Horn Speakers - Is it me or.......

[Floyd Toole]

Thank you. It makes sense that the horizontal reflections are what matters most, and that getting them right takes priority.

Only if audience "coverage" is at stake does performance at most other angles matter. In sound reproduction it is substantially unimportant, in spite of the colourful sound distribution graphs.

 

[Duke]

Only if audience "coverage" is at stake does performance at most other angles matter. In sound reproduction it is substantially unimportant, in spite of the colourful sound distribution graphs.

Very interesting! THANK YOU!!

 

[Duke]

Only if audience "coverage" is at stake does performance at most other angles matter. In sound reproduction it is substantially unimportant, in spite of the colourful sound distribution graphs.

The late great David Smith (designer of the landmark JBL Model 4430 among others) posted this on another forum:

"... we can't get too pedantic about speaker directivity and polar patterns. If an on-axis dip can be corrected with an off-axis peak, then polar smoothness is not essential. Also, energy spectrum of particular reflections don't seem to matter, as long as total response is correct, again implying that polar performance is a loose descriptor.

"Constant directivity (at least above a certain frequency) can work but it isn't the only answer."

 

[Bjorn]

Which ones out of curiosity?

Rob

Horns that Don Keele designed. For instance the butt cheek 4430/4435 horns.

On-axis they were not great, but let's also remember that driver quality wasn't great then and limited EQ was used. EQ will of course only work well if it's minimum phase behaviour.

 

[Bjorn]

The late great David Smith (designer of the landmark JBL Model 4430 among others) posted this on another forum:

"... we can't get too pedantic about speaker directivity and polar patterns. If an on-axis dip can be corrected with an off-axis peak, then polar smoothness is not essential. Also, energy spectrum of particular reflections don't seem to matter, as long as total response is correct, again implying that polar performance is a loose descriptor.

"Constant directivity (at least above a certain frequency) can work but it isn't the only answer."

I very much disagree. I find constant directivity in small acoustic rooms very important. But obviously you want to have the on-axis right, and there''s no need to sacrifice any today.

Remember that none of the JBL horns had broadband constant directivity combined with even on-axis response. They only had one of the features, and none with a fairly narrow directivity that avoids the closest side wall reflection down to Schroeder. It may be that have never experienced or heard it!
Typically, Harman speakers loose their directivity either horizontally or vertically (or sometimes both) fairly high in frequency.

 

[Bjorn]

They are also remarkably short. Only a couple of inches deep measured from the mounting plate to the outside edge.

Rob

Yes. Wider horns don't need much depth. And unlike many believe they can still go low with the right type of compression driver.

Here's a prototype we did some years ago with quite shallow profile and wider dispersion horizontally.

Horizontal polar measured indoor at 40 cm distance with no gating below. Note that such a close up measurement of this size horn makes the directivity in degrees inaccurate and become wider than that it actually is. But the smoothness and evenness is very accurate down to a certain frequency where the room comes into play.

 

[jhaider]

Only if audience "coverage" is at stake does performance at most other angles matter. In sound reproduction it is substantially unimportant, in spite of the colourful sound distribution graphs.

I’ve wondered why the Spin included a sound power DI and not a horizontal DI.

 

[Bjorn]

The so called "leading pro brand" has clearly shown how much the room influences the on-axis response, and thus also how much the directivity of the speaker is involved. It's only above about 2000 Hz we see little deviation

A well design speaker with constant broadband directivity has on the other hand far less deviations across different rooms and positions.

 

[robh36062]

Here's a prototype we did some years ago with quite shallow profile and wider dispersion horizontally.

Nice looking horns! Those for a ribbon? Don't see throats attached for a CD.

Rob

 

[Digital_Thor]

Only if audience "coverage" is at stake does performance at most other angles matter. In sound reproduction it is substantially unimportant, in spite of the colourful sound distribution graphs.

So... Constant smooth directivity for home cinema, and more focus on the direct sound for home stereo?
Until now, I've definitely found my KEF coax way more pleasant, than any combination of midrange and tweeter that I've tested - even though the direct sound has been measured and designed within +/-1dB from around 700-15.000Hz.
My room seems easier to please with the coax, rather than more typical designs.
Any horn I've tried, are just too close for my room size, making them kinda annoying and a bit too much in your face.

 

[Floyd Toole]

So... Constant smooth directivity for home cinema, and more focus on the direct sound for home stereo?
Until now, I've definitely found my KEF coax way more pleasant, than any combination of midrange and tweeter that I've tested - even though the direct sound has been measured and designed within +/-1dB from around 700-15.000Hz.
My room seems easier to please with the coax, rather than more typical designs.
Any horn I've tried, are just too close for my room size, making them kinda annoying and a bit too much in your face.

Home cinema/theater and home stereo have identical requirements. It is real cinemas and concerts with hundreds of seats that focus on "coverage". It is always important to listen in the far field of a sound source. For small coaxes that is not far - maybe 1m . For large multiway systems it can be much more.

 

[Digital_Thor]

I do use my system for equal amounts of movies and music. Finding my DIY KEF's with a relative narrow construction and smooth even power response, to almost disappear, letting me focus mainly on the illusion of a 'sound scape' and almost forgetting that I listen to two towers and 4 subwoofers.
And that is kinda what I felt was the goal after reading your book, that you should aim for a system - no matter the type, size or looks - that makes you personally enjoy the sound in general as much as possible.

 

[Newman]

...Bumps that show up in on and off-axis curves indicate resonances. So all curves being smooth, and off axis curves gradually changing (for forward firing loudspeakers) are key factors. The on axis response- direct sound - is the prime determinant of sound quality, so if that is wrong, the rest is relatively unimportant. Anechoic data and dedicated EQ can help....

