Front or Back wall diffusers

Diffusers at first reflections on side walls and ceiling. Also wall behind listening position.   This works for my Sashas 

@seanheis1 @axo0oxa I’m seeing several people here advocating for diffusion over absorption.  Are there any general rules as to when/where it’s better to use diffusion or absorption?  I’m very interested and not clear on this at all.  My guess is it’s largely room, system, and personal-taste dependent, but just wondering if there are any generally accepted rules on this.  Also surprised someone argued against bass traps that I’d never heard before and had me scratching my head a bit.  Thanks for any thoughts and/or hard-won personal experience. 

General rules? You asked ;-)

1. Leave the first sidewall reflection untreated or diffuse it. 

2. Don't create a row of just absorbers or just diffusers. Leave space between treatments. 

3. Rotate between diffusers and absorbers every other or use hybrid treatments. GIK has scatter plates that go on top of absorbers.

4. If you have a wall right behind your head use a 2 inch absorber there.

5. If you want your room to sound hi-end, diffusers with deep wells is the secret.

6. Scatter plates will preserve precious high frequency energy and help prevent dead room effect, but they aren't a replacement for diffusers with deep wells that diffused midrange frequencies. 

7. The strongest reflection in most rooms is the reflection that pings behind your listening position and then to the front wall...and it will keep doing laps so you need to either diffuse or absorb it. 

8. The best bass trap is free. It's the air gap behind a bass trap which should ideally be the same as the thickness of the bass trap. 

9. The only full range bass trap I know of is an open window or possibly an open door (depending on what's on other side of door). I'm lucky to have a door behind my listening position so I keep it open and my room sounds so much more open and the bass more even compared to when I close the door. 

10. Argument against bass traps? Bass boom can be fun...when the room is excited and ringing it can be thrilling...especially if you're a teenager. ;-)  

@seanheis1 

Can you please post pics of your own setup as an example of your general rules? Thanks

I would be embarrassed to show a picture as my room is such a cluttered mess (free diffusion, right?). 

Here are some good diagrams. https://www.audioholics.com/room-acoustics/room-acoustics-acoustic-treatments/room-acoustics-acoustic-treatments-page-4

I made a lot of treatment mistakes until Michael Green Audio started saying things in the forum here that got me curious....he was right so I started digging deeper. I discovered the Anthony Gramani video series on the Audioholics YouTube channel during covid times. I followed his advice and it was GOLD for me. So now I just pass on what worked for me and warn people about what didn't work for me (mostly conventional wisdom from pro audio).  

@seanheis1 I think I may speak for many here that we care a lot more about sound than clutter, and since a picture is worth 1000 words I think many here (including me) may benefit from seeing what you’re talking about.  But, if it really makes you uncomfortable please just disregard.