AVS Forum banner
1 - 20 of 41 Posts

·
Registered
Joined
·
172 Posts
Discussion Starter · #1 ·
I have had two MFW-15's for over two years now in the same spots. I recently started reading a little more into sub placement and realized how I had them positioned may not have been the most effective. I only have two choices for placing the subwoofers in the room due to other things in the room that cannot be moved. The sub in the front of the room near the screen cannot be moved and has to stay where it is. The sub in the rear of the room can be moved to the opposite side of the wall or turned around so that it projects towards the sub in the front of the room.


Just by looking at the pictures I provided, which of the two "possible" setups would look to be better? In the first picture is how I currently have the sub's and yes the rear sub is pointed in the opposite direction towards the wall. It would be difficult for me to try out different positions because I would have to order longer cords and I do not want to do that unless it would "probably" sound better there. If I turned the rear sub to fire towards the front of the room as in picture # 2, would they cancel each other out and not good?






 

·
Registered
Joined
·
8,701 Posts

Quote:
Originally Posted by GPBURNS /forum/post/19642546


good read here
http://www.audioholics.com/tweaks/ge...-calibration-1


Mid walls work fantastic

its worth the effort if you can swing it

Mid-walls will probably provide you with the flattest response, but at the expense of less output. It's best to experiment and find which sounds best to you.

I have both of mine seated inside to my mains in the front of my 10x20 ft room, about 2.5 feet from each corner. The "sweet spot" is pretty much anywhere I sit.


Ian
 

·
Registered
Joined
·
1,400 Posts

Quote:
Originally Posted by mailiang /forum/post/19642975


Mid-walls will probably provide you with the flattest response, but at the expense of less output. It's best to experiment and find which sounds best to you.

I have both of mine seated inside to my mains in the front of my 10x20 ft room, about 2.5 feet from each corner. The "sweet spot" is pretty much anywhere I sit.


Ian

I thought only subs at all 4 wall midpoints would cause a loss of output but that subs at 2 wall midpoints would be ok in that regard. I've gotta find that white paper and read it again.


Edit: I do agree that of the three present #3 seems like it would provide the flattest response, but you still need to try it out by listening and measuring (if you are inclined to do so).
 

·
Registered
Joined
·
1,528 Posts
All rooms react differently as there are so many variables to be accounted for (what walls made of, other stuff in room...). The places shown to be good and recommendations are a great starting place. The only way to really find best place is to try several different setups with measurements. Of the three shown I would guess opposite corners, but this is just a guess as nobody can tell from pics which will work best in your room.
 

·
Registered
Joined
·
1,390 Posts

Quote:
Originally Posted by mailiang /forum/post/19642975


Mid-walls will probably provide you with the flattest response, but at the expense of less output. It's best to experiment and find which sounds best to you.

Ian


good advice...also a strong argument for multiple subs. i have a trinity located halfway on each sidewall, a s/c reference to the inside of each front main and an MBM12 directly behind listening position...


flattest response....mucho output


actually could use another MBM to keep up with the other subs...


as always...headroom is king



of your present choices, i would look at option 3 as well...
 

·
Registered
Joined
·
172 Posts
Discussion Starter · #8 ·
Thanks everyone... Unfortunately due to other things in the room I can only position the subs in those three different configurations. I guess I will buy a longer LFE cable and extension cord to try out the sub like in picture # 3. How do i take measurements of the subwoofer to see which location provides a "flatter response?" What kind of equipment would one need?
 

·
Registered
Joined
·
687 Posts

Quote:
Originally Posted by B Feelgood /forum/post/19644523


Thanks everyone... Unfortunately due to other things in the room I can only position the subs in those three different configurations. I guess I will buy a longer LFE cable and extension cord to try out the sub like in picture # 3. How do i take measurements of the subwoofer to see which location provides a "flatter response?" What kind of equipment would one need?

If you don't have all the equipment, symmetrical placement usually works well.
 

·
Registered
Joined
·
5,003 Posts
At one time I had mine placed in your option2 config. In my room, it caused about a 20db loss of output! Didn't work for me.


After dozens of configs, I ended up in the middle of my front wall and symetrical on either side of the center channel. I'm not flat, but hoping to EQ that.
 

·
Registered
Joined
·
2,401 Posts
B Feelgood, #1 & #2 look problematic, and there really isn't much difference between the two. I like #3. I have heard MFW-15's in this configuration, although that doesn't mean anything in YOUR room. I would try #3 first, though.


Put one in the corner and turn the other one off. Dial it in and move it around a bit. Then switch it off and do the same to the other one. Fire em both up and let it rip. Run room correction software at this point if needed.


