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Perceptual Effects of Room Reflections

amirm

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#1
Perceptual Effects of Room Reflections
By Amir Majidimehr
[Note: This article was originally published in the Widescreen Review Magazine, titled "it is not simple!"]

When Gary Reber asked me to write an article for the 20th anniversary of Widescreen Review magazine I was stumped at first. What should I write about that relates to such an important occasion? For the answer I thought back to what I knew 20 years ago and what I know now: how complex Audio/Video technology can be. Our systems are deceptively simple especially with the advent of digital technology. Hit the power button, queue up your music or video, press play and enjoy. Now add the fact that “bits are bits” as is often said about digital audio and video and you have what seems to be a very straightforward system to use and understand.

It is hard to argue against that point of view at high level. The system does perform and work that simply. But peel the layers of the onion and a far more complex picture emerges. And one that is anything but intuitive at times. In my article on room dynamic range I showed how the simple computation of the noise floor of a room requires understanding pretty complex science of psychoacoustics (how we hear). Without that understanding you would easily miscompute the dynamic range by tens of decibels! Not a small error. So I thought I would continue the theme by covering more topics related to how we hear sound in a room. Specifically how we perceive sound above the so called “transition frequency.“ I covered that concept in my earlier article on optimization of bass frequencies. Here is a useful graph from that article:​



As explained in that article and is evident in the graph above, below the transition frequencies we have a straightforward problem of frequency responses being (wildly) modified for the room. Techniques for dealing with that were covered there. This article focuses on what happens above the transition frequencies where the speaker controls the overall frequency response more or less. But that is not the full story. The sound reflects from wall surfaces and arrives at our ears in addition to the direct sound. Perceptually this creates a very complex situation, one that is usually way oversimplified. The first step in understanding that is analyzing the effect through a kind of distortion called "comb filtering."

Comb Filtering
Take the simplest situation of a sound hitting just one wall, reflecting and then arriving at the same point as the direct sound. In doing so, it gets delayed and its level decreases some. Here is a simulation of it that I have created by taking a signal, delaying and reducing its amplitude and then combining it with itself as would happen with a reflection:​



Not a pretty sight. Our flat response has notches in it now which is where the name comes from (i.e. they resemble the teeth in a comb).

The natural reaction is to attempt to absorb the reflection as to restore the direct sound of the speaker and hence flat response. Indeed, if you search for room acoustics online nine out of ten articles or forum posts will tell you the exact same thing. Pictures like the above are put in front of you and the decision of what to do becomes obvious. It can be good to follow the crowd in some occasions but this is not one of them! The reason is that neither the measurement nor how we perceive the distortion is represented by what I have explained so far.​

The Measurement

Let’s start by examining how our hearing system works courtesy of Fletcher who in 1940 performed a series of listening tests leading to the discovery that our hearing system becomes less and less selective in frequency discrimination as frequencies went up. Fletcher’s model was later refined by Moore resulting in what is called Equivalent Rectangular Bandwidth or ERB. Plotting that with source frequency (coming out of our speakers) on the horizontal axis and the bandwidth of our auditory filters on the vertical axis we get the graph to the right. As we see in the graph there, the resolution or our ears is inversely proportional to the frequency we are trying to hear. The higher the auditory filter tuning frequency, the lower the resolution of the ear at that frequency.

As an example, at 300 Hz source frequency (horizontal axis), the ear’s sensitivity or discrimination is a narrow 60 Hz (vertical axis). At the other extreme, for a source frequency of 10 KHz, the level climbs way up to 1.1 KHz. This readily shows that we are far less sensitive to frequency variations at 10 KHz than we are at 300 Hz.

Now let’s apply the learning there to our comb filtering example. There, I used the assumption of the reflection path causing a 10 millisecond delay. If we invert the delay, we arrive at the frequency of the comb filter notches which in this case will be 100 Hz. If we take 100 Hz on the vertical axis and find the source frequency at which our auditory filter becomes that wide, we land at 700 Hz (where the green line is). Therefore for source frequencies above 700 Hz, our hearing system lacks sufficient resolution to properly hear the notches in this example.

Considering that the lower end of interest is the transition frequencies of 200 to 400 Hz, we have barely climbed up the range to 700 Hz before the audibility of those notches becomes questionable. Yet the display of distortion in our original simulation happily goes to 10,000+ Hz, portraying a far more serious issue than exists in reality.

