Why don't all speaker manufacturers design for flat on-axis and smooth off-axis?

[MZKM]

Spinoramas are certainly a clean and concise way of representing a speaker, but I do personally prefer being able to see the specific responses at different angles a-la soundstage network's NRC measurements.

Also, I thought there was a dipole that did perform well in one of these blind tests? I can't remember which though.

Same reason I don’t prefer polar plots over seeing the actual FR measurements; our ears may be more forgiving, but I’d rather have more data.

The directivity plots are good though.

As notes by others, Spinorama’s don’t tell the full story on their own, you still need things like distortion graphs (including at reference loudness levels) and FR linearity (aka compression), vertical measurements (not just listening window) are good as they show what the intended listening axis is (usually tweeter, but some have it between the tweeter and mid/woofer), and a waterfall plot is good as if the decay is very uneven that will change the sound (e.g., if there’s is a huge dip at 3kHz after 0.1ms, that will be audible). Impedance and phase graphs will also tell you how difficult of a load the speaker is.

 

[napilopez]

Same reason I don’t prefer polar plots over seeing the actual FR measurements; our ears may be more forgiving, but I’d rather have more data.

The directivity plots are good though.

As notes by others, Spinorama’s don’t tell the full story on their own, you still need things like distortion graphs (including at reference loudness levels) and FR linearity (aka compression), vertical measurements (not just listening window) are good as they show what the intended listening axis is (usually tweeter, but some have it between the tweeter and mid/woofer), and a waterfall plot is good as lid the decay is very uneven, that will change the sound (e.g., if there’s is a huge dip at 3kHz after 0.1ms, that will be audible). Impedance and phase graphs will also tell you how difficult of a load the speaker is.

For sure there's a lot that matters that especially should be optimized in high-end products, but FR, Directivity, and Bass extension appear to be the top factors for preference, so it seems like those should be optimized where possible (hence this thread).

The early reflections line includes vertical data, but yeah, I certainly prefer having plots for specific angles. These rarely go above 15 degrees in the vertical, but I like seeing what to expect from ceiling reflections in particular.

 

[Juhazi]

I guess that others read this thread too. One must understand a bit of the basic principles behind directivity of sound radiation, the influence of driver diameter and wavelength mainly. Price tag has zero effect to this!
...
Dr. Toole's book is a good collection of basics and examples of how directivity alters the perceived sound in a room. Here is a short article by him
https://www.audioholics.com/room-acoustics/sound-reproduction

I was too tired to write "Conclusions". Recent posts cover this well, but I want to summarize how I see that "full picture". An important thing not discussed yet is the D/R ratio of perceived sound at listening spot/area. When discussing hifi speakers intended to be used in "small rooms" at home, we must always include speaker postioning/boundary effects whic contribute a lot to perceived sound (psychoacoustics and listening tests). On- and off-axis responses and directivity indexes are just some technical parameters of the radiator. So are distortion graphs and group delay curves.

Harman spinorama, IEC, NRC, Princeton, Genelec etc. off-axis measurements are based on same kind of measured data, but the analysis is different. Harman uses only horizontal dispersion to certain narrow angle (listening window etc.) NRC shows further off-axis but doesn't count any DI. Princeton measures in 3D, but graphs have low limit at 500Hz, etc. You must not directly compare measured values and graphics/DI from different sources! And be careful to guess how those speakers sound in a room!

NRC and Harman have conducted several listening test and based on those Harman/Toole chose to show narrow horizontal coverage DI, because it has high correlation to listener rating! On the other extreme VCAD simulation shows simulated full bandwidth 3D (up to 180deg hor and vertical) DI like the Taipuu speakers that I linked, but there is zero evidence of the validity of this index to perceived sound, it is just technical trickery and personal opinion, until some listening tests get published.

Directivity pattern and indexes have no ideal value or curve. There is evidence of validity of some specific measurements, but still individual listeners have their own personal preferences. This is why this discussion will never be totally closed.

 

[Krunok]

Yes M2 has higher DI at 10kHz than F208, but not high at all compared to a deep horn or a panel speaker.

