optimal placement for dual subs in 5.2 for music - AVS Forum
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post #1 of 3 Old 10-28-2014, 10:49 PM - Thread Starter
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optimal placement for dual subs in 5.2 for music

I have asked a similar question to this but only in passing on another post and I am having a hard time finding a clear cut answer (perhaps that is because there isnt one ) as to how to calibrate my two SVS SB2000s in my 5.2 set up (majority of the time I am listening to music so it could be considered 2.2 for the purpose of this question).

Here is my setup so far...
Front LR = B&W CM10
Surround Left and Right = Polk T15
Center (not currently used so not relevant) = Klipsch Icon KC-25
2 X SVS SB2000 subwoofers

Currently running a few sources but right now as I tweak the setup to my liking I am only using my Marantz UD7007 which feeds my Marantz SR5009 with either HDMI or Analog and 90 percent of the time this is 2 channel audio coming through via compact disc, Audio DVD and a NAS device all playing at different levels of quality as I SLOWLY transition myself to as much hi res audio music as possible. Most of the time I prefer, time willing to create the physical disc and play it through the UD7007 rather than pick it up via SR5009 from my network (everything is hardwired that matters) but I also have two AC wifi routers and an additional Marantz 1605 running my just replaced Infinity Alpha 50s in the room primarily dominated by my wife and dog and a lot of reruns/shows I am not interested in.

the room I am seeking help in is our basement and is essentially a 17 ft x 17 ft X 8 (ceiling) I have attached a pic or two to help show the oddities of the shape of the room that make it kind of difficult to place furniture and most importantly subwoofers/speakers...FYI yes that is a fireplace the TV and stand are setup in front of.

I have run audyssey many times with mixed results and I am aware that I need to go about a bit of manual listening/calibrating of the subs prior to running audyssey because it cannot process a two sub setup (from what I have read specific to MultEQ XT that is)

How should I go about (besides the subwoofer crawl which I am not convinced helps with two subs) measuring or calibrating the subs prior to running audyssey? The only really consistent answer that seems to come up is to use an SPL and level match/gain match the subs and that they should be equidistant to the MLP. Because of my room that is not easy and I have experimented with a few different setups including subs up front, one sub in corner FR and one next to MLP diagonally from first sub. One sub each on left and right walls as close to the half way point to MLP and opposite each other as possible. Half way is almost impossible given the setup.

I can add more details if necessary but right now the CM10s are sounding better and better each day but I have spend little time rather than measuring MLP to each sub to get it pretty close to equidistant prior to running Audyssey.

Also - I have a boom for the calibration mic and have read the FAQ and setup guide enough that I can and probably have tried to do it in my sleep Differerent mic positions does effect hte results but its really hard to tell why/how or if one is better than the other.

Help please!
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post #2 of 3 Old 10-29-2014, 10:02 AM
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Below is my standard procedure for dual subs with Audyssey. The sub crawl does work with multiple subs.

It's not the end of the world if the subs aren't equidistant to the MLP either. If you're really worried about getting them time aligned, get an AVR that can do dual subs or a MiniDSP.

When you perform the Audyssey calibration, keep the mic positions tightly clustered around the MLP (I know this goes against the Audyssey standards, but trust me, it works better). Only move the mic a couple of inches at a time between measurements, to either side of the MLP (I just rotate the mic boom). I typically do the first measurement at the MLP, 3 measurements to the right (in 2"-3" increments), the same on the left, and then the final measurement back at the MLP.

You mention gain/level matching as if they are the same thing...they are not.

Level matching = matching each subs level at the MLP with an SPL meter.
Gain matching = matching the gain of each sub to be equal, typically with extreme nearfield measurement (1"-2" from driver) with the sub placed in a neutral position (middle of the room)

Personally, I prefer gain matching. See this post by Craig John.

One last comment...get your seating away from the back wall for God's sake!!

EDIT: I see now that that green couch may not be the MLP, hard to tell from the pics....is the MLP up against a wall as well?


