Why does pulling out main speakers from wall improve sound?

Great thread!  Great question. Here’s my simpleton take:

The sound from your speakers bounces all over the place, like light in a mirrored room.  When speakers are near back and/or side walls, the sound off the wall comes back to yours ears so fast that the reflected sound interferes with the sound coming from your speakers. Moving the speakers into the room lets you hear more sound from your speakers, less of the reflected sound from the walls. Moving the speakers into the room can also actually help the reflected sound improve the sound of your speakers. 

Even a couple inches change in speaker placement can have outsized changes in sound quality. Experimenting with placement is a lot of fun…

According to an expert speaker guy, whom I don’t recall his name said 5’-6 is the magic number for speaker setup, the ear can pick up on the timing difference below this distance, so if your ears are 10’ from the speakers and a reflection path distance from a sound wave is 16’ then all is good, however if it’s less, then it will muddy the sound stage, so the if the speakers are 2’ from the back wall, we’ll that’s 4’ timing offset to your ears… so you pull them away 3 or more feet from the back wall to be greater than 5’-6… I think this would apply to the front wall too…

whose right… who knows… always fun to experiment though….

Steve

As I reflect back on all the hours viewing system set ups as lovely as they are with all those expensive components, I dare say most of these pictures have the speakers pretty damn close to the wall.  Dealers Display the speakers pretty damn close to the wall.  Then I began noticing a few set ups where the speakers looked weird being pulled so far from the wall. 
 

My large basement on the habitable side has my speakers right in the middle of the room and they are older and they really fill the room extremely well. I thought it was just the speakers but it was more than that.  In my other rooms and systems it's tougher to get those speakers very far from the walls, but I am rethinking things with a goal of pulling the speakers way the hell away from the walls.  Rectangular rooms are difficult where the long wall is being used for the system.  Points of egress and windows and doors make it difficult to use the Wall on the short side of the room for the system, very sad.

@aewarren ,

“I suggest you find a new dealer”

agreed. 

It is generally suggested that the front of the loudspeaker be placed 3ft (approx 90cm) from the front wall as a starting point.

The midrange is approx between 3khz and 90-100hz

The wavelength of a 200hz frequency is approx 171.6 cm. The half wave would be 85.8cm (approx 34.2 inches).

The wave is spherical in nature, so half the wave wraps around behind the loudspeaker and the other half wave is in front of the loudspeaker.

The lower frequencies of the midrange lie between 400hz and 90-100hz. 

As the loudspeaker is moved nearer to the front wall (2ft) the lower end frequencies get reflected off the front wall - as a result these lower frequencies reinforce the lower frequencies of the front half of the soundwave and we begin to hear muddiness in the midrange.

a simple test would be to - with your back to the front wall start speaking with a consistent loudness - now slowly walk away from the front wall until your voice sounds more natural  (ie: without the reinforcement of the lower midrange frequencies). This too would be a good starting point for the placement of the loudspeaker.

I hope this helps.