PS Audio sent Erin their speaker??!!

[amirm]

Take a look at Prof. Klippel's presentation, where the exact definition of amplitude compression is given and various types (short-term and long-term amplitude compression) and measurement methods (from 0.2s signal measurement to 1h measurement) of compression are discussed.

I have watched that video in the past. Those short-time compression effects were for little BT drivers, not kind of speakers we are talking about. Further, microphone in those tests is kept at 1 or 2 cm from the driver, which excludes the room effects. None of this applies to Erin's tests. Strangely, Erin shows anti-compression where levels at some frequencies increase more than it should. Nothing in the world of "compression" explains such things. Maybe something in his room starts to resonate, make noises, etc. when playing louder. Who knows.

Further, that kind of graph with such high resolution is not shown. Instead, what Dr. Klippel showed was the same graphs I did, not a differential focusing down to the smallest differences.

 

[GXAlan]

That is the reason you do NOT want to evaluate a speaker in stereo! Instead of properly focusing on tonality, your mind shifts to admiration of spatial qualities of stereo recording. It is for this reason that surround sound with its more captivating and "real" version of this, further neuters listener ability to tell the good speaker from bad.
…
And remember, according to Dr. Toole, no speaker that has done well in mono, has lost in stereo. Goodness in mono directly translates to stereo.

The only “devil’s advocate” perspective is to ask where the threshold swings.

If you listened to multichannel music or a well-mixed surround sound movie, would the Polk ES60x5 at $1750 beat a mono Neumann KH150 at $1750?

Probably…. For a soloist doing a spoken word poem? Probably not…

What if you had a single KH150 center and now 4 Dayton MK402X? $1900. Would that beat the 5 ES60? Would that beat 7 x Revel M16?

Knowing that stereo and multichannel help to blur differences, how do we budget to maximize the performance of a mixed movie and music setup by taking advantage of this psychoacoustic phenomenon as a “feature” not a “limitation?”

 

[Duke]

... what if directivity isn't even all around?

Imo the net result of uneven directivity can be good or it can be bad - it depends on the specifics. Can you give me an example or two of what you have in mind?

Some speakers are very wide up to say, 50 degrees, then drop off more quickly. And now with beam forming speakers and the like, there's more research to be done.

There are areas where good wide-pattern speakers excel. There are areas where good narrow-pattern speakers excel. There are areas where good multi-directional speakers excel. There are areas where good omni speakers excel. There are areas where good line-source-approximating speakers excel.

And they all have trade-offs.

Beam-forming speakers that you mentioned arguably offer the greatest potential in the area of spatial quality improvement because they offer the greatest adaptability to the room and to the listeners in the room. But their multi-driver complexity presumably makes parts quality trade-offs relative to similarly-priced "conventional" speakers. I hope the audio industry thrives to the extent that the "more research" you mention gets funded!

 

[Blumlein 88]

And yet the test tracks used for single speaker evaluations are stereo, contain individual left and right content, precisely placed and moved objects and contain deliberate phase, level and other manipulations- all of which disappear when summed into mono for a single speaker "evaluation" of spatial qualities. It's hilarious.

I wonder how much this effects someone's perception of one speaker listening. I wonder the size of the effect not whether there is one. One of the very best speakers for mono I've ever had were Quad ESL-63's. Sighted listening of course. And it sounds like a high end mag review, but with genuine mono recordings I enjoyed those far better than over other speakers. I think that actually fits with Harman's ideas, as the speaker's deficiencies stuck out more noticeably in mono than stereo mono or stereo stereo. It was very noticeable when I happened upon some Mercury Living Prescence Mono LPs at an estate sale. Those were recorded with one quality omni condenser microphone.

If you know the provenance of a recording some stereo will work for this. The John Cuniberti One Mic recordings will work for this. He used a crossed coincident stereo ribbon. You can combine those channels to mono. The early days when Chesky made his recordings using the same method those will mono down properly as well. Mario's recordings offered here at one time would work mono'd for this. Near coincident closely spaced stereo recordings will often work nearly as well. Wide spaced omni's usually not. If you have any of the unusual 3 channel recordings and you know the center was an omni just using that center would work. Close miked, multi-mike recordings may be okay or may be weird. The general highly processed stuff for most music is charitably described as a crap shoot.

Might be nice if Amir did some mono listening trying some of the things I listed above to experience the effect.

 

[CleanSound]

As for the second part, we already determined earlier we were talking about spatial qualities for different purposes (comparison and review in my case) so I'll leave that for someone else to address if they wish.

