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Research on reflections

Kvalsvoll

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Yep, as You said. Advertising--at You website, isn't meant to be a scientific publication. I still think this state of affairs is a pitty. Fair enough, though. Amps, I always thought this case is settled. I personally cannot imagine to question my humble AVR, if my goal is to just fancy me with interesting musical presentations. It does the trick, so what else to expect? More detail? Not really ... More volume would entertain my neighbours next street ...

I think our little conflict is settled. As I, for the time being are not that much into "imaging" with stereo, I can't appreciate audio systems that claim for themselves to be superior in this respect. For whatever reason. Would You mind to link some scientific sources here anyway?

Last, to tell that Your subwoofers are technically "horns" is a bit of a hyperbole. Just my impression. Performance still is pretty much o/k for the formfactor.
As much as I like to talk about my speakers, this is perhaps not the best place for that.

It is not only about imaging. Having very good early reflection attenuation increases clarity, gives better instrument separation, preserves the room information from the recording better.

Some systems project images - small images - of the instruments, accurately placed in a 3D-landscape. This can be fun, but it can also be questioned whether this is accurate and true.

Then you can have imaging that presents some objects very sharp and accurate, while other objects are big and diffuse - there is huge contrast.

Some audiophiles choose to place the speakers as far away from walls as possible, others choose to install large horn systems. They both try to minimize early reflections - though the resulting sound experience is very different.

So reducing early reflections as much as possible and having a controlled decay for what happens further out in time, will improve sound quality.

We can find support for why this is so theoretically.

In an article/thread I try to describe how acoustics are fixed in a small room. Look at the measurements, and compare to your own room, if you are able to do similar measurements there. The owner of this room wrote a brief impression, which I find is quite good at describing what this is about and how bit relates to sound quality: https://www.kvalsvoll.com/blog/foru...coustics-for-a-f205-system/?part=2#postid-237
 

fineMen

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Some audiophiles choose to ...
The strawman argument - don't worry. I do it all myself all the time. I know it's not for bad. For the other, I think it was Dick Feynman You once quoted a fellow in his field of science: "I don't understand it--it must be wrong!" Something around that lines creeps into my mind here. It's hard to convey a complicate topic in a foreign language, though. Guess how I know ;-)

For the time being I keep my lazy attitude. Or "relaxed", if You mind. The "imaging" with stereo is to needy for my. To much effort to concentrate etc pp. I settled into an attitude that it wouldn't add much to the musical expression. It seems to be more about the technical quality of the stereo as such, if at all. When listening to my beloved music, I don't care about the stereo system anymore.

edit, edit .. one question: what may be in the rcording, that allows to change the position of the head when focusing on the "imaging"? I personally didn't find an escape yet. I triple-checked so many aspects only to end up with nothing. Every means would destroy the uptight illusion. I chose to unbend myself.
 
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dasdoing

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we all grow up in terrible rooms. we grow up hearing it is all about the bass. we grow up we stereos in terribly steep stereo triangles.
than you put a bunch of us to AB treated vs untreated rooms for a few seconds. we obviously chose what we are used to.
now put a guy who chose untreaded in a perfectly treated room for a few hours. minute after minute he will start to hear more and more stuff in the recordings. than send him back to his room and the next day he will start to treat his room
 

fluid

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The strawman argument - don't worry. I do it all myself all the time.
This suggesting of strawmen annoys me no end, it is the worst kind of deflection. Instead of actually confronting the topic or discussing how you see the issue. To me that meets the definition much more closely than the behaviour complained about in the first place.

I see Kvalsoll describing methods by which people attempt to reduce early reflections whether they know it or not.

It's hard to convey a complicate topic in a foreign language, though. Guess how I know ;-)
It is equally hard to follow, but is that reason to give up?
 

fineMen

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This suggesting of strawmen annoys me no end, it is the worst kind of deflection. Instead of actually confronting the topic or discussing how you see the issue. To me that meets the definition much more closely than the behaviour complained about in the first place.

I see Kvalsoll describing methods by which people attempt to reduce early reflections whether they know it or not.


It is equally hard to follow, but is that reason to give up?
We must not refer to other people and their alleged motivations in order to make our point.

I'll later this week open another thread in the acoustics department. I'll give a graphical presentation of what my current stereo looks like.

To begin with You'll see, to what degree and by which means my original stereo set is close to be devoid of early reflections. Maybe that's a sufficiently personal starting point.
 

Schollaudio

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Environment is a huge factor. Find a space that has very high diffusion and very low boundary reflections and no nodes, no pressurization. An inexpensive speaker will sound like a million bucks. The only concern with dispersion would be how many people you want to cover with sound.

In a typical household room it we'll still have to mix and match speakers for our desired sound and again how wide a listening space is needed for the family and friends. That's happening a lot in this thread.
 

Kvalsvoll

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edit, edit .. one question: what may be in the rcording, that allows to change the position of the head when focusing on the "imaging"? I personally didn't find an escape yet. I triple-checked so many aspects only to end up with nothing. Every means would destroy the uptight illusion. I chose to unbend myself.
Yes, this is a problem with stereo, and it is irritating, and it certainly breaks the illusion when you move your head a little and everything collapses. I have found that the speaker makes a difference here, and some recordings are much better - some will even present a good soundstage far off center. Try the Voices Of Music recordings.

