The name Tony Hooley came to mind when you mentioned this - was his company '1...Limited' what you were thinking of? I recall going to visit him at least 15 years ago....
Speakers give voice to digital symphony | Electronics Weekly
So then, to do this at 24 bits, you need a square array 341 feet by 341 feet, with 16 .7 million drivers.
...per channel.
trivial
jn
Silly that's the equivalent of a thermometer DAC, how about segmenting a few "bits". the possibilities are endless.
There is a flaw inherent in arrays of multiple sources which is not apparent looking at the magnitude view.
The flaw is Huygens wavefront construction is the part used to sell the approach but the flaw is each source has an individual directivity, rather being an acoustically small source has little directivity.
If one is in a room, particularly a large space and understanding words matters, that is a bad thing (although curiously array directivity is pitched as an advantage, not present in measurements).
In an array, one does generate a beam but this only happens with the energy radiated forward from each source. While multiple acoustic sources will combine into one new radiation (akin to adding signals through resistors etc), this only happens if the sources are less than about ¼ wavelength apart.
Once one has reached about ½ wavelength or greater spacing, the two sources radiate independently, producing an interference pattern (lobes and nulls) and this is the case in most arrays. The energy each source radiates in other directions remains.
Part B of the flaw is not only do we hear amplitude but for some kinds of music or voice, time is important as well. When one is in front of any large array and the sources are fed a single impulse, what arrives at your ears is a train of arrivals, starting with the closest source, ending with the farthest.
These sources are dispersive in time and if you have dsp, you can adjust each so that at some single location everything is “right”, at best it can only emulate a single source at one point in space.
The “large array” works very well for sonar or other applications which are not as wide band but with our hearing covering a 1000:1 span is wavelengths, it is VERY hard to make a loudspeaker that behaves the same up high as it does down low.
Conversely, all of our audio signals represent a single point, an electrical signal, what the loudspeaker delivers even anechoic, is scattered in time and direction no wonder a typical loudspeaker will sound bad after just one generation in a generation loss recording, signal faithful they arn’t..
Tom Danley
Danley Sound Labs
The alternative to DS disappeared like parallel printer I/O went to serial-USB. Possibly for similar reasons..... like speed (that parallel printer cable didnt help the cause).
THx-RNMarsh
yup.
However, the problem with digital actuators is even worse....
as I said prior;
The MSB will push half the actuators.. Which ones? What is the physical pattern? The LSB will push one actuator..again, which one?
jn
Is your company offering to supply one..... got a loaner? It would also be good to know just how a Microsonics in the link compares to what most people purchase and listen to.
THx-RNMarsh
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But in post 62959 you said 'There you are! This is exactly what I/anyone with the appropriate test equipment can do, easily. And we have poor levels of distortion at higher levels (than -60) as well. These are quit audible levels to me. ' clearly implying that the higher low level distortion of the DS DAC shown were audible to you.
I'm intrigued as this might suggest that your route to nirvana might be a 24/96 multibit rather than the noise shaped output of a DS.
Personally I used a marantz CD80 for 20 years and only when I went server based for other rooms did I change DAC. I'm only about 12 years behind the curve now
No but the guy keeping the flame alive is local. I remember being kicked out of his store at at least one point in the past.
Goodwin's High End - Pacific Microsonics Model Two
If you read about the elements activation grouping, then page 23 (examples), as well as the other patents from the same assignee, you will notice that they are fully aware of the physical limitations due to micro diameter and micro excursion of each moving element, as well as of the benefits.
For now, they have reached the point of producing and testing a chip designed for portable devices, the market where the money is and IMO the market that technically fits perfectly this technology.
http://www.audiopixels.com.au/index.cfm/investor/asx-announcements/asx-announcements-2015/performance-specifications/
The published measurement results are very limited for to form a distant opinion.
I guess that next step for them is mass production.
Then licensed OEMS will be able to parallel and appropriately group hundreds of chips (as I see from the simulation results, squaring the number of chips raises SPL by 12dB) for building some mini size loudspeakers).
And when these loudspeakers are sold by the thousands, there will come the recycling worms (us, the diyers) for to start testing, using these chips, building things from them, modifying them, ect, ect.
