Gel Speakers
- Thread starter bdblkta
- Start date
Register to hide this ad
Interesting. When the frequency sweep hit multiples of the video refresh rate you could see interference patterns on the material. That makes it seem like the NXT panel technology. They make working speakers but I have never heard anything that I would categorize as hifi.
I.R.Brainiac
Super Member
Looks like we might finally get our ideal sound emitting sphere. (in my lifetime please)
ken kantor
Fowl Humor
Looks like we might finally get our ideal sound emitting sphere. (in my lifetime please)
There is nothing ideal about a sound emitting sphere. On the contrary, good reproduction requires controlled directivity.
-k
What if we could come up with a reciprocal transducer to record the sounds in the first place. We could put a bubble around a violinist and record the sound going in all directions. Then playback by a truly omnidirectional sphere speaker would be ideal.
Of course to do it right would mean capturing the directional data and magnitude at all points on the spherecorder (I just made that up) so it's not something that will happen in the next 6 months or so. I just like the idea.
ken kantor
Fowl Humor
What if we could come up with a reciprocal transducer to record the sounds in the first place. We could put a bubble around a violinist and record the sound going in all directions. Then playback by a truly omnidirectional sphere speaker would be ideal.
Of course to do it right would mean capturing the directional data and magnitude at all points on the spherecorder (I just made that up) so it's not something that will happen in the next 6 months or so. I just like the idea.
I don't see how a point source transducer would be what you want in that case, anyway. Perhaps you can explain more?
-k
I.R.Brainiac
Super Member
Controlled directivity is great,but I would also like to have a radiating sphere...several in fact.
One for each instrument/voice.Add some captured reverb and close my eyes.
Last edited:
I.R.Brainiac
Super Member
This goes right along with my dream TV.What if we could come up with a reciprocal transducer to record the sounds in the first place. We could put a bubble around a violinist and record the sound going in all directions. Then playback by a truly omnidirectional sphere speaker would be ideal.
Of course to do it right would mean capturing the directional data and magnitude at all points on the spherecorder (I just made that up) so it's not something that will happen in the next 6 months or so. I just like the idea.
A hemisphere screen and 360 degree camera work...you could look at the action from any direction.(Computer animated stuff would be a cinch) A screen that could make sound and you have true surround sound.
A globe microphone sounds cool...pressure sensitive on the entire surface.
A globe speaker could then just play back exactly what the microphone picked up...on the exact corresponding surfaces. As long as I'm dreaming,just make it one device that does both.
I could already simulate one.I used to bolt speakers face to face for recording.The signal was large...very large.
Maybe just setup a small geodesic microphone array and multitrack it.
Play it back on a geodesic speaker matched to the microphones.
Last edited:
I'm not really talking about a point source. It would have to be bigger. To make things realistic it would have to be the same size as the recording sphere. The idea, as it sits in my noggin, would be to have a sphere around an instrument, singer or whatever source you choose that would record all sound leaving the sphere. Playback would be an identical sphere that would radiate outward what had been "passing through" the recording sphere so it would be simply continuing the sound field that had originated with the instrument. That would be the "they are here" version.
For the "you are there" version, a recording sphere would be set in a seat at the orchestra and would record everything coming into it. Then at home you would sit inside a sphere that would radiate that same sound field inward.
ken kantor
Fowl Humor
A pulsating sphere of any size is equivalent to a point source.
I understand your method. Using it, all directional information would be lost, and you would get an integration of the energy crossing the surface of the recording sphere. At best, you would hear tonally odd mono. However, if you want to introduce directionality to the playback sphere, then the concept of a "pulsating sphere" is irrelevant. You might as well put discrete transducers around the listener.
-k
Last edited:
ken kantor
Fowl Humor
This goes right along with my dream TV.
A hemisphere screen and 360 degree camera work...you could look at the action from any direction.(Computer animated stuff would be a cinch) A screen that could make sound and you have true surround sound.
A globe microphone sounds cool...pressure sensitive on the entire surface.
As long as I'm dreaming,just make it one device that does both.