And don't get me wrong about the audiophiles - I consider myself to be one - a person who has an affection for sound.
 

Kvalsvoll

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I see Kvalsoll describing methods by which people attempt to reduce early reflections whether they know it or not.
When working with sound, we often experiment, move things around, and suddenly, we experience an improvement. Some people will be quite content with just getting this improvement, without needing to know in detail what kind of technical explanation lies behind.

As for the speakers far away from walls - finding this actually worked, the same can then be tried out the next time, and if the same improvement is experienced, then you have a general rule that can be used over and over again. No need to understand exactly why and how.
 

fluid

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We must not refer to other people and their alleged motivations in order to make our point.
Of course, but forum communication is not perfect and it is easy to "see" things in peoples writing that they did not intend or just wrote badly.

Asking them to clarify or explain further helps everyone to understand and if their argument really is baseless it will be exposed. Throwing them under the strawman bus doesn't help anyone.

https://www.merriam-webster.com/words-at-play/why-do-we-throw-someone-under-the-bus
 

bo_knows

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When working with sound, we often experiment, move things around, and suddenly, we experience an improvement. Some people will be quite content with just getting this improvement, without needing to know in detail what kind of technical explanation lies behind.

As for the speakers far away from walls - finding this actually worked, the same can then be tried out the next time, and if the same improvement is experienced, then you have a general rule that can be used over and over again. No need to understand exactly why and how.
"As for the speakers far away from walls," Which walls (side wall, front wall?) and how much space are we talking about? What about us that don't have that space luxury? Any suggestions? Just curious. FWIW, I prefer to listen to my speakers (KEF R500, I guess narrow dispersion, in the RFZ for the primary reflections.
 

Kvalsvoll

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What about us that don't have that space luxury? Any suggestions?
Most do not have that luxury, at least not from what I see. Dedicated rooms are often quite small, and when placed in the main living room, there are practical considerations that confines speakers to a smaller part of the room, often placed close to both front wall and side wall.

This with the speakers far out from any walls is mostly seen on pictures from larger showrooms or the one rich guy with a very large, dedicated room.

It is also a waste of space.

Speakers with better radiation pattern, and acoustic absorption on close surfaces that works well down to around 100Hz, gives a similar - or even better - result. Also reducing the listening distance will give more direct sound (the sound directly from the speakers, before any reflections), and can make it possible to move the speakers a little further away from walls.

If you have a larger living room, you can try it, just to see and experience the difference. If the speakers are run full-range, there will be less bass, may be too little, and if you get too close to many speakers, they no longer sound right because the sound from different drivers do not blend into one coherent source at close distance.
 

Trdat

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Thanks for having me,

<edit, language barrier>:

why not going for two distinctive speaker systems working in unison
1) something that would give directional clues for stereo sensation, namely high directivity left/right
2) additionally something that would support (1) by adding as much reveberation as is needed for a well balanced timbre. Could be a mono speaker, technically realized as e/g a DML with wide, de-correlated directivity

Why would one expect from a pair alone to fulfill the combined requirements for directivity and tonal balance in all directions?

Tried with a narrow professional speaker pair and a larger DML capable of high output. It worked out fine.

Benefit: cheaper, actually; more power; and foremost adjustability to preference every other minute

My set up defnitely goes against the grain of what is recommended for surround systems and it uses a similar concept to what you have suggested above. I have narrow dispersion horn speakers for my mains providing the strong direct sound cues and for my side surrounds I have wide dispersion speakers that are placed to provide maxiumum reflections that come off the side walls and from the larger horn speakers cabinet to the other side. This adds a great element to the sound but only for live recorded music. I can't say the measurements look superb but I can't do without it when listening to live music with guitars or string instruments.
 

bo_knows

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Most do not have that luxury, at least not from what I see. Dedicated rooms are often quite small, and when placed in the main living room, there are practical considerations that confines speakers to a smaller part of the room, often placed close to both front wall and side wall.

This with the speakers far out from any walls is mostly seen on pictures from larger showrooms or the one rich guy with a very large, dedicated room.

It is also a waste of space.

Speakers with better radiation pattern, and acoustic absorption on close surfaces that works well down to around 100Hz, gives a similar - or even better - result. Also reducing the listening distance will give more direct sound (the sound directly from the speakers, before any reflections), and can make it possible to move the speakers a little further away from walls.

If you have a larger living room, you can try it, just to see and experience the difference. If the speakers are run full-range, there will be less bass, may be too little, and if you get too close to many speakers, they no longer sound right because the sound from different drivers do not blend into one coherent source at close distance.
Thank you. I would like to think that I'm on a right track. I sit 8.1 feet from the speakers.
There's still more work to be done in my room (currently experimenting with qrd 734 diffusers on sidewalls above the absorbers.) I know they make a nice difference but my listening position allows for only 6 feet of distance from them. They bring a lot of energy that I can feel it in my ears. Strange feeling that almost overwhelms my ears and makes the sound a touch brighter but gives a more feel for the front of the sound stage.
My KEF R500 apparently has narrow dispersion but the first reflection are being absorbed. The sound stage is a big as the recording is calling for. So for me, absorption on the sidewall works fine.
 

