Directivity characteristics - what's the effect?

[markus76]

Not sure what you're expecting. There's a complex interaction of recorded space, reproduction space and reproduction technique. Our understanding of that interaction is rudimentary. Without a better understanding of this interaction, your question about directivity becomes arbitrary and is nothing more than the result of a certain school of thought.

[EngelholmAudio]

Originally Posted by markus76

Not sure what you're expecting. There's a complex interaction of recorded space, reproduction space and reproduction technique. Our understanding of that interaction is rudimentary. Without a better understanding of this interaction, your question about directivity becomes arbitrary and is nothing more than the result of a certain school of thought.

Apart from the unpolite stuff: what do you propose?

[markus76]

Originally Posted by EngelholmAudio

Apart from the unpolite stuff: what do you propose?

If stating the truth is impolite to you then be it. Apart from that my proposal is: we need to gain much more knowledge.

[EngelholmAudio]

Originally Posted by markus76

If stating the truth is impolite to you then be it. Apart from that my proposal is: we need to gain much more knowledge.

The truth is neve impolite, but phrasings can be.

So thanks for your input to this thread. You're welcome to stop while I encurage other participants to join.

[phase_accurate]

"Next one please ........ !!!"

...sorry, but couldn't resist ;-)

Regards

Charles

[gedlee]

Originally Posted by EngelholmAudio

Not all speakers have a listening height leveled tweeter/midrange. Should the loob point at the listening position? If not, should it be positivly or negativly phase shifted? How much?

I design the crossover lobes such that the nuls are equaly spaced up and down. This yields the widest vertical height before one enters this nul as a listener.

[gedlee]

Originally Posted by markus76

If direct sound is all that counts, yes, but is direct sound the whole story? In a free field, yes, but we tend to listen to speakers in rooms. So we first would need to answer the question "how do we perceive sound in an enclosed spaces?". There's not much we know about it.

Markus
Considering second oder effects, yes their will be an effect on the power response due to the vertical lobes and this is likely to be audible. To what extent depends on a lot of factors, mostly having to do with the room. If the floor and ceiling are fairly well absorbing, but the side walls are all highly reflective (as I suggest and do in my designs) then this issue is minimized - I would say to the point of being insignificant. Other rooms will differ in this regard.

[EngelholmAudio]

Originally Posted by gedlee

I design the crossover lobes such that the nuls are equaly spaced up and down. This yields the widest vertical height before one enters this nul as a listener.

Ok - and at the height of the listener, I assume?

Any consideration to the ceiling reflex? Pardon the swedish, but you'll get it:

If you have a null at "Takreflex" (/ceiling reflex) I say it's bad.

[gedlee]

Originally Posted by EngelholmAudio

But he says that "the horizontal directivity is much more important" which - in my interpretation - says exactly that it's much more than direct sound.

If I continue interpreting, gedlee says that horisintially originated reflections are more important than vertical ones. If interpreted correctly, I am curious as to why.

Not selldom, my measurements of hifi rooms shows a ceiling reflection absolutly to dominant in magnitude as well as to close in time. This makes me conclude that also vertical directivity is important.

Short explaination: Our ears are horizontal and as such we have very high spatial resolution horizontally. This makes horitonal directivity control critical. There really are no "good" vertical reflections and vertical directivity has little to no influence on imaging.

The vertical reflections can be very degrading and should not be there, which, if you think about has only two solutions. Very narrow vertical directivity (not feasible) or absorb or redirect them (what I do).

Horizontal reflections are critical in that they dominate both the perception of image and spatiousness. They are therefor good (> 15 ms) and bad (< 10 ms.). Controlling this aspect (horizontal directivity) of a loudspeaker thus becomes critical and a central focus of my work.

[gedlee]

Originally Posted by EngelholmAudio

Any consideration to the ceiling reflex?

We are typing past each other, but yes, you don't want those reflections. They need to be dealt with somehow.