I could already simulate one.I used to bolt speakers face to face for recording.The signal was large...very large.
Maybe just setup a small geodesic microphone array and multitrack it.
Play it back on a geodesic speaker matched to the microphones.
Wavefield synthesis, what you are describing, is more complex than this. You need to account for the processes that the "ear" uses to determine direction and distance, and you need to account for differing boundary conditions between recording and playback. Believe me, this stuff has been tried ad infinitum.
-k
Dr. Morbius
I.N.T.E.R.O.C.I.T.O.R.
What if Gus Gorman built a stereo and powered it with a Dyson sphere? 
Yeah, I was just talking about a really big point...although I really wasn't talking about a point. It's a bit more complex than that. Read on, if you dare.
That's why, in my first post, I said...
Of course to do it right would mean capturing the directional data and magnitude at all points on the spherecorder (I just made that up) so it's not something that will happen in the next 6 months or so. I just like the idea.
A myriad of discrete transducers might potentially do it. I was thinking more along the lines of something like this...if the gel stuff were amorphous and the sphere were held in place by cohesion and a static internal pressure (remember superlastic bubble plastic?
) then any sound wave within the sphere would push out where it contacted the sphere. If the new shape of the former sphere could be approximated by a complex equation or a digitized model or whatever then the magnitude at each point would be preserved. I recall solving a 2D wave equation for something like a drum head back in college and the math was moderately horrendous so that may or may not be possible in real time. Of course my current phone has more computing power than almost anything I had access to back then (I say almost because there was a Cray on campus but I never got any time on it except once when I was working for the Corps of Engineers and even that was indirect).Playback would have to be the reverse with power (don't know if the gel is voltage or current activated) being induced at the right places at the right dosage.
If we approximate an instrument as a point source (which it really isn't) then directional data could be approximated as radial to the sphere. The sound would be captured before it hit any boundaries so the diffuse field would be dictated by the playback room.
Note that this isn't something I'm trying to develop. It isn't a PhD thesis. It isn't even something I've really thought seriously about. It's just an idea I was mulling around probably while I was on a long run on a Saturday morning and had nothing else to ponder. Feel free to pick it apart at your leisure. It's a heck of a lot more coherent than most things that appear, unbidden, in my head while I'm out on the road.
What if Gus Gorman built a stereo and powered it with a Dyson sphere?
:lmao:
ken kantor
Fowl Humor
What if Gus Gorman built a stereo and powered it with a Dyson sphere?
If it were a Dyson Sphere, it would lose oribital stability and crash into your head.
-k
ken kantor
Fowl Humor
Yeah, I was just talking about a really big point...although I really wasn't talking about a point. It's a bit more complex than that. Read on, if you dare.
That's why, in my first post, I said...
A myriad of discrete transducers might potentially do it. I was thinking more along the lines of something like this...if the gel stuff were amorphous and the sphere were held in place by cohesion and a static internal pressure (remember superlastic bubble plastic?
Playback would have to be the reverse with power (don't know if the gel is voltage or current activated) being induced at the right places at the right dosage.
If we approximate an instrument as a point source (which it really isn't) then directional data could be approximated as radial to the sphere. The sound would be captured before it hit any boundaries so the diffuse field would be dictated by the playback room.
Note that this isn't something I'm trying to develop. It isn't a PhD thesis. It isn't even something I've really thought seriously about. It's just an idea I was mulling around probably while I was on a long run on a Saturday morning and had nothing else to ponder. Feel free to pick it apart at your leisure. It's a heck of a lot more coherent than most things that appear, unbidden, in my head while I'm out on the road.
Oh, it's a cool concept, for sure, but it really doesn't have much to do with the pulsating sphere/point source idea. IMO.
I've heard really good systems that used wavefield "spheres" surrounding me, but these were built with a limited number of discrete speakers. The higher order Ambisonic implementations are like this.
-k
Well...they're both round. :thmbsp:
I totally agree. I followed up the pulsating sphere reference with mine without separating the ideologies. They're vastly different beasties.
