Component placement for open baffles?

What are you guys using for diffusion behind your OBs?

I found that moving the equipment to the side wall improved the depth and image precision of the soundstage. I also far prefer diffusion behind the speakers over absorption, but I have my OB speakers about 7ft into the room (measured from the front baffle). My speakers are open baffle for the full frequency range. 

I design loudspeakers I use the back wave to load the room with low bass pressure as a back-loaded horn would. My OB system is 2:32 in.

@johnk what open baffles are designed for near-wall placement? Any idea what the idea is with what happens to the rearward energy? Does the manuf suggest a ton of absorption behind them?

Would enjoy seeing you post a system page with pics. Cheers,

Spencer

My open baffle speakers are designed for near-wall placement it depends on the overall design. I think it's a poor use of space to have loudspeakers pulled so far out into a room to function. It also greatly reduces any low bass. Feel one would be better off with a larger speaker if you can devote so much room space to house an OB or planar design.

IMHE, open baffles and planars still will benefit from removing the rack from between the speakers. Yes most of the output is directly forward and back, freeing you from the side wall reflections you get with dynamic speakers. But planars and open baffles generate plenty of backward energy. Diffusion in the center can often be beneficial. Absorption behind the speaker on the front wall is mostly a basic requirement to get the best performance that you paid for. Cheers,

Spencer 

That's about how I do my planars too @coralkong. Speakers 5' from the front wall, equipment racks about a foot away from the wall, their front edges about 2.5' behind the speakers. 

I don't know.

My OB's are a couple of feet out into the room.

My rack is between them, but situated BEHIND the speakers.

Seems to work well for me.

You're SO right about scale @hleeid. After experiencing big planars, box enclosure speakers sound like the whole soundstage has been miniaturized and squeezed through two little holes in the wall. Huge grand pianos sound like a child's doll house looks. Voices sound like the singer is resting on his or her knees (or is a midget ;-). The suspension of disbelief evaporates! 

The speakers are PureAudioProject Trio 15 Coax 10. 

The room is 12.5' x 38' with hardwood floors. This is the top floor so the ceiling has slants about 4' on either side running the long way.

There is just shy of 5' between the rear of each speaker and the front wall (one of the 12.5' walls). 

There is about 6" between speaker and side wall. Speakers are slightly toed in.

I have noticed a big difference when experimenting with varying distances from the front wall. Mostly in bass clarity. Gets bloated when approaching 3'.  Nice that they are light and easy to move around. 

These are my first open baffle speakers. What an experience! The scale in all directions is incredible! But not like things sound bigger than life.

The PureAudioProject site suggests 200 - 250 hours for break in. These are the first new speakers I bought and actually started tracking the break in time!

Didn't realize how long it took just to log 62 hours! I wanted to see if I can hear the difference rather than leave the system playing 24/7.

Still working out placement. But what a fun speaker to listen to!

@hleeid

Open baffles and di-pole speakers also need room behind them. I have panel speakers and they want to be at least 4’ from the front wall. Once you get them set even close, they will really open up like a blossom.

Cool @hleeid, whatta ya got, Spatial Audio Labs? I don’t have open baffles, but I have a long history with planars, with which ob’s have much in common. Yes, the lack of output to the sides of both ob’s and planars mitigates the degree of both side wall and between-the-speakers first reflection problems. Not eliminates, but mitigates.

One recommendation I can make is to position your ob’s as far from the wall behind them as possible, with a minimum of 5’ a good number. That eliminates one problem: the rear wave arriving back at the ob before the 10ms delay necessary for the brain to perceive the front and rear waves as separate events, rather than the rear wave being a smearing of the front.

Then to be aware of the fact that the reflected rear wave will when arriving back at the ob will interact with the wave now coming out of the front of the ob. That front and rear wave interaction can cause comb filtering: the combined waves can be in prefect phase with each other (producing a boost in frequency response at some frequencies), or 180 degrees apart in phase (their combined outputs being the same as on the sides of the ob---a null at some frequencies).

So as you may surmise, it will take some experimenting to find good/better/best speaker positioning, and some prioritizing of your sound quality goals. Compromises may be necessary! But that’s true with "box" speakers too.