Thank you for once again articulating a distinction that is easily overlooked but which offers valuable insight. If I understand correctly, what matters more in home audio is not necessarily the radiation pattern shape in and of itself, but its effect, which (imo) is ideally the best presentation of direct + reflected sound to the listener's ears....

Vertical walls are the dominant reflecting surfaces so far as ears in the horizontal plane are concerned - what happens at other angles is less important because of longer path lengths, inverse square law and air attenuation.

Thank you. It makes sense that the horizontal reflections are the ones which matter most, and that getting them right takes priority. Normally the first same-sidewall reflections also arrive fairly early, and if I understand correctly, that contributes to their perceptual significance.

Only if audience "coverage" is at stake does performance at most other angles matter. In sound reproduction it is substantially unimportant, in spite of the colourful sound distribution graphs.

@Duke it is possible that Dr Toole is using the term sound quality, in his first post above, with precision. In his books Dr Toole distinguishes between the terms sound quality and spatial quality. Reflected sound is especially important for the latter, so quality of reflected sound is still important, but not so much in relation to the precise term sound quality.

The general readership, reading recent posts to this thread, could easily conflate sound quality with 'all aspects of listener preference for quality'. Even when audience coverage is not an issue and only one listener is present, reflected sound remains a notable component of listener preference, and even more so for listeners who still restrict themselves to 2-channel playback of 2-channel source material.

Perhaps we should check with Floyd if I am understanding correctly. @Floyd Toole

 

[Duke]

@Duke it is possible that Dr Toole is using the term sound quality, in his first post above, with precision. In his books Dr Toole distinguishes between the terms sound quality and spatial quality. Reflected sound is especially important for the latter, so quality of reflected sound is still important, but not so much in relation to the precise term sound quality.

The general readership, reading recent posts to this thread, could easily conflate sound quality with 'all aspects of listener preference for quality'. Even when audience coverage is not an issue and only one listener is present, reflected sound remains a notable component of listener preference, and even more so for listeners who still restrict themselves to 2-channel playback of 2-channel source material.

Perhaps we should check with Floyd if I am understanding correctly. @Floyd Toole

I think you're right. Thanks for the reminder.

I am under the impression that reflections can have a significant (though secondary to the direct sound) effect on sound quality, in particular on timbre, for better or for worse.

 

[Sal1950]

Home cinema/theater and home stereo have identical requirements.

Thanks for posting that!
I get so tired of hearing folks insist that they have different demands.
Good is Good, Stinkers are Stinkers.

 

[Bjorn]

With home theater you have the spatial cues in the the recording. Thus it's more important to deal with specular energy, and narrow dispersion can be benefit to minimize treatment. That is of course if you want to hear accurately how it's mixed.

 

[Digital_Thor]

Thanks for posting that!
I get so tired of hearing folks insist that they have different demands.
Good is Good, Stinkers are Stinkers.

That's why I asked, because I get so equally tired of people who insist on all sorts of alternative and creative roads to audio nirvana - totally ignoring the basics.
But I like that the word "coverage" was included, and the distinction between home and bigger events, was pointed out.

Another good point Floyd included, was the fact that we need to understand a given speaker construction, to know when we are actually in its far field, which I always experienced was farther away with bigger horns. Combining horns with direct radiators in smaller rooms, also seems tricky... unless the horn is quite small - same size as the neighboring driver.

You might be equally qualified to answer this question, then.
Isn't it true, that we mostly like reflections beyond 20ms and mostly wish to dampen the ones below this threshold?
Because the reason I entered this debate at all, was because horns and waveguides, was my first experience with a speaker, that gave me the best imaging and stereo perspective. Which I believe stems from their possible even and smooth power response. Which again seems to fit well, with the idea that early reflections that has the same signature as the direct sound, creates the most coherent sound for us humans, with our lack of abilities to discern sound within the 20ms window. Is that somehow correctly understood?

 

[Bjorn]

There's no proper studies that show that reflections later than 20 ms is preferred. Not with different types of treatment.

The audibility is also very dependent on how much the earlier ones are attenuated, and at what angle they arrive from. Studios generally diffuse later rear reflections, and which also IMO the best approach as long as the diffusers hold a certain quality. This deals with the negative attribute of the reflections, without deadening much and also adds spaciousness and envelopment.

Reflections can be diffused that arrive earlier than 20 ms of course too. Most have rear reflections that arrive much earlier. But you need a certain distance from the diffused energy to avoid combing and lobing

 

[fredoamigo]

There's no proper studies that show that reflections later than 20 ms is preferred.

I think the opposite, or rather, I have learned the opposite. Reflections that arrive within 30 to 50 milliseconds after the direct sound are generally perceived as part of the direct sound and can enhance clarity and sound localization. However, these reflections are often considered early reflections rather than late reflections. As for reflections that arrive after approximately 50 to 80 milliseconds, they are generally considered late reflections. At this stage, they begin to contribute to reverberation and the perception of space. These reflections can add depth, richness, and immersion to the sound experience.
can you find one or more studies that contradict what I've learned ? Please be as objective as possible in your response, as I know you are biased since you are a professional who sells acoustic treatments aimed at suppressing acoustic reflections.

 

[Keith_W]

There's no proper studies that show that reflections later than 20 ms is preferred. Not with different types of treatment.

I believe you are right. The studies show that reflections arriving later than 20ms shows that the detection threshold (of the reflection being perceived as a separate event) is increased. There is that paper by Haas which I won't link to because it's in German. But this paper by Olive and Toole is in English, free to download, and shows the same thing. As to whether it is "preferred" I am highly sceptical. As far as I am aware the studies say it is detectable, not whether it is preferred. Anybody know of a good study?

Olive S, Toole F "The Detection of Reflections in Listening Rooms", JAES Vol. 37, No. 78. Link to free download