Speakers with long waveguide (or "deep horn" as you call them) and panels are quite the opposite thing in the context of DI. I was expecting a speaker with long waveguide (like M2) to have lower and smoother DI at high frequencies than F208.

As I said - looking at both spinorama graphs I wouldn't be surprised at all if I would be voting for F208 in a blind test.
And of course that price matters, especially in the scenario where cheaper loudspeaker outperforms expensive one.

 

[Krunok]

Harman uses only horizontal dispersion to certain narrow angle (listening window etc.)

This is simply not true.

I suggest before making such statements you familiarize yourself with the way Harman spinorama charts are generated.
Here is a short summary, more you can find here and here.

Listening window is the average of 9 measurements: 0°, ±10°, ±20° & ±30° in the horizontal plane and ±10° in the vertical plane.

Early reflection curve is the average of eight responses: ±40°, ±60° & ±80° in the horizontal plane and ±50° in the vertical plane.

Sound power curve is a weighted average of all 72 measurements.

Directivity index = On-axis response - Sound power
Early reflections DI = Early reflection - Sound power.

 

[Krunok]

Yeah, it's amazing how long I've heard "ML used to be more sweet-spot finicky, but curving those panels really helps widen the sweet spot."

Nope..nope...nope. Not once have I encountered a ML speaker that didn't have a super picky, narrow sweet spot, including their flagship. Nature of the beast. Looks like one has to do something more radical like Muraudio. (Or, actually, I seem to remember my Quad 63s had a slightly wider sweet spot for a panel speaker, presumably due to the concentric radiator "point source" design of the panel).

Discussions about MLs are a long lasting topic on various forums. Just take a look at this one. You will also find some familiar faces there..

 

[Blumlein 88]

Discussions about MLs are a long lasting topic on various forums. Just take a look at this one. You will also find some familiar faces there..

Yeah, they should use a good panel speaker like my Soundlabs. Or some Quad ESL63's. (Don't tell Ray I said this, keep it mum ).

It does strike me in the picture from your linked thread, that the ML's were much too close to the rear wall. As Harman says bass is responsible for 30% of ones ranking of speakers I think they should be at least twice that far from the rear wall. I actually doubt it would raise their ranking above others speakers, but I bet it would raise it a non-trivial amount.

Way back when I owned the original Klipsch Forte speakers. I ended up with some second hand Maggies after hearing a co-worker's system with them. Then some Acoustats. I sold the Maggies after getting the Acoustats. That guy stumbled across a super deal on some Quad ESL63's. He called me up and told me what he had, and said "you need to hear these". I went to his house, and heard them and have never heard a single thing that impressed me like those did. I became good friends with him. And immediately decided I would have some ESL 63's. I did some two months later. Kept them for over a decade. I've got a couple Harman designs now and they are impressive in the sound quality for money quotient. And for just plain sounding good quotient. But they aren't the kind of thing to cause a reaction like those Quad ESL63s.

I would later own some Quad ESL57's. I can only imagine how mind blowing that must have been in the late 50's, the 60's, and the 70's. To hear the old Quads and anything from those earlier eras, and you just shake your head and wonder why Quad didn't sale a few million of them.

 

[Krunok]

Yeah, they should use a good panel speaker like my Soundlabs. Or some Quad ESL63's. (Don't tell Ray I said this, keep it mum ).

So true. Those MLs are anyway not a true panel speakers but some weird mutants they call "hybrids".

 

[Cosmik]

Audiophiles are always expecting surprises. But is it not the case that a speaker's Spin-o-Rama characteristics are already fundamentally set by what drivers it uses and the dimensions of the box they're put in? A slim floorstander based on a 5" woofer and a 1" tweeter cannot deviate very far from a defined characteristic, and all the designer can do to change that is to make a mess of it. The most expensive 5"/1" slim floorstander in the world will measure - and sound - very similar to the cheapest if they're both designed sensibly. And that sound will not be good:

What is true of the mini-monitor, that it cannot be EQed to sound right, is also true of narrow-front floor-standers. They sound too midrange-oriented because of the nature of the room sound. This is something about the geometry of the design. It cannot be substantially altered by crossover decisions and so on. How then can it be that narrowfront speakers are nearly ubiquitous? How did audio wander off into what amounts to a blind alley?

