To help make it more clear I'll repeat the information from post 20. Notice it is expanding surface area that matters. Also, pretend the goal is to maximize attenuation.
The maximum amount of attenuation you can achieve is an omnidirectional point source radiating into a sphere, which is -6dB. If you radiate into a surface area less than a sphere -- a spherical cap -- you can't achieve -6dB.
The maximum amount of attenuation you can achieve is an omnidirectional point source radiating into a sphere, which is -6dB. If you radiate into a surface area less than a sphere -- a spherical cap -- you can't achieve -6dB.
wesayso referenced Danley's FAQ. What does it say?
A point source is omnidirectional radiating into the surface area of a sphere. The line array is directional on the vertical and radiates into the surface area of a cylinder.
Sphere = 6dB
Cylinder = 3dB
Danley continues on about the array.
We've already discussed how arrays control frequencies at a fraction of their length. Thus, there's nothing new in that FAQ that we haven't already covered.
A point source is omnidirectional radiating into the surface area of a sphere. The line array is directional on the vertical and radiates into the surface area of a cylinder.
Sphere = 6dB
Cylinder = 3dB
Danley continues on about the array.
We've already discussed how arrays control frequencies at a fraction of their length. Thus, there's nothing new in that FAQ that we haven't already covered.
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Neat. I don't know how to use sim software. Sure would be good to see an omnidirectional point source simmed against a directional source over distance in the frequency range controlled by the horn (not the longer frequencies that radiate omnidirectionally).
Danley's designs are point source, basically all of them in his catalog. If you don't tryst me, just ask him. One of his representatives will surely tell you if you ask that question on Facebook. Danly doesn't do line arrays, even his SBH series that looks like a line, still is a point source. As that one is limiting the vertical behavior, it may act a little different in nearfield conditions.
The horns are acting as a point source though, just check with his firm on Facebook or through email. If they answer, I hope you will believe their word for it.
The horns are acting as a point source though, just check with his firm on Facebook or through email. If they answer, I hope you will believe their word for it.
Maths to rescue
area of the spherical cap, using distance r from the center ( point source ).
A = 2*pi*r^2*(1- cos(the angle)). Area of the spherical cap depends on the distance r squared, just like with a sphere, no matter what the angle.
Area of sphere is calculated as so, Area is connected to the r squared.
A = 4*pi*r^2
Surface area of a tube, a line source, at given distance r is calculated like so
A = 2*pi*r*h
You see it is directly proportional to the distance, not squared as with the sphere and spherical cap.
To add to the mathematical explanation above
Here is a horn in a BEM simulation with the output at 1m, 2m and 4m
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Line arrays don't radiate as tubes IRL. Distance variation will introduce diffraction variation which is also frequency-dependent.
At very long distance, air friction will tame high frequencies more than lows. This effect is not noticed at home (overruled by effect of typically narrower radiation)
The Edge simulations don't show spl drop based on mic distance, only interferences.Here 2m vs. 6m tall arrays
At very long distance, air friction will tame high frequencies more than lows. This effect is not noticed at home (overruled by effect of typically narrower radiation)
The Edge simulations don't show spl drop based on mic distance, only interferences.Here 2m vs. 6m tall arrays
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Jeah measurements show whats happening more easily than trying to tackle the situation with maths. Maths get complicated the moment one realizes sound isn't radiating from single point in space, or from a perfect line and then there is the environment.
There was some confusion how much sphere and spherical cap area expands in relation to the distance from the center, they expand as much, doubling distance quadruples the area.
There was some confusion how much sphere and spherical cap area expands in relation to the distance from the center, they expand as much, doubling distance quadruples the area.
line arrays drop off slower than 6dB/doubledistance because the target isn't in the far field. Like if you measure a cone driver close up it doesn't drop 6dB per till you get out away from the cone some distance. Make a cone 12 feet tall and measure it out 5 feet or less, the dropoff rate will be slower.
Yes! Far field is defined by the distance that 6dB/doubledistance begins.
Inside that is nearfield, dominated by multiple arrivals.
Just as there is no such thing as a true point source, there is no such thing a true line source.
Which means to me, there is no such thing as a spherical or cylindrical wave front.
Theories walk, measurements talk
As an add on to my prior post...
Outdoors, it's easy to measure when far field begins.
Indoors, not easy at all, as reflections/reverb often swamp measurements.
Here's maybe the best method indoor method I've come across...Direct-Field Coverage - A practical way to check it
Why i think all this is important, is because ime both our measurements and listening are best in the far field.
Outdoors, it's easy to measure when far field begins.
Indoors, not easy at all, as reflections/reverb often swamp measurements.
Here's maybe the best method indoor method I've come across...Direct-Field Coverage - A practical way to check it
Why i think all this is important, is because ime both our measurements and listening are best in the far field.
Hi
There is a way one could observe a horn in use and conclude that it did indeed defeat the inverse square law. In fact this is done fairly often by us at work in installed sound.
The basic idea comes from the olden days, a single horn projects a lobe and if one raises the height of the horn and aims it at the back row, one makes the spl much more uniform front to back than a low height (on axis).
This reduces the difference in distance between the front and back rows AND as you move forward to the front, you are gradually moving out of the lobe.
This can't be done as well when one has multiple sources which produce both lobes and nulls or even that well with traditional horns which get narrower as the frequency climbs. But was "the way" pro's did it and the same principal is why one toes in speakers (aim at the far seat)
What the Synergy horn does is give one a way to make a much wider bandwidth high power horn that still radiates simply as if it were one source in one CD horn. It can do this because all the sources are less than 1/4 wl apart where they interact or combine resulting in coherent addition (like two very close together subwoofers do but inside of the horn).
