Home Theater Speaker Placement

[Chemist1]

I am a brand new member to this site, but I am a current member of your Audiophytes YouTube channel after learning great information from your videos. I am a scientist by trade, but I am one of those weird people who actually likes to play with electronic equipment and try to figure things out to provide the best performance or help my girlfriend try to figure out why her Lifetime show is not on TV because she can't figure a remote to save her life.

I recently purchased a MARANTZ SR7005 to replace a lower end 5.1 Surround Sony receiver to more utilize the subwoofers and speakers that I have also acquired. I live in a open concept floor plan on the top of a red barn like structure, and it is not that conducive to setup a home theater. The room that my sitting room shares a space with the kitchen on one side, and there is the steps leading from downstairs and the dining room on the other side. My current sitting position on my sectional is also to the right of the area that my main speakers are playing, and this is the spot on the sofa she likes to sit, so the other side does not work. However, I am thinking of swinging the back around to the main sitting position, so I am facing the TV that is mounted above the fireplace in the back corner of the room. I really don't have a mid wall to place the subwoofers, but one is wireless, so it could be plugged in almost anywhere in the room. I have been thinking about grabbing a MINIDSP HD and a MIC to get them working together, but I am fairly new to all this stuff and want to get the best out of my equipment.

My equipment consists of the following equipment:
Marantz SR7005
Martin Login Dynamo 1000W Sub 1
SVS PC 2000 Sub 2
Klipsch RP-260F Tower Fronts
Pinnacle BD 600 Center Channel
Kilpsch R-41SA Front Height
In-Wall Side Surround
In-Ceiling Back Surround
Harmony Elite Remote

I have attached a couple image of my sitting area with my current layout. I am planning on moving the sectional as mentioned above to get more in line with the center channel and front speakers. The speakers in the wall and ceiling were in the place before I moved in this place, and I am looking at putting the Kilpsch R-41SA speakers to replace the two back surrounds and mount them close to wall instead of on top of the two front speakers. I have run Audyssey, but I know my setup needs some work. Any more help would be greatly appreciated.

 

[MalVeauX]

Hi,

Definitely look into optimal placement of the speakers relative your sitting position. As it is, you're pretty much off-axis from your mains and center and then your view is not even where the imaging will place things. I imagine its weird to listen to a movie on this if you're not already just used to the placement and the imaging being all over. I realize not everything is an option in each room. But as it is, the TV over the fireplace thing and trying to work around that is going to be tough. But I would try to do something with this so that you're imaging is more appropriate. And I would start with Dolby's guide to speaker setup for the angles for ideal placement.

A calibrated microphone and REW will certainly reveal a lot of information, but its actual practicality for a room like this is very limited. But it's still a great way to get a sense of what your bass range is doing (as this is important with those walls and bass radiates as a sphere, its not directional, so good sub integration matters a lot; and two is even better for covering up your SBIR generated null).

Very best,

 

[Chemist1]

Hi,

Definitely look into optimal placement of the speakers relative your sitting position. As it is, you're pretty much off-axis from your mains and center and then your view is not even where the imaging will place things. I imagine its weird to listen to a movie on this if you're not already just used to the placement and the imaging being all over. I realize not everything is an option in each room. But as it is, the TV over the fireplace thing and trying to work around that is going to be tough. But I would try to do something with this so that you're imaging is more appropriate. And I would start with Dolby's guide to speaker setup for the angles for ideal placement.

A calibrated microphone and REW will certainly reveal a lot of information, but its actual practicality for a room like this is very limited. But it's still a great way to get a sense of what your bass range is doing (as this is important with those walls and bass radiates as a sphere, its not directional, so good sub integration matters a lot; and two is even better for covering up your SBIR generated null).

Very best,

I really appreciate the help, and I have since angled my listening position to face the corner of the room with the TV mounted above the fireplace, and my front speakers are now facing my listening position. It does sound better, but the lower frequencies sound kind of muffled. I am thinking of moving one of the two subs on the opposite side of the front wall, so it is diagonal across from the other sub on the side wall to see if it will help.

I have been reading about the MiniDSP 2X4 HD and thinking of purchasing one along with a mic to help with the placement of the subs. I noticed the distance in Audyssey are off after I did a calibration, and I am not sure if it will help to input the correct values. I really am new to all of this stuff, and it can be a bit confusing at first to know how to proceed.

 

[MalVeauX]

Hi,

So before buying the MiniDSP 2x4 HD, get the microphone and run REW and measure your room first. Know what you're getting into.