Which seems to be why the Grimm people, for example, created a different speaker; not slapping something together and then measuring it, hoping for a miracle, but predicting in advance the simple (for them) characteristics of driver beaming and baffle step and creating the nice response they desired before starting to build anything. And then using DSP to make everything clean and neutral.

 

[Blumlein 88]

Audiophiles are always expecting surprises. But is it not the case that a speaker's Spin-o-Rama characteristics are already fundamentally set by what drivers it uses and the dimensions of the box they're put in? A slim floorstander based on a 5" woofer and a 1" tweeter cannot deviate very far from a defined characteristic, and all the designer can do to change that is to make a mess of it. The most expensive 5"/1" slim floorstander in the world will measure - and sound - very similar to the cheapest if they're both designed sensibly. And that sound will not be good:


Which seems to be why the Grimm people, for example, created a different speaker; not slapping something together and then measuring it, hoping for a miracle, but predicting in advance the simple (for them) characteristics of driver beaming and baffle step and creating the nice response they desired before starting to build anything. And then using DSP to make everything clean and neutral.

Harman in a few models uses a modest 8 inch woofer, with an additional 8 inch woofer/midrange, with a 4.5 or 5 inch midrange and a tweeter in a slim floorstanding design. Apparently that fits with the needed result from the spin-o-rama.

 

[Krunok]

A slim floorstander based on a 5" woofer and a 1" tweeter cannot deviate very far from a defined characteristic, and all the designer can do to change that is to make a mess of it. The most expensive 5"/1" slim floorstander in the world will measure - and sound - very similar to the cheapest if they're both designed sensibly. And that sound will not be good:

Does Revel performa3 F208 (or it's smaller twin, F206) fall into cathegory "slim floorstander"?
I'm asking this because it seems to be a number of objective reviews that seem to think they do sound good.

Just a few examples:

https://www.stereophile.com/content/revel-performa3-f208-loudspeaker-measurements

https://www.soundstagenetwork.com/i...&catid=77:loudspeaker-measurements&Itemid=153

 

[Cosmik]

Harman in a few models uses a modest 8 inch woofer, with an additional 8 inch woofer/midrange, with a 4.5 or 5 inch midrange and a tweeter in a slim floorstanding design. Apparently that fits with the needed result from the spin-o-rama.

It can't be all that slim, I suppose...?

My usual speakers use 8"-3"-1" on a 12" wide baffle. Looks-wise, they're about half way between 'slim' and the less fashionable wider alternative. I am aware that they would probably sound even better with a wider baffle.

My other, less living room-friendly, speakers do the KEF 105 trick of putting the drivers in different boxes, with the 12" woofer in a huge box.

 

[Cosmik]

Does Revel performa3 F208 (or it's smaller twin, F206) fall into cathegory "slim floorstander"?
I'm asking this because it seems to be a number of objective reviews that seem to think they do sound good.

Just a few examples:

https://www.stereophile.com/content/revel-performa3-f208-loudspeaker-measurements

https://www.soundstagenetwork.com/i...&catid=77:loudspeaker-measurements&Itemid=153

RE Green makes a few suggestions starting at the part titled "How Things Can Go Wrong".

One feature of this situation is that almost all audio evaluation, whether more or less professional or by consumers, is comparative. “Does this sound better than that?” is usually the question, for all our intentions. But the right question would be “Does this sound RIGHT?” Actually, even a brief comparison with a real piano, say, will reveal the midrange-orientation of the narrow- front wide radiators.

And he goes on.

 

[Krunok]

It can't be all that slim, I suppose...?

My usual speakers use 8"-3"-1" on a 12" wide baffle. Looks-wise, they're about half way between 'slim' and the less fashionable wider alternative. I am aware that they would probably sound even better with a wider baffle.

My other, less living room-friendly, speakers do the KEF 105 trick of putting the drivers in different boxes, with the 12" woofer in a huge box.