Do We Measure What We Hear?
We clearly have a problem of measuring more precisely than our hearing system. In the example I purposely selected the highest resolution the tool can provide at just 0.3 Hz. That is far narrower than our ear’s selectivity. You probably could not tell the resolution was that high because it is obscured in the FFT size parameter. Let’s simulate what happens if we reduced the measurement resolution to 44 Hz:




Now it does not look remotely as alarming. Granted, we should be applying variable resolution to the measurement per the ERB graph so this version probably errs too much in the other direction. Still, it is representative of how the tool can be used to show too much detail relative to what we are interested in, i.e., what distortion we are likely to hear.

Just to emphasize the point, let’s look at an actual room measurement at high resolution:




Just like our simulation we get a disturbing display showing massive amount of comb filtering. Now let’s apply a 1/3 octave smoothing to it:



As with the reduction in resolution in the simulation, a more appropriate picture appears. It shows that we have a high frequency roll off which like is more audible than the jungle of notches in the previous graph. In some way this over analysis is a symptom of modern computing power. In the old days when this was a very slow process, everyone ran 1/3 octave analysis. Today computers are very fast so we opt for the much higher resolution and with it arriving at misleading data. It is the old forest from the tree problem.

As mentioned, the ideal measurement system would apply variable filtering as the frequencies climb. The only system I have seen that does this is the JBL Synthesis ARCOS automatic equalization system. Its frequency response display is adaptively filtered allowing the troughs and variations to be shown at proper resolution of our hearing system. This not only makes it easier for the user to analyze the room performance, but it also assists the automatic correction system to arrive at the right corrective equalization settings. It would avoid having it chase problems that don’t exist audibly. Put another way, you want to please your ears, not the meter, or the graph in this instance!

There is more yet. At the risk of stating the obvious, we have two ears, not one. Yet the standard practice for room acoustic measurement calls for the use of a single microphone. This is a problem as the two ears do not hear the same sound as frequencies climb. Think of a center speaker directly in front of you sending a reflection to the left wall. The left ear is closer to that wall than the right ear by a few inches. In time domain that translates to about 0.4 msec of extra delay for the right ear. Recall that comb filter frequency is directly proportional to time delay. If you change that value, the frequency of the notches changes with it. Since we are talking about 5 to 10 milliseconds for the typical reflection in the typical home listening space, 0.4 milliseconds is a significant change in the frequency of the comb filter.



Additionally, your head becomes an acoustic filter as the frequencies climb and their wavelength becomes smaller than your head. The fancy term for this is Head Related Transfer Function or HRTF. It is the science behind how we simulate surround sound using headphones for example.

The filtering due to HRTF is direction and frequency dependent. On the right is an example measurement performed in a similar scenario to ours as published by Macpherson in his AES paper. Notice how the ear that is not being blocked by the head is picking up a stronger signal (the curve on top) and how the effect gets exaggerated as the frequencies climb and the head becomes a more effective acoustic filter for the other ear. Note also that even for a single ear what we measure is not what we hear. Measurement microphones are calibrated to provide near flat frequency response yet our ears do not at all follow such a curve as is evident by the above graph.

Since the comb filter is the result of the direct sound being combined with the reflected one, if we filter out a good chunk of the spectrum of the latter for the ear in the shadow of the head, the comb filter will become less extreme. Importantly the waveform will be different than the other ear not being subjected to this filtering. The one microphone measurement errs significantly here by only showing us a poor facsimile of one ear and ignores the HRTF effect on the other altogether.

Putting the above two concepts together, what the brain is receiving is two different waveforms arriving from each ear. If this were your eyes, you would be seeing double vision and double tint! Fortunately that is not how we perceive it. Our everyday life is full of reflections due to enclosed spaces we live in. It is not surprising then that our brain has adapted to not only avoid being confused, but to put this situation to good use. Research indicates that the brain invokes a “central summation” which roughly combines the two signals as opposed to hearing each one independently. The net result is that much of comb filtering washes out, leaving us with the sum total of what the two ears hear. And that summing helps increase the total sound energy, helping with such things as intelligibility of speech.

So far I have only talked about how there is only a single reflection in the room. That is not going to ever happen in a real room which almost always has other wall surfaces, each of which also reflects the sound. Since each reflection distance is different and so are the levels of each, the result is countless variations of comb filters. They all mix up together and statistically become far less pronounced than the clean notches in our simulation. This helps yet again to reduce detectability of comb filtering.

