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

[Miley_B]

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

I would suggest there is some frequency dependancy in the significance and effect of reflection times and it may be a mistake to look for a single time to base perception from.
This study may be of interest although I don't think the listening test conditions are clearly stipulated.

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[rank]

A new one (well, for me) = Staccato Horn System MAX (only 79 000$). The hangers are missing.

​

 

[Floyd Toole]

The Olive and Toole AES paper linked to above has a lot of info. My books distill and advance the understanding in some ways, as we learn more. In short: the precedence effect interval - some call it the Haas effect, or the integration time - varies enormously with signal type. Haas used speech, on a hemi-anchoic rooftop, and the delayed sound (the reflection) was the same amplitude as the direct sound, which is impossible in nature. So his 30 ms applies only to speech, and only in anechoic conditions, yet it gets widely misapplied in audio. Add more than one reflection and the situation changes dramatically - the window is much longer. Reduce the amplitude of the delayed sound and the window is much longer. Use impulsive sounds and the window is shorter. And so on. It is not a single-number situation. AND, even though the precedence effect determines localization, the later sounds are not masked, they contribute to timbral coloration and loudness.

What is discussed in the 4th edition being written now, is the effect of mostly large-room reflections in the recordings themselves. When presented in stereo or multichannel the large rooms in recordings dominate the small listening room, among other things making us much more forgiving of loudspeaker flaws - poor loudspeakers get higher ratings, but the best loudspeakers in mono remain the best in any channel count. Likewise, the listening room itself appears to matter less. However all recordings and movies have intervals of hard panned, mono, sound during which we are able to focus on the flaws. So mono listening tests remain compulsory. Interesting how two ears and a brain work.

Stereo = double-mono = a fundamental problem in audio. Sadly, it is the default.

 

[Floyd Toole]

@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

You are right. When I talk of sound quality I am referring to timbral effects, aiming for neutrality as the ideal. Spatial qualities are there as well, and we value them in almost equal balance with timbre, although we often (always?) perceptually confound them. The listening room reflections matter most in mono listening, less in stereo and even less in multichannel, as there are more sources of direct sound. We are most sensitive to loudspeaker flaws in mono, less in stereo, and even less in multichannel - with all channels active! However, monophonic components exist in all programs, so we still need mono listening tests. There are significant advantages to multichannel systems, even upmixed stereo. The center channel remains an issue for mixers.

 

[Bjorn]

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.

Reflections later then about 30 ms is echo. We are not operating in concert halls or churches. Reflections as late as 50-80 ms will have died out and aren't audible in small rooms and also earlier than this.

In a small room, early reflections are generally what's within 10-12 ms or even earlier. Reflections at about 15-22 ms are late ones in a small room.

For accuracy late reflections is considered detrimental, though less detrimental than early ones. Which can be seen in the study below.

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With personal preferences there isn't really a definite answer but I have yet to hear someone not preferring late diffuse energy instead of specular or absorbed ones when they have heard it. But as always, diffusers vary greatly just like speakers. There are good, mediocre and poor designs.

 

[Bjorn]

You are right. When I talk of sound quality I am referring to timbral effects, aiming for neutrality as the ideal. Spatial qualities are there as well, and we value them in almost equal balance with timbre, although we often (always?) perceptually confound them. The listening room reflections matter most in mono listening, less in stereo and even less in multichannel, as there are more sources of direct sound. We are most sensitive to loudspeaker flaws in mono, less in stereo, and even less in multichannel - with all channels active! However, monophonic components exist in all programs, so we still need mono listening tests. There are significant advantages to multichannel systems, even upmixed stereo. The center channel remains an issue for mixers.

A high amount of reflections does of course greatly change the sound. So when you they "matter" less with multiple sources, I think this innaccurate. A more accurate description would IMO be thay we hear the invidual ones much less. The high amount masks our ability to hear the dicrete reflections to a large degree. But as a whole, the difference is huge.

A good example here would be the difference between a omni speaker and a large horn speaker with narrow directivity placed in a small room. The way the present the music is radically different. Anyone who has listened to both knows that well, and even the difference between an omni and a180° directivity speaker is considered big.

 

[Sal1950]

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?

If your question was posed to me I'll only answer that no, I'm not technically qualified to answer.
I can only state that I prefer a well dampened room for my surround music system.

 

[Bjorn]

Guys. Seriously, many of you need to stop obsessing over studies and start to experiment yourself.

If you think some preference study in a room that's different from yours, with certain music material, treatment that you don't have or other than yours, and possibly different speaker directivity is going to give objective and science based answers for all you are seriously fooling yourself!

Not to mention that preferences can vary between short and long listening. For instance will opposite side wall reflections that arrive later then at 7 ms always be more impressive right away, but is often perceived different over time with various music material.

