The State of High End Audio

[ack]

Tim, I don't think that ack is advocating the complete elimination of the room. He is talking about absorbing the first refection point. We have all been in overly damped listening rooms. The sound is dead. I don't think many hear dispute that. I am talking about a balance. A room that sounds, pardon the dreaded descriptor, "natural". If a room sounds natural while conversing with others in it, then that is a pretty good sign. Speakers are of course, different. I prefer dampening first reflection points. I have tried diffusors in those locations, and did not like them as much.

Yes that's exactly what I am advocating. You don't want floor reflections, you don't want ceiling reflections, and you don't want side reflections starting with first reflections. And I really don't like overly damped rooms, and mine, on the other hand, is bit too live for my liking, but others have to live in this space as well.

 

[JackD201]

It's two sides of the same coin Peter. You can achieve a curve passively and by direct signal manipulation. The choice of using one, the other or both in tandem is just that, a choice. That said it is always more practical to have an objective to guide the design and implementation process. Amir is right elimination is not a priori. As Klaus rightly says because sound events are not static the first reflection thing has become blown way out of proportion in the audiophile world. What's more important in terms of averaging is the decay/reverberation times. People usually think in terms of sub schroeder frequencies but control of long delay times over that are just as important. Fortunately most US homes are not highly reflective because of building materials. That is not the case here for example where code specifies lots of very dense surfaces and structures, poured concrete and load bearing CHB with plaster.

 

[PeterA]

Yes that's exactly what I am advocating. You don't want floor reflections, you don't want ceiling reflections, and you don't want side reflections starting with first reflections. And I really don't like overly damped rooms, and mine, on the other hand, is bit too live for my liking, but others have to live in this space as well.

Ack, that is interesting. I don't like overly damped rooms either. I wonder if an overly damped room sounds the same as one without any perceptible reflections?

Are you advocating completely eliminating all reflections? How is that even possible without putting your system in an anechoic chamber, a really huge room, or making the sound "correct" by altering the signal via DSP or some other correction software to some target curve?

Your room does not seem to have any treatment except for your leather sofa up against the back wall and a small rug under your coffee table. Every other surface, including the large coffee table in front of your listening seat is hard and reflective. The side walls are far from your speakers, which must be good and consistent with you wanting to lesson the impact of first reflection points, but I thought panel designs don't have side reflections like conventional box speakers. Perhaps the curved panels of Martin Logans do have first reflection points, unlike flat panel speakers. You also seem to avoid Martin Logan's common placement utilizing the careful use of the back wave on a front wall behind the speakers by placing your speakers in a location in your room where there is open space behind them, an open stairwell on one side and an open kitchen on the other. How does this placement effect the dipole design?

I agree that your room is somewhat live sounding and that it is more or less a compromise given the design and function of the room. My listening room is also quite compromised, as you well know.

 

[ack]

Ack, that is interesting. I don't like overly damped rooms either. I wonder if an overly damped room sounds the same as one without any perceptible reflections?

Are you advocating completely eliminating all reflections completely and thus the room's influence on the sound?

No, rather damp them, or avoid them - this is why a lot of folks put a carpet in front of the speakers, for example; or why my side walls are so far away from the speakers. Crazy as I am, I actually have a wall rug that I no longer use, but I have had people place it on the ceiling for me so I can experiment, and I liked the sound, but it's obviously not practical. All in all, just look at the Goodwin's big room: treated (not deadened) ceiling, walls and a big carpet on the floor. That's what I am advocating.

Your room does not seem to have any treatment except for your leather sofa up against the back wall and a small rug under your coffee table. Every other surface, including the large coffee table in front of your listening seat is hard and reflective.

Yeap and I let the carpets and furniture do the dampening, and don't forget, this is not a listening room, it's a living room. And I hate placing silly-looking audiophile traps or anything non-artistic. There are artistic articles I could use to deaden the place even more, but again, it has to match the decor and others do live in the same space. Ideally, we would all have dedicated listening rooms.