Listening Tests
This is all fine in theory but how does it work in practice? There is good news and bad news. The bad news is that little of it will likely make sense to you! The good news is that for a change, distortion will become our friend and not the enemy.

First let’s dispense with a myth. In home listening spaces, a reflection is not an echo. Yes, the sound is bouncing and then arriving at our ear. But due to a phenomenon known as the “Haas” effect, what we hear is that the reflection “fuses” with the direct sound and will be heard as a “single event.” For an echo to occur you need to have reflection paths that are longer than 30 feet typically which likely is not going to be the case in even large listening spaces at home. So don’t think there is an issue here due to what you may hear in much larger public spaces where distinct echoes can be indeed be a problem. It is not here.

So if we don’t hear reflections as echoes how do we hear them? The answer to that depends on direction of the reflection. Let’s focus for now on the so called first reflection points on the side walls where “common wisdom” says should be eliminated. Experiments conducted by Dr. Toole and Olive show that such reflections, when perceptible, serve to widen the apparent source of the sound (i.e. no longer just coming out of a small speaker). Turns out this is a preferred outcome and one that human listeners in controlled settings indicate as being a good thing! There simply is more realism to an image of sound that extends past the speakers and better mimics our everyday experiences in reflection-rich environments. You probably are still scratching your head wondering how what I just said can be true. So let me quote some sections of Dr. Toole’s AES paper and book in this regard:

“Most reflections arrive from directions different from the direct sound, and perceptions vary considerably. Two ears and a brain have advantages over a microphone and an analyzer. The fact that the perceived spectrum is the result of a central (brain) summation of the slightly different spectra at the two ears attenuates the potential coloration from lateral reflections significantly [34]. If there are many reflections, from many directions, the coloration may disappear altogether [35], a conclusion to which we can all attest through our experiences listening in the elaborate comb filters called concert halls. Blauert summarizes: “Clearly, then, the auditory system possesses the ability, in binaural hearing, to disregard certain linear distortions of the ear input signals in forming the timbre of the auditory event.”

“It was in this room [Dr. Toole’s Reference IEC room at National Research Council] that experience was gained in understanding the role of first reflections from the side walls. The drapes were on tracks, permitting them to easily be brought forward toward the listening area so listeners could compare impressions with natural and attenuated lateral reflections (see Figures 4.10a and 8.8). In stereo listening, the effect would be considered by most as being subtle, but to the extent that there was a preference in terms of sound and imaging quality, the votes favored having the side walls left in a reflective state. In mono listening, the voting definitely favored having the side walls reflective."

"See the discussions in Chapter 8, and Figures 8.1 and 8.2, which show that attenuating first reflections seriously compromises the diffusivity of the sound field and the sense of ASW/image broadening. One of the problems with both music and movies is that sounds that in real life occupy substantial space—multiple musicians or crowds of people, for example—end up being delivered through a single loudspeaker—a tiny, highly localizable source. The precision of the localization is the problem. Most of what we hear in movies and television is monophonic, delivered by the center channel, so a certain amount of locally added room sound may be beneficial; this is definitely a case where a personal opinion is permitted."


Expanding on the last sentence, there is indeed a subset of people who are sensitive to comb filtering and hence strive to eliminate them. A prime example is recording engineers. Since they are able to electrically generate comb filtering they have learned what it sounds like and hence have well above average ability to hear them. And at any rate, the process of mixing and creating music requires being able to detect small changes to the parameters in that work. Both of these factors explain their preference for absorption of reflections. Such characteristics are not shared for the most part by the general public or audiophile community who aims at enjoyment of music. So be careful in following “what the PROs do” when it comes to room acoustics. You are unlikely to fit in that group.

As further evidence here, Clark in 1983 set out to test to create four different scenarios that involved comb filters:

1. Using two speakers playing a mono signal. The second speaker’s sound combines with the first creating comb filtering.

2. A reflector held vertically to the right of the listener and in between him and the speaker. While the distance there was shorter than typical wall reflection, the reflection nevertheless creates comb filtering just the same.

3. Same as #2 but the reflector held horizontally.

4. Creating the comb filter electronically by delaying the signal and combining it with itself. This is the same thing I did in my earlier simulation.


The important factor is that Clark made sure that the amplitude of the reflection (simulated or otherwise) was kept constant in all four scenarios. On the surface one would expect the effect to be similar because the reflection levels were the same. Yet the results were anything but!

