Room layout and acoustics, what to do?

tyhjaarpa

tyhjaarpa

Audioholic Field Marshall
Ratings
471 3 10
#1
I have been waiting for quite long to get dedicated movie room and finally it is coming reality as we bought a house and there is one room where I have pretty much free hands. The room size is not ideal but that is what I have to work with, dimensions are 390cm (12.8ft) x 440cm (14.4ft) x 250cm (8.2ft) and the room has laminate flooring. There is 2 windows and one door in the room. I'm thinking on placing some big soft carpet in front of seats and also thinking about using couple acoustic panels. Question about acoustic panels is how many should I get, what size they should be and where should I be placing them? I have included two floor plans I made with paint that I would like to use as starting point. Would it be bad idea to place shelves on side of the room like I have them in second plan?

I have also been thinking on using bass traps in corners of room and possibly in corners of ceiling as well. How ever I have been thinking do I get real benefits in doing this? And what kind of bass traps would I need to use to get those benefits? Does the size and shape matter much? How about the material they are made from?

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Drunkpenguin

Audioholic Chief
Ratings
672 4
#2
Welcome to the start of a long journey. Start with the floor and windows. Maybe some heavy duty curtains. A base trap in every corner and acoustic panels in the first reflection points. Google the mirror trick. Generally start with a few things and test. Still not enough? Add more. Dont expect to get it right the first time. Itll take some trial and error. But it will be very rewarding in the end.
 
tyhjaarpa

tyhjaarpa

Audioholic Field Marshall
Ratings
471 3 10
#3
Welcome to the start of a long journey. Start with the floor and windows. Maybe some heavy duty curtains. A base trap in every corner and acoustic panels in the first reflection points. Google the mirror trick. Generally start with a few things and test. Still not enough? Add more. Dont expect to get it right the first time. Itll take some trial and error. But it will be very rewarding in the end.
I have plans for using heavy curtains to block light coming from windows anyway as I want the room to be dark when I watch movies. So the windows shouldnt be big problem.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Ninja
Ratings
1,746 6 1
#4
I would get ahold of these guys. Iirc, Brian is known to peruse some forums, and I believe support diy efforts.
https://www.gikacoustics.com/
Also, not sure if your diagrams are to scale but I would definitely not put the seats in the center of the room. That can be a vacuum for bass, and also you’ll want your surrounds more to the sides than noted in the diagrams. Moving the LP back a little, (but not against the wall) will address both.
Also as DP mentioned, the mirror trick works great. I wonder though, being the room isn’t terribly large if you’ll get good enough results just by having furnishings and the big curtains in there. Seems like toole has done research finding favor in basic room furnishings than full acoustic treatments. Obviously there are testimonies to the contrary but I would recommend going a little at a time and seasoning to taste vs going crazy with a room full of treatments. Nobody likes a room that’s toooo dead.
 
TheWarrior

TheWarrior

Audioholic Samurai
Ratings
1,231 14 4
#6
Without measurements you are flying blind!

Full Bookshelves make great diffusors so I would start with the shelves behind the seats, first. I also agree with a thick rug with a pad underneath.

Beyond that, you are just making guesses with your money without taking acoustic measurements.
 
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Drunkpenguin

Audioholic Chief
Ratings
672 4
#7
Without measurements you are flying blind!

Full Bookshelves make great diffusors so I would start with the shelves behind the seats, first. I also agree with a thick rug with a pad underneath.

Beyond that, you are just making guesses with your money without taking acoustic measurements.
Oh come on, don't get all AVS on us over here. Great sound can be achieved using your ears.
 
tyhjaarpa

tyhjaarpa

Audioholic Field Marshall
Ratings
471 3 10
#8
I would get ahold of these guys. Iirc, Brian is known to peruse some forums, and I believe support diy efforts.
https://www.gikacoustics.com/
Also, not sure if your diagrams are to scale but I would definitely not put the seats in the center of the room. That can be a vacuum for bass, and also you’ll want your surrounds more to the sides than noted in the diagrams. Moving the LP back a little, (but not against the wall) will address both.
Also as DP mentioned, the mirror trick works great. I wonder though, being the room isn’t terribly large if you’ll get good enough results just by having furnishings and the big curtains in there. Seems like toole has done research finding favor in basic room furnishings than full acoustic treatments. Obviously there are testimonies to the contrary but I would recommend going a little at a time and seasoning to taste vs going crazy with a room full of treatments. Nobody likes a room that’s toooo dead.
Those plans are just quickly thrown with oainy, seating will be more to back wall that centre. As for rear speakers I need to see how much space I have when I have found fitting seating if I can move them more to sides.

What I'm looking more into is bass traps. But would like to know what difference there is between different bass traps. I really like how these look and ease of their usage: https://www.amazon.com/Auralex-Acoustics-Acoustic-Absorption-Charcoal/dp/B00MHWB7IS Question is how much would I benefit from bass traps like these? Or would there be a lot better options available?
 
