Open Baffle Experience

@erik_squires

I get edge diffraction, but my speakers have 1/2" rounds on the edges and I defy anyone to tell me they can hear where the speaker is.

If a box is unavoidable, it should definitely have the largest radius edges possible, and ideally the curvature should go all the way to the driver frame - like the concrete speakers I had once. Think those were made in some Scandinavian country - wish I could remember the name. Someone on A-gon probably knows this company. But I wasn’t referring to edge-diffraction (that’s a whole separate issue), I was talking of flat front baffle reflecting surface area (initial reflections allow acoustical localization).

I’ve heard many other speakers that do a great job of disappearing as well, some with very narrow (Vandersteen)...

Yes, to maximize ’disappearance’, surface area perpendicular to the listener should be minimized - like you said... narrow baffle. My GoldenEar Tritons are an example of this, also most KEF and many others including the Anthony Gallo Strada’s as an extreme example and the tweeter pods on most B&W - for that matter we all know what the B&W Nautilus looks like (all the same philosophy).

Both of my above statements are witnessed in the KEF Blades and B&W Nautilus (extremely rounded and narrow-as-possible front baffles) - I count these as great designs (judged soly by their visual aspects).You can look at either of these and say, "Those are likely to disappear in a room" because of how they are shaped. Now, there are other factors that can draw attention to a speaker, like resonances, drivers sounding forward or unnaturally bright - but at least these designs have a shape that will allow greatness.

and some with broad baffles (SF Amati Heritage). I’ve never felt this was an attribute of baffles which could not be dealt with.

Yes, your correct in the statement, "...which could not be dealt with." Notice what SF have done to "deal with it"; front baffle narrow as the drivers will allow (does this sound familiar?), entire front baffle surface covered in (expensive) absorptive material, the front-baffle is also curved and the cabinet sidewalls are curved and form a triangular profile. I said in previous post of this thread, "...throw $ at it", and Sonus Faber exemplifies this method.

Also note that controlling reflections in a room can cover-up speaker localization too - I put that in the category of "throw $ at it".

The OB may be out of polarity, but who cares in the upper freq ranges?
You used the term “not in time”.

A lot of folks do care. Magico, Kef, B&W, Wilson Audio, Focal, Genelec, Revel,

Unless you only like listening to upper freq range then its a big problem.

Theres more closed box speakers than open. What do you gain by throwing the box away? you just LOSE all the bass. I dont see any advantages whatsoever.

I switched to OB speakers (Emerald Physics) a while ago, and I don't think I could ever go back to a box speaker.

They need lots of room to breathe and placement can be tricky, but they sound absolutely glorious when you get them dialed in. Anyone who tells you differently is talking out of their ass.

The best sound I’ve ever heard to date was the Nola Grand Reference open-back dynamic towers driven by top ARC electronics. You can say whatever you want about OB designs, but that sound will live with me forever, and if it’s wrong I don’t wanna be right. Just sayin’. Also, if you pluck an acoustic guitar in open space it seems to me the sound that travels backwards will be at least somewhat out of phase kinda like a dipole driver, and a non-dipole speaker greatly misses or greatly diminishes the backward sound projection that is projected by an actual instrument yet could be captured in a good recording. Could be wrong, but this makes intuitive sense to me.

I've used B&W 804S speakers with their passive crossovers, then went active with digital xo, then into DIY boxed and eventually open baffle. Of course I do measurements for design work. System has now 2 sealed subs to 80Hz, 18" OB midbasses in H panel, and tweeter and midrange sitting above on a much slimmer panel. My tweeter is Beyma TPL-150H, which is actually the same one Spatial Audio uses on their X3 and X4, and I used to use it in a closed box and now open in the back. In fact, when I first ventured into OB I followed the back-to-front symmetry mantra and used a back waveguide like the one it has on the front and eventually realized it sounded as well without it so the back horn was removed (like Spatial does). The TPL is directly driven from Yamamoto 45-type SET...so much definition yet sweetness. The tweeter and midranges sound better to me in OB than boxed - same drivers - however I can easily compensate for the lower frequency decay in the mids, which is a natural phenomenon from the physics of drivers in OB. With passive XO this is trickier to get good results.

There were comments about wide panels. Of course wide panels are needed to support the lower end. However for midranges the wide panel is an issue: above the dipole peak the response is all over the place, especially noticeable at varying angles from the center. Narrow baffles allow reaching higher without this issue, to the point some people use baffleless (been there and came back). Crossing over before the dipole peak is preferred. Spatial Audio, to keep the example above, doesn't do this. Never heard one, but tend to think this would be audible.

Midbass is where I'm still not sure. OB definitely has more definition. However, even using 18" midbasses the sense of impact is much lighter than sealed. Maybe it's because I'm using a Faital driver that is not designed for OB and has low Qts, or because my room can't accommodate speakers 6 feet away from the front wall. I'm contemplating getting 15" Acoustic Elegance LO15, designed for OB, or a slot-loaded open baffle design that apparently conveys more impact while keeping the definition of OB. TBD.

For subs I experimented a bit, exchanged with Danny Richie at GR Research, who developed OB subs with Rythmik, and concluded my room wasn't suitable for such subs. I'm getting two additional sealed Rythmik kits to have 4 sealed subs.

Erik, I remember you at DIY Audio, so you probably have the skills and have fun building stuff. Would encourage you to do so, learn and listen for yourself. I have learnt some "laws" that are commonly accepted in audio fora that turned out not to be audible to me.

Have fun!