Do yourself a favor and test and try different approaches and let go of the preference studies that are highly dependent on how and where they were conducted. To a some degree they are anecdotal.

As of researchers in to accuracy, these are more trustworthy. And most of these were conducted in the 70s and 80s and earlier. Seldom available on internet since they were published in books or news magazines from certain groups. There are only snippets here and there and summaries in some available papers. For instance are Don Davis AES papers short summaries of their testings over many years.

 

[Digital_Thor]

Well.... I'm really satisfied with my system as is. And the only way I got to that point, was to realize that every loudspeaker I liked, no matter which room or event, always had some kind of controlled dispersion throughout the midrange and tweeter + some kind of active EQ'd bass and/or subwoofer. So that is what I build for myself.

I'm only juggling these theories, because they seem to fit pretty well with what I ended up with... so does most systems I like - so I find it interesting to geek out a bit - that's all.
And there's always something to fiddle with and adjust... so why not research a bit and improve a bit here and there - when I feel like it. It is a hobby after all.... not a job

 

[multichannel_guy]

I haven't read this entire thread, and this may already have been mentioned. I have probably heard as many lousy horn loudspeakers as anyone on this forum, honky, shrill, nasal, you name it. Long throat horns that identify their principal axis with a distinctive very high frequency sizzle. But, now there are better designs and this one got my attention, and has my respect. It will be mentioned in the 4th edition of my book now being written, and was on the cover of the 3rd edition.

The JBL Professional M2 Master Reference Monitor. This is an active loudspeaker, with a dedicated outboard power amplifier/equalizer. The 15-inch woofer is crossed over to a 120° Horizontal by 100° Vertical horn of unconventional shallow design. The crossover frequency is 800 Hz. It is rated at 117 dB continuous, 123 dB peak at 1 m. 108 dB peak at 8 m distance.
This is an example of competent engineering. It is a high-power, high-sound-quality loudspeaker intended for control-room monitoring, high-end home theaters, and the like. It is expensive, large, heavy, somewhat “industrial” looking, but it can play louder than humans can safely enjoy and compete in double-blind listening tests with highly rated neutral cone and dome loudspeakers in terms of sound quality.

There are smaller siblings.

Thanks for the recommendation, I have not heard these JBLs, but, i would much rather pursue pro-speakers like these without the insane audiophile mark-up. The best sound i've ever heard came out of pro Meyer Sound speakers. Some of the audiophile speakers popular on forums sound silly in comparison. These JBLs seem more affordable, reachable at some point.

 

[jeffaegrim]

Since the topic of horn directivity has come up again, I would like to kindly ask for some further explanation regarding the JBL 4660 (or latter h2600) horn that Don Keele designed (if anyone has any ideas, of course):

In the white paper for the DD55000 it says that the on axis DI of the system is 9-10db from 800-20.000hz. This would be considered a very narrow directivity, if I’m not mistaken. Yet the speakers don’t behave in a way that narrow DI speakers usually do - the speakers don’t beam and off axis measurements look pretty much the same as on axis measurements.

I have a pdf of The Book but I don’t think Dr. Toole talks about these horns and I’m trying to learn everything I can about this relic and understand if there is any scientific merit in the design. I might also need to pair their smaller brother with a center one day somehow

 

[Flaesh]

This would be considered a very narrow directivity

I would consider this a (well, almost) "normal" directivity. For example, XT1086

 

[morphemes]

OK, it happened again. I recently listened to some large horn speakers. I have periodically done this over many years at various hifi shows. I came away again with the same thoughts. I just don't get them.

Firstly they were clearly highly directional. Unless I was right bang in the firing line on axis they had no high frequencies.

Secondly, mid range seemed over emphasised with a "cuppy" effect. Exactly like the sound you get if you cup your hands around your mouth.

Lastly they were no more dynamic than any other large speaker.

All the same characteristics I have heard previously.

Is it me? Am I biased? Heard the wrong horns? Some rave about horns but it's lost on me.

What are others experiences?

why horns? it's a sensitivity thing. we're only ever really using horns in order to increase sensitivity. you take that one inch soft dome, put it in a horn and all of a sudden it's twice as loud in the band you wanted it for... but horns can compound preexisting issues within a space. it's the opposite of something like diffusion... horns do this passive thing to the noise floor, they echo on their own, you can localize it from the horn, even when they're off. if the tune on a horn isn't a good match for a space it's in, it can and will sound awful... if we follow rule of thirds methodology, this helps reduce this. all speakers are like horns in that they have passive emission characteristics. we don't want this beam generator (horn) interacting with the room in a way that makes it sound "cuppy"... this is telltell of bad geometry, bad placement, the cuppy sound is comb filtered. the waveguide is choking on one of its own reflections.. it's a delicate balance with a horn because it's already exploiting that phenomenon. so we're really only using them for the 10dB (ish) boost when we really need it... because we need the sound to go twice as far without adding more drivers because it's high frequencies and they'll kill eachother. most small rooms only really need horns for the most distant drivers.

i wonder if it'd make more sense to reinforce highs from the VOG spot with some kind of keystone driver like a dual dipole blumlein ribbon tweeter that helps create a field of high frequency reinforcement from the center out, in all 4 cardinals along the primary XY axes.. if that's the only reason we're using horns. maybe we should think about actually solving the problem instead of putting a bandaid on it?