Here is some more info, and other useful links at the bottom.

http://forum.blu-ray.com/subwoofers/...justments.html
http://forum.blu-ray.com/subwoofers/...tml#post843868
http://forum.blu-ray.com/843868-post2.html
 

·
Registered
Joined
·
172 Posts
Discussion Starter · #12 ·
Thanks for the advice everyone. So I ended up order some longer cables and positioned the subs as in picture # 3 in opposite corners. I set both subs to 75DB with an SPL meter, ran Audyssey and watched Inception. I have to say that I do not really care for this setup in my particular room. The sub is literally firing like 3 feet away into the 2nd seating position and it just sounds way to prominent and doesn't blend in well because you know it is right next to you.






I could do this mid wall setup but it would require a fair amount of work moving things around. The other problem would be that I could not have the subs pointed towards the back of the room towards the listeners like in the picture above. They would have to be pointed towards the center of the room directly across from each other and firing at each other as in the picture below. Also, they would only be located 1/4 of the way along the walls towards the front and not 1/2 way or midpoint. In theory would this be ok or would there be problems with the drivers facing/firing towards each other? The would be about 8' apart.


 

·
Registered
Joined
·
5,003 Posts
Inception is not a good movie to make judgements on your LFE by. It was a very "stylized" bass that sounds like no other movie, and in my room it was about 10db hot to boot.


Also, to clarify...did you set them individually to 75db or together they equel 75db? And did you do one at a time and compare to show you what sort of gain you're getting with the second?
 

·
Registered
Joined
·
172 Posts
Discussion Starter · #14 ·
Quote:
Originally Posted by tony123
Inception is not a good movie to make judgements on your LFE by. It was a very "stylized" bass that sounds like no other movie, and in my room it was about 10db hot to boot.


Also, to clarify...did you set them individually to 75db or together they equel 75db? And did you do one at a time and compare to show you what sort of gain you're getting with the second?
Thanks for the reply. I set them each to 75DB one at a time turning one off while setting the other. The result was the sub in the front of the room had the gain at right about 12PM and the gain on the rear sub was only at about 8-9PM since its so close to the seating position.
 

·
Registered
Joined
·
1,163 Posts

·
Registered
Joined
·
5,003 Posts
Don't know for sure if we're saying the same thing or not, but here's my take on the proper way to set them up.


If you set them each to 75db, then the sum is going to be higher than that. You DON'T want that. You want the sum to be 75db. I think you can still put the closer one at a lower volume if you'd like, but the total subwoofer output should be 75db. Once you have that, you should be able to measure each one independently and find that they are several decibals lower as an individual. This represents the gain you get in the room simply from adding a second sub!
One of the goals of running duals is that each can carry a lesser load and thus, less distortion or stress. If you're running both at 75db independently, you don't get that benefit.


In my room, they are both located in the front of the room and with the gains at the same position on each, I get 75db combined, and only 69db individually. Which means they are coasting along, yet I get HUGE impact!
 

·
Registered
Joined
·
172 Posts
Discussion Starter · #17 ·

Quote:
Originally Posted by TnTBigman /forum/post/19801569

http://www.harman.com/EN-US/OurCompa...s/multsubs.pdf


Note that the study's listening/measuring positions were at the center of the room. Page 28 has the results/conclusions
. Rooms chracteristics differ but its a good starting point so I hope this helps.


Also a good read for output matching same subs.
http://www.avsforum.com/avs-vb/showthread.php?t=1282064


Thanks for those, going to read them now




I always thought the proper way to set two subs was to unplug sub #1, turn on the test tone, and adjust gain on sub #2 until you hit 75db. Then unplug sub #2, turn on the test tone, and adjust gain on sub #1 until you hit 75DB?
 

·
Registered
Joined
·
476 Posts

Quote:
Originally Posted by Luke Kamp /forum/post/19802500


Have you checked out the gain match vs. level match thread. I agree to gain match as both subs run out of steam at the same time. It may help you get your levels set better.

http://www.avsforum.com/avs-vb/showthread.php?t=1282064

Yup, see this thread also.
http://www.avsforum.com/avs-vb/showthread.php?t=1304059


Why not try to place the subs in front like I did in that thread?


Btw, the Mains in the pic are now in front of the subs, and the subs about a half a foot from wall.


They sound great located their.


Test
 

·
Registered
Joined
·
187 Posts

Quote:
Originally Posted by test4echo101 /forum/post/19802585


Yup, see this thread also.
http://www.avsforum.com/avs-vb/showthread.php?t=1304059


Why not try to place the subs in front like I did in that thread?


Btw, the Mains in the pic are now in front of the subs, and the subs about a half a foot from wall.


They sound great located their.


Test

This seemed to work well in my room with my stereo mirage subs. I plan on putting the new paradigm ones behind and outside of the speakers. The difference from one side to the other is only 1 ft, less than yours. I think I will try to place the symmetrically from the center of the width, and then try them equidistant from the sidewalls. I hope this will allow me to minimize room modes as best I can before applying PBK.

Nice set-up BTW.
 
1 - 20 of 41 Posts
Top