Looks like you are in NYC, I'm close by. Let's meet up one day, I will bring my Neumann's over for you to have a listen. I will let you experience the 3D imaging magic yourself. Then you can assess the value (or lack of) of doing listening evaluation in stereo.

 

[napilopez]

Imo the net result of uneven directivity can be good or it can be bad - it depends on the specifics. Can you give me an example or two of what you have in mind?



There are areas where good wide-pattern speakers excel. There are areas where good narrow-pattern speakers excel. There are areas where good multi-directional speakers excel. There are areas where good omni speakers excel. There are areas where good line-source-approximating speakers excel.

And they all have trade-offs.

Beam-forming speakers that you mentioned arguably offer the greatest potential in the area of spatial quality improvement because they offer the greatest adaptability to the room and to the listeners in the room. But their multi-driver complexity presumably makes parts quality trade-offs relative to similarly-priced "conventional" speakers. I hope the audio industry thrives to the extent that the "more research" you mention gets funded!

I've recently been talking about the JBL L52's I just bought, speakers I sent to Erin measured and he didn't like, but I am enjoying a lot. I spent several days comparing them directly with Revel M126Be's and though the Revels were better, I found the differences to be very minimal in my space. And I think the revels are some of the best speakers I've ever heard.

They have asymmetrical tweeters and the directivity especially when viewed in a contour plot or polar map is uneven. However the cumulative horizontal directivity performance is as smooth as anything else. I've found my impressions of soundstage generally line up most closely with the sidewall and total horizontal reflections components of the early reflections curve(and respective custom DI curves) more than any other method of assessing directivity.

But there's a bit more to it. I think I mentioned earlier in the thread that I've theorized that with mirrored asymmetrical tweeters, the directivity toward the side closest to the nearest sidewall has a dominant perceptual effect, helping to explain the difference in spatial presentation with the tweeters out vs in, even when trying to match the acoustic centers.

Of course there's sighted bias galore here too, but it makes sense to me since sound has a much longer path to travel toward the other wall and will be comparatively attenuated.

I do think also that directivity is also where there is most room for individual preferences. My personal experience in the last three apartments (and a home studio I occasionally listen in) is that wider directivity suits my tastes more for stereo, though I haven't listened to something quite as wide as the Philharmonics or Sierra 2's. The more spatial cues in the music, the less it matters. In multichannel, I'm not sure it matters at all.

 

[beefkabob]

Unless somebody is a trained listener, what good is their subjective opinion? Even then, subjective impressions are questionable for reviewers. Too much pressure.

Great dispersion. OK frequency response. $10k a pair. No thank you...

 

[sigbergaudio]

I wrote in my original post the monitor in question was a Genelec main, not a "typical studio monitor." Take for example the 1238A. It's height is 81cm and the vertical acoustic axis is 65cm. If the ear level in the seating position is 81m, then the monitor stand height should be 16cm. That's pretty close to the floor.

We may be discussing past each other somehow, but I still don't understand the scenario. Genelec creates mainly studio monitors, and it would make sense for any recommendation to mainly be about that type of use. In a studio the engineer typically sit in a regular / office type chair. Typical ear height would be, I don't know, somewhere around 130-140cm. In such a situation you can't have a 16cm stand on a monitor that is 81cm tall. Also, the monitor is typically on or behind a large mixing desk that would mean if the monitor was on the floor you wouldn't even see it behind the desk with a 16cm stand.

 

[Sokel]

That is the track. It has uncanny ability to audibly show distortion. I don't have any other content that can do this so easily and readily. I don't usually use it for dynamics as I am worried about damaging speakers. But do use it that way with headphones.

The track is also useful for setting headroom when you have EQ. If you boost bass without enough headroom, it will clip/crackle badly on this track.

Best of all, the revealing part is right at the start so quick to run it.

Similar one that people can find easily as the band is super popular is this one:

It's short and has some really good low-high antithesis (along with the weird effect) and one can cut through the noise performance as well as it has quiet spots.