To the degree one can also make it a "constant directivity" horn, then one finds that as one moves out of the pattern, the SPL still falls but unlike "not CD" horns that narrow up high, the spectrum stays much more constant off axis than normal.
By choosing a large horn with the right pattern angles and aim point, it is possible to get even sports stadiums to + - 2dB level in every seat and the comment "it sounds the same everywhere" has even been heard.
If you have heard any of the recordings like the fireworks I have made with a microphone experiment, it would not be a surprise to learn how we hear and the capture and reproduction of the "image" is a long time interest of mine.
About a year ago, I was pretty much caught up on my official "wish list" at work when the Virus and the slow down hit. I build some of our prototypes or the ones i can anyway, I like that part and it's a big part of what i love about speakers "this is how we make the sawdust" (moonshiners show reference) ending with listening and measuring haha.
I have some of the oldest SH-50's from 2005 in my living-room with sub-woofer. I thought a lot about what would i build for me when the time came, what i would want.
I like to crank it up occasionally and its part of the home theater but It doesn't have to be that powerful or large, i only sit 15 feet away but it does need to image like that or better and still be able to do the fireworks recording.
After a few months, I brought them in to work and Mike wanted to keep them in the demo room, so i made a second pair, then our wood shop made some and enough people wanted them then that it became it's own thing.
Hope that helps
Tom Danley
There is a way one could observe a horn in use and conclude that it did indeed defeat the inverse square law. In fact this is done fairly often by us at work in installed sound.
The basic idea comes from the olden days, a single horn projects a lobe and if one raises the height of the horn and aims it at the back row, one makes the spl much more uniform front to back than a low height (on axis).
This reduces the difference in distance between the front and back rows AND as you move forward to the front, you are gradually moving out of the lobe.
This can't be done as well when one has multiple sources which produce both lobes and nulls or even that well with traditional horns which get narrower as the frequency climbs. But was "the way" pro's did it and the same principal is why one toes in speakers (aim at the far seat)
What the Synergy horn does is give one a way to make a much wider bandwidth high power horn that still radiates simply as if it were one source in one CD horn. It can do this because all the sources are less than 1/4 wl apart where they interact or combine resulting in coherent addition (like two very close together subwoofers do but inside of the horn).
To the degree one can also make it a "constant directivity" horn, then one finds that as one moves out of the pattern, the SPL still falls but unlike "not CD" horns that narrow up high, the spectrum stays much more constant off axis than normal.
By choosing a large horn with the right pattern angles and aim point, it is possible to get even sports stadiums to + - 2dB level in every seat and the comment "it sounds the same everywhere" has even been heard.
If you have heard any of the recordings like the fireworks I have made with a microphone experiment, it would not be a surprise to learn how we hear and the capture and reproduction of the "image" is a long time interest of mine.
About a year ago, I was pretty much caught up on my official "wish list" at work when the Virus and the slow down hit. I build some of our prototypes or the ones i can anyway, I like that part and it's a big part of what i love about speakers "this is how we make the sawdust" (moonshiners show reference) ending with listening and measuring haha.
I have some of the oldest SH-50's from 2005 in my living-room with sub-woofer. I thought a lot about what would i build for me when the time came, what i would want.
I like to crank it up occasionally and its part of the home theater but It doesn't have to be that powerful or large, i only sit 15 feet away but it does need to image like that or better and still be able to do the fireworks recording.
After a few months, I brought them in to work and Mike wanted to keep them in the demo room, so i made a second pair, then our wood shop made some and enough people wanted them then that it became it's own thing.
Hope that helps
Tom Danley
Super to see you post on DIY again, Tom !
Many thanks for all the kind generous help you've given the DIY community over the years.
And Best of Luck to DSL, with the home/studio products!
That said, my next post will be speculating about the Hyperion, trying to crack it, as all we DIY'ers are known to do Lol
Many thanks for all the kind generous help you've given the DIY community over the years.
And Best of Luck to DSL, with the home/studio products!
That said, my next post will be speculating about the Hyperion, trying to crack it, as all we DIY'ers are known to do Lol
Ok, trying to guess more about the Hyperion.
I'm thinking the top section is very similar to the SM-60F...both appear to have a 5" coaxial, and two 8" drivers. We can see both mid-range ports and reflex ports for the 8 inchers.
In the lower section, I love the opposed side firing 15" sub drivers. Big time vibration reduction.
I think the reason for the feet is what appears to be incorporating a downward firing reflex port.
Whether that Hyperion sub take is correct or not, i think side-firing opposed, with downward reflex port, is a great idea.
Less volume needed than my current clamshell slot loaded subs (no slot volume needed). And the box height could make make reflex port length much easier to fit in, for going lower.
Opposed firing sub drivers are simply a must imho.
I'm thinking the top section is very similar to the SM-60F...both appear to have a 5" coaxial, and two 8" drivers. We can see both mid-range ports and reflex ports for the 8 inchers.
In the lower section, I love the opposed side firing 15" sub drivers. Big time vibration reduction.
I think the reason for the feet is what appears to be incorporating a downward firing reflex port.
Whether that Hyperion sub take is correct or not, i think side-firing opposed, with downward reflex port, is a great idea.
Less volume needed than my current clamshell slot loaded subs (no slot volume needed). And the box height could make make reflex port length much easier to fit in, for going lower.
Opposed firing sub drivers are simply a must imho.
