^ at least I've been talking about first reflections because they are the ones that matter, take another pass on it 🙂 forums are nice way to get understanding on stuff, although sometimes discussion of others might be hard to follow.
Second order reflection points could matter as well but any other reflection point in the room just contributes to late reverberation and are interchangeable, meaningless. First 10-20ms perhaps matters, there is some literature on this but can't remember which one, perhaps there is passage in Toole book and Geddes has mentioned 10ms. It was on some studio control room design related white papers that had this early reflection time figured out like so: Typical studio/recording situation early reflections arrive to mic before this and if control room reflections came earlier they would mask whats on the recording, spatial cues would mix up. It would make sense try and preserve this at home as well, reduce effect of early reflections for example <10ms to hear the space from recording. Or contrary, If its the listening room one wants to listen to then perhaps increase stuff <10ms to hide whats on the recording. Then there is hearing system, haas effect and perhaps others, that matter, affect to perception. I'm not too much into the subject but here is some quick info, seems legit http://www.acousticfrontiers.com/early-reflections-101/
There is perceptual difference with a reflection, if it was from side, up, down, back or from speaker direction. Behind link says the lateral reflections might be usefull but those arriving from up, down, back and from the speaker direction are not and just mess with the direct sound.
Physics of the reflection is same though, sound doesn't mind which way is it while its propagating. Speaker directivity mainly affects the ceiling and floor and sidewall reflections (frequency spectrum). Front wall and back wall reflections happen about the same plane as speaker and listener so the back wall reflection gets roughly the direct sound no matter the directivity. Front wall reflection gets what goes around the baffle (read up about baffle edge diffraction and bafflestep). Positioning the speakers and listener affects the reflection points, relative path lengths. Rotating and tilting speakers affects angles towards reflection points, the spectra again, amplitude.
Hopefully everyone are now following whats going on and able to make their own mind on it, imagination rolling 🙂
Second order reflection points could matter as well but any other reflection point in the room just contributes to late reverberation and are interchangeable, meaningless. First 10-20ms perhaps matters, there is some literature on this but can't remember which one, perhaps there is passage in Toole book and Geddes has mentioned 10ms. It was on some studio control room design related white papers that had this early reflection time figured out like so: Typical studio/recording situation early reflections arrive to mic before this and if control room reflections came earlier they would mask whats on the recording, spatial cues would mix up. It would make sense try and preserve this at home as well, reduce effect of early reflections for example <10ms to hear the space from recording. Or contrary, If its the listening room one wants to listen to then perhaps increase stuff <10ms to hide whats on the recording. Then there is hearing system, haas effect and perhaps others, that matter, affect to perception. I'm not too much into the subject but here is some quick info, seems legit http://www.acousticfrontiers.com/early-reflections-101/
There is perceptual difference with a reflection, if it was from side, up, down, back or from speaker direction. Behind link says the lateral reflections might be usefull but those arriving from up, down, back and from the speaker direction are not and just mess with the direct sound.
Physics of the reflection is same though, sound doesn't mind which way is it while its propagating. Speaker directivity mainly affects the ceiling and floor and sidewall reflections (frequency spectrum). Front wall and back wall reflections happen about the same plane as speaker and listener so the back wall reflection gets roughly the direct sound no matter the directivity. Front wall reflection gets what goes around the baffle (read up about baffle edge diffraction and bafflestep). Positioning the speakers and listener affects the reflection points, relative path lengths. Rotating and tilting speakers affects angles towards reflection points, the spectra again, amplitude.
Hopefully everyone are now following whats going on and able to make their own mind on it, imagination rolling 🙂
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When you say rotating and tilting affects reflection points, it just confuses things. Only insomuch as the location of the driver changes, or loses its direct path to the listener.
There is only 1 set of angles by which sound gets from the position of the driver, to the ear of the listener, off of the floor, which I see you've written earlier.
Even within your post it is confusing to decipher what you're talking about.
Also we don't perceive floor and ceiling reflections the same. Our brains are quite good with floor reflections, given that they have been a constant throughout our evolution, but ceiling reflections we have a much harder time with. Of course the configuration of our head has a lot to do with it. Obviously lateral reflections are the most important spatially, and of course for speakers and our perception of "soundstage."
And because the reflections up, down, sideways are perceived so differently, I just don't see how you can lump all early reflections into this boat of "wider or narrower directivity influences perceived reflection point." Not in a quantifiable way. If the discussion was just limited to single driver horizontal directivity and its early reflection off of each wall, we could get somewhere, but add in anything else and it's a mess.
There is only 1 set of angles by which sound gets from the position of the driver, to the ear of the listener, off of the floor, which I see you've written earlier.
Even within your post it is confusing to decipher what you're talking about.
Is it a single driver or multiples on a baffle? Both have been discussed. Whether both these quotes can be true or not depends on what kind of speaker you are talking about.
Also we don't perceive floor and ceiling reflections the same. Our brains are quite good with floor reflections, given that they have been a constant throughout our evolution, but ceiling reflections we have a much harder time with. Of course the configuration of our head has a lot to do with it. Obviously lateral reflections are the most important spatially, and of course for speakers and our perception of "soundstage."
And because the reflections up, down, sideways are perceived so differently, I just don't see how you can lump all early reflections into this boat of "wider or narrower directivity influences perceived reflection point." Not in a quantifiable way. If the discussion was just limited to single driver horizontal directivity and its early reflection off of each wall, we could get somewhere, but add in anything else and it's a mess.
