AVS Forum banner
1 - 20 of 23 Posts

·
Registered
Joined
·
7,040 Posts
Discussion Starter · #1 ·
I have my 10" sub(front firing) in front of the wall under my screen. About how many inches of space should I leave between sub and wall? Thanks.
 

·
Registered
Joined
·
22,860 Posts
What positions have you tried so far?

Does the sub have a rear port? A rear passive radiator? Make/model may help for suggestions.



I'd suggest moving the sub around and try what sounds best to you. There's really no "simple" answer.
 

·
Registered
Joined
·
7,040 Posts
Discussion Starter · #3 ·
Thanks Ratman. It's a KLH sub, rear ported. This is for home theater use only. I just thought there might be a "rule of thumb" for min. and max. inches from wall.
 

·
Registered
Joined
·
3,258 Posts
There is a rule of thumb -- to prevent 1/4 wave cancellation from the front wall. For an 80 Hz crossover frequency, the distance from sub to front wall should be no greater than about 3 1/2 feet.
 

·
Registered
Joined
·
7,040 Posts
Discussion Starter · #5 ·

Quote:
Originally Posted by Terry Montlick /forum/post/18276866


There is a rule of thumb -- to prevent 1/4 wave cancellation from the front wall. For an 80 Hz crossover frequency, the distance from sub to front wall should be no greater than about 3 1/2 feet.

Are you saying the rear of sub should be 3.5' from the wall behind it?
 

·
Registered
Joined
·
5,249 Posts

Quote:
Originally Posted by Terry Montlick /forum/post/18276866


There is a rule of thumb -- to prevent 1/4 wave cancellation from the front wall. For an 80 Hz crossover frequency, the distance from sub to front wall should be no greater than about 3 1/2 feet.
Quote:
Originally Posted by Jim McC /forum/post/18287918


Are you saying the rear of sub should be 3.5' from the wall behind it?

No, it should be no further away from the wall than 3.5 feet. It should also be no closer than about 4" - 6" to allow room for the port to "breath". So the sub should be > 4" - 6" from the wall but
 

·
Premium Member
Joined
·
2,246 Posts

Quote:
Originally Posted by bluesky636 /forum/post/18287954


No, it should be no further away from the wall than 3.5 feet. It should also be no closer than about 4" - 6" to allow room for the port to "breath". So the sub should be > 4" - 6" from the wall but


I don't think I agree with that assumption. I would consider calculating where your modal frequencies are and determine best placement based on that method. Keep in mind there are length, width and height modes. Unfortunately, the best placement for a single sub is often in the middle of the room. If you don't want to use your sub as a coffee table, then I would consider the addition of a second sub. Best wishes!
 

·
Registered
Joined
·
5,249 Posts

Quote:
Originally Posted by SierraMikeBravo /forum/post/18288858


I don't think I agree with that assumption. I would consider calculating where your modal frequencies are and determine best placement based on that method. Keep in mind there are length, width and height modes. Unfortunately, the best placement for a single sub is often in the middle of the room. If you don't want to use your sub as a coffee table, then I would consider the addition of a second sub. Best wishes!

Ummm, Mr. Montlick was the source for the

And anyone that puts a sub in the middle of the room doesn't know what they are doing. If you said "middle of the wall" then that is a different story.
 

·
Premium Member
Joined
·
2,246 Posts

Quote:
Originally Posted by bluesky636 /forum/post/18290295


And anyone that puts a sub in the middle of the room doesn't know what they are doing. If you said "middle of the wall" then that is a different story.



Not trying to argue with you, or anyone, I just resepctfully did not agree fully with your statement, nor do I entirely agree with your middle of the wall statement.
We are not dealing with only one dimension. There are three dimensions to a room. Consider why Dr. Hsu will also recommend, if you have a single sub, to place it behind the couch if the wife will allow it. When I said "middle of the room" perhaps I should not have given the impression of exactly in the middle. It isn't smack in the middle of the room, but somewhere out in the room, assuming you have a single sub, is a more accurate statement. I have found the best way to determine the best placement of the sub is to deal with the axial modes individually. I usually determine the length first, then deal with the width. By determining what your modes are first mathematically, you can then determine a good place to start without dealing with trial and error as much. For kicks and grins, give it a try, and see what you come up with. Also, I should mention that the fundamental frequency of each axial may or may not be the best place to start. I have also had great success with placing subs (notice the plural) near the middle of the wall in the single dimension. Sometimes, one configuration may work better than another. It just depends on the room and the subs you are dealing with IMHO. Best wishes!
 