Before that though, since you mentioned some bass problems, my bet is you're noticing some nulls in some important ranges in your bass. This is caused by reflections off the all behind your speakers. This is 100% in every room, every time, just to different degrees dependent on placement and whether or not the room is treated. Usually its expected for a null to occur in upper bass frequences on your mains, so you use a subwoofer to then cover that null. And your sub's null is farther up in frequency range so your mains cover its null, and the result is smooth flat response at listening position. But if your speaker placement is not optimal for this, you may be getting a pretty hungry null from both and causing big problems for your bass.

So to quickly figure this out, because its completely calculable actually, we can tell you what your null(s) will be in your bass frequencies based on their placement and the wall behind them and your listening position.

So if you will, provide the following measurements in inches (be as accurate as you can be):

1) Distance of front of your speaker (each main L & R individually) from it's face (where the drivers are) to your listening position (where you ears are; X) and also the distance from the face (where the drivers are) to the wall directly behind it (on axis both ways).

2) Distance of your subwoofer(s) also from its face (closest wall of the sub cabinet to you) to your main listening position where your ears are (X) and also from that closest wall of the cabinet again to the wall directly behind it. Do this for each sub in its location.

Very best,

 

[Pogre]

Distance is more about delay or timing than the actual measured distance. I've even added distance and got a better response. It's used to keep your subs in phase with everything else so I wouldn't mess with it.

Subs are tricky and placement can be challenging. Have you heard of the sub crawl? Seems a little goofy, but as a scientist I think you'll appreciate how it works because you're using physics in your favor. You put your sub in your seat, play something bassy and crawl around the room to find the spot where it sounds best. That's where you want to put your sub. Having 2 of them is a plus and can help with room modes.

How to Place a Subwoofer For Best Bass Performance

Subwoofer Placement: An easy guide for placement of your home theater subwoofer. Crawl for bass to find the optimal location and achieve the best sound.

www.audioholics.com

 

[MalVeauX]

Distance is more about delay or timing than the actual measured distance.

The context I bring up in, it's for SBIR (nulls) calculations. If you're calculating speaker boundary interference response, the null that is in bass when speakers are near a wall, then yes the actual distance is important (it's rather precise; this is why I'm asking for distance measurements) and its not the delay or timing in this context, it's the two equal magnitude waves meeting out of phase at the listening position and generating that ugly null. This can be figured out without a microphone and can't be fixed with anything other than placement and treatment in a room. You can calc it and then measure it and it will agree rather precisely.



Very best,

 

[Chemist1]

Hi,

So before buying the MiniDSP 2x4 HD, get the microphone and run REW and measure your room first. Know what you're getting into.

Before that though, since you mentioned some bass problems, my bet is you're noticing some nulls in some important ranges in your bass. This is caused by reflections off the all behind your speakers. This is 100% in every room, every time, just to different degrees dependent on placement and whether or not the room is treated. Usually its expected for a null to occur in upper bass frequences on your mains, so you use a subwoofer to then cover that null. And your sub's null is farther up in frequency range so your mains cover its null, and the result is smooth flat response at listening position. But if your speaker placement is not optimal for this, you may be getting a pretty hungry null from both and causing big problems for your bass.

So to quickly figure this out, because its completely calculable actually, we can tell you what your null(s) will be in your bass frequencies based on their placement and the wall behind them and your listening position.

So if you will, provide the following measurements in inches (be as accurate as you can be):

1) Distance of front of your speaker (each main L & R individually) from it's face (where the drivers are) to your listening position (where you ears are; X) and also the distance from the face (where the drivers are) to the wall directly behind it (on axis both ways).

2) Distance of your subwoofer(s) also from its face (closest wall of the sub cabinet to you) to your main listening position where your ears are (X) and also from that closest wall of the cabinet again to the wall directly behind it. Do this for each sub in its location.

Very best,

HI!

I have been traveling for work, but I really appreciate your willingness to help me out.

#1. Distance from front of right speaker to listening position is 15’1” and the front of speaker to wall is 17”. Distance from front of left speaker to listening position is 16’ 5” and the front of speaker to wall is 16.5”.

2.Distance from front of Sub 1 to listening position is 19’ 11” and the front of Sub 1 to wall is 13”. Distance from front of Sub 2 to listening position is 14’ and the distance from Sub 2 to wall is 4”. It is a downward firing subwoofer.

I tried to get as accurate as possible and what you are saying makes sense after reading more about it.

Thank You!

 

[Chemist1]

Distance is more about delay or timing than the actual measured distance. I've even added distance and got a better response. It's used to keep your subs in phase with everything else so I wouldn't mess with it.

Subs are tricky and placement can be challenging. Have you heard of the sub crawl? Seems a little goofy, but as a scientist I think you'll appreciate how it works because you're using physics in your favor. You put your sub in your seat, play something bassy and crawl around the room to find the spot where it sounds best. That's where you want to put your sub. Having 2 of them is a plus and can help with room modes.

