Open Baffle Opinions - I Won't go back to Boxed Speakers Evr Again (maybe....)

Just noticed that autocorrect changed "wing" to "wrong" in my post. Meant side wing on the inside side of the speakers. 

Yes, the one big problem is OB’s will tell you immediately how good/bad your room acoustics are. You do "hear" the room. My listening space is not ideal. Basically a square room with the hallway down the left side Speaker and a pocket where the entrance is and a lot of Glass on that side.

You mentioned center fill as an issue. The way an OB system is supposed to work is that the rear firing information bounces off of the wall behind the speaker and thus arrives at least 10mS later than the first arrival.


If it does that the ear uses the delayed information to echo-locate, IOW to help out the sound stage. If it is less than about 10mS then the information contributes to harshness. As a general rule of thumb you want such a speaker to be at least 5 feet from the wall behind it. If less than this it won't image right because of the reasons I stated.

I wonder if the center image problem is because of the deep walls on either side of the midrange drivers. I have never seen an open baffle speaker that looked like that before. 

Ralph's (atmasphere) advice matches my experience with planar loudspeakers. The common wisdom for dipole/wall spacing is at least 3' from the front wall (behind the speakers), but that is incorrect. As Ralph said, we want the rear wave to reach our ears no less than 10ms after that from the front of the speaker. Any less than that, and the rear wave in effect sounds like a smearing of the front signal, rather than a separate event. As sound travels at approximately 1' per ms, that requires the dipole be 5' from the wall (5'/ms from speaker to wall, 5'/ms from that wall back to the speaker). 

And diffusers on that wall can help disperse rather than absorb the rear wave, a good thing if your room is on the warm side. Absorption on that wall will reduce the amount of life and energy the speaker produces, which can be good if your room is too live, and perhaps cold/bright.

As sound travels at approximately 1' per ms, that requires the dipole be 5' from the wall (5'/ms from speaker to wall, 5'/ms from that wall back to the speaker).

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The main reason I had a difficult time getting a Dipole common baffle to work.  You cannot get the timing correct front to rear. The further you get from the front wall the WORSE the timing will be not better. Lets move it closer to the wall. HOW will you ever get the timing correct. Front to rear. 

The only way is to separate the poles and add drivers to the rear pole also.

A rather sloppy way is to add a WEIR, to the inside of both monitor sections. I chose to hinge mine and set the toe on the baffle face. After the phantom speaker is kinda figured out you set the inside weirs parallel to each other.
 
What about the outside of the baffle adjacent to the outside wall, where do you think all that "out of time" stuff is going.. NOT WHERE YOU WANT.. I assure you..

So a box (It has to be a box it can't be open) has to be DEAPER and that distance from the front wall to the rear pole is the distance from the rear pole the front pole BUT only if the distance is the same. So a 20" deep speaker would be 20" from the FRONT wall. The further you pull the speaker into the room the more of a 3/D effect you get BUT loss of imaging. There will be a point where your ears will just QUIT making sense of the music. A sound effect chamber...

The numbers you quote are arbitrary. I've never heard the "within10ms rule" I've found in speaker building that it to be just the opposite.

If you want to smear the image and ruin the sound stage, let like firing drivers fire at different distances from your ear as you're proposing with a common Dipole baffle. You will get one thing "SOUND EFFECTS"

OB Look cool though..