[JohnR]

I've sometimes wondered whether/if one could do something like this with planar dipoles, e.g., direct sound to the first sidewall reflection with a >10 ms delay.

I'm using the front wall for that. It's about 1.5m away and fairly reflective. it just occurred to me to have a look in the recent measurements I did and yep, there it is:




In other measurements the reflection was more prominent, but that was also with the speakers closer to the front wall. I'll try getting some more data on this when I next measure them.

With the right room, I suppose you could situate them so that the rear reflection was heard from the side walls.

With small panels like these, it would be easy to mount an angled ambiance panel above or below the on-axis one. However, off the top of my head, I'm not sure what the effect would be -- I imagine you'd end up with a quadrapole, and four nulls.

No, you wouldn't have four nulls...

[josh358]

Pretty cool. It looks like it's what, 13 dB down in this measurement. So it should be audible, though I think the level would have to be higher to widen the image the way an omni does.

I think in general that if you sent the backwave to the sides, you'd gain width but lose depth.

[Johnzy]

Hi JohnR

Your more than welcome to come to Involve and have listen to our panels and other technologies here in Braeside. You might like to reprot back to the forum on what you see/hear.

Feel free to give me, Dawson or Charlie a call on 95805911 and arrange a time.

[satie]

I was wondering if bouncing the front output off the sidewalls would solve some of the dispersion problem by creating a greater beam width off the virtual speaker. The imaging performance coming from the combination of large spacing and great distance the back wave travels is quite spectacular once it is "tuned".

[JohnR]

You mean the "Rooze" arrangement? I don't think I have a room that is well suited for that but it's certainly an interesting idea.

[JohnR]

Hi JohnR

Your more than welcome to come to Involve and have listen to our panels and other technologies here in Braeside. You might like to reprot back to the forum on what you see/hear.

Feel free to give me, Dawson or Charlie a call on 95805911 and arrange a time.

Hi Dawson, thanks, appreciate it I have a pair that I am playing with, but I'll be sure to drop by anyway next time I get to Melbourne. rick57 is in Melbourne and would I hope take you up on your offer.

[satie]

You mean the "Rooze" arrangement? I don't think I have a room that is well suited for that but it's certainly an interesting idea.

Well, it does not have to be edge on in the original "rooze" \ / geometry, it may work out closer to the front wall too. You just need to have a clear wall segment on either side and no major piece of furniture in the path from the reflection area.

[Luigi]

I know no-one has posted on these for a bit, but thought I would add my 2c worth, given I've just set up a pair.
For background, I have been using open baffle B200s with Heil AMTs on top and AE15s open baffle from 200Hz down. My active crossover is an old analogue Beveridge RM-3 design set at 200Hz and works a treat, I reckon anyway.

So the minipanels needed a resistor inserted in line with the transformer, which was a bit of a mission to insert in the small enclosure but snugged it in there okay.

These are my first ESLs, and they remind of some Aussie ribbon speakers (Ambience Ultra 16s, something or other) I had some years ago in terms of a relaxed presentation, only the detail and musicality are on another plane altogether. Sure, the imaging is a bit head in a vice like and you have to get the tilt right, but overall they're very good and a bit special. When you're in the sweet spot, it's real sweet. Music seems more intoxicating than usual; it's hard to switch the system off at the end of the evening. And they're absolutely dead quiet. Surprisingly, they're about as light as a frisbee. Currently the transformers support the panels, but Im going to re route them and attach the panels to the H-frame open baffles.
In short, these are an amazing value.

[James Romeyn]

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[JohnR]

Yes, I know the above is anathema to panel lovers because it converts the dipole into a mono pole,

Well, and then you also have to add a second pair of panels to recover the "ambiance" radiation...  It seems a lot simpler and cheaper to just get the panels far enough away from the rear wall. If that's not possible, then maybe try a reflective surface to bounce it towards the side walls... or even the ceiling.

[JohnR]

These are my first ESLs, and they remind of some Aussie ribbon speakers (Ambience Ultra 16s, something or other) I had some years ago in terms of a relaxed presentation, only the detail and musicality are on another plane altogether. Sure, the imaging is a bit head in a vice like and you have to get the tilt right, but overall they're very good and a bit special. When you're in the sweet spot, it's real sweet. Music seems more intoxicating than usual; it's hard to switch the system off at the end of the evening. And they're absolutely dead quiet. Surprisingly, they're about as light as a frisbee. Currently the transformers support the panels, but Im going to re route them and attach the panels to the H-frame open baffles.
In short, these are an amazing value.