How to Place a Subwoofer For Best Bass Performance

Subwoofer Placement: An easy guide for placement of your home theater subwoofer. Crawl for bass to find the optimal location and achieve the best sound.

www.audioholics.com

I have two Subs in the room. The back facing sub is up front SVS PC 2000 and the downward facing Sub Martin Logic Dynamo 1000W is in the back again the side wall adjacent to the listening position. Not sure which location is best but I was thinking of the crawling trick to help. Do you do it with both Subs?

 

[Chemist1]

The context I bring up in, it's for SBIR (nulls) calculations. If you're calculating speaker boundary interference response, the null that is in bass when speakers are near a wall, then yes the actual distance is important (it's rather precise; this is why I'm asking for distance measurements) and its not the delay or timing in this context, it's the two equal magnitude waves meeting out of phase at the listening position and generating that ugly null. This can be figured out without a microphone and can't be fixed with anything other than placement and treatment in a room. You can calc it and then measure it and it will agree rather precisely.



Very best,

I am starting to understand it but it is really the first time I have looked into it. I am looking at a pair of DT SR-9040 to replace the in wall surrounds, but I am trying to figure out the whole bipolar speaker thing too. LOL

 

[Jerkface]

The context I bring up in, it's for SBIR (nulls) calculations. If you're calculating speaker boundary interference response, the null that is in bass when speakers are near a wall, then yes the actual distance is important (it's rather precise; this is why I'm asking for distance measurements) and its not the delay or timing in this context, it's the two equal magnitude waves meeting out of phase at the listening position and generating that ugly null. This can be figured out without a microphone and can't be fixed with anything other than placement and treatment in a room. You can calc it and then measure it and it will agree rather precisely.



Very best,

Looking at the room, the biggest parallel reflection point I'm seeing is ceiling to floor, no?

It's a shame they did that flat ceiling in the loft of a barn like this, because the high angled ceiling would have been great for acoustics.

 

[MalVeauX]

#1. Distance from front of right speaker to listening position is 15’1” and the front of speaker to wall is 17”. Distance from front of left speaker to listening position is ” and the front of speaker to wall is 16.5”.

2.Distance from front of Sub 1 to listening position is 19’ 11” and the front of Sub to wall is 13”. Distance from front of Sub 2 to listening position is 14’ and the Sub 2 to walk is 4”. It is downward facing.

Hi,

Mains:

So at 15 feet 1 inch distance (I will assume both speakers are this since your left speaker is missing this information. So the direct path from your speaker to your listening position is 15 feet 1 inch (4.525 meters). The indirect path is the 17 inches to the back wall, plus the 17 inches back from the wall to the front reflected, and then the 15 feet 1 inch to your listening position (5.375 meters). The difference is 34 inches (0.850 meters). That's going to generate a null at 202hz in your upper bass. Keep in mind, this is well above your cross over. So you simply will not cover this null most likely. The only way to fix this is with broadboad low frequency absorption treatment behind the speakers (like 4 inch to 6 inch very dense material), and/or pulling the speaker away from the wall to increase the indirect path to drive the null deeper into low frequency where it can be covered by your subs (but this requires you pull the speakers from the wall significantly, ie, a few feet). So if you did a frequency response of these speakers even with your subs, you'd see a huge null (dip with no audible SPL basically in the 202hz range with a curve on each side of it for a small range of frequencies that are canceled out and inaudible).

Sub 1

So the first sub is 19 feet 11 inches (239 inches) to your listening position, as the direct path. The indirect path, the reflection, will be 13 inches to the wall, 13 inches reflected back, then 19 feet 11 inches to your listening position (265 inches). That's 6.625 meters indirect and 5.975 meters direct, for a difference of 26 inches or 0.650 meters. This will generate a null at a 264 hz, this is fine because that's way above it's crossover and is covered by your mains.

Sub 2

I can't really follow through the typos (walk?) and stuff, but the wall behind the sub, not the floor, isn't likely 4 inches away. So I guess I'll just assume it's another 13 inches to the wall like your other sub, just because I don't have that measurement, so will just guess. But 14 feet direct path (168 inches) and then a reflection of 13 inches back to the wall, 13 inches forward again then another 14 feet for the total direct path (194 inches), is a difference of 26 inches, or basically the same as your Sub 1 for this purpose, resulting in the same null at 264hz. Again, covered by your mains.

So ultimately the main null to deal with is with your mains, at 202hz and you can address it with placement or treatment. The subs won't cover it.