>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Set the gain on both subs to the same level - around 12:00-2:00 on the gain knob is a good starting point (just a starting point, gain structure can vary greatly from one manufacturer to another). Set phase to "0" on both subs for now.

1. Connect sub #1 only and place it at the MLP
2. Do the sub crawl to determine the best position for sub #1
3. Place sub #1 in that position
4. Connect both subs and place sub #2 at the MLP (with sub #1 playing as well)
5. Do the sub crawl to determine the best position for sub #2
6. Place sub #2 in that position
7. Playing the AVRs test tone, adjust phase on one of the subs until you get the maximum SPL at the MLP (could be variable or a simple 0/180 switch)
8. Run Audyssey, first mic position only, and "calculate"
9. Look to see where Audyssey has set your sub trim, you want it to be around -5db to -8db ideally
10. Adjust the gain on both subs by the same amount up or down as needed
11. Repeat 8-10 until you get the sub trim around -5db to -8db
12. Run the full Audyssey calibration
13. Set all speakers to "small"
14. Set all crossovers to 80hz (or, if set higher than 80hz by Audyssey, leave them alone)
15. Bump up the sub trim by 3db to 6db to your preference
16. Enjoy!

Hope this helps!
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post #3 of 3 Old Yesterday, 08:36 PM - Thread Starter
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Quote:
Originally Posted by Alan P View Post
Below is my standard procedure for dual subs with Audyssey. The sub crawl does work with multiple subs.

It's not the end of the world if the subs aren't equidistant to the MLP either. If you're really worried about getting them time aligned, get an AVR that can do dual subs or a MiniDSP.

When you perform the Audyssey calibration, keep the mic positions tightly clustered around the MLP (I know this goes against the Audyssey standards, but trust me, it works better). Only move the mic a couple of inches at a time between measurements, to either side of the MLP (I just rotate the mic boom). I typically do the first measurement at the MLP, 3 measurements to the right (in 2"-3" increments), the same on the left, and then the final measurement back at the MLP.

You mention gain/level matching as if they are the same thing...they are not.

Level matching = matching each subs level at the MLP with an SPL meter.
Gain matching = matching the gain of each sub to be equal, typically with extreme nearfield measurement (1"-2" from driver) with the sub placed in a neutral position (middle of the room)

Personally, I prefer gain matching. See this post by Craig John.

One last comment...get your seating away from the back wall for God's sake!!

EDIT: I see now that that green couch may not be the MLP, hard to tell from the pics....is the MLP up against a wall as well?


>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Set the gain on both subs to the same level - around 12:00-2:00 on the gain knob is a good starting point (just a starting point, gain structure can vary greatly from one manufacturer to another). Set phase to "0" on both subs for now.

1. Connect sub #1 only and place it at the MLP
2. Do the sub crawl to determine the best position for sub #1
3. Place sub #1 in that position
4. Connect both subs and place sub #2 at the MLP (with sub #1 playing as well)
5. Do the sub crawl to determine the best position for sub #2
6. Place sub #2 in that position
7. Playing the AVRs test tone, adjust phase on one of the subs until you get the maximum SPL at the MLP (could be variable or a simple 0/180 switch)
8. Run Audyssey, first mic position only, and "calculate"
9. Look to see where Audyssey has set your sub trim, you want it to be around -5db to -8db ideally
10. Adjust the gain on both subs by the same amount up or down as needed
11. Repeat 8-10 until you get the sub trim around -5db to -8db
12. Run the full Audyssey calibration
13. Set all speakers to "small"
14. Set all crossovers to 80hz (or, if set higher than 80hz by Audyssey, leave them alone)
15. Bump up the sub trim by 3db to 6db to your preference
16. Enjoy!

Hope this helps!
Thanks! Quick reply to answer your question - MLP is not the green couch. It is a black couch about 10 feet from front wall and 7 feet from back wall.

More to come....
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