Not sure if I understand the question, but I will say that in the modal region modes are not localized, they are everywhere. You cannot have a situation where a mode is active in one place and not another except at the nodal lines, which are precisely defined lines of stationary velocity and maximum pressure. If you were to plot out the intensity in the room, then it would be uniform throughout. above the modal region "hot spots" or focal points can occur, but this would be a unique situation.
I see what you mean, I'm not expressing it correctly when I say modes elsewhere. I think I'm looking for a problem where one doesn't exist. It doesn't matter in the listening spot where I have a well balanced sound that there is say a node of maximum pressure a few feet away? Just wondered.....too much time on my hands, haha.
I once made a sub filter that made a corner sub flat down to 16 hz. Maybe at 95dB
The problem was that nodes ratteled objects near the walls so I only got distracted by the dzzzz and mmmmm the objects made. So yes, nodes outside listening position can matter🙂
The problem was that nodes ratteled objects near the walls so I only got distracted by the dzzzz and mmmmm the objects made. So yes, nodes outside listening position can matter🙂
Double walls: Just keep in mind that the absorption falls greatly at low frequency
Double Stud Wall Soundproofing Performance
And the air will be stiff between the original and the damping wall at some frequency.
Just saying.
The room will not be dead and it should not be to dead either.
Double Stud Wall Soundproofing Performance
And the air will be stiff between the original and the damping wall at some frequency.
Just saying.
The room will not be dead and it should not be to dead either.
Another way to ask your question might be: can I equalise the bass to my listening position and ignore the modes..
Almost, what I've done is move the speakers and my position to get it as flat as possible and then done a little bit of EQing, mostly cutting a very stubborn peak I had at 40 Hz. But yes, I'm guessing what goes on in other places doesn't matter, other than what torgeirs mentions
Problem is that those curve show Sound Transmission loss not sound absorption. From inside the room, transmission to the outside is absorption. We really do not know how much sound is absorbed by those structures.
That's not necessarily a mode (which is what I think you meant, nodes don't excite anything,) most likely not. It is simply a mechanical vibration excited by the sound field - at a modal frequency or not.
Yes, but the topics are related.
Just tried to warn that such modifications should be done by qualified personell, as yourself.
Damping of bass with panels is a difficoult task. The mid can be overdamped and the bass underdamped so the room sounds strange.
Regarding corners: This paper shows the complexity, but also that corner absorbers, here active, can work
https://infoscience.epfl.ch/record/...stic absorbers in the low frequency range.pdf
https://infoscience.epfl.ch/record/...stic absorbers in the low frequency range.pdf
Thank you for the link. Do you know what was the value of damping resistor used? I didn't find in the paper any value to start with.
Sorry, I don`t know
A later 2016 AES article from the authors, that I was allowed to download, they have replaced the passive load with an acrive one to broaden the freq area that is dampened.
Was only trying to find measurement of corner bass traps to see if it was only a hype.
A later 2016 AES article from the authors, that I was allowed to download, they have replaced the passive load with an acrive one to broaden the freq area that is dampened.
Was only trying to find measurement of corner bass traps to see if it was only a hype.
Since an active unit like that is so much more efficient in this application than passive absorbers.. well it takes so much of the passive absorbers to do well it is fairly impractical, I think that is the point.
I wouldn't call that active, it's a passive system that can be tuned by the load resistor, and has a limited frequency range. It is certainly seems more efficient than the normal passive absorbers, and more easily adjusted
... a link to what seems a sequel of the 1st paper: https://pdfs.semanticscholar.org/30df/8faa9df8575a9919b561283b79c4b6f3c243.pdf
Sorry, I assumed without reading 🙁 But isn't the point that this device would respond reasonably well to pressure variations where absorbers would not? The corner itself has obvious properties.
Probably, cheaper I would imagine too, I wonder whether you can use any old cheap driver, I don't see why not?
Seems like just a shunt (short circuit) of the speaker terminals is the simplest passive electroacoustic absorber: https://www.comsol.com/paper/download/101117/Lissek.pdf
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