = 'lowpass';
But what if I want to turn the filter off? Do I have to re-connect the source every time I need to remove the filter? Would this have any negative effect on performance?
Related question: how much performance loss would I experience if I have two two sources, from the same audio source, and apply the filter to one of them?
how much performance loss would I experience if I have two two sources, from the same audio source, and apply the filter to one of them
You can connect a single audio node to multiple destinations, thus you never need a duplicate source just to spread-connect it. If you need filtered and raw audio simultaneously, you can just setup your connections accordingly:
var filter = context.createBiquadFilter();
source.connect(filter);
source.connect(context.destination);
filter.connect(context.destination);
filter.type = "lowpass";
Anyways, setting the type property of a FilterNode to "allpass" will effectively disable all filtering, without having to reconnect:
filter.type = "allpass"