F206 uses 6.5" woofers, width of the speaker is 9.8" (24.9cm). In my eyes that is slim.

 

[Krunok]

RE Green makes a few suggestions starting at the part titled "How Things Can Go Wrong".

And he goes on.

Are you saying his "suggestions" are more relevant than objective measurements?

 

[Cosmik]

Are you saying his "suggestions" are more relevant than objective measurements?

The point is that objective measurements don't capture how we hear! There is no 'target curve'. This is the very nub of the matter.

 

[Krunok]

The point is that objective measurements don't capture how we hear! There is no 'target curve'. This is the very nub of the matter.

Isn't Harman's spinorama confirmed in multiple tests to reflect what we hear and what we like?

 

[Juhazi]

F206 and F208 are more than 5" with 1". I agree that a simple 2-way with two drivers is very basic and trusted combination, but it definitely needs support below baffle step (around 500Hz) from woofer(s). It has smooth and low DI and thus typical neutral sound in a room.

Different concepts that aim to different radiation pattern or DI curve give different sound despite of eq'ing on-axis flat - because of different full sphere radition, relation of on-axis and power response. Radiation pattern control in 3D is a real challenge to manage and there are many ways to do that - panel, dipole, omni, bipole and with multi-unit/dsp tricks like KiiAudio Three and Beolab 90.

BeoLab 90 is a real masterpiece and tour-de-force anniversary flagship that demonstrates what modern knowledge and skill can achieve! Way too far out to copy by diy. Basically it gives the user possibility to change it's radiation pattern, directivity (mainly horizontlly)
https://www.tonmeister.ca/wordpress/2015/10/06/beolab-90-behind-the-scenes/

 

[Bjorn]

I always see them placed just like normal box speakers.

On and on. If the company doesn't do anything special with them, then it reasons that nothing special is required.

What I heard in double blind tests at Harman, I hear in all the demos of ML speakers ever since.

So while your argument is often made, I don't see it being relevant in my experience.

So what? I also see at most shows acoustic treatment that is crappy or misplaced, no crossover used for an external subwoofer integration, not optimal speaker placement for other speakers, etc. We can't pass an objective judgement based on something subjective or poor choices. There may also be practical limitations that were done at such demos and the time to set up speakers are most often very limited. Most setups at shows are done by sellers by the way and not the company itself and few of those even know how to measure!

The fact is that a dipole triggers room modes differently than a monopole and in most case requires a very different position for a flat response. This is shown in studies FIY. And as mentioned before, the front wall contribution has a great effect on dipoles - thus will both the distance to front wall and treatment effect the result a lot. Harman didn't seem to take any of this into consideration and I'm not surprised since the speaker here is a competing brand.

 

[Krunok]

So what? I also see at most shows acoustic treatment that is crappy or misplaced, no crossover used for an external subwoofer integration, not optimal speaker placement for other speakers, etc. We can't pass an objective judgement based on something subjective or poor choices. There may also be practical limitations that were done at such demos and the time to set up speakers are most often very limited. Most setups at shows are done by sellers by the way and not the company itself and few of those even know how to measure!

The fact is that a dipole triggers room modes differently than a monopole and in most case requires a very different position for a flat response. This is shown in studies FIY. And as mentioned before, the front wall contribution has a great effect on dipoles - thus will both the distance to front wall and treatment effect the result a lot. Harman didn't seem to take any of this into consideration and I'm not surprised since the speaker here is a competing brand.

From the Electromotion ESL manual.. Nothing specatular about positioning there.

Toe-in:

"Now you can begin to experiment. First begin by toeing your speakers in towards the listening area and then facing them straight into the room. You will notice the tonal balance and imaging changing. You will notice that as the speakers are toed-out, the system becomes slightly brighter than when toed-in. This design gives you the flexibility to compensate for a soft or bright room. Generally it is found that the ideal listening position is with the speakers slightly toed-in so that you are listening to the inner third of the curved transducer section. A simple, yet effective method to achieve proper toe involves sitting at the listening position, holding a flashlight under your chin and pointing it at each speaker. The reflection of the flashlight should be within the inner third of the panel (see figure 5) ."