 

[Tim Link]

why horns? it's a sensitivity thing. we're only ever really using horns in order to increase sensitivity.

I don't know that we only ever use horns to increase sensitivity. It's a very nice perk, but for me it's been largely about dispersion. I was shocked at how much calmer and clearer my condo sounded with a pair of K-horns compared to any direct radiators I had tried before. That condo had a lot of glass and hard wood floors. The direct radiators could all get plenty loud in there without sounding stressed, and I didn't have anything impressive in terms of amplification. But they just ignited that room. The direct to reflected ratio seems better with the horns. I could get the direct radiators to sound good if I put lots of heavy curtains up that went all the way down to the floor. My girlfriend at the time didn't like the look, and I didn't either.

 

[jeffaegrim]

I would consider this a (well, almost) "normal" directivity. For example, XT1086
View attachment 399173

Thanks for visualising what that would look like, I guess you’re right!

And I agree with @Tim Link above; it has been stated a few times already but the main purpose of horns for a domestic environment is their pattern control and dynamic range.

Just to add my own anecdote here - my horn system is much less impacted by the left/right imbalance I get with normal speakers in my highly asymmetric room. They don’t radiate much sound into the side walls (one of which is a large window), so proper center image is preserved.

I feel like I can hear the mismatch in directivity between the woofer/horn sometimes, but it never becomes an unpleasant listening experience. Still, a speaker system with controlled directivity lower than 750Hz would be very interesting to audition

 

[Hear Here]

why horns? it's a sensitivity thing. we're only ever really using horns in order to increase sensitivity. you take that one inch soft dome, put it in a horn and all of a sudden it's twice as loud in the band you wanted it for...

That is not why people use horns. Perhaps high sensitivity has as many disadvantages as advantages:

Pros - high sensitivity means low-power amps (including ones such as SETs) can be used. A greater choice and a cost saving - maybe

Cons - the amp has to have a very high SN ratio as any noise will be amplified far more than with low sensitivity speakers. Lots of amps are too noisy for horns

There are far greater factors at work than sensitivity. Horns are usually far less concerned about the presence of nearly walls, they can often be placed wherever convenient (within reason) but they still need very careful setting up, In fact, they are far more room tolerant than box speakers because they squirt most of their sound directly at the listening position, so fewer reflections to worry about. They offer a small sweet spot, but it's exceptionally sweet if properly set up. Imaging in particular is exceptional. Their delivery of life-like music is hard to match, let alone better, by any other speaker type, except perhaps electrostatics, but they need more attention to positioning and getting the room right.

My experience of horns is of one brand in particular (Avantgarde) but I'm sure these generalisations are true of other good horn designs.

 

[Purité Audio]

I started out selling conical horns ( Cessaro which used expensive compression drivers dual skinned horns etc) but the only really convincing horn I have heard is the multi entry Danley design.

Keith

 

[Bjorn]

The reason I like horns are because:
1. Possibility of broadband constant directivity combined with minimizing early detrimental reflections.
2. Very low distortion. A compression driver or horn loaded driver combined with a uniform directivity sounds more realistic compared to front firing drivers. The clarity, detail and resolution is simply better.
3. More engaging sound. I personally believe this is primarily related to a quicker impulse response and not so much do to with the dispersion. After all, other speakers with a narrower directivty simply don't have this trait. An elecronic speaker does for example sound far less engaging, and the B&O Beolab 90 doesn't get closer to a horn in its narrow (cardioide) mode.
4. One driver can cover a larger frequency area with the result of a more coherent sound stage. While this is possible with certain oterh drivers and desings, it will come at a cost which the horn doesn't have.
5. Higher sensitivity. A nice benefit, but not very important in these days with low cost powerful amps.

There are also drawbacks:
1. A quality horn needs to be big and thus doesn't have a lot of WAF
2. More tricky to design. Many pitfalls that can make them sound bad. Most commercial horns are not very good IMO
3. Can be very revealing of the music material (drawback for some)

 

[Flaesh]

mismatch in directivity between the woofer/horn sometimes

And also, an array of subwoofers in a normal room has a more or less infinite directivity index

 

[jeffaegrim]

And also, an array of subwoofers in a normal room has a more or less infinite directivity index

Realising now that I probably need to read up more on directivity to understand that. Why is that the case? Because the lower hz wavelengths are so long?