"First reflection"...what it means, why it's important, how to find it

[tomlinmgt]

My dilemma now is do I buy two GIK 242 square panels for the first reflection points.
I can then move the square Alpha panels (the current 1st reflection panels) to the back wall and put the long skinny Alphas in the rear corners?
Would this be over kill?

More absorptive surface area on the walls will reduce reverberation in the room...which can indeed be taken too far. I think you're still a good distance from reaching the point of creating a dead room, and pretty much have all of your critical areas dealt with (early reflections) and are pretty close to creating a reflection free zone (RFZ) at the listening spot. However, one thing I see that I'm inclined to point out is that area on the front wall directly in front of the listening spot. That's usually a hot spot if it's acoustically reflective and/or has a tall gear rack there...both of which you have going on. I and others have had some success with getting the gear relatively low to the floor (lower than the distance of your head above the floor when seated in the listening spot) and placing diffusion or a mix of diffusion and absorption in that spot on the front wall directly in front of the listening spot. I think the two narrow panels w/gridfusors that you currently have on the back wall would be great in that front wall spot if you just butt them together and create one larger panel. You may have to move the wall art up a little bit...but first you can just take it down temporarily and put the panels there temporarily (place them on a chair or something so they're raised up to an appropriate height. And after you've done that and heard the result, maybe take the turntable off the rack and remove that top tier/shelf from the rack to see if you can find further improvements. An absence of panels on the rear wall might thin out the upper bass a little, but additional absorption on the front wall might get it back. Having that open door directly behind the listening spot is a definite asset as it eliminates that wall as a generator of early reflections...so at this point I wouldn't bee too concerned about not having any absorption on the rear wall. You can add it back with a few 242 panels if this front wall experiment works out.

 

[tomlinmgt]

Here’s an example of what I’m talking about for the area of the front wall directly in front of the listening spot. I recently set up a system in my son’s bedroom (since he’s gone off to college) as I’ve not yet attempted to set up a “small room” system. I listened to it first with no treatments, then treated early reflection at side walls and rear wall, then added panels to front wall then a diffuser to front wall. The diffuser added noticeable clarity to image and sound stage resolution and depth.



Here’s the thread with more info and pics...
https://audiokarma.org/forums/index...uild-a-small-room-system-for-a-change.881646/

 

[OllieMeyer]

This is great and something I hadn't considered.
I will try it out after work tonight.
Thanks for the advice

 

[OllieMeyer]

I had thought about splitting my rack into two parts but I can't get individual pieces needed.
I have to say I do like having the TT at that height for convenience.

 

[tomlinmgt]

I know what I'm hearing and applying that to the knowledge I've learned about acoustics I know it's right.
All these little tweaks we make to our systems, power cords, cables and such all help but you will never get such a huge leap in sound quality as you will with acoustic treatments.
Treat the space then the system!

I experimented again last night with the panels at 1st reflection. I put the plate back on with the cut outs vertical but didn't like it. It's hard to put a finger in what it was but it didn't sound right.
It later occurred to me that as they are square I can rotate it and they would be horizontal.
Bingo!
Much much better than without and vertical.

The one thing that stands out the most after a few days playing around with placement is how much bigger the sound stage is and most of all the black space.
Those quiet spaces in music are so important and have a huge impact.

That's interesting about the orientation of the scatter plates...I'll definitely make a note of your finding.

And yes...no doubt about it...just about all domestic living spaces are infested with acoustic issues that compromise fidelity. Most just never get the opportunity to hear the extent of the compromise and have convinced themselves that the silver bullets are something more tangible...like gear and cable tweaks. i think the psychology is at a primal level....we are attracted to things we can see and touch. Acoustic treatments don't really offer that sort of tactile and visual satisfaction, so it's not given much priority. Although I think well made and properly executed diffusion can be a beautiful thing.

 

[tomlinmgt]

I had thought about splitting my rack into two parts but I can't get individual pieces needed.
I have to say I do like having the TT at that height for convenience.

Understood. Lowering the gear may not even make a difference for you...so I wouldn't fret over it. Might be worth seeing what happens if you try it, though. Just for the sake of data acquisition.

 

[tomlinmgt]

This is great and something I hadn't considered.
I will try it out after work tonight.
Thanks for the advice

Also, you probably already intend to do this, but try the front wall experiment with and without the scatter plates on the panels. You’ve already figured out the importance of experimentation, so create and explore all possible scenarios.

 

[OllieMeyer]

Here’s an example of what I’m talking about for the area of the front wall directly in front of the listening spot. I recently set up a system in my son’s bedroom (since he’s gone off to college) as I’ve not yet attempted to set up a “small room” system. I listened to it first with no treatments, then treated early reflection at side walls and rear wall, then added panels to front wall then a diffuser to front wall. The diffuser added noticeable clarity to image and sound stage resolution and depth.

View attachment 1624534 View attachment 1624535

Here’s the thread with more info and pics...
https://audiokarma.org/forums/index...uild-a-small-room-system-for-a-change.881646/

I'm tempted to build a diffuser from the thread you started.

 

[tomlinmgt]

I'm tempted to build a diffuser from the thread you started.

Lol. I’m warning you...it’s addictive. Has been for me, at least.

