As you know, we can mix signals inside MSP implicitly by just connecting two outlets to the same inlet or by using [+~] explicitly. But there is more to routing and organizing mixes of course. Before looking at an attempt to make mixing in Max a bit more convenient, let's look at a simple mixing block that's needed quite often: a dry/wet mixer. We need this quite often; as soon as we build an effect or want to do a crossfade, we'll need to think about this. A naive approach would look like this:

We just scale one signal by a fade value f, and the other one by 1-f. However, this idea has a problem: when the signal at the control inlet is at 0.5, we multiply both inlets with 0.5 (which is equal to an attenuation by 6 dB). The problem is that adding two correlated waves is equal to an amplification by 6 dB, but by mixing two uncorrelated signals (two noise sources for example), we will only get an amplification by 3 dB. So the upshot is that we are too quiet in the...