·
Registered
Joined
·
7,040 Posts
Discussion Starter · #10 ·

Quote:
Originally Posted by SierraMikeBravo /forum/post/18290778


Not trying to argue with you, or anyone, I just resepctfully did not agree fully with your statement, nor do I entirely agree with your middle of the wall statement.
We are not dealing with only one dimension. There are three dimensions to a room. Consider why Dr. Hsu will also recommend, if you have a single sub, to place it behind the couch if the wife will allow it. When I said "middle of the room" perhaps I should not have given the impression of exactly in the middle. It isn't smack in the middle of the room, but somewhere out in the room, assuming you have a single sub, is a more accurate statement. I have found the best way to determine the best placement of the sub is to deal with the axial modes individually. I usually determine the length first, then deal with the width. By determining what your modes are first mathematically, you can then determine a good place to start without dealing with trial and error as much. For kicks and grins, give it a try, and see what you come up with. Also, I should mention that the fundamental frequency of each axial may or may not be the best place to start. I have also had great success with placing subs (notice the plural) near the middle of the wall in the single dimension. Sometimes, one configuration may work better than another. It just depends on the room and the subs you are dealing with IMHO. Best wishes!

Why does he recommend placing a single sub behind the couch?
 

·
Registered
Joined
·
391 Posts

Quote:
Originally Posted by Jim McC /forum/post/18290803


Why does he recommend placing a single sub behind the couch?

I know nothing about subs, but based on the conversation... it must mean that this is a way to get it out in the middle of the room (assuming your couch is not against the wall).... . da
 

·
Registered
Joined
·
142 Posts

Quote:
Originally Posted by Jim McC /forum/post/18290803


Why does he recommend placing a single sub behind the couch?

Shake the couch I would guess and cancel out other frequencies like a treatment? Thats just a guess.
 

·
Registered
Joined
·
5,249 Posts

Quote:
Originally Posted by Jim McC /forum/post/18290803


Why does he recommend placing a single sub behind the couch?

Near field placement eliminates many room problems and allows you to run the sub at a lower level but sound just as loud.
 

·
Registered
Joined
·
5,249 Posts

Quote:
Originally Posted by SierraMikeBravo /forum/post/18290778


Not trying to argue with you, or anyone, I just resepctfully did not agree fully with your statement, nor do I entirely agree with your middle of the wall statement.
We are not dealing with only one dimension. There are three dimensions to a room. Consider why Dr. Hsu will also recommend, if you have a single sub, to place it behind the couch if the wife will allow it. When I said "middle of the room" perhaps I should not have given the impression of exactly in the middle. It isn't smack in the middle of the room, but somewhere out in the room, assuming you have a single sub, is a more accurate statement. I have found the best way to determine the best placement of the sub is to deal with the axial modes individually. I usually determine the length first, then deal with the width. By determining what your modes are first mathematically, you can then determine a good place to start without dealing with trial and error as much. For kicks and grins, give it a try, and see what you come up with. Also, I should mention that the fundamental frequency of each axial may or may not be the best place to start. I have also had great success with placing subs (notice the plural) near the middle of the wall in the single dimension. Sometimes, one configuration may work better than another. It just depends on the room and the subs you are dealing with IMHO. Best wishes!

Have you read the Harmon Kardon papers on sub placement? I can't find the link right now but a Google search will pull them up.
 

·
Registered
Joined
·
1,011 Posts
Exactly what room problems is nearfield placement of a sub supposed to eliminate?
 

·
Registered
Joined
·
5,249 Posts

Quote:
Originally Posted by glaufman /forum/post/18296982


Exactly what room problems is nearfield placement of a sub supposed to eliminate?

I dunno. That's what Hsu says. My VTF-2 Mk 3 is in the far right front corner. Definitely not nearfield.
 

·
Registered
Joined
·
1,011 Posts
With all due respect to Dr. Hsu, I don't know of any room problems that can be corrected simply with nearfield placement.
 

·
Registered
Joined
·
5,249 Posts

Quote:
Originally Posted by glaufman /forum/post/18298968


With all due respect to Dr. Hsu, I don't know of any room problems that can be corrected simply with nearfield placement.

Then I guess you will have to ask him, won't you?
They have a forum on their website where you can discuss things like that. Like I said, I don't use near field placement, so I really don't care. I was merely responding to a question. Perhaps I should have said "Hsu believes that near field placement ..." but that should have been obvious.
 
1 - 20 of 23 Posts
Top