Room layout (plan)

[AceOfBase]

I’m in the planning phase of a home theatre room in my basement, with the space that I have I’m coming up with a few ideas the following is one of them;
Would this be OK for acoustics?
Please provide any feedback would be appreciated.

 

[Wayne A. Pflughaupt]

The dead center of any square or rectangular room is going to be a "bass hole," so to speak. I.e., the perceived bass level is lowest there, and increases as you move from that point towards any boundary. Not necessarily a problem, except that it'll require more subwoofer output than would be needed for a seat near a boundary.

Regards,
Wayne A. Pflughaupt

 

[JStewart]

Where will the screen or display be located and what size?
Are those the mains in the diagram or sub(s)?
How high is the ceiling?

 

[sm52]

If you leave the speakers in the corners, you"ll have extra bass. If they have port at the back, the speakers should be moved 60-70 cm away from the front wall. It is better to change the listening location to something between the center and 3/4 of the front wall. The reason was indicated by Wayne A. Pflughaupt.

 

[AceOfBase]

So the exact placement of the audio components isn’t exact, I could move the audio components around to maintain better sound quality.
I do, however, have two subs that were not included because I’m not sure where to place them yet (thanks for your reply Wayne A. Pflughaupt).

The ceiling is going to be 6 feet high, I am gonna go with a 7.2 set up, the length of the room is negotiable, but the width is not (since the screen width is almost 11 feet, the width of each main is about a foot I would require a minimum 13 feet width on the larger width portion of the room, unfortunately, I cannot maintain a symmetrical rectangle or square which explains why the incline on each side, which is about a foot (per side). There will be a couple of columns within the room, but I’ll make sure they’re not in the way of viewing.

Here is another picture in 3-D, same room plan on a “ home planner” app

 

[AceOfBase]

If you leave the speakers in the corners, you"ll have extra bass. If they have port at the back, the speakers should be moved 60-70 cm away from the front wall. It is better to change the listening location to something between the center and 3/4 of the front wall. The reason was indicated by Wayne A. Pflughaupt.

So are you suggesting (changing my listening location) as in my seating?
Between center and 3/4 of the front wall?
I can alter (lessen) the length of the room which I have diagramed at 18 feet, but the width (13feet upper portion and 11feet lower portion) cannot be altered.
I can always move the speakers away from the front wall as indicated by yourself thank you for that!

 

[AceOfBase]

The dead center of any square or rectangular room is going to be a "bass hole," so to speak. I.e., the perceived bass level is lowest there, and increases as you move from that point towards any boundary. Not necessarily a problem, except that it'll require more subwoofer output than would be needed for a seat near a boundary.

Regards,
Wayne A. Pflughaupt

The dead center of any square or rectangular room is going to be a "bass hole," so to speak. I.e., the perceived bass level is lowest there, and increases as you move from that point towards any boundary. Not necessarily a problem, except that it'll require more subwoofer output than would be needed for a seat near a boundary.

Regards,
Wayne A. Pflughaupt

I have (2) FOCAL SUB 1000F (110V) not included in the photo, to your point about bass level and any suggestions as to where I should place the subs? I am going to run a 7.2 set up.

 

[AceOfBase]

Where will the screen or display be located and what size?
Are those the mains in the diagram or sub(s)?
How high is the ceiling?

Sorry, I didn’t initially mention where the screen would be, the screen is between those two mains in the front. They are not subs.
Ceiling height, unfortunately is 6 feet
Would it be a good idea to put my centre channel above the screen just touching the ceiling? Or should I leave it where it is? Illustrated in the second photo?

 

[sm52]

Now your chair is in the center. The interval where it is worth trying other places is indicated by the red line.

 

[ddude003]

Something to consider... https://www.cardas.com/system-setup

 

[JStewart]

Sorry, I didn’t initially mention where the screen would be, the screen is between those two mains in the front. They are not subs.
Ceiling height, unfortunately is 6 feet
Would it be a good idea to put my centre channel above the screen just touching the ceiling? Or should I leave it where it is? Illustrated in the second photo?

Do you have the screen already? I ask because at your screen width and a choice of room length, an acoustically transparent screen with the speakers behind seems like it would work better. Especially for the center. If not then center below and angled to ear height at the seating position. We don’t know the aspect ratio of the screen, so I’m guessing based on the width you’ll have only a little more than a foot below it, so keep in mind with the center tilted it’s effective height will be greater than it’s actual height measurement.

As has been mentioned the seat position isn’t the best for bass, but horizontal viewing angle is also important. While it’s somewhat a matter of preference, 45° is the THX standard and I believe @Matthew J Poes (Poes Acoustics) would recommend 60°ish (a range of 45 to 70° if memory serves. Maybe others here will chime in with their preference. So that said, here’s a good tool you can use to arrive at a seating distance based on screen size and viewing angle.

PHFX.COM | tools - optimalViewing

Optimal Viewing Distance Calculator by Phil Holland

phfx.com

Anyway, I think you’ll find at 60° the seat will move closer to the screen from the current position. And I think it will get you closer to an equilateral triangle with the seating position and mains. Let the math begin

 

[JStewart]

A question for @Todd Anderson or anyone else with Auro 3D speaker setup experience. The OP asked about Atmos in another thread and with the ceiling height of 6’, not a good idea. But would an Auro layout without the VOG channel work? If the speaker layout would work, then do processors do a good job when remapping native Atmos to an Auro layout? Thanks!

 

[AceOfBase]

Do you have the screen already? I ask because at your screen width and a choice of room length

The screen is already purchased. It is not acoustically transparent., it is a 2.35:1, 140 inch diagonal

The seating location in the diagram isn’t actual, it was only put there as a reference to be included in the room layout most likely I will push the chair back a little.