Anyhow, that's the kind of exercise I was thinking of since you can calc this before measuring and get a good idea of what to expect and where you might want to put your attention when working out room treatment and placement of speakers.

Very best,

 

[Chemist1]

Hi,

Mains:

So at 15 feet 1 inch distance (I will assume both speakers are this since your left speaker is missing this information. So the direct path from your speaker to your listening position is 15 feet 1 inch (4.525 meters). The indirect path is the 17 inches to the back wall, plus the 17 inches back from the wall to the front reflected, and then the 15 feet 1 inch to your listening position (5.375 meters). The difference is 34 inches (0.850 meters). That's going to generate a null at 202hz in your upper bass. Keep in mind, this is well above your cross over. So you simply will not cover this null most likely. The only way to fix this is with broadboad low frequency absorption treatment behind the speakers (like 4 inch to 6 inch very dense material), and/or pulling the speaker away from the wall to increase the indirect path to drive the null deeper into low frequency where it can be covered by your subs (but this requires you pull the speakers from the wall significantly, ie, a few feet). So if you did a frequency response of these speakers even with your subs, you'd see a huge null (dip with no audible SPL basically in the 202hz range with a curve on each side of it for a small range of frequencies that are canceled out and inaudible).

Sub 1

So the first sub is 19 feet 11 inches (239 inches) to your listening position, as the direct path. The indirect path, the reflection, will be 13 inches to the wall, 13 inches reflected back, then 19 feet 11 inches to your listening position (265 inches). That's 6.625 meters indirect and 5.975 meters direct, for a difference of 26 inches or 0.650 meters. This will generate a null at a 264 hz, this is fine because that's way above it's crossover and is covered by your mains.

Sub 2

I can't really follow through the typos (walk?) and stuff, but the wall behind the sub, not the floor, isn't likely 4 inches away. So I guess I'll just assume it's another 13 inches to the wall like your other sub, just because I don't have that measurement, so will just guess. But 14 feet direct path (168 inches) and then a reflection of 13 inches back to the wall, 13 inches forward again then another 14 feet for the total direct path (194 inches), is a difference of 26 inches, or basically the same as your Sub 1 for this purpose, resulting in the same null at 264hz. Again, covered by your mains.

So ultimately the main null to deal with is with your mains, at 202hz and you can address it with placement or treatment. The subs won't cover it.

Anyhow, that's the kind of exercise I was thinking of since you can calc this before measuring and get a good idea of what to expect and where you might want to put your attention when working out room treatment and placement of speakers.

Very best,

I apologize for the typos, and I did go back and try to correct them. The second Subwoofer is downward firing into the carpeting, so the back of it is only 4 inches from the side wall. The first subwoofer if a cylinder style that is firing back into the angled corner below the TV, and it is in the front of the room on the stone fireplace mantle.

I am thinking of possibly switching them, so I have the downward firing subwoofer on the stone fireplace mantle. It does have the spikes on the bottom for the carpet, and it is wireless, so I can place it most anyplace in the room. I am not sure of the best spot to put them with the weird shaped room.

I will need to go through your post again to understand it better, but I really appreciate all your help. I was thinking of possibly doing the consultation that is currently being offered on the Audioholics website to help me figure this all out. I am not apposed to adding acoustic treatments if needed to improve the sound, and I have a Digital Sound Level Meter if it would help here at all.

Thank you again!

 

[MalVeauX]

Hi,

The main goal of the exercise was to see where the null was for your mains and subs to ensure they were covering each other at listening position so that you had smooth response. Your null from the subs is out of the subs's range, so your mains cover it. That's good. Leave your subs as they are likely. Your mains however have a null that is not covered by the subs, as they're so close to the wall that their null is in upper bass. So this is the only big null in your bass that needs to be considered, if you want to even bother. You may not notice it that much, but it will impact how dialog sounds at that frequency and some common effect sounds, etc. Since you cannot pull them way out from thew all (understandable, its a living space, not a dedicated audio room) you can explore putting thick broadband absorption treatment behind the main speakers instead to dampen that reflection which should help calm down the SBIR in the first place.

Very best,

 

[Pogre]

The context I bring up in, it's for SBIR (nulls) calculations. If you're calculating speaker boundary interference response, the null that is in bass when speakers are near a wall, then yes the actual distance is important (it's rather precise; this is why I'm asking for distance measurements) and its not the delay or timing in this context, it's the two equal magnitude waves meeting out of phase at the listening position and generating that ugly null. This can be figured out without a microphone and can't be fixed with anything other than placement and treatment in a room. You can calc it and then measure it and it will agree rather precisely.



Very best,

Right. Agreed. What you're talking about refers to the length of the waves and how they interact with the room. What I'm referring to is more about processing time.