The side walls are far from your speakers, which must be good and consistent with you wanting to lesson the impact of first reflection points, but I thought panel designs don't have side reflections like conventional box speakers.

Not true, and this is why I quoted ML's own language, upthread. I am not aware of any speaker with no side reflection issues. Actually, ML even have a set-up video to show where to put the first-reflection absorbers.

Perhaps the curved panels of Martin Logans do have first reflection points. You also seem to avoid Martin Logan's common placement utilizing the careful use of the back wave on a front wall behind the speakers by placing your speakers in a location in your room where there is open space behind them, an open stairwell on one side and an open kitchen on the other. How does this placement effect the dipole design?

There are two approaches to the backwave: absorb it, or give a lot of room (and I give it a LOT of room, more than the front wave)... again, look at Goodwin's: they demonstrate electrostatics by placing them effectively in the middle of the room. There is nothing groundbreaking here, these are all common techniques to deal with panels' backwave. By contrast, listen to Magnepans the way they set them up at Natural Sound, and see how weird they sound with the backwave pinned against the back wall. At least that's what they did when I listened to the 3.6s years ago (lovely speaker, otherwise).

 

[Rodney Gold]

Well , I have a dedicated and fully treated room , 8m x 6m , all the walls are double walls with slotted and pierced mdf acoustic panels on battens with 2" thick medium density uthermo behind.. this has both diffusion and absorption properties.. treated ceilings with diffusers, big rugs, tube and flat panel bass traps etc etc...
Its a quiet room , a little deader than most , but the overriding comment I get is that folk find their voices and conversation very natural in the room

The room has evolved from fairly lively to this more natural sound. speakers are in free space.. swarm of subs used as well as DRC.
There is less of the airy fairy type sound I had previously , which I miss a little , BUT there are other aspects that more than compensate. If I want more lively , all I have to do is hang more reflective art on my walls..

My imaging is amazing , truly holographic , with a soundstage that is way wider and deeper , perceptually , than the room

Its an all immersive experience where you can hear the artists intent and the true timbre of the music without the room colouring it , the louder you go , the better it gets...
I hear my music I know differently than before, far more detail without harshness , far more subtleties revealed etc, hearing stuff that was previously masked.
I am now closer to the illusion of a real performance than before

I have helped many of my friends with DRC and passive treatments and in EVERY case , it has always helped and never harmed.
I have been in ultra dead rooms , and the issue mainly with these is that they absorb way too much HF leading to a lack of sparkle and lack of a sense of decay...

 

[Geardaddy]

http://www.whatsbestforum.com/showthread.php?12853-Sublime-Sound/page10

He and I have heard live solo cello performances together a few times and understand what it sounds like. I have heard few systems even begin to portray the sheer level of energy or timbral information that the cello, or piano, or violin present when heard live and fairly close.

I think that's a very important point: energy transmission and preservation in a room. Very few normal living spaces or even dedicated rooms I have heard pull it off. Most technologies at play (whether they be electronic or physical media) are passive and reactionary and fail to deliver the vibratory violence and splendor of live music.

 

[Rodney Gold]

They can't reproduce the dynamics of live as the live is "captured" by mics and electronics etc and not our ears.
I have just come back from Ireland , pubs with live unamplified music there..sitting right next to the musicians.. wishing my hifi could do that!!!!

 

[DaveC]

???

The point was, in a concert hall the reflections are taken as spatial information while the brain locks onto the direct sound. In typical listening space at home, the reflections are too short and combine with the direct sound, smearing it. There's a huge difference between a concert hall and a home listening environment for that reason and the example you give of the critical distance in a concert hall left that key piece of information out. You don't need to make a point by not giving all the information, especially when it's a huge, major point. Reflections in a concert hall are arranged intentionally and are percie3ved totally differently vs short reflections in a home listening environment.

 

[DaveC]

They can't reproduce the dynamics of live as the live is "captured" by mics and electronics etc and not our ears.
I have just come back from Ireland , pubs with live unamplified music there..sitting right next to the musicians.. wishing my hifi could do that!!!!

