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This is important ! It was exactly the pivoting of the head sideways that caused the speaker to be localised on the floor. With fixed head position it was much harder. But this is no good also, because the situation is unstable and image is jumping in vertical direction if head is mobilised.
Not sure yet how to solve this.
- Elias
oh yes - You're right - my mind is too slow 😱
I should have said: "welcome in THE club" 🙂
You mean "mobilised" or "immobilised" ("as well")?
Markus, I was referring to interaural differences (hence the cone of confusion) I am guessing that you are calcualting arrival time (or latency) differences between the direct and reflected sounds. Are we talking about the same things?
not sure what you are asking.. I put about 3" of foam on top of the speaker, protubering enough in front to tame the reflexion at the listening position. Not ideal, but gave me an idea of what a ceiling acoustic treatment could give. The reflexion which was at 3ms went 15db down.
and this affects the perceived frequency response, I think that such a change in the perceived frequency reponse can be effected by means of equalization as well
not only, the virtual sources got somewhat "lifted". I would not want to touch the direct sound with eq for only one spot, sorry, as then all the reflexions will get coloured. I also believe you need a few ms ITD gap, 3ms is just not enough. The sound now is more detached from the speakers, less "upfront". I like it much better.
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Did you try to put the absorption panels on the floor instead of ceiling ? How would it compare in your perception ?
(I know it may not be practical in a living room, but for a sake of science 🙂)
Hi Elias, I did. I actually have a very thick and dense wool carpet on the floor, and added two 4" DIY rockwool panels in front of the speakers. Not much difference, strangely. Even in the measurements. 😕
What should be done exactly and how ?
So far it looks that the speaker close to the floor level produces very pure wavefront at the listening position below 500Hz (higher freqs will be confirmed in the further study 😉), but if head is mobilised by sideways pivoting the perceived image is close to the floor.
Are you suggesting to put the speaker at the ear height and absord floor and ceiling reflections, below 500Hz ?
It strange indeed. The measurements should reveal similar (15dB) difference as you measured on ceiling absorption.
Or are your speakers somehow nonconventional ? 🙂
Deflect the wave back to the front wall with panels. Could you run a simulation if this is feasible?
Interesting idea !
The size of the panels is limited in normal living room having 2.5m height. In order to act as reflector the panels size should be higher than about wavelength, if not it acts as a diffuser radiating strongly to the listening position too but with (somehow) randomised wavefront phase.
I'll run some FDTD to check this.
The IRN is a very unusual signal. It would never exist "in nature". It is quasi alien. They built it to have something that doesn't suit the fusion zone of the precedence effect.
Why doesnt it suit? Because it doesn't have a "gestalt". Sounds without a gestalt are not registered as an own entity by the brain.
Two wavefronts (now the wikipedia definition) of two tones of same frequency, coming from almost the same direction, but one starting with a delay, will never be registerered as different entities by the brain, regardless how short or long the delay is. What you recognise is, that it gets louder after the delay.
Look at the wavefront definition in wikipedia. And then look at the example you linked to. To me both are very different things. The latter would be more envelope than wavefront to me.
Rudolf
oh c'mon Scott! 😀 I know what's diffraction
what I don't know is what You mean by "the point of diffraction" 🙂