In scenario #1, the addition of a second speaker was considered to have “moderate and pleasing effect.“ This, despite the fact that comb filtering was generated as a result of the second speaker. Clearly the listeners liked the effect more than they were concerned with any frequency response variations.

Scenario #2 was stated as having “very small effect.” What looked awful on a frequency response measurement was barely noticed. Turning the reflector horizontal did make it a bit more noticeable (for this reason you should absorb floor reflections with thick carpeting/pad). But still, in the grand scheme of things, it did not have the same magnitude effect as scenario #1.

The most surprising was scenario #4 where the outcome was “greatly degrading effect.” Let me repeat: the same distortion created electronically and sent out of the speaker was a very negative thing. The reason is that when comb filtering is created that way, we don’t get the nice benefit of the image widening, or the psychoacoustic factors that reduced its severity. This is how Clark concludes the paper:

“Two speaker mono was considered superior to the one speaker, one path mono. A reflection from a vertical surface was barely audible but a horizontal reflector was more audible. An electronic delay comb filter was highly audible and annoying.”

He goes on to emphasize how misleading measurements in both time and frequency domains can be in determining the audible effects:
  • A comb filter response can be preferred over flat [frequency response].
  • More lateral sound than a single speaker provides can be preferred.
  • Response notches are almost inaudible if the notches are filled in by reflections within 10 ms.
  • Response notches are annoying if not filled in by reflections.
  • Vertical (wall) reflection notches were subtly audible.
  • Horizontal (desk) reflection notches are more audible.
  • Time responses can look the same and sound different.
  • Frequency responses can look the same and sound different.
  • A single test mic hinders getting directional information relevant to audibility.
Considering how long ago this test was done and how simple it is, isn't remarkable that we still cling to conclusions completely counter to this research?

Conclusion
So what seemed like an open and shut case of eliminating wall reflections due to anomalies in frequency response of the room becomes much more complex when one considers how we hear sounds in our home listening spaces. It shatters “gut feelings” one might have about the problem and solution thereof. I don’t know about you but I am fascinated by all of this. It is not every day that we get to like some distortion and save money not trying to eliminate it! So complexity and deep understanding of the science does have its virtues.

References
"Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms,"Dr. Floyd Toole, 2008 [book]
“The Detection of Reflections in Typical Rooms, ”Olive, Sean E., Toole, Floyd E., AES Convention: 85 (November 1988)
“A Computer Model of Binaural Localization for Stereo-Imaging Measurement, ”Macpherson, Ewan A., AES Convention: 87 (October 1989)
“Measuring Audible Effects of Time Delays in Listening Rooms, ”Clark, David, AES Convention: 74 (October 1983)
 
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Bruce B

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#4
What interested me when I went to Japan are the mastering rooms. They are totally different than the rooms in the U.S.

The rooms at JVC and Sony are totally dead, almost anechoic chamber like. Even more absorption than the typical theatre, whereas the mastering rooms in the U.S. reflect (pun intended) the typical home listening environment or 2-channel listening room.
 

TBone

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#6
What interested me when I went to Japan are the mastering rooms. They are totally different than the rooms in the U.S.

The rooms at JVC and Sony are totally dead, almost anechoic chamber like. Even more absorption than the typical theatre, whereas the mastering rooms in the U.S. reflect (pun intended) the typical home listening environment or 2-channel listening room.
Interesting observation, makes me wonder if audiophiles there tend to do the same with their listening rooms?
 

NorthSky

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#7
I know this thread is about perceptual effects of room reflections; but because the quality music recordings are the main essence, the source that rules all others, and the results will affect everything else, including our perceptual effects of the music we listened in our rooms.

I googled Japanese versus USA music CD recordings, and every single entry praises the better music CD quality made in Japan than in the USA.
People always (in the vast majority) prefer the Japanese versions for the same music recordings.
In Japan quality control is much better, they are more attentive to their products, CDs.

I was going to provide links but there are simply too many of them, all praising the Japanese pressings as the best...JVC XRCD24 just as one example.
I know some people who strictly buy their music from the Japanese versions. USA and UK CDs are inferior sounding quality, generally.
In Japan CDs are preferred to downloads.

I mentioned this because Bruce mentioned the difference between the recording studios in Japan and in the USA.
You can get the perfect calibrated room acoustically but it means dickinos if you are listening to an inferior music recording.
Buy quality music recordings, buy Japanese CDs, even if they cost more, because your perfect room all perfectly balanced for best reflections will appreciate it much more. Read about how they produce better music recordings; they are much better than the USA plants @ making CDs.