That's not really true, recorded music is purposefully dynamically limited. It doesn't HAVE to be that way... I've heard uncompressed drum recordings on huge line arrays and it was pretty darn close to the dynamics of a real drum set.

 

[TBone]

That's not really true, recorded music is purposefully dynamically limited. It doesn't HAVE to be that way...

true, but unfortunately dynamic limiting is much the norm. I often refer to this online DR-db http://dr.loudness-war.info/ researching pressings ...

 

[amirm]

The point was, in a concert hall the reflections are taken as spatial information while the brain locks onto the direct sound.

As I gave in my example of Boston Symphony Hall, the critical distance is very close to the stage. The direct sound continues to drop off proportional to square of distance as you walk back from the stage. But reflections do not suffer the same since the are coming from many other directions and sum together. Here is a graph on critical distance I created for another use but is useful here too:

The X axis is in log so the drop off in sound shown in the graph becomes a straight line. The red line is the critical distance. Once you hit that, notice how moving backward does NOT reduce the sound amplitude the same amount Keep going and you hit a plateau where the sound level stays constant! That is because the direct sound contributions have zeroed out so moving away from it doesn't matter and all you hear is the overall energy of the sound in the whole room.

What this means is that in most seats in a concert, most/all you hear is the reflected sound. The direct sound plays little to no role. If reflections are bad, then concert halls should sound bad but obviously they do not. We need to start off with this reference with respect to reflections rather than our view that reflections are interferences and hence bad by definition.

In typical listening space at home, the reflections are too short and combine with the direct sound, smearing it.

That is our intuitive understanding of it. But it doesn't work that way. Reflections actually work to enhance richness of timbre. Here is a simple experiment. Listen to a loved one speaking 10 feet away in an open field. Then compare their voices in your home. I bet you find the former flat and uninteresting. The notion of one liking their voice in the shower is based on this very principal.

The appeal of side reflections is so high to us perceptually that we prefer its existence even when it is faulty. From Dr. Toole's book, Sound Reproduction:

"A speculation: In Chapter 8, an experiment was described in which two
wide-dispersion loudspeakers were compared to a loudspeaker with reduced
lateral dispersion. The wide-dispersion loudspeakers were preferred, in spite of
them both having irregular off-axis frequency responses. Even with this defect,
the wide-dispersion loudspeakers were judged to be superior in terms of both
sound quality and spatial quality. The stronger lateral reflections would generate
a greater impression of ASW/image broadening, which is probably a positive
attribute, and the same reflections, and those that follow them, will contribute
to an enhanced sense of timbral richness, which is probably also beneficial.
It is something to think about."

I also pointed to other references, i.e. Clark, in my article in room reflections. Please read those. And I can literally write a book with countless other references confirming the same. We have two ears and a brain interpreting the differing sound coming into each one. It does not work on our simple view of direct sound and interference.

All of this makes sense of course from evolutionary point of view. Once we moved into caves, the brain adapted and started to use the constant reflections in our everyday life in closed space into additional sound power rather than annoying delays and echos. It is very fortuitous thing or we would go crazy in our everyday life with our voices constantly bouncing from surfaces around us.

There's a huge difference between a concert hall and a home listening environment for that reason and the example you give of the critical distance in a concert hall left that key piece of information out. You don't need to make a point by not giving all the information, especially when it's a huge, major point. Reflections in a concert hall are arranged intentionally and are percie3ved totally differently vs short reflections in a home listening environment.

They are different. And I explained that in my posts to Peter in how in a concert hall we hear almost a fully diffused soundfield. It is not different in the manner you say.

 

[DaveC]

As I gave in my example of Boston Symphony Hall, the critical distance is very close to the stage. The direct sound continues to drop off proportional to square of distance as you walk back from the stage. But reflections do not suffer the same since the are coming from many other directions and sum together. Here is a graph on critical distance I created for another use but is useful here too:

The X axis is in log so the drop off in sound shown in the graph becomes a straight line. The red line is the critical distance. Once you hit that, notice how moving backward does NOT reduce the sound amplitude the same amount Keep going and you hit a plateau where the sound level stays constant! That is because the direct sound contributions have zeroed out so moving away from it doesn't matter and all you hear is the overall energy of the sound in the whole room.