Cool

I've still to revise my crossover, hopefully soon..

[josh358]

Use two of the mini stat panels but damp the rear wave of both, then set them up as I described earlier, one firing normal (main panel), the other panel is for ambiance: horizontal on the floor, behind the main primary panel, firing up toward the ceiling.   The shorter the ceiling the better it is to space the ambiance panel farther behind the main panel or closer to the adjacent side wall, which increases delay time (delay time = vertical line from ambiance panel to ceiling + diagonal line down to listener - straight line from main panel to listener).  Toole's goal is 10ms and this method not only achieves it but offers several other unique highly desirable audible benefits. 

OC703 ceiling tile directly above the ambiance panel helps immensely, small tile is OK 12" x 12", cover the face with ultra high tech dispersion film ala space age material (newsprint).

Yes, I know the above is anathema to panel lovers because it converts the dipole into a mono pole, but the overall results might will likely make you quite disinterested in any other radiation pattern, especially after you walk around the room. 

I apologize for not suggesting this earlier.  For some stupid reason I thought I implied it or suggested it outright, but in re-reading my post it's not there.

You really must have available acoustically opaque material like masonite to cut and place "shadow" whose purpose is to minimize direct off-axis output from the ambiance panel to the listener.  The less is off axis output, the tighter is the radiation pattern, the less this shadow is required.  But you have to put the shadow in place to determine its value or lack thereof.  The shadow is same width as the panel and extends from the front edge of the panel up toward the ceiling.  The less is off-axis direct ambiance output the greater is the ceiling effect intensity and the greater is effective delay.

My own application is a bit different, since my "new" speakers are a pair of Tympanis and my main interest in this thread (apart from general interest) has been whether the mini panels would make a good replacement for the original Maggie midrange. But the principles are the same. I'm wondering about JohnR's suggestion for the mains -- keep them 5' out for a 10 ms delay, the effect of which can then be enhanced by adding diffusion at the front wall first reflection points to further increase the apparent acoustical size of the space, or by using angled walls or surfaces to deflect the backwave. The walls in the bay window in HP's listening room does that naturally and according to Wendell Diller, the room is spectacular with Maggies.

One advantage of that approach is that since you retain the dipole pattern from the main panel the nulls should minimize early floor, ceiling, and wall reflections. These could then be filled in with electronically or acoustically delayed ambiance speakers.

Don't you have trouble with diffraction when you shade the speakers? The main problem with achieving directionality through means other than phase cancellation (dipoles, cardioids, etc.) seems to be getting drivers or surfaces that are large compared to the longer wavelengths. One of the advantages of dipoles I think comes from the fact that their radiation pattern is essentially invariant with respect to frequency. According to Toole, Linkwitz, and others this contributes to spatial reproduction by allowing the ear to associate direct sounds and their reflections, which requires similar spectral content. In theory, it should also keep timbre realistic because power response and on-axis response can remain consistent with one another, which again according to Toole has a large effect on subjective quality. But conventional boxes are omni in the bass and cardioid higher up, as are controlled directionality speakers like horns, and controlled-directivity hybrids like the Martin Logans actually go from omni in the bass to dipole in the mids to controlled "pie wedge" directionality in the highs.

The big Sound Labs get things right because they're large enough to create a controlled directional pattern throughout most of their range but they're impractical for many of us. The IRS V may have had the most spectacular imaging of any speaker I've ever heard, and that was a cardioid line source design (but omni in the bass), also not very practical.

I don't know any way around the directionality/size problem other than ultrasonics, which doesn't seem to be terribly practical in a full-range audio application, and tricks that are already used. The Rooze arrangement is just about the cleverest I've seen -- listening to the dipoles *on edge,* in a V-shaped configuration, which has the effect of creating a vast acoustical space since you're listening not to the speaker itself but to its first reflections off the side walls. I stumbled across it one day when fooling around and was blown away by the effect, and when we were trying to figure out what was happening on the Planar Asylum we learned that it had originally been discovered by a friend of Rooze's.

[James Romeyn]

error, deleted

[josh358]

error, deleted

You mean that interesting post that I haven't had time to read all the way through or reply to?