Open Baffle Experience

@johnnycamp5 wrote: "We read in this thread a redundant dimension of about 3’ off front wall as a minimum with OB.

"I wonder if less distance (approx. 2’) with heavy drapes behind might work…"

Not really. Imo the issue is time delay, and you can’t get 3 feet worth of time delay with 2 feet plus heavy drapes.

Also a benefit of many open-baffle speakers is that the backwave has essentially the same spectral balance as the frontwave, and heavy drapes would selectively attenuate the short wavelengths (high frequencies), degrading the spectral balance of the backwave.

I find that my apogee duetta 2 sounded best about 7' off the wall.

 

It is really sad to see more and more dogmatists spoiling this forum, which I thought was meant to create an easy way to exchange our experiences: EXPERIENCES, not theoretical arguments.

It is not that sad…
There is kind of room for both theory and experience.

(And I am only a dogmatist about woofers.)

In case of the open baffle loudspeakers and the voiced criticism that the back-aiming sound wave is out of phase (probably correct) one concludes that because of this, they are "wrong". This sounds almost like evangelical argumentation.

“Reversed polarity” is probably better than “out of phase.”

In any case a box speaker have very little back wave, and if it has a port there is not much back wave except near the post freq.

If having a back wave with the opposite polarity is bad, then a dipole should be really bad, because the back wave is many dB higher than anything sneaking around a closed box.

The closer the OB is to the front wall, the higher the cancellation that between front and back wave, and the shorter the time difference in arrival times between the direct and reflected sound (per Ralph's post above). So further away from the way is better for both how low end reach and the sense of envelopment.

Linkwitz recommended a reflective front wall, which happened to be what he had at home. I happened to have a treated room with absorbent front wall and can get my speakers 3 feet away from the front wall, and I'm happy with the sound. Maybe I would be happier with a reflective wall? Dunno. The midbass, as noted, lacks some impact even though it's 18", have a dedicated Hypex class-D directly powering it and it's adjusted to measure flat...yet the sense of impact is different in my case. 

Thanks @audiokinesis 

I should be more specific- Are all OB open back tweeter? I thought some had forward only directivity . So the heavy drapes question was more for the mid range and bass frequencies.

@invalid your comment about sounding best at 7’ off front wall is always why these types of loudspeakers (dipole) are “non starters” for me.

I just can’t kill a whole room with that kind of placement. I have a 21’x22’ garage I’m completing mostly for stereo and media…and Still these distances are unacceptable to me. I’m sure it’s why I’ve always been attracted to horns for their controlled directivity.

But man that open spacious sound of OB is hard to beat if set up right…just a whole different flavor of goodness.

I suppose I could move the OB’s back-and-forth all the time for use…but what a BS hassle…