TheWarrior

TheWarrior

Audioholic Samurai
Ratings
1,231 14 4
#9
Oh come on, don't get all AVS on us over here. Great sound can be achieved using your ears.
What I'm looking more into is bass traps. But would like to know what difference there is between different bass traps. I really like how these look and ease of their usage: https://www.amazon.com/Auralex-Acoustics-Acoustic-Absorption-Charcoal/dp/B00MHWB7IS Question is how much would I benefit from bass traps like these? Or would there be a lot better options available?
I think AVS would tell tyhjaarpa to spend way too much money on panels!

A few inches of foam hardly makes a bass trap. Your couch and pillows are better for that purpose. But without acoustic measurements, you can't be sure what frequencies are overly excited or just not being heard. Without physical measurements (including listening position distance from boundaries and loudspeakers),you will not know when and where the rooms influence dominates those measurement. (Positional EQ vs DSP)
 
tyhjaarpa

tyhjaarpa

Audioholic Field Marshall
Ratings
471 3 10
#10
I think AVS would tell tyhjaarpa to spend way too much money on panels!

A few inches of foam hardly makes a bass trap. Your couch and pillows are better for that purpose. But without acoustic measurements, you can't be sure what frequencies are overly excited or just not being heard. Without physical measurements (including listening position distance from boundaries and loudspeakers),you will not know when and where the rooms influence dominates those measurement. (Positional EQ vs DSP)
So you think I should get rew or something before buying any acoustic materials? What size bass trap would be effective if 12" x 12" foam triangle is not good?
 
D

Drunkpenguin

Audioholic Chief
Ratings
672 4
#11
Someone correct me if Im wrong, but rew isnt going to tell you what kind of traps to get or where to put them. Its gonna measure the frequency response. You have to run it every time you put a panel up to see what the effect is. This can be accomplished with your ears as well as far as Im concerned.
 
TheWarrior

TheWarrior

Audioholic Samurai
Ratings
1,231 14 4
#12
So you think I should get rew or something before buying any acoustic materials? What size bass trap would be effective if 12" x 12" foam triangle is not good?
Someone correct me if Im wrong, but rew isnt going to tell you what kind of traps to get or where to put them. Its gonna measure the frequency response. You have to run it every time you put a panel up to see what the effect is. This can be accomplished with your ears as well as far as Im concerned.
Bass trapping can be expensive, so you need to know what you are trapping and where before emptying bank accounts or creating the above mentioned "dead" sound. But that does require mapping out your room with both physical and acoustic measurements. Due to the cost of panels, I can't comfortably recommend that you guess!

While I absolutely agree that trained ears can be very effective measurement instruments, the fickle nature of humans will make it nearly impossible to determine how much absorption is 'correct'. Or could you have chosen a different furnishing instead?

I use GIK Acoustics Art Panels so I can speak to the quality of their work, but in a room that size, I would focus on getting all your furnishings in place before putting a dime toward 'room treatment'. If you have booming bass, you're going to need a lot more than a few inches of foam!
 
Y

yepimonfire

Audioholic Samurai
Ratings
431 13 5
#13
Placing the couch/seats as close as possible to 38% to either the front wall or back wall will drastically flatten out the response below 200hz at the listening position. Bass trapping below 100hz (where the biggest problems generally lie) is impractical unless you want several feet thick rigid fiberglass paneling. Your main problem frequencies will lie at about 50hz and 40hz. The best way to deal with this is smart seat/sub placement, and beyond that, room eq to smooth out the rest. Large bass traps will likely function as broadband absorption (above 100hz) and may have a side effect of overly deadening the room.

As previously mentioned, you don't want to overdo it with the acoustic panels. assuming the tweeters are at ear level, a thick rug placed directly halfway between the speakers and seats will dampen most of the floor bounce, acoustic paneling placed on the ceiling in the same position will dampen most of the ceiling bounce. Personally, I like Auralex style panels. Though thinner than your typical OC 703 style panels, the alternating angles of the wedges have greater absorption above 500hz because of the angle of incidence of early reflections. Have someone sit in the center most seat and use the mirror trick to find reflection points. a 24"x48" or 24"x36" section of paneling at each early reflection point will do a lot in taming an overly live room without making it sound too dead. The nice thing about Auralex style foam panels is you can attach and remove them with t-pins temporarily to gauge their effects (good or bad). Because of the size of the room, diffusion is rather useless, and absorption is a better solution.

Shelves or a bookcase directly behind the seating will absorb and diffuse a good deal of the back wall reflections, without overly deadening the room.
 
tyhjaarpa

tyhjaarpa

Audioholic Field Marshall
Ratings
471 3 10
#14
Thanks for the input. I will be moving in 2 weeks and then I will need to paint the room and figure out how I want the curtains to work in the room as well. I will also need to find the seating for the room. After that I can setup the system and see how it works in this room without any added acoustic materials. I was thinking that there would be some general guide how to work with your room so I could prepare it before installation but apparently that is not the case. I will post results and more questions when I have the system installed and running.
 

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