My room has "zero" slap echo. Do I need room treatments?

I have absorption panels on the rear wall directly behind the speakers, but also diffusion panels on the adjacent side walls behind the speakers as well, and also between the speakers. Also have diffusion panels on the side walls well in front of the speakers,

But, that’s in my case, with my Vandy 2CE Sigs, in my room. 2CE’s and not like normal ‘box speakers’ and the sound truly surrounds them because of how they are designed. Thus, as I say, you may need to experiment for your particular speakers and room.

Probably; yes. I would have to think any non-treated room can be improved with treatments.

My room had no ’slap echo’ either, but in reality, it was a bit ’dead’, lifeless, and also built-up too much localized bass pressure. I didn’t think I needed any for the same reason until I tried experimenting.

In my case, I did find strategic dampening helped, but got my most positive results with diffusion, which helped break-up the sound and provide better imaging and soundstage. Your room may be different.

Suggestions? Experiment inexpensivly (foam or dense insulated sheets/panels) before spending more on specifically made acoustical treatments. Or, take what you used for experimentation and ’dress them up’. Though, this is easier to do with absorption than diffusion.