The Advantages of Floor Coupled Up-Firing Speakers

ceiling reflections are good, IF they come from the sides, not from the center. Unless you want to kill the stereo separation?

I agree but most ceiling firing designs create first order ceiling reflections that are detrimental. Psychoacoustically most effective are side reflections from around ±60° and elevated (2nd order) side reflections from around ±45°. The relationship between those reflections and the direct sound in terms of level is critical.
If energy radiation into all other angles isn't controlled, clarity lacks considerably. Simply pointing a rather wide dispersion speaker to room boundaries can increase spaciousness but it doesn't sound necessarily good.
 
Yes, but the effect depends on the recording as do most "extreme" speaker configurations, in my limited experience.

I agree. The reflection level should be adjustable by the user. I don't believe there's a one-size-fits-all solution. Reflection patterns need to be adjustable to the room and the recording. These are issues multichannel is trying to solve. We're not there yet.
 
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really? What then the fuss about IACC for hall designs?
How can ITD not change? No difference between a 2.5 high ceiling and a 4m one?
I thought the worst offender was actually the ceiling, conclusion from the Archimedes project in DK, read it somwhere.. :confused:
Same goes with the front wall, the middle is no good.. loss of clarity and no particular spatial contribution.
 
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really? What then the fuss about IACC for hall designs?

IACC is much more complex entity. The result is depending on temporal, spectral and spatial domains. Not just simple ceiling reflection.


How can ITD not change? No difference between a 2.5 high ceiling and a 4m one?

It's simple geometry only. Assume a symmetrical spherical head for yourself, and then draw a cone coincidencing the ears. You'll see the cone surfaces are parallel with the paths from the speaker and from the ceiling reflection.


I thought the worst offender was actually the ceiling, conclusion from the Archimedes project in DK, read it somwhere.. :confused:

Offender in terms of what exactly ?


- Elias
 
It's simple geometry only. Assume a symmetrical spherical head for yourself, and then draw a cone coincidencing the ears. You'll see the cone surfaces are parallel with the paths from the speaker and from the ceiling reflection.

Not sure what exactly you guys are discussing but the delay of the ceiling and floor reflection varies relative to the direct sound with source/receiver position and ceiling height. Please see
Floor/Ceiling Reflection Calculator
 
IACC is much more complex entity. The result is depending on temporal, spectral and spatial domains. Not just simple ceiling reflection.

It's simple geometry only. Assume a symmetrical spherical head for yourself, and then draw a cone coincidencing the ears. You'll see the cone surfaces are parallel with the paths from the speaker and from the ceiling reflection.

- Elias

agreed on both points
 
IACC is much more complex entity. The result is depending on temporal, spectral and spatial domains. Not just simple ceiling reflection

I meant.. Initial Time Delay Gap, not Interaural Level Difference! :D
Why is IACC not relevant to listening rooms?
Depending on the room, the ceiling is the 2nd offender for the ITD gap.. and not particularly a good contributor to spaciousness. for a direct radiator of course!
 
Depending on the room, the ceiling is the 2nd offender for the ITD gap.. and not particularly a good contributor to spaciousness. for a direct radiator of course!

more broadly speaking - for a speaker design which doesn't take it into account - or even better - uses it like in a flooder type speaker, the name of which draws an analogy to a "flood lamp" used for: "Indirect lighting, or uplighting, [which] create a low glare environment by uniformly lighting the ceiling"

the ceiling is the 2nd offender for the ITD gap.

exactly what sort of sonic offence do you mean precisely?

I believe that ITD gap is just part of a complex "effect on sound" equation which should be resolved for each and one reflection quite independently ONLY

other important parts of the equation are level, angle and frequency spectrum of the reflected sound
 
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My ceiling is only 2.2 high.. pure concrete. I suspect it to be responsible for my unhappiness,

with conventional loudspeakers that's very probable


but wait a couple of weeks so I treat it properly.. and I can then report back. :)

perhaps You could try the flooder approach more thoroughly first, with more suitable speakers

but it's up to You of course