 

[Shadrach]

For those members who advocate listening/testing speakers in stereo I have to ask how Amir is supposed to achieve this. The Klipple measuring machine only measures one speaker at a time. To the best of my knowledge there is no reliable way to measure soundstage; it's hard enough to get people to agree on what the term means.
Say Amir got both speakers and set them up in a suitable location, how would he go about measuring something that is undefined?
ASR was when I joined about measuring the technical performance of equipment. At best Amir could write about his subjective assessment of the performance of a stereo pair. Given that this nebulous notion of soundstage is I believe dependant to some degree on speaker positioning and room volume how would one go about setting the parameters to make any listening impressions more than this is what I heard under these conditions with the caveat that in your listening enviroment with you hearing acuity they will probably sound rather different.
Isn't this a subjective evaluation and as such is no different from the sujective reviews that many are scornfull of when read on other audio sites?

 

[thewas]

Hopefully the above L/R response graphs help show that even matched L/R pair are going to be mismatched in a room.

As you know though above transition frequency the direct sound dominates our impression so even if the in-room measurement shows such a deviation we usually don't perceive it as such, while we rather hear if the anechoic measurements show some significant deviations between the left and right loudspeaker, thus for companies which don't have high quality control like for example Genelec this can be a topic and therefore pair matching measurements can be useful.

 

[audiofooled]

Looks like you are in NYC, I'm close by. Let's meet up one day, I will bring my Neumann's over for you to have a listen. I will let you experience the 3D imaging magic yourself. Then you can assess the value (or lack of) of doing listening evaluation in stereo.

IME "3D" imaging is no magic at all, nor is anything magical about stereo. For extremes in depth, even height perception along the listening axis to happen, the sound field should be such that there's mostly direct sound. By that I mean that anything in the recording which is summed to mono, as in central phantom image, should be as clean as it gets when it comes to excess phase, excess group delay, distortion, also with no major FR irregularities. Music is a lot about transients and hearing is a lot about timing as well, having in mind the "Haas effect".

That being said, lateral reflections will mess everything up and perceived lateral image shifts would closely depend on loudspeaker radiation pattern and setup, also room acoustics. Having a wide band constant directivity may be helpful in generating a 3D sound field you are talking about. Such speakers would reveal spatial qualities even in mono, but I agree that a proper setup and some in room measurements would be required to see if the sound field could have such characteristics. In a nutshell, measure if the loudspeakers are positioned, aimed and spaced right. This is time consuming and IMO generally a moot point when it comes to evaluating many, many pairs of loudspeakers.

This is how my in room measurements would vector average across central axis with varying distances within the sound field:

There are recordings that would subjectively make sonic images sort of "materialize" in space, but this is no magic. But, what you hear may be different from what I hear and I think this is why subjective evaluation should be taken with a grain of salt.

 

[Sokel]

So in short:
We want Amir to listen to stereo and then describe all the qualities we seek?
And how would that be useful?Other than the obvious flaws that a trained listener would detect and do so also in mono can't think of any other way.
Amir's room,ears and taste are his own,there's no way to translate that to mine.

Other than entertaining or in-hobby old practices can't find any other purpose.
Heck,Erin talked about punch and midbass sweetness,stuff that are far more easily detectable even by looking at a speaker if you have seen enough.Did anyone saw that at the measurements?

Nope,I prefer more speaker reviews (big ones please! ) than some subjective text.
(match between samples is something anyone can test as soon as he get it's speakers,is dead easy and useful,doesn't need Klippel for that)

 

[ctrl]

I have watched that video in the past. Those short-time compression effects were for little BT drivers, not kind of speakers we are talking about.

Just because Prof. Klippel used a small sample speaker, short-term compression measurements are still interesting for every speaker

For a professional PA speaker, long-term compression is certainly important, as nobody wants a PA speaker that completely changes its sound characteristics after an hour.

For home speakers, short-term compression is more interesting, as almost immediate changes in frequency response at high SPL are indicated. This provides information about the design, quality of the drivers used, used limiter and DSP behavior for active speaker at high SPL and indicating possible unintended, disturbing changes in sound at high SPL.

In the case of the PS Audio FR10, short-term compression is not perfect, but relatively inconspicuous. The dip at 14kHz will probably not be noticed by anyone:


On the other hand, there are speakers that show pronounced short-term "negative compression"***, for example around 6kHz, which could be disturbing during high SPL:

Further, microphone in those tests is kept at 1 or 2 cm from the driver, which excludes the room effects. None of this applies to Erin's tests.

As long as the room does not exhibit resonances, room reflections are not a problem at all (when the results are normalized to the reference measurement), as the position of the DUT and microphone are not changed during the measurements.
Take another look at the video by Prof. Klippel; he explicitly addresses this issue here. In the video, he chooses the smallest possible distance to the DUT to keep the Signal-to-Noise Ratio as small as possible.