The Leanfuser stepped diffuser is the way to go if you want a diffuser project that’s not so time consuming. That’s what’s on my front wall in the pics with the big JBL’s and little Kefs.

 

[OllieMeyer]

Very informative site

After reading that I'm thinking maybe diffusers on the rear walls might be the way to go.

Plus one on the front wall

 

[tomlinmgt]

Very informative site

After reading that I'm thinking maybe diffusers on the rear walls might be the way to go.

Plus one on the front wall

As long as your listening spot is more than four feet from the wall, diffusion is a fine option for that location. Keep in mind that low frequencies migrate and accumulate at the front and rear walls, so thicker absorption at those locations is a good idea and I've found having panels thicker than 2" on the front and rear walls tightens up mid and upper bass content which helps solidify imaging of the instruments that play in that spectral range. Of course, low frequencies accumulate most in the corners, so traps in the corners is obviously the best spot for absorbing low, first octave frequenices (provided the device is actually effective at absorbing that frequency range), but my experience is that thicker panels on the front and rear walls makes a significant contribution toward improved sound stage/ image resolution and tonality, and particularly with mid and upper bass content. It's remarkable how much better the music sounds when that particular region of the spectrum is "cleaned up" and it seems to be the part of the spectral range that often gets overlooked as most people are focused on lows, mids and highs.

 

[GuyK]

Great thread.

Looking for some advise on my panel placement and additional panels.
I did the RT60 calculator with the following results.

I have GIK panels as shown in the pics below.

I've played around with the placement and with what I have this sounds good.
According to the calculator I need 133 sqft. I currently have 44 sqft.
All the panels I have are bass traps. The two square panels have diffusers that I've taken off for now.
I'm thinking I need to get the 242 panels for the side reflections allowing me to put the square panels on the back wall and the skinny panels in the corners of the same wall.
Any ideas?

Don't forget to add floor/ ceiling coverage into your total. I don't know how thick your area rug is or if you have a nice thick pad under it, but if you put that much absorbtion on the walls I would expect a very dead room. Granted, the rug will not have the same coefficient as the rest of your traps, but it has a huge area.

 

[slippers-on]

That's interesting about the orientation of the scatter plates...I'll definitely make a note of your finding.

And yes...no doubt about it...just about all domestic living spaces are infested with acoustic issues that compromise fidelity. Most just never get the opportunity to hear the extent of the compromise and have convinced themselves that the silver bullets are something more tangible...like gear and cable tweaks. i think the psychology is at a primal level....we are attracted to things we can see and touch. Acoustic treatments don't really offer that sort of tactile and visual satisfaction, so it's not given much priority. Although I think well made and properly executed diffusion can be a beautiful thing.

View attachment 1624554

View attachment 1624559

Michael...is that your room?

 

[tomlinmgt]

Michael...is that your room?

Yes sir

 

[slippers-on]

Yes sir

Beautiful !

I hope to get pics up sometime this week.

 

[tomlinmgt]

Don't forget to add floor/ ceiling coverage into your total. I don't know how thick your area rug is or if you have a nice thick pad under it, but if you put that much absorbtion on the walls I would expect a very dead room. Granted, the rug will not have the same coefficient as the rest of your traps, but it has a huge area.

I’m starting to think these online room treatment calculators are little more than virtual salesmen for absorption panels.

 

[tomlinmgt]

Beautiful !

I hope to get pics up sometime this week.

Thanks man! I know how immersed you are in the hobby, so that means a lot coming from you.

Excellent...let’s get your space dialed in.

 

[Brindabella]

That's interesting about the orientation of the scatter plates...I'll definitely make a note of your finding.

And yes...no doubt about it...just about all domestic living spaces are infested with acoustic issues that compromise fidelity. Most just never get the opportunity to hear the extent of the compromise and have convinced themselves that the silver bullets are something more tangible...like gear and cable tweaks. i think the psychology is at a primal level....we are attracted to things we can see and touch. Acoustic treatments don't really offer that sort of tactile and visual satisfaction, so it's not given much priority. Although I think well made and properly executed diffusion can be a beautiful thing.

View attachment 1624554

View attachment 1624559

Michael...is that your room?

Yes sir

Beautiful !

I hope to get pics up sometime this week.

Like Charles Dickens immortal Oliver "Can I have some more please?" but instead of gruel, pictures of your listening spaces......what you have shared only makes me want to beg for more, love it, love it, love it. Agreed @slippers-on "BEAUTIFUL"

This whole thread is going to be one of my go-to reads for room treatments.

Thank you to all who have contributed.

Rob

 

[OllieMeyer]

Had an hour last night to experiment, moving the skinny Alpha panels to the front wall and found no improvement. Infact it muddied the lower range. I guess not having any absorbtion on the rear wall was the problem.
After reading through the Arqen site I think I need to deal with absorbtion first.
The plan is to get two GIK 242 panels for first reflection.
I will put the Alpha panels on the rear wall. The skinny panels will go in the corners to mirror the front wall and the square panels having the speakers.
All my panels are 6" thick so I think I'll be covered after this.
The second step will be to build diffusers for the front wall.
I plan on splitting my audio rack today. Does any one know how to get individual parts for Solidsteel S3 racks?

 

[OllieMeyer]

This what the rear wall will look like plus or minus the scatter plates.