What this means is that in most seats in a concert, most/all you hear is the reflected sound. The direct sound plays little to no role. If reflections are bad, then concert halls should sound bad but obviously they do not. We need to start off with this reference with respect to reflections rather than our view that reflections are interferences and hence bad by definition.


That is our intuitive understanding of it. But it doesn't work that way. Reflections actually work to enhance richness of timbre. Here is a simple experiment. Listen to a loved one speaking 10 feet away in an open field. Then compare their voices in your home. I bet you find the former flat and uninteresting. The notion of one liking their voice in the shower is based on this very principal.

The appeal of side reflections is so high to us perceptually that we prefer its existence even when it is faulty. From Dr. Toole's book, Sound Reproduction:

"A speculation: In Chapter 8, an experiment was described in which two
wide-dispersion loudspeakers were compared to a loudspeaker with reduced
lateral dispersion. The wide-dispersion loudspeakers were preferred, in spite of
them both having irregular off-axis frequency responses. Even with this defect,
the wide-dispersion loudspeakers were judged to be superior in terms of both
sound quality and spatial quality. The stronger lateral reflections would generate
a greater impression of ASW/image broadening, which is probably a positive
attribute, and the same reflections, and those that follow them, will contribute
to an enhanced sense of timbral richness, which is probably also beneficial.
It is something to think about."

I also pointed to other references, i.e. Clark, in my article in room reflections. Please read those. And I can literally write a book with countless other references confirming the same. We have two ears and a brain interpreting the differing sound coming into each one. It does not work on our simple view of direct sound and interference.

All of this makes sense of course from evolutionary point of view. Once we moved into caves, the brain adapted and started to use the constant reflections in our everyday life in closed space into additional sound power rather than annoying delays and echos. It is very fortuitous thing or we would go crazy in our everyday life with our voices constantly bouncing from surfaces around us.


They are different. And I explained that in my posts to Peter in how in a concert hall we hear almost a fully diffused soundfield. It is not different in the manner you say.

It's different in exactly the manner I say... I understand what you're saying, but your views and research are simply based on the average person's acclimation to a particular kind of sound, one with close reflections. There is a better way.

In a concert hall the direct sound arrives first (in many seats) and your brain locks onto the direct sound while taking the reflections as "hall ambiance", and in this case reflections ARE good and are produced intentionally by the design of the hall. Because of this, the relationship between direct and reflected sound and the critical distance is MUCH DIFFERENT vs what happens in a small room. In a hall, there are NO SHORT REFLECTIONS that are detrimental to the sound like there are in a small room.

In a home environment you think the short 1st reflections add timbral richness and a sense of space, and that may appear to be true but there are some major issues associated with that kind of setup and the truth is you are smearing a lot of the fine detail in the recording and will never achieve the best results that way. People only like it because that's what they are acclimated to and, if given the proper re-acclimation to better sound, it is my experience that they will prefer it. The truth is, people are used to hearing things a certain way because of the size of our living spaces combined with the dispersion characteristics of the cheapest speaker systems, but that does not mean it's the best way to do things, it's only what people are more used to.

Hopefully you'll get to hear exactly what I'm talking about at the next RMAF, I'm putting my money where my mouth is and am building a controlled dispersion speaker that greatly reduces 1st reflection issues. IMO, Earl Geddes is right and his ideas about controlled directivity work and produce better results than conventional dynamic speakers, or designs like the latest Harman/JBL waveguides that have too-wide dispersion. People that have given Geddes designs a fair trial seem to agree, although it does take a few minutes for the brain to adjust to the new type of sound they produce.

Anyway, that's why there are lots of different kinds of speakers, people have different preferences and IMO, the typical wide-dispersion dynamic speaker sounds flat and 2 dimensional compared to a good waveguide CD speaker although the typical dynamic speaker can be greatly improved by room treatments that absorb first reflections.

