Subwoofer placement - does it matter?

@emergingsoul

If I need to measure it, it seems it can’t be heard.

Is that a question, or have you made up your mind?

You certainly will hear that bass is uneven. How well you can translate that into varying effects at different frequencies, and how they change with position, is difficult to say. Most mere mortals find a graph helps -- a lot! That way, your experiments can be a lot more systematic.

And when adjusting phase, a graph helps a lot. There are makeshift ways to do it without, but you can do it in 30 seconds with a sweep or pink noise and acoustics measuring software.

@emergingsoul  You can measure it if you want to understand it.  bass is difficult to get right.  In my opinion the way to go is main speakers that have a slow drop in response starting at a fairly high frequency.  Mains that are flat to 20hz are likely to cause all sorts of bass problems when they are placed in the best position for the rest of the frequency spectrum. Full range mains are a terrible idea. And you almost certainly want multiple subs.  

This is an easy place to start.
https://www.youtube.com/watch?v=AV3oLLMgS-M

Even if you can’t locate your subwoofer in your rooms main mode locating it the general area can help the effect at your listening position.

Hi OP,

So the buzz words you are talking about are "room modes" and "Shroeder frequency" and "standing waves."   They are VERY much in play in your average living room, creating almost perfect nulls and up to 200x power (~ 20 dB or more) magnification in tight bands.

I strongly encourage you to read up on the subject outside of here. It is exactly because of these issues that trying to get a flat response down to 20 or 16 Hz is the most dangerous and vexing problem for most audiophiles. In these depths is where the mermaids and dragons live.

Best,

Erik

If I need to measure it, it seems it can’t be heard.  Diff spots in room are diff for sound which makes sense.  It sucks that main speakers generally don’t do well with wide dispersion, which is another issue.

Placement makes a huge difference that is easily measured with a real time analyzer and measurement microphone.  I did a bunch of that when I was younger and differences can be huge.  Resonances build up and the sub in a certain spot will excite certain resonances way more than in another spot.  You can just put on some bass heavy content and walk around the room and notice huge differences.  Some places will be very bass shy but if you stick your head near a corner the bass will be much stronger.  It's not subtle.

The lenghth of a 40 hz sound wave is 28 feet.  I don’t see placement of a sub to matter all that much unless it’s in an auditorium

Positioning is the *most* important thing in locating a sub. Then level matching, then phase adjustment.

Simulators are great for giving you ideas. When I’ve used them, I’ve never had measured response in the room agree with the simulator. Maybe simulators have improved since -- I would expect the REW one to be top of the class -- but don’t rely on them too heavily.

Thanks, Erik. Didn't realize it had that!

Yes. 

To play with this idea, try out the room simulator built into the Room EQ Wizard software, which is free.
Best,
Erik

I moved my sub around and measured from the sweet spot with a mic. It makes a big difference, and one can also hear it if you do a "sub crawl." (Google that.) Besides moving it to different locations in the room, try raising or lowering it. Also generated big changes. 

please consult your subwoofer manual.  positioning is the first step and there are many more to follow.  REL has some good online videos about subwoofer basics.  

If you're limited in locations because of decor try facing the woofer in various positions. Someone here suggested up and it helps with one of mine.

Seems it would do the same where ever it is since wavelengths are so big.

Yes. This is exactly correct. Moving a sub around merely moves the modes around. They are still there, just different locations. 

This is why locating one sub is so frustrating. Moving the sub changes nothing fundamentally, but it does move the peaks and dips around. This is why the Distributed Bass Array works so well. The peaks and dips are still there but with four subs each one is a little different and so all together they add up to smooth response. Smooth bass is fast bass, and so its also incredibly tight and articulate. 

With four it doesn't hardly matter where they go. Usual approach is along the walls, one near each corner, but asymmetrically a different distance from each corner so as to create as many different modes as possible.

That's the frequency response aspect to it. In terms of imaging, timing or whatever you want to call it, then definitely what you said, does not matter.

Yes.  There will be major differences depending on where they are with respect to the nulls and nodes in the room.