It is very hard to "imagine" what you "mean" if you don't explain that yourself. 🙂
What is "colouration" for one person, might not at all be a "colouration" to another. It depends on the state of one's hearing.
Ondesx.
And there was me thinking , all I want is my speakers ,whatever they are, is to sound real.
As if the musicians and their instruments are in the room with me.
I didn't realise I'd have to make them sound bad to do it ?
I'm Sorry it sounds like I cannot help you.
Steve.
And there was me thinking , all I want is my speakers ,whatever they are, is to sound real.
As if the musicians and their instruments are in the room with me.
I didn't realise I'd have to make them sound bad to do it ?
I'm Sorry it sounds like I cannot help you.
Steve.
What you hear from your speakers, whatever they are, is what the sound directors mixed and created on their mixing tables. So, you won't find the musicians and their instruments in your room though your speakers. The sound directors decide what you hear. 🙂
Hopefully.
Everything we hear from any speaker system, TV, radio or any other sound reproduction medium is what the sound engineers/directors had decided, the music, songs, speech, background sounds and whatnot. Even at the live concerts, they decide what we hear.
Might be the first patent on distributed mode.
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Abstract
A panel-form loudspeaker has a resonant multi-mode radiator panel which is excited at frequencies above the fundamental frequency and the coincidence frequency of the panel to provide high radiation efficiency through multi-modal motions within the panel, in contrast to the pistonic motions required of conventional loudspeakers. The radiator panel is a skinned composite with a honeycomb or similar core and must be such that it has a ratio of bending stiffness to the third power of panel mass per unit area (in mks units) of at least 10 and preferably at least 100. An aluminium skinned, aluminium honeycomb cored composite can meet this more severe criterion easily.-----------------------------------------
Thank you for the math Eric. The art of patenting?
Fully agree also with the driving point approach you have summarized.
Good thing also to have posted again the link to M Zenker's paper. Page 2 there is an approximation of the natural frequencies of a clamped plate. I just used it as a comparison for an FDM script, the mean error between this formula and the script output for a 600x400mm plate simulated with a 10mm mesh is 3.5% (min 0%, max 6%) over the 25 first modes. Good point for the script...
The way to change the mode aspect to show possible driving points seems also possible way with a Python script!
Christian
All this means is you are used to hearing and prefer a certain presentation of sound. Point source speakers are far from perfect and absolutely not like live music. You cannot be absolutist about this as all current methods of sound reproduction include distortion mechanisms. Just the simple fact you are replaying a recorded sound many involves layers of interactions and energy transfers that the original event does not include. By all means state a preference, that is perfectly reasonable thing to do.
Burnt
To the contrary, you just need better source material.
I have a friend who has spent much of the past 30 years making high quality direct (unadulterated) recordings of live jazz performances from the audience. He makes these recording for his own use and will sometimes share them with friends.
I've never heard any recordings as realistic to the performance, the space, or the precise location in the space.
I have used these recording to evaluate changes in my audio system - new electronics, new drivers, new cross over points.
I use them the demonstrate changes to friends (a number of them DIYers ;-) who come to listen.
Nothing could have prepared me for the experience of listening to a recording of John McLaughlin playing with Chick Corea during Chick's 70th birthday celebration at the Blue Note, in New York on my first pair of DMLs (during Covid).
I described the experience among my earliest posts on this thread.
I sat across the table from my friend, while he recorded this - center stage, less than 8 feet from McLaughlin.
Listening through the DMLs put me at that table. They recreated the lived remembered experience more profoundly than anything I had previously experienced from recorded music anywhere.
At one point, someone pushed back their chair and I immediately and instinctively turned fully expecting to see them.
These rare and wonderful recordings stand as my standard of what recorded music can achieve.
DML's rise to the occasion.
"He makes these recording for his own use and will sometimes share them with friends." says all. 🙂 A marginal case. How many mikes, did he use to record that jazz? One? Ten?
The rest of the music production in the world does that for the customers, worldwide. You buy them is shops, stream them and so on. All live concerts have sound engineers. Everything is planned, mixed and adjusted by them. A multi-billion dollar industry can't act like a beach party. There's a multitude of microphones everywhere in any symphonic orchestra next to the players. You live in NY, so why not check that at New York Philharmonic? You can buy CDs there. They are all mastered. I can imagine your friend sitting in the 1st or 2nd row and recording at the Philharmonic...🙂
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Ah, you found one of my all time favorites! This is the one I was referring to recently as being the "precursor" to the NXT patents, and in which the significance of low density is emphasized. It also recognizes the significance of the shear stiffness for the upper frequency limit, and of panel area for lower frequency limit.
But did you notice the panel details! It's a monster 40 mm thick aluminum honeycomb. It's about 1000 times stiffer than any modern DML panel as far as I know!
He thought it needed to be so thick and stiff that the coincidence frequency (fc) would be below the operating range of the panel. Later, Azima and NXT came along and realized that fc could (or even should) be much higher, perhaps even above (not below) the operating range of the panel.
So a lot has changed since Heron, but in my mind he is one of the grandfathers of the DML.
Eric
Not sure, if Heron was the inventor, or was just for the US patent. He might've been the head of the group, the manager/director.
I didn't read it that thoroughly, maybe tomorrow. Verity Group had bought the license from DERA. NXT was a company of Verity Group. Azima must've been either an employee of NXT or connected to it on contract.
By the way, can you give links to your DML builds in this thread, Eric? I'd like to read your experiences. Thanks!
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If you were to make a panel that stiff, and that thick, the wavelength at hf would be smaller than the panel thickness. Thin plate theory does not hold even approximately I think under those conditions, so who knows what you would get out of it. And it would be very difficult to drive. I think coincidence freq may be a bit of a red herring for DML.
Paul,
So true. It's a "thin" plate at the fundamental frequency, possibly. But not at any higher frequency.
It's still one of my favorite of the patents, as it lays out some good fundamentals of plate "figures of merit".
You may be right about the coincidence frequency, at least for our purposes. I know there is a real and significant effect when you are trying to use plates to block sound. But for our purposes, I'm not so sure it matters as much as one might expect. Still I do want to "observe" it experimentally, if only to help me decide if I should care about it or not!!
Eric
Can you provide the full address of the work? I have not found it looking at the publications.
Can someone identify that clear, soft and flexible, transparent stuff that is sometimes used on packaging to stick plastic together temporarily. Its goopy, very stretchy and sticks well but can be removed by pulling or rubbing. Some sort of modified silicone? Can you buy it? Could be useful for damping & mounting.
The use of a tweeter, ribbon in my case solves the problem of a defused stereo image, that I also find is a week point of DML panels.