[JohnR]

In a nutshell, anyway.

Green is 1 meter from listener, 2.5m from wall.

Purple is 1 meter from wall, 2.5m from listener.



Full article here: http://www.hifizine.com/2012/03/on-dipole-subwoofer-placement/

[tryman]

may be near listener the wave  that reflect from back wall of speaker are weak so the cancel of front and back wave are reduce.

[Gothover]

Intersting, and a good read, thanks for the link.

Dave

[JohnR]

Thanks Dave

may be near listener the wave  that reflect from back wall of speaker are weak so the cancel of front and back wave are reduce.

This is analysed in the article. The distance from the back wall does affect output, but isn't the most significant factor. There is an effect identified by JohnK related to the listener-dipole distance. I've realized that it's a very important factor to know about if you are interested in dipole/OB subs

[InfernoSTi]

Nice article, thank you. 

I have been a fan of more room to the front wall for some time.  I have found that it can have a positive impact on image clarity, as well.  It's great to know this helps with bass, too.

I typically encourage people to start with the placement too far from the wall and move back, rather than too close and move forward.  Seems funny, but it works. 

Best,
John

[sfdoddsy]

This is equally true for monopole woofers.

Where possible, I like to have the sub directly behind my sofa.

It often creates a flatter response, and for movies and surround has the benefit of adding real impact as well as disguising the fact that my rears are much punier than my mains.

I recall Hsu used to recommend near-field placement as well.

[JohnR]

This is equally true for monopole woofers.

Hi Steve, good point. The two do behave a little differently, as the monopole gets better again when it's put against the wall. That is in terms of output level, I didn't measure decay times. If you can get either of them very close, that seems to be best. With the monopole, more than a small distance away and you are better off putting it on the wall. With the dipole, as close as you can accomplish - whatever that is - is the best choice.

I'd love for others to post their own measurements of similar experiments.