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dasdoing

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Thank you. I would like to think that I'm on a right track. I sit 8.1 feet from the speakers.
There's still more work to be done in my room (currently experimenting with qrd 734 diffusers on sidewalls above the absorbers.) I know they make a nice difference but my listening position allows for only 6 feet of distance from them. They bring a lot of energy that I can feel it in my ears. Strange feeling that almost overwhelms my ears and makes the sound a touch brighter but gives a more feel for the front of the sound stage.
My KEF R500 apparently has narrow dispersion but the first reflection are being absorbed. The sound stage is a big as the recording is calling for. So for me, absorption on the sidewall works fine.

lol. I can relate to that tape on the floor.
ceiling/wall corner traps are so space effective, very nice. to make it perfect you would have placed triangular traps where the 3 surfaces meet.
Is the setup suficient though to efect the 1st longitunal room mode? probably not right? in this small of a room you only get it with very thick absorbers at the backwall
 

bo_knows

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lol. I can relate to that tape on the floor.
ceiling/wall corner traps are so space effective, very nice. to make it perfect you would have placed triangular traps where the 3 surfaces meet.
Is the setup suficient though to efect the 1st longitunal room mode? probably not right? in this small of a room you only get it with very thick absorbers at the backwall
My small room leaks bass through every pore (drywall, door, windows, and ac diffuser on the ceiling. LOL. Yes, the plan includes adding ticker absorbers on the back wall, behind my head. I think positioning the absorber a little further from the back wall (quarter length of the bass wave) will make it more efficient without adding more porous material. This is all good to maybe 80Hz. After that, one will need to deploy some kind of diaphragmatic absorber or limp mass membrane. Btw, I try to stay away from any fiberglass or Rockwool material and use only eco-friendly (recycled paper). To me, it's not worth taking a chance of being exposed to breathing that stuff.
Down the road, I may experiment with vinyl limp mass trap for the 50-60Hz range. For me, experimenting with the room treatments is the name of the game at this point.
 

Kvalsvoll

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Thank you. I would like to think that I'm on a right track. I sit 8.1 feet from the speakers.
There's still more work to be done in my room (currently experimenting with qrd 734 diffusers on sidewalls above the absorbers.) I know they make a nice difference but my listening position allows for only 6 feet of distance from them. They bring a lot of energy that I can feel it in my ears. Strange feeling that almost overwhelms my ears and makes the sound a touch brighter but gives a more feel for the front of the sound stage.
My KEF R500 apparently has narrow dispersion but the first reflection are being absorbed. The sound stage is a big as the recording is calling for. So for me, absorption on the sidewall works fine.
Nice room and nice treatment. And to me it looks like you have good distance to side-walls from the speakers.
 

bo_knows

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Nice room and nice treatment. And to me it looks like you have good distance to side-walls from the speakers.
Thank you! I'm an IT professional by trade and my woodworking skills are below amateurish but I learned a few things as I went along. During my room acoustic building experience, I knew I wanted to use as much wood as I could. I think wood gives out a very neutral sound. In the beginning, I had 9 inch deep qrd diffusers on the side of the wall for the first reflection point and they eat up a lot of real estate without addressing the bass. Then I build the absorbers with the scatter plate and the sound was way too bright! So much for KEFs narrow dispersion. I had to tear up one by one scattering plates on the sidewall treatments until the sound was more balanced and less ear fatiguing. The distance from the sidewall to the center of the tweeter is 38 inches. Speakes are slightly toed in which provides a more focused sound stage with adequate width. Maybe if I read Dr. Floyd Toole's book about sound reproduction first, I would take a different approach but here I'm experimenting on my own trying to please my ears.
 
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Kvalsvoll

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I had to tear up one by one scattering plates on the sidewall treatments until the sound was more balanced and less ear fatiguing.
Building absorbers like that, with plates/slats to scatter and reflect sound, gives great flexibility for adjustments. If it is too dead - add more wood, if it is too bright or lively - remove some.

Those designs with different width slats looks great, I have seen them elsewhere, on a yt-channel called "Acoustics insider".
 

richard12511

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Thank you. I would like to think that I'm on a right track. I sit 8.1 feet from the speakers.
There's still more work to be done in my room (currently experimenting with qrd 734 diffusers on sidewalls above the absorbers.) I know they make a nice difference but my listening position allows for only 6 feet of distance from them. They bring a lot of energy that I can feel it in my ears. Strange feeling that almost overwhelms my ears and makes the sound a touch brighter but gives a more feel for the front of the sound stage.
My KEF R500 apparently has narrow dispersion but the first reflection are being absorbed. The sound stage is a big as the recording is calling for. So for me, absorption on the sidewall works fine.
Damn! That's a nice purpose built room. I like it.
 
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