Erin shows anti-compression where levels at some frequencies increase more than it should. Nothing in the world of "compression" explains such things.

Each resonance of the speaker or driver is able to do that. Instead of compression, one can obtain "amplification", "enhancement" or "negative compression"*** whatever one want to call it.

An example of this was given in post#239 - driver resonance fs. "Negative compression" can occur around the resonance frequency of the driver or fc of the speaker.
In the video, Prof. Klippel briefly touches upon this here, or you can find the explanation in the "Loudspeaker Nonlinearities – Causes, Parameters, Symptoms" paper by Klippel:

But as mentioned, surround resonance, driver cone eigenmodes, driver frame resonance,... are all possible causes of "negative compression" in compression measurements.

Further, that kind of graph with such high resolution is not shown. Instead, what Dr. Klippel showed was the same graphs I did, not a differential focusing down to the smallest differences.

Amir, as already mentioned, the visualization of the compression measurements normalized to a reference measurement is common and facilitates the evaluation and identification of interesting frequency ranges.

Prof. Klippel also shows this type of graph in the video. The DUT also shows "negative compression" at two points in the frequency range in the Klippel measurement, as mentioned above, this is not unusual.



Please watch the whole video again, your memory seems to mislead you on some points.

*** Compression is per definition is positive, so amplification is negative. A more intuitive approach is probably the inverse representation (compression as negative value). Ultimately, it doesn't matter as long as it is clearly indicated what is meant.

 

[restorer-john]

So in short:
We want Amir to listen to stereo and then describe all the qualities we seek?

Nobody actually cares how Amir listens to a single loudspeaker in his room. It tells nobody else anything.

It doesn't remotely relate or equate to anybody else's experiences somewhere else. Not even close. Nobody ever uses a single loudspeaker in a room, playing one channel of a stereo recording (what a joke) and equally few ever listen to even mono content on a pair of loudspeakers in a room. The entire premise is flawed in the extreme.

The single speaker listening test for "spatial qualities" idea of using a single channel of a stereo recording is so faulty, misguided and plain stupid, it's totally hilarious. Sadly, some misguided people apparently think it has some value. I pity them.

I wonder if some reviewers actually have any concept of what stereophonic recordings are, why we even have 2 channels and what is good reproduction is, and what isn't.

Take the Klippel results with a grain of salt, and use them, ultimately listen and decide. Throw everything else out.

 

[CleanSound]

So in short:
We want Amir to listen to stereo and then describe all the qualities we seek?

Not I.

But I am:

1) Defending that there is value when others do.

2) Defending there is value in subjective listening test when it comes to loud speakers, regardless if someone does it before or after they saw the measurements.

3) I am saying the reporting from the subjective listening should only be taken with a grain of salt. And if there is too much flowery non sense, you can fast forward or skip.

4) Finally one should never buy a loud speaker without seeing the measurements AND without either a return policy or auditioning them, preferably in a close enough of an environment to a realistic home.

 

[CleanSound]

IME "3D" imaging is no magic at all,

I think you are taking my hyperbole literally. Of course there is science to it (albeit, people smarter than me consistently say we are still learning a lot about room acoustics).

It's "magic" because no other speakers I have listened to does 3D imaging to the level that these Neumann do, and they do it in few places in my house.

EDIT: I also want to add, I am almost certain there is more to this "3D imaging" to what you have explain.

 

[Chester]

I feel like that about my Revels, which you didn’t feel the same way about. Guess it just goes to show it’s all very subjective and probably not worth spending too much time worrying about.

 

[RobL]

I think you are taking my hyperbole literally. Of course there is science to it (albeit, people smarter than me consistently say we are still learning a lot about room acoustics).

It's "magic" because no other speakers I have listened to does 3D imaging to the level that these Neumann do, and they do it in few places in my house.

They’re simply more directional. Higher direct vs reflected sound ratio. IME, wider dispersion speakers can also image very well but require more careful placement and room symmetry.

 

[CleanSound]

I feel like that about my Revels, which you didn’t feel the same way about. Guess it just goes to show it’s all very subjective and probably not worth spending too much time worrying about.

Fair. But let me ask you this: what else have you listened to in your own home, besides these Revel's and which model Revel? Everything is relative, for example if you never been in a car that went 150mph, 100mph is fast.

Prior to my Neumann KH 120, Perlisten S7t and Ascend Sierra LX, the best speaker (objectively and subjectively) I had was the Revel F226Be and the Revel M16 (still have it, but demoted to my wife's office).