I want one too! But it's huge (6 feet wide) and expensive. But maybe I can build something like it?
I think yes, it uses a compressor driver over 600Hz, but I think you could use whatever you like. It might be a way to take the narrow HF beaming of a large full-range driver and spread it more widely.
It claims to give good stereo imaging anywhere in a room, but presumably you'd still have to somewhat face it, rather than listening to it from the side.
I agree that messing with a matrix may not be the way to go. But at least it's fun to play with.
Speaking of woodgrain curved JBL, here is a current wifi/bluetooth streaming speaker from them, the L75ms. Oddly, the center driver is the mid speaker, while the two outer ones are the woofers. I can't find any mention of stereo width anywhere, can it be this this $1500 box is actually in mono?
I think yes, it uses a compressor driver over 600Hz, but I think you could use whatever you like. It might be a way to take the narrow HF beaming of a large full-range driver and spread it more widely.
It claims to give good stereo imaging anywhere in a room, but presumably you'd still have to somewhat face it, rather than listening to it from the side.
I agree that messing with a matrix may not be the way to go. But at least it's fun to play with.
Speaking of woodgrain curved JBL, here is a current wifi/bluetooth streaming speaker from them, the L75ms. Oddly, the center driver is the mid speaker, while the two outer ones are the woofers. I can't find any mention of stereo width anywhere, can it be this this $1500 box is actually in mono?
The Metregon does not have a LF horn. I want to try this reflector thing with two full range boxes. Just a piece of 3mm HDF bent into a radius.
So, I just googled "JBL Paragon small clone" and came back with this; https://www.coastalvectors.com/blog/2013/04/mini-jbl-paragon-project/
Just a wonderful design. If one forgets trying to do bass at all, then surely there would be a way to get this into a small format without going to those lengths. My only thought is that I would imagine the HF horn would be crucial to the whole reflector thing working at all. A horn with no more than 45degree dispersion (if that makes sense). Theres probably some geometry there that makes it work.
"I agree that messing with a matrix may not be the way to go. But at least it's fun to play with."
In relation to what you are trying to achieve and the problems you've had, perhaps its not the way to go. The JBL reflector thing seems to invert the traditional stereo triangle in on itself, presumably also reducing the room interaction. Might be a way of thinking.
On another note, there is this; https://www.stereolith.com/en/
Which uses one tweeter and two woofers. Go figure.
Just a wonderful design. If one forgets trying to do bass at all, then surely there would be a way to get this into a small format without going to those lengths. My only thought is that I would imagine the HF horn would be crucial to the whole reflector thing working at all. A horn with no more than 45degree dispersion (if that makes sense). Theres probably some geometry there that makes it work.
"I agree that messing with a matrix may not be the way to go. But at least it's fun to play with."
In relation to what you are trying to achieve and the problems you've had, perhaps its not the way to go. The JBL reflector thing seems to invert the traditional stereo triangle in on itself, presumably also reducing the room interaction. Might be a way of thinking.
On another note, there is this; https://www.stereolith.com/en/
Which uses one tweeter and two woofers. Go figure.
JBL Minigon. Note tweeters facing 45degrees into the curve. Worth a go using a full ranger (to 500hz or so).
Very quick sketchup visualisation for 2x 2" full range drivers and a 5" mid bass-reflex. Crossover about 300-400hz. No idea how it would sound.
Those Sketchups look pretty reasonable!
When I scratch my head and think about it, I'm not totally clear why this would give a wider stereo image than regular wide dispersion direct speakers...
The center of the two curved surfaces are only about 300mm apart. To the man with the dinosaur shirt and ukulele, would it sound like the sound is primarily emanating from that small curved surface, or something wider?
Some foam core experimentation next week!
With the curved surface JBLs (and workalikes), in a sense you are relying on the sound not bouncing once (like some Bose designs), but TWICE.
Once it bounces off the curved front, and secondarily, because of its (presumably) wide dispersion, off the walls in your listening room.
I guess it's not THAT odd - many omnidirectional designs also rely on a double-bounce.
When I scratch my head and think about it, I'm not totally clear why this would give a wider stereo image than regular wide dispersion direct speakers...
The center of the two curved surfaces are only about 300mm apart. To the man with the dinosaur shirt and ukulele, would it sound like the sound is primarily emanating from that small curved surface, or something wider?
Some foam core experimentation next week!
With the curved surface JBLs (and workalikes), in a sense you are relying on the sound not bouncing once (like some Bose designs), but TWICE.
Once it bounces off the curved front, and secondarily, because of its (presumably) wide dispersion, off the walls in your listening room.
I guess it's not THAT odd - many omnidirectional designs also rely on a double-bounce.
I just started perusing a long thread, running between 2003 and 2019 about Stereolith.
It might take me a while to weed through all the opinions and mumbo jumbo before I can figure out how it actually works. At first glance it looks like it's another case of relying on well-placed reflective walls, but presumably it does NOT use a Sum/Difference matrix.
https://www.diyaudio.com/community/threads/stereolith-loudspeakers-question.10962/
From Paragon wiki;
"....by projecting the sound from each speaker against a curved surface which acts as a convex lens for the sound and directs it more strongly to the side opposite the speaker than it does to its own side. The convex refractor thus eliminates the sharp axis of symmetry where the slightest movement of the listener is so disturbing."
