Then how do you avoid a horn flare that narrows as you transition from the box to the real wall? The only way is to have the same 90° corner scaled down, but then you have to have it widen in order to go from box to wall, and then it's narrowing again back at the wall. I suppose probably not a big issue if you made it huge enough...
A projected tetra box box flaring to walls. You need but a few inches. I suppose it could be called a false wall but it has no negatives. It would be large but wouldn't look that large as it effectively has no "box" mostly open space. Also no reason to start the Tet at 60 degrees either as the wall forms the last flare, if that's of any benefit. Actually this approach solves a bunch of problems, far more than it creates.
Seriously, I have always thought that Voight did his speakers completely upside down. This is a practicality issue no longer as valid. Those ceiling corners are IMO by far the most logical place to at least put the "above Shroeder" speakers in most rooms.
May need a lot of small woofers in this application then. There would be room for them though with all if that "lip"
Actually it would be very easy to make a corner line of woofers, then add midtweeter some height. A line of mid/tweeters leads to serious lobing unless delay shading is used.
Here is a quick Edge simulation of 2500mm line of "el cheapo" 200mm/8" woofers. Without wall and ceiling effects. Edge suggests that drivers are fullrange. We see that response at 2m is dropping at 500Hz and with offset we see lobing at higher frequencies.
Imagine a synergy horn to the midpoint of that line, response starting at 400Hz...
Pi speakers six Pi is close to this idea...
Here is a quick Edge simulation of 2500mm line of "el cheapo" 200mm/8" woofers. Without wall and ceiling effects. Edge suggests that drivers are fullrange. We see that response at 2m is dropping at 500Hz and with offset we see lobing at higher frequencies.
Imagine a synergy horn to the midpoint of that line, response starting at 400Hz...
Pi speakers six Pi is close to this idea...
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WRT the discussion on synergy..
The cues that a mid horn is in its own separate space aren't that large, but they're also not necessarily detrimental to imaging or fatigue. It's hardly the kind of thing that sounds 'bad'. As an example for me a mono recording images as if coming through a small window between the tweeters across the spectrum. Instruments that span the three ranges image coherently in a single location .
Earl and Tom Danley have had this discussion. Earl notes the benefits of keeping a pristine waveguide, and Tom notes that his prime directive included arrayability.. but both are good.
The cues that a mid horn is in its own separate space aren't that large, but they're also not necessarily detrimental to imaging or fatigue. It's hardly the kind of thing that sounds 'bad'. As an example for me a mono recording images as if coming through a small window between the tweeters across the spectrum. Instruments that span the three ranges image coherently in a single location .
Earl and Tom Danley have had this discussion. Earl notes the benefits of keeping a pristine waveguide, and Tom notes that his prime directive included arrayability.. but both are good.
And both are precisely correct for their application. Mine in small rooms for HT or Hi-Fi and Tom's in large venues for maximum coverage and SPL. They are not competing technologies because they target completely different applications.
Hi Pete, all
Actually one can make a Synergy horn that fits in a room corner; I had them in my old listening room where the room geometry / listening position lent itself. Like any speaker with a radiation lobe, ideally one wants that on axis lobe pointed at the farthest seat and so with a couch, what looks like kitty corner aiming is usually best so far as the widest sweet spot. This is old hat in commercial sound as by using the shape of the lobe (the loudest point) pointed at the farthest seat, you use the shape of the lobe to reduce the change in SPL vs distance or here position.
For the corner speakers I used small neo hf, 3 mids and 3 shallow woofers. This made the horn walls parallel to and as close as possible to the room wall / ceiling.
At one point I had two not exactly identical pairs of synergy corner horns working and had one set in the ceiling and other pair at the floor boundary and that was interesting except no recordings contained channels for R&L plus R&L upper information. With simple pan pots and delay one could assign a convincing image anywhere in that box between the rooms corners.
