sorry, can you expound on what you are suggesting. im not quite sure im following.
Well when you put in foam in your waveguide, three things can happen:
- amplitude response changes (this is for sure, it will result in a low pass filter)
- directivity changes
- HOMs are reduced
The idea is, that the latter is responsible for the audible improvement. But the only way to know is by making sure the other two are not the case. So you need to correct the amplitude response after inserting the foam, and measure the directivity to make sure it's equal. If it's not, than you might take them into an anechoic environment (like outdoors) to reduce the effect the directivity has on the audible quality. But it's a hassle, i understand .