Uh, this is getting silly, although it is good to try and solve misunderstandings 🙂
I mentioned lumping but not lumping of first reflections. Lumping all other points of reflection in room was the message. These are not the first or second order reflection points through which sound reaches the ear before so called reverberant field sets in but nth order reflections. On the reverberant field there is so many reflections coming from all directions it is impossible to discern between them, reverberation. Smaller rooms this happens faster than with larger, something between 10-20ms perhaps.
Sound goes to all directions and reflection happens everywhere, most of it comes as lumped late reverberation and thus these points of reflection dont matter, or they do as a whole but not individual angles or points or what ever. Individual reflections happen about at the first 10-20ms, all the first reflections and then possibly some second order reflections, perhaps even few third order.
Hopefully this helps to clear it out?
You could take horizontal reflections into more specific discussion and how we perceive them and what not. Physics of sound and how it propagates and reflects are the same be it horizontal or vertical reflection.
ps. usually I add plethora of simulations to illustrate the stuff but I'm on a holiday and try avoid opening the computer. it would have taken less time to make the sims than try and explain multiple times with mobilephone, so perhaps on next discussion there is sims included again 😀
you need to read carefully, here is quote from above "Positioning the speakers and listener affects the reflection points, relative path lengths. Rotating and tilting speakers affects angles towards reflection points, the spectra again, amplitude." and it should read "... affects radiation angles towards..." to reduce confusion.
There is one angle per boundary for first order reflections and another (point of first reflection) for second order reflections etc. I agree these would need to be more specific but it doesn't matter which first order reflection we talk about as per the physics is same for all. How we perceive it is another discussion, not touched on my posts at all. My posts tried to explain exactly this, that there is one meaningfull reflection point on a boundary and its position is not affected by speaker directivity and rest of the posts are attempts to make this clearer, as there seemed to be confusion around the subject.
Sorry about it, I try to be clear enough and also try to trust forum format, people will ask and correct or comment what is going on and discussion emerges. Hopefully at the end everyone following got something out from it.
Mainly thinking about sound source, could be a transducer or fingersnap if you wish. Sound goes to all directions no matter what it is, unless beaming. If whole loudspeaker all trabsducers on it, or more accurately all sound sources port and panel resonances included, have slightly different points of reflection as they are at different location each. This gets too complicated for the discussion though. Any of these sources can be inspected individually. All this is moot though, as points of reflection change as you nod your head jamming with the music. Main takeaway is that sound reflects out with same angle as incident angle to the boundary normal. A specular reflection. Everyone can utilize this to their own projects and scenarios. I've been using it here to demonstrate "bounce" is not affected by loudspeaker directivity. Not very well as there is still confusion 😀 Did this answer you question?
I havent talked about audibility that much other than saying I dont know what to prefer and I currently think I dont need any of them first reflections on my imagined ideal sound which might be different what other ppl prefer. I could change my mind after having more experience as there is no other way to learn than trying and listening. For tgis reason I try to use directivity well, reduce sound towards first reflections and perhaps other tricks, to neutralise any possible ill effects.
I mentioned lumping but not lumping of first reflections. Lumping all other points of reflection in room was the message. These are not the first or second order reflection points through which sound reaches the ear before so called reverberant field sets in but nth order reflections. On the reverberant field there is so many reflections coming from all directions it is impossible to discern between them, reverberation. Smaller rooms this happens faster than with larger, something between 10-20ms perhaps.
Sound goes to all directions and reflection happens everywhere, most of it comes as lumped late reverberation and thus these points of reflection dont matter, or they do as a whole but not individual angles or points or what ever. Individual reflections happen about at the first 10-20ms, all the first reflections and then possibly some second order reflections, perhaps even few third order.
Hopefully this helps to clear it out?
You could take horizontal reflections into more specific discussion and how we perceive them and what not. Physics of sound and how it propagates and reflects are the same be it horizontal or vertical reflection.
ps. usually I add plethora of simulations to illustrate the stuff but I'm on a holiday and try avoid opening the computer. it would have taken less time to make the sims than try and explain multiple times with mobilephone, so perhaps on next discussion there is sims included again 😀
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Constant directivity horns are designed to minimize the on axis "beaming" side effect of axi-symmetric exponential horns like the Zingali Omniray.
MEH (multiple entry horns) can appear as a virtual point source, eliminating the comb filter response from multiple path length arrival times from individual sources .
Large MEH can increase the in-room direct to reflected ratio, increasing signal coherence, reducing "ambiance".
10 DML driven acoustic tiles creating a "room inside a room" would certainly result in a more coherent listening experience than a low DI speaker in the same warehouse.
I'm still here and have some measurements from that era, if of interest. Not directional or reflection stuff.
Just freq plots.
I moved to Tractrix on the mid (200Hz) and upper mid (550Hz), compression driver horns, and a more compact exponential for the mid bass.
The tractrix offer a smoother, less intense, or is it "In your face" listening experience. No by much and in larger rooms the conicals worked very well.
The Tapped horns have remained.
Tweeters have been Raal Lazy Ribbons since 2012 or 2013.
Recently (last year 🙂 ) I moved the upper mids to Le Cleach profile 550Hz. This offered further refinement, to my ears.
Just freq plots.
I moved to Tractrix on the mid (200Hz) and upper mid (550Hz), compression driver horns, and a more compact exponential for the mid bass.
The tractrix offer a smoother, less intense, or is it "In your face" listening experience. No by much and in larger rooms the conicals worked very well.
The Tapped horns have remained.
Tweeters have been Raal Lazy Ribbons since 2012 or 2013.
Recently (last year 🙂 ) I moved the upper mids to Le Cleach profile 550Hz. This offered further refinement, to my ears.