Dipole speakers, subwoofers and that rear wall

helmholtzsoul

The ear does not perceive comb filter effects from reflections the same way a microphone registers them, so in general reflections are far more benign than they look "on paper". But if reflections arrive too early, they still can be detrimental to clarity. According to acoustic and psychoacoustic researcher David Griesinger, ten milliseconds of essentially reflection-free time is sufficient.

Sound travels approximately one foot per millisecond, so the implication of Griesnger’s finding is that ideally we’d want to position dipole speakers about five feet out from the front wall, which would result in a backwave reflection path length of ten feet, and a delay of about ten milliseconds.

In my experience, if dipoles (or bipoles) are placed less than 3 feet from the wall behind them, aggressively treating the backwave is usually a good idea. This can be absorption or diffusion or re-directing the reflection away from the listening area.

At distances between 3 and 5 feet it’s more of a judgment call as to whether or not you need to treat the backwave. Imo in general re-directing the reflection and/or diffusion are preferable to absorption.

Duke

dipole dealer, bipole manufacturer

What is a "tuned chamber?" I've never heard of this room treatment.

Instead of dipole, use both front and rear baffles and both are enclosed within the cabinet design. RM50 VMPS. There are a few more now. The old QLS Infinity.  NOT the RS OB design. RS1 & Bs and the 2 and 2Bs or the IRS series.

A boxes (or cabinet) with TWO active baffles, front and rear.

Tune the room?

Read my Handle.. Helmholtz. The only way to properly tune a room.. 

There is a guy that post here that uses the term "Embedding" he has 3 major areas. HE is very close on his design.. A little muddled in his room, BUT he did it by reading and experimenting. A brave endeavor by my standards. :-)

Helmholtz, I use adjustable slot resonators for above 120hz and adjustable tube traps for 120hz and below. All designed by SB/SAT. Oldhvymec's design, it works VERY well. I've used them for over 10 years. He's been at it for over 45 years. 

Curtains, Resonators and Tube traps. OHM bass system is the bomb. Ask him. He always helped me. I have one of his air ride decoupling systems from way back.

For clarity, do you mean the front wall???  

Think of it like this.  When you go to a performance, are the performers in front of you or in back?

Dipoles are unique and enjoyable speakers.  As noted above, embrace and don't destroy the rear wave.  Use diffraction, NOT absorptive surfaces on the front wall.  Why would you want to defeat what this design type is all about?  If you can't pull them well off the front wall you will miss out on what these speakers can do.

For me, in the final analysis, dipoles are fun but not always the most accurate.  But in the right room with the right music, well you may be a very happy camper indeed.