What Tom wrote about multiple point sources is true of course but if we put our magnifying lenses on, 99.999% of speaker drivers (not to speak about loudspeaker systems) suffer from the same ills actually or not?
George
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Interesting. I filed a provisional on a system like this back in the '80s. I never did get it to work satisfactorily, so abandoned it. A couple of workarounds:
1. You can reduce the number of elements by allowing them to be different sizes.
2. You can make use of element resonance by doing this as a modulated system.
1. You can reduce the number of elements by allowing them to be different sizes.
2. You can make use of element resonance by doing this as a modulated system.
It is a pity that you didn’t insist on your idea (I know. I have abandoned perfectly valid ideas because I found some small disadvantage, then I saw such ideas worked out by somebody else less perfectionist than me).
Both of these workarounds are addressed in the patents
>Edit: The moving element's resonance is also a key concept for the operation efficiency
George
Both of these workarounds are addressed in the patents
>Edit: The moving element's resonance is also a key concept for the operation efficiency
George
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If I remember correctly with a phase array like is being spoken of here you can use delay in devices to create the dispersion similar to a normal speaker driver. Actually having all the devices reacting at the exact same time would seem to be counter productive. I have read some of the strange ideas about some of these arrays and some not using any moving elements if I am remembering correctly. But as is said is there really any advantages to any of these methods over the standard device, I don't think so and that is why none of the systems I have ever read about have become commercially viable.
I see this as similar to some of the problems that had to be overcome trying to make flat panel speakers, there were many issues with a flat diaphragm held by a non flexible frame and no real suspension to speak of. A very difficult device to work adequately over a wide bandwidth. I am not speaking of electrostatic or other typical membrane speakers here, but a tightly held membrane attached to a frame and moved with a dynamic magnet system. I consulted on the design and helped with materials selection and application. It was not a pretty picture once the details were closely looked at. I think someone in the orient finally did make the speakers but I have never actually seen a production unit. The diaphragm material was Kapton and it was a miserable choice in my eyes for many reasons.
I see this as similar to some of the problems that had to be overcome trying to make flat panel speakers, there were many issues with a flat diaphragm held by a non flexible frame and no real suspension to speak of. A very difficult device to work adequately over a wide bandwidth. I am not speaking of electrostatic or other typical membrane speakers here, but a tightly held membrane attached to a frame and moved with a dynamic magnet system. I consulted on the design and helped with materials selection and application. It was not a pretty picture once the details were closely looked at. I think someone in the orient finally did make the speakers but I have never actually seen a production unit. The diaphragm material was Kapton and it was a miserable choice in my eyes for many reasons.
Through controlled delay, beam steering, beam focusing and beam shaping can be achieved. (ready and tested methods used in medical diagnostics and industrial NDT with ultrasonic transducer arrays)
George
No, not speed. Manufacturing costs! Decent digital filter plus two monaural multibit D/A s will set you back around $100. Similarly specced delta-sigma will be somewhere between $10 and $20.
Of course it is, George, I realise now some people here didn't get that I'm "fully aware" of DAC behaviour - I just assumed that the technical types here would realise that ...
.It's all about separation of labour - either the DAC and attendant circuitry do it at the time of playback, or it's done beforehand, in an offline operation. What my experiences have led me to believe is that the extra "work" having to be done - the circuitry is processing the data more "aggressively" when normal, lo res audio comes through - effectively creates more interference, and more artifacts are injected into the analogue. Obviously, in a well engineered component this won't be an issue; but the reality, on the ground, at the moment, is that it often is ...
George,
Thanks you confirmed what this old mind was attempting to remember. Practically speaking for a loudspeaker none of this makes much sense in a typical application. I can see beam steering could be advantageous in specific applications, but for music I don't see it having much use.
Thanks you confirmed what this old mind was attempting to remember. Practically speaking for a loudspeaker none of this makes much sense in a typical application. I can see beam steering could be advantageous in specific applications, but for music I don't see it having much use.
Thanks, Richard, I'm pretty sure this was the one I was thinking of - the name "1 Limited" does ring a strong bell ...
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