Also, any of the Synergy horns can conceptually operate next to a boundary. If one places one of ours on the floor, or wall on an angled side, one finds the horn wall and room wall are parallel, that the distance between wall boundary and horn wall are a small fraction of the horn mouth dimension.
The result is the horn governs the radiation angle down to some frequency given by the horn angle and mouth dimension (Keele’s pattern loss frequency).
If the step in area between the horn wall and room wall, is a small fraction of the wavelength in the region the horn is losing it’s pattern control, the effect of the step is negligible and the walls become a continuation of the horn. What one sees is nearly identical to what one measured in free space using two cabinets tight packed on the angled sides. The region below a few hundred Hz has gradual rise due to the boundary loading.
After a while, I switched to side wall mounted speakers in that room as for normal stereo made a more useful image level in front. Also, the side wall mounting allows one to place the speakers far forward of the front wall if needed if you used the same “point the lobe at the farthest seat” thumb rule. My current listening room doesn’t lend it self to either of these approaches but if you guys are building them and it’s something your room permits, try it.
Sonically the effect is you have a wider room (speakers are farther apart) and the normal close to speaker side wall and rear reflections are so suppressed, it sounds more like a window into another acoustic space that extends slightly past the actual speaker locations to where the boundary is.
Best,
Tom
FWIW, here is a thread I started last year when I knew even less than I do now, but it has a drawing. Then I realised that Tom had for the most part solved this already. I later realised that the Synergy did it all if you made it tet shaped and on ceiling corner. http://www.diyaudio.com/forums/multi-way/225302-side-entry-compression-driver-2.html
Hi Tom,
This is exactly what I did with the SM60Fs in my home theater. Imaging is wide and simply amazing to me all the guests that have heard them. You can walk throughout the area and feel like you are still in the sweet spot. Contrary to what's been stated by some, these are exceptional speakers for HT.
Mike
I love the constant directivity cornerhorn approach. In fact, I'm not sure I would even have embraced constant directivity if it hadn't been what I thought was a natural extension of the cornerhorn design.
It drew attention to itself, did something so right I had to learn what it was. My conclusion was its "magic" was from constant directivity, the uniform reverberent field and the lack of anomalies from self-interference from nearest boundaries.
My earliest loudspeaker experiments in the late 1970s used CD horns on Klipschorn-like designs. I quickly got rid of the folded horn in order to reduce path length for phasing issues, leaving just the expansion from the corner apex as the lower midrange "horn."
I use this design approach still, to this day. Everything after that has been incremental improvements in HF horns to use with this design paradigm.
I've been making speakers like this now for over 30 years, and I still don't think there's anything better, provided the room is laid out right for this kind of setup.
The only downside is many rooms aren't right for this setup, so when I saw the DI-matched approach a few years later, I began to build speakers that way too. But to tell the truth, I've always seen DI-matched two-ways as a compromise. It's a prety good compromise, I think, and it allows me to make a speaker that can be used just about anywhere. But I don't think anything can beat a well-made constant directivity cornerhorn.
It drew attention to itself, did something so right I had to learn what it was. My conclusion was its "magic" was from constant directivity, the uniform reverberent field and the lack of anomalies from self-interference from nearest boundaries.
My earliest loudspeaker experiments in the late 1970s used CD horns on Klipschorn-like designs. I quickly got rid of the folded horn in order to reduce path length for phasing issues, leaving just the expansion from the corner apex as the lower midrange "horn."
I use this design approach still, to this day. Everything after that has been incremental improvements in HF horns to use with this design paradigm.
I've been making speakers like this now for over 30 years, and I still don't think there's anything better, provided the room is laid out right for this kind of setup.
The only downside is many rooms aren't right for this setup, so when I saw the DI-matched approach a few years later, I began to build speakers that way too. But to tell the truth, I've always seen DI-matched two-ways as a compromise. It's a prety good compromise, I think, and it allows me to make a speaker that can be used just about anywhere. But I don't think anything can beat a well-made constant directivity cornerhorn.
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