My Japanese CDs are my best sounding ones. Most USA and Canadian CDs, excuse my honesty, are crappy sounding compared to the same music on Japanese CDs.
Even the audiophiles from the UK know that as well. ...I'm talking generally here.

I just thought of mentioning this very important factor in this room reflection equation.
And Bruce's above post incited me to look for professional Japanese recording music studios.
But their dedication to solid quality music sounding CDs is unparalleled, without equal in the world.

What's the use to have the perfect room if the music we play sound like hell? ...Bad bad bad.
Heavy Metal music and Classical music and small Jazz acoustic ensemble or Chamber music, or Chorales and Opera, and Folk and Rock, New Age etc. all have different recording attributes about reflections. Not all rooms are perfect for all type of music recordings genre. IMO. Some music genre might like a little more reflective room and others less. ...Food for thought; the science in audio is the exploration of all possibilities and variables.
There is no absolute IMO when it comes to the right amount of reflections and absorption of sounds...music recordings of various qualities; their masterings, the plants, the presses used and for how many disc replications, from 2,000 in Japan and up to 8,000+ in the USA. ...The less the better. And etc., etc., etc.
 

TBone

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#8
My Japanese CDs are my best sounding ones. Most USA and Canadian CDs, excuse my honesty, are crappy sounding compared to the same music on Japanese CDs. Even the audiophiles from the UK know that as well. ...I'm talking generally here.
agreed, although some of my orig US/CAN/UK pressings sound pretty darn good. I find the Japanees pressings much leaner sounding at the freq.extremes. I often wondered, since they tend to live in smaller living quarters, if their mastering suited their specific environment? I certainly wouldn't want over-bloated bass and spiked highs in a small'ish listening room ...
 

RayDunzl

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#9
upload_2016-6-19_2-1-54.png


Black is the impulse response of the MartinLogan reQuests, Green is Infinity P-363, standing directly in front of the reQuests., with the microphone at the listening post.

Looking at Black, I'm used to seeing the 7ms dipole reflection, and the 27ms down-the-room-and-back reflection, with a ghost of the initial dipole reflection after going down the room and back at 34ms, and not much else.

Looking at Green, wow... The magnitude may not be exactly comparable here, although the source levels were similar, so maybe not so far off. I'll have to run a better test at some future date, but I think the trend is clear, reflections from lots of places.

I wasn't unhappy with the P-363 but after a week when I switched back I didn't miss them.

Anyway, this overlay shows a pronounced difference in Room Reflections (the theme of this thread) between the wide-dispersion P-363 and the more narrow dispersion reQuests, in my room, at that time.

What do you think?

Posted strictly for your viewing pleasure, as always.
 
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amirm

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#10
What do you think?
The fact that there are reflections does not aid in knowing their perceptual effect. That requires knowing the direction of those reflections which these measurements don't show. Nor are the measurements needed when the deciding factor is the direction which can visually be ascertained.
 

Sal1950

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#13
Humm, I wonder if we could get some room measurements on some of these. :eek:
http://www.highendnovum.de/en/
Paul McGowan wrote in his blog: "...placed between your speakers, it stares back at you like some piece of Asian dinnerware or ornament. But holy cow, it works! Immediately, vocals get more lifelike, the sound sweeter and easier to listen to..."

 

Thomas savage

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#14
My thought is that article is way too wordy and takes too damn long to get to the point. Without even seeing one photo of his setup nothing I read even makes sense. :eek:
Yes it does rather seem like a protracted love letter to ones subjective delusion, in the vein of any audiophile component review.

It's a Intresting area though imo, a little more than disparaging supposition from our more technically aware members would be welcome.

Countering like with like.. Rather undermines one.
 

Scott Borduin

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#15
Amir,

I stumbled across this site a few days back, and have read a great deal since then. Congratulations on creating a sane, respectful, science-based audio forum, and having managed to keep it that way for at least a couple of years now :)

One intriguing note on the desirability of first reflections: the usual citation for on this is Floyd Toole's research at Harman. But of course Toole himself noted that some listeners like mixing engineers exhibited a preference for no early reflections. Perhaps more interesting is that Kevin Voecks at Harman, who was the engineer on Revel Speakers among many other things, disagrees with Toole on this point. Indeed, as a Revel owner yourself you've undoubtedly noted that the Revel manuals specifically recommend damping first reflections.

