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Suggestions on placement of 2 18's nearfield (Am I out of my mind?)

1K views 31 replies 8 participants last post by  PM-Performance 
#1 ·
Some may have seen my other posts on some changing around I am making.
I decided I am going to go with 2 SI-HT18's in seperate ported boxes.
I did a sub crawl with my SVS again tonight and confirmed all my heavier bass seems to linger around the back of the room, so I am considering placing them nearfield flaking the corners of my theater seats, but I am weary of this as I dont want everyone else to go in bass overload. Also to the one side there is a pole close by, so I am not sure of the effect of a metal pole with bass close by from subs that big.

I am thinking of either DiySound StoneHenges or Maybe a Fully Marty's (Stonehenges being more manageable sized and cheaper though)

Here are some pics of what I am dealing with. If I go up front by my screen, I can only do like MartyCubes which are smaller and not in the optimal bass zone, but will punch head on.
Suggestions?

The white things in the back are what I could find to similate subwoofer boxes for now. lol, but I was thinking of angling in like that.
 

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#2 ·
There's nothing magical about placing subs close to the LP. Depending on the distance relationships between the subs, LP and room boundaries you can end up with less bass. That especially applies to cancellation modes resulting from ceiling bounce. So while it may work out for you, it also may not. Only by trying and measuring the results will you know.
 
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#4 ·
From a frequency response standpoint, I would agree. In fact, many times it can adversely affect the FR if they are close together.

However, IME, from a tactile feedback standpoint, near field placement is much more visceral as opposed to further away.
 
#5 · (Edited)
The problem is enclosure size.
I can go smaller with the Marty cube and move them around if needed. But the minimarty and Stonehenge will likely only work in that spot, so I don't have room to play if I don't get the desired effect.
I can do the cube up front flanking my towers facing towards seating position, just may get less response there and they will be significantly closer together

Sooo hard to figure this out with nothing to measure and a smaller sub
 
#6 ·
If I go with front stage, I have about 38" maybe between each tower and the center stand.
A minimarty would almost touch side to side I think and stick out fairly far and up. Also worried about screen shake on that wall, but I guess not a big worry since its concrete under the floor.
 

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#8 ·
I say go for the bigger, badder subs and sort it out later. :)

Looks to me like you have a lot of free space in that room to play with that you're not considering as "free space". ;)
 
#9 ·
I have alot of other crap in there you cant see in the pictures.
There is a desk on the far left of the screen towards the other wall and a door about 5 ft from the tower on that side.
On the other side of the right tower there is a door about 6 inches from that tower and then a dog kennel in the other corner.
I suppose I could go bigger and bring the subs out more (left side closer to the door and right side past the door and move the dog cage somewhere else)

If I run in the back, I am limited by poles and steps on the one side. (this is where the crawl test is best for me though)
So if I go big, I am limited. If I go smaller like the Cube or Stonehenge, I can pretty much put anywhere without a problem.

Also my thoughts are if I spread them out too far, I may lose too much impact with filling the rest of the room and having a gap closer to where we watch.

I can post more pics of the room layout if anyone thinks it will help more. I really want to decide on a box like tonight since I have the money now.
 
#31 ·
You should paint those poles black! It seems like it may make them disappear from your peripheral. Sorry, off topic but I couldn't help it :)

I have my large 15" slot ported sub near field and love it. Doing a sub crawl made me think that under my screen would be the best but after testing, near field was MUCH better in my room. But then again, my room is very sub-optimal (20ft high ceilings and opens to a kitchen and upstairs).
 
#12 ·
Corner loading is 20 ft in each direction though. I would think I would lose more over distance?
I guess I could try angling them in from the far corners and see.
I would just need to move that bookshelf and dog crate to the other side of the room or use the back corners of the room
 
#14 ·
Like derrick said you, should experiment with all placement options and go from there. Even tho my subs are nearfield, I still get the same amount of output 18ft across the room, so I would not be concerned with distance. What you should do is start getting familiar with the freeware progam REW and prepare to start taking measurements. I spent several weeks off and on when I had time moving,measuring, and tweaking my subs until I found the best spot for my room. I can say REW and my 80.00 UMM-6 mic was one of the best investments I have made.
 
#15 ·
Thanks for the info guys. I decided to play with more bassy material that went fairly low today to get some measurements on my SPL app. (i know this is not a great tool, but can atleast tell me where my dead spots are compared to the other spots)

I found right up by my front stage it was very dead. Anywhere along the back was quite a bit hotter. I tried the front corners and on the lower notes seemed to be very hot also. So I guess I will plan on front corner loading and move around from there. I measured and will be about 16ft from the MLP to each driver, so I guess thats not too bad.
Now my other issue will be if 2 18's will be enough. lol. I see all these guys in here throwing around atleast 4-8 18's and still want more. . . . . .
Is it feasible to be hitting 115-120db from 2 HT-18's in a smaller ported box? I remesured the room and its closer to 3600ft3

I have 2 bass shakers coming in too to help and will likely grab another 2 for tactile response. I just want to make sure this is going to be worth the investment and not going to find out its barely louder than my pieced together setup now.

I will need to invest in a proper mic and understanding the rew software. Seems a bit intimidating, but I guess at this point, I need to make the most of what I have. I think I will have a fairly good foundation, I just need to tweak it all.
 
#18 · (Edited)
I have ordered the Si HT-18's and still trying to decide between the Stonehenge and the Marty cube. If I keep them in the front corners I can stretch to the mini marty or full marty, but may need to rethink when I move.


18 in. subs in a ported box should be good to around 15 Hz. Somewhere in the 16-63 Hz band you should hit 115 db. Do you have sub EQ and check the room's response like BH suggested?

Basshead81, I think I read you have some big Klipsch speakers?
I do not have any measuring equipment. I have been just ordering equipment all day yesterday for the subs and amp and connectors and waiting to figure out the boxes. I guess next step is to get a mic and figure out how to use all the software and make sense of the graphs. I will deff need alot of help.
Should I get a mic before I decide on boxes so I can see where the best positioning will be and let that decide on which box? If so do I just keep taking measurements at each spot with the sub at the listening position? Or physically moving the sub to each spot and taking measurements from the MLP?

Is SUB EQ software i assume?
 
#19 ·
First of all, invest in a decent mic like one from Cross Spectrum and move your current sub around the room and measure at the MLP to help decide where to place the new builds. Post the measurements if needed and ask for more help.

If you find that the section under the base of the stairs is good, then you don't need to keep the same form factor. A triangular enclosure of the same internal volume will give the same result as the Marty's at 2x2x4'. It will just take a minor redesign which is not difficult.

Lastly, angling a sub will make no difference as bass is omnidirectional.
 
#22 ·
Thanks, I gonna grab a mic today online and try to figure out measurements next week
 
#29 ·
Problem is I didn't not know I needed to buy an spl meter too. I thought this did everything I needed.
I guess I can buy a radio shack one to calibrate and then Just return it
 
#30 ·
There is nothing wrong with having a spl meter on hand. They serve well for other purposes. If you do not want to mess with all of that then purchase the UMIK-1 directly from cross spectrum. The only reason why I did not recomend it is simply because some have had issues running higher level sweeps. I am not sure if it is mic, user, or setup related, but I do know I can perform up to 140db sweeps with the UMM-6 with no issues.
 
#32 ·
Yea I have been contemplating painting them and the wall behind me black too. I may do them this weekend actually as I have some flat black in a rattle can
There is a lot I want to do.
 
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