 

[AceOfBase]

Was wondering if I went with a perfectly symmetrical (without inclines as diagramed above) 13 ‘ X 16’ room instead of the above mentioned layout plan.
Would that serve as a more acoustically richer environment?

 

[ddude003]

A perfectly symmetrical rectangle 13' x 16' would likely be better than the shape you show in your above diagram... However, your ceiling hight of 6' is not optimal...

The The Golden Ratio, named phi, of height to width to length of a room to achieve optimal sound in a room is approximately the width 1.6 times the height and the length 2.6 times the height, and was named for the Greek sculptor Phidias...

I am sure there are other ways to optimally shape a room... And there are physical acoustic treatments and Digital Room Correction for less than optimal room shapes...

 

[AceOfBase]

The The Golden Ratio, named phi, of height to width to length of a room to achieve optimal sound in a room is approximately the width 1.6 times the height and the length 2.6 times the height, and was named for the Greek sculptor Phidias...

That’s news I can use, I’ve never heard of that before, but I will definitely use it as a reference moving forward, thanks dude.

In order to digitally correct a room using REW, would this;

miniDSP UMIK-1 USB Measurement Calibrated Microphone​

be the correct microphone to purchase for DRC, or is there any other microphones that are more effective and/or less in cost?

 

[ddude003]

Your welcome... Both a UMIK-1 or a UMIK-2 would be more than be sufficient for your DRC using REW... For less cost I could not suggest much...

You might look for a copy of Master Handbook of Acoustics F. Alton Everest & Ken C. Pohlmann online for some basics... Journeyman...

 

[JStewart]

That’s news I can use, I’ve never heard of that before, but I will definitely use it as a reference moving forward, thanks dude.

In order to digitally correct a room using REW, would this;

miniDSP UMIK-1 USB Measurement Calibrated Microphone​

be the correct microphone to purchase for DRC, or is there any other microphones that are more effective and/or less in cost?

To save a couple of bucks there’s Dayton audio umm-6. Personally I’d also stick with UMIK though for piece of mind and resale value. If you want to go an extra (and probably unnecessary) step you can purchase an individually calibrated umik from

Cross·Spectrum - Calibrated MiniDSP UMIK-1 Microphones for Sale

Purchase calibrated MiniDSP UMIK-1 measurement microphones, low-cost option for performing precise and accurate sound measurements

cross-spectrum.com

Which DRC will you be using?

The idea behind the golden ratio or room ratios is distribution of room mode frequencies. Since there’s always practical limitations and compromises… to the extent possible, try to keep from having any dimension from being an even multiple of another. This will also hold true for speaker and seating positions i.e. speakers not same distance from side and front walls, speaker and MLP not same distance from front and back walls, etc.

Construction materials and how reflective they are of the lowest frequencies will also come into play to an unknown extent (without an acoustician and design and engineering involved, that is ).

 

[AceOfBase]

Which DRC will you be using?

To be totally honest, I’m not sure yet, I’m totally new to the concept of using computer assisted programs that measure frequencies!
I’ve seen REW mentioned on this forum, I’m not sure how to attain it, I went online and searched, and it mentioned that the REW is free of charge to download the program. So I’m guessing it could be available to download from this website.?
Any recommendations as to what DRC works best?

to the extent possible, try to keep from having any dimension from being an even multiple of another

So basically, I shouldn’t keep items such as speakers,seating, symmetrically spaced?
Eg. Have the left speaker 6 inches from the front and side wall than the right speaker 1 foot from the front and side wall, possibly offset my seating position to the right or left instead of the center.? is that what you’re referring to?

 

[ddude003]

The latest and greatest releases of REW can be found here... https://www.avnirvana.com/threads/rew-api-beta-releases.12981/

In practice you would want a symmetrical speaker to Main Listening Position and walls in the room layout... I'll let JStewart give an explanation as to what he was referring to...

There are many methods of hardware and/or software solutions for DRC...
And then there is

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[JStewart]

So basically, I shouldn’t keep items such as speakers,seating, symmetrically spaced?
Eg. Have the left speaker 6 inches from the front and side wall than the right speaker 1 foot from the front and side wall, possibly offset my seating position to the right or left instead of the center.? is that what you’re referring to?

Definitely keep them symmetrical for best imaging as @ddude003 already said. Just not same distance from front (the wall behind them) and the side walls, if possible. Sound reflects from boundaries and causes peaks and dips (called constructive and destructive interference) when the reflection combines with the direct sound. Not having boundary distances the same spreads out and lessens the effect. The effect is known as SBIR (speaker boundary interference response). Same holds true for the listener position, although hopefully the seat is further from boundaries which lessens the effect. This can be combatted with acoustic panels also.

What is Speaker Boundary Interference Response (SBIR)?

Learn about Speaker Boundary Interference Response (SBIR). Optimize speaker positioning to improve low-end sound. Explore tips for better acoustics!

www.gikacoustics.com

As far as room correction (DRC) is concerned, most AVRs or Processors have some form of room correction on board. Audyssey, Dirac, and ARC are most common. REW is a measurement system and it can be used for many different purposes but a typical use is to check automated processor DRC (like the ones I listed) results to allow the user to make adjustments to the extent possible with their DRC software/hardware for better results.

Then there is a variety of DRC software that can run on computer based systems. These can be much better (meaning higher frequency resolution and can make adjustments in the time domain) but also can’t easily be used when Dolby or DTS decoding is also involved and Atmos is completely out so far as I last knew. So they’re typically used for music and it’s common for folks to use one system for movies and another for their computer based music. @ddude003 is very familiar with setting those up if you go down that route.