As a former owner of Revels myself (purchased from a certain dealer in the Seattle area :), I have moved hard in the direction of maximizing direct sound via Sanders electrostatic speakers. For me, this provides the most "hear through to the source" experience, and I find it hard to beat for my personal preferences. But as Toole himself says, horses for courses ...
 

Kal Rubinson

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#16
Humm, I wonder if we could get some room measurements on some of these. :eek:
http://www.highendnovum.de/en/
Paul McGowan wrote in his blog: "...placed between your speakers, it stares back at you like some piece of Asian dinnerware or ornament. But holy cow, it works! Immediately, vocals get more lifelike, the sound sweeter and easier to listen to..."
Really? I mean, REALLY? The idea makes my brain hurt.
 

amirm

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#17
Amir,

I stumbled across this site a few days back, and have read a great deal since then. Congratulations on creating a sane, respectful, science-based audio forum, and having managed to keep it that way for at least a couple of years now :)
Hello Scott. It is so good to hear from you again! I really missed your departure from the last place we hung out together. :) And thanks for the kind words regarding ASR Forum. That is what we strive for and good to see that it shows.

One intriguing note on the desirability of first reflections: the usual citation for on this is Floyd Toole's research at Harman. But of course Toole himself noted that some listeners like mixing engineers exhibited a preference for no early reflections. Perhaps more interesting is that Kevin Voecks at Harman, who was the engineer on Revel Speakers among many other things, disagrees with Toole on this point. Indeed, as a Revel owner yourself you've undoubtedly noted that the Revel manuals specifically recommend damping first reflections.
Yes, Kevin is a very good friend and he and I have talked a number of times about this. My sense is that like other professionals you mention, through so much exposure trying to hear speaker sound itself, may have evolved his hearing to be much more sensitive than the rest of when it comes to reflections.

BTW, there was follow up research on Dr. Toole's hunch regarding mixing and mastering engineers in a rather recent AES paper The Practical Effects of Lateral Energy in Critical Listening Environments, this very thing was tested in controlled environment to determine preference for diffusion, absorption or doing nothing (reflections). Here is the test subjects the outcome:

upload_2018-1-16_16-21-18.png


upload_2018-1-16_16-19-48.png


As you see, it turns out the majority of these professionals actually side reflections than not.

upload_2018-1-16_16-20-45.png


As a former owner of Revels myself (purchased from a certain dealer in the Seattle area :), I have moved hard in the direction of maximizing direct sound via Sanders electrostatic speakers. For me, this provides the most "hear through to the source" experience, and I find it hard to beat for my personal preferences. But as Toole himself says, horses for courses ...
:)

As you say, the panel speakers have a sound that when combined with right music, is a very unique experience.

Hope we see you more here.
 

oivavoi

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#18
My subjective experience is as follows: avoiding side reflections indeed allows hearing more through to the source. But it sounds "fake" to my ears, it doesn't sound like real music happening (because real instruments always excite reflections). Having broad directivity and more reflections diffuses some of the uniqueness about the source, as one hears one's own room as much as the recording venue. It does sound much more real to me though, much closer to how I perceive real acoustic music to be.

My personal experience is that I often prefer the low-reflection type of listening for modern electronic studio music (in a broad sense), since this kind of music is inherently artificial and doesn't resemble real acoustic events. It's like my brain allows me to get fooled by the reflection-free stereo image. Recordings that try to either capture or recreate real acoustic events, on the other hand, feel much more real or convincing to me when listened to on a system with broad directivity and a generous amount of reflections. I have a fair bit of experience with acoustic music, and I suspect that my brain protests when presented with an acoustic image which purports to be real but doesn't excite reflections.

Others will have other experiences and preferences, I guess.
 

amirm

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#19
My personal experience is that I often prefer the low-reflection type of listening for modern electronic studio music (in a broad sense), since this kind of music is inherently artificial and doesn't resemble real acoustic events. It's like my brain allows me to get fooled by the reflection-free stereo image. Recordings that try to either capture or recreate real acoustic events, on the other hand, feel much more real or convincing to me when listened to on a system with broad directivity and a generous amount of reflections. I have a fair bit of experience with acoustic music, and I suspect that my brain protests when presented with an acoustic image which purports to be real but doesn't excite reflections.
That is my impression too. On orchestral music reflections can be heavenly. But on some rock/pop music it can get excessive if the room is too live. So a balance is needed.
 
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