How Do You Deal With Baffle Edge Diffraction?


I recently purchased new bookshelf speakers and set up my system in a new room, and after implementing my usual tweaks (power cables, outlets, sound treatments, etc.) I found that the highs were a tad irritating at higher volumes, which caused listener fatigue. My setup was mostly the same as before, except for the speakers. “Perhaps these speakers are just brighter than the last ones,” I thought to myself. But still, bright or not, a decent speaker should not be causing listener fatigue, especially with decent gear upstream. 

I remembered that on my last setup I had made custom speaker grilles out of 1” thick wool with cutouts for the speaker drivers and wrapped it in an acoustically-transparent cloth. The idea behind these is that the wool absorbs the higher frequencies on the face and edges of the baffle, which knocks down baffle edge diffraction. I dug those out and affixed them to my new speakers. It solved most of the problem! They don’t perfectly align with the old speaker driver locations so I need to remake them, but for now I am a happy camper.

I’ve read that felt around a tweeter works very well for this purpose but for whatever reason (probably looks) very few manufacturers implement this. Is anyone else using custom built grilles to help knock down baffle edge diffraction? How do you all deal with this issue? Are you all aware of this issue? If you are currently less than happy with your speakers’ higher frequency performance or struggle with listener fatigue, I highly recommend you try this. In my case, I had all of the materials already, so besides time it was a free upgrade and one of the better tweaks I’ve implemented. 
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Showing 3 responses by mkgus

Try it out and let me know what you think. Two challenges are affixing it to the speaker so it doesn’t cause damage (tape not leaving residue, etc) and making it look presentable. :) I’m currently supporting mine with some dental floss but I will work on a better solution. 
Erik, do you mean the area directly between the speakers or the back wall behind the speakers?
You’re correct Erik. I am referring to baffle edge diffraction. Both that and baffle step are important concepts. Good information all around. 

It’s my understanding that edge diffraction will cause the higher frequencies to “re-emit” from multiple points around the speaker which causes a number of issues. Perhaps worst of all, this “re-emittance” happens out-of-phase with the original sound wave created at the tweeter which really mucks up the sound. I believe this contributes to listener fatigue because the sound doesn’t quite make sense to the brain. (That’s my personal theory. Not sure if tests have been done to verify it.)