When you move to the left, you get more of the right and vice-versa. Also, I imagine having the drivers facing inwards and not directly reflecting (first reflection) from walls can only improve things in a bad room.
"....by projecting the sound from each speaker against a curved surface which acts as a convex lens for the sound and directs it more strongly to the side opposite the speaker than it does to its own side. The convex refractor thus eliminates the sharp axis of symmetry where the slightest movement of the listener is so disturbing."
When you move to the left, you get more of the right and vice-versa. Also, I imagine having the drivers facing inwards and not directly reflecting (first reflection) from walls can only improve things in a bad room.
I read the full thread about Stereolith (again) yesterday. It seems to use only side firing woofers and a central mono tweeter. Unfortunately, most of the measurements are lost...
This is a very useful effect. But I can't quite visualize how the curved surfaces would achieve this. If you sit far to either side, you won't see the opposite side's curved surface at all, and presumably would only hear the (twice) reflected sound from that side. Or at an extreme angle, does the convex lens effect actually strengthen the volume of the opposite side speaker somehow?
Alright, I've perused most of the thread. It appears to me that the Stereolith company took a rather simple concept, and tried to make it seem complicated and magical for the sake of marketing.
Here's how I understand it to work (possibly I got it wrong):
Left and right mid-bass speakers each fire completely to the sides (in earlier models, somewhat upwards, I think). Just like two regular speakers, back to back. This produces a spacious wide sidewall bounce. But normally an all-bounced sound can get pretty diffuse and washy at high frequencies, so a front facing (somewhat upwards angled) mono tweeter is employed to help with clarity and intelligibility.
The concept relies on the idea that spacial left-right clues are most strongly perceived in the high mids (around 1K), so the fact that the tweeter is mono doesn't detract from the image width. And I think that's about it, really!
There may or may not be a time delay needed for the tweeter to compensate for the fact the bounced side signals will take a longer path than the direct signal from the tweeter. This probably depends on the size of the room.
This concept still relies on sidewall bounce, so it is likely less effective with an asymmetric placement in a room. But since there is no need for a coherent acoustic blending of Sum and Difference signals to produce the stereo image, it may be less finicky than a matrix solution.
When I put aside the irritation of the manufactured mystique, I think this could be worth some experimentation!
I had some really nice results with back to back speakers placed diagonally in a corner - ca 1 m away from walls. Then I had suddenly the stereo effect across most of the room.
No, but you see the opposite side's driver itself. So as you move to the left the right driver becomes more direct. See sketchup demo.
Attachments
But this is still reliant on a symmetrical (or thereabouts) room. You are basically creating the same stereo triangle, but with wall reflections. What if one wall is higher, or you spend most time closer to one wall than the other.
I guess I'm getting confused as to whether we are trying to reduce the reliance on the room or increase it. I assumed that in an asymmetrical old English house I was aiming at reducing.
Anyways, I get annoyed at long theoretical threads where no-one actually builds anything, so I better go away and put my money where my mouth is!
Yeah, wall reflections it is if one desires stereo from small structure. Or just make two speakers for real stereo. I don't think there is other ways around other than trying all kinds of gimmicks which are just variations of the same reflection theme. Btw, it is reflections we listen most of the time anyway, unless veryvery directional speakers / acoustically dead room / nearfield, both very hard to achieve at home so reflections it is. Don't be afraid of them, just incorporate to the design like having good off-axis response, minimize diffraction and do other good practices with the construct to get good sound. All things you'd do with normal stereo speakers.
I'm listening single speaker mono and it is very nice, not sure stereo would make single box any better. This one I built some years ago with small fullrange drivers and it was nice http://elias.altervista.org/html/SingleSpeakerStereo.html but does not beat proper big single mono multiway speaker overall, not even close 🙂 Mind you stereo is of course very nice when seated at sweet spot and you need to arrange the sweet spot in the first place. I bet most of the listening does not happen this way (except for those who have space to have proper listening situation and time for proper listening) so mono speaker is very fine most of the time, for casual listening while doing chores and what not. That said I'll build stereo pair at some point because I want to listen to stereo with proper sweetspot. Been prototyping with mono for long time and that is why there is no stereo, yet.
I'm listening single speaker mono and it is very nice, not sure stereo would make single box any better. This one I built some years ago with small fullrange drivers and it was nice http://elias.altervista.org/html/SingleSpeakerStereo.html but does not beat proper big single mono multiway speaker overall, not even close 🙂 Mind you stereo is of course very nice when seated at sweet spot and you need to arrange the sweet spot in the first place. I bet most of the listening does not happen this way (except for those who have space to have proper listening situation and time for proper listening) so mono speaker is very fine most of the time, for casual listening while doing chores and what not. That said I'll build stereo pair at some point because I want to listen to stereo with proper sweetspot. Been prototyping with mono for long time and that is why there is no stereo, yet.
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The biggest difference is, that while using reflections in a smart way, the sweet spot is not a small spot, but a large area of the room. By the way, a very nice soundstage / 3D effect across a large area of the room can be provided by the MDD style speaker (you need two, but the placement is not that critical and the objects look pretty good, my build is here: https://www.diyaudio.com/community/...rectional-full-range-with-3fe22-build.344096/). In my experience, there is not so much need for the pendulum mounting. These created nice soundfield even in a nonsymmetrical room. The disadvantages are two. First, in this form they cannot get very loud and second, for the lowest notes, a subwoofer is handy (or bass control on an amplifier for faking them).