 

[Geardaddy]

They can't reproduce the dynamics of live as the live is "captured" by mics and electronics etc and not our ears.
I have just come back from Ireland , pubs with live unamplified music there..sitting right next to the musicians.. wishing my hifi could do that!!!!

To accurately make that assessment, you need to control for BAC. I am assuming it was higher in the pubs than in your listening room on an average day. I do wonder if Guinness is more efficacious than the Pinotage you are sipping in your fancy room in creating that "live" vibe....

 

[TBone]

To accurately make that assessment, you need to control for BAC. I am assuming it was higher in the pubs than in your listening room on an average day. I do wonder if Guinness is more efficacious than the Pinotage you are sipping in your fancy room in creating that "live" vibe....

 

[PeterA]

Amir, regarding first reflections, my experience seems to closer match that of DaveC's. In my listening room, I only absorb the first reflections, and only partially with two short ASC panels. I do not address with specific acoustic treatments the many other reflections ocuring on my side walls and they do contribute positively to the sound of my room. I even have glass covered painting hanging on the walls. I do absorb the reflection on the back wall 12" directly behind my head as that reflection does terrible things to the sound. I find it is all a balance. The sound is more intelligible in my room when the first reflections on the side and floor are absorbed.

Regarding Boston Symphony Hall, of course there are many reflections, but given the distances to the side walls and ceiling, the direct sound from the instruments on stage arrive at my seat in the seventh row much sooner than the reflected sounds which all blend together and create the hall ambience that DaveC describes. That is very distinct from the direct sound of the instruments on the front of the stage. The situation in my listening room, where the sound is coming from two speaker point sources in a small room, is completely different. Here, I have control over how much I choose to damp the sound. I am still working on that, but recently, I draped a furniture blanket over the mantle above my fireplace, dampening the upper mid and higher frequencies, and the sound became much more detailed, resolution improved, timbral accuracy improved. I think it has much to do with dampening the reflections that were bouncing off of my fireplace surround which extends into my room.

I have also made note of how friends' voices change as I add or remove absorptive material from my listening room. Voices are less clear when the walls are bare. I don't know how to describe it more clearly than I just did in this post. I appreciate your knowledge in this area and the graphs and measurements which you post to support your position, but experimentation has led me to the results I now enjoy.

Do your own listening impressions of your system in your room support what the research tells you regarding first reflection points? And what does the research say about first side reflections versus other side reflections? Remember, I'm only partially absorbing my first reflections. The rest scatter and add life and naturalness to the sound of my room and the reproduced music I listen to.

 

[andrew_stenhouse]

Amir, regarding first reflections, my experience seems to closer match that of DaveC's. In my listening room, I only absorb the first reflections, and only partially with two short ASC panels. I do not address with specific acoustic treatments the many other reflections ocuring on my side walls and they do contribute positively to the sound of my room. I even have glass covered painting hanging on the walls. I do absorb the reflection on the back wall 12" directly behind my head as that reflection does terrible things to the sound. I find it is all a balance. The sound is more intelligible in my room when the first reflections on the side and floor are absorbed.

Regarding Boston Symphony Hall, of course there are many reflections, but given the distances to the side walls and ceiling, the direct sound from the instruments on stage arrive at my seat in the seventh row much sooner than the reflected sounds which all blend together and create the hall ambience that DaveC describes. That is very distinct from the direct sound of the instruments on the front of the stage. The situation in my listening room, where the sound is coming from two speaker point sources in a small room, is completely different. Here, I have control over how much I choose to damp the sound. I am still working on that, but recently, I draped a furniture blanket over the mantle above my fireplace, dampening the upper mid and higher frequencies, and the sound became much more detailed, resolution improved, timbral accuracy improved. I think it has much to do with dampening the reflections that were bouncing off of my fireplace surround which extends into my room.

I have also made note of how friends' voices change as I add or remove absorptive material from my listening room. Voices are less clear when the walls are bare. I don't know how to describe it more clearly than I just did in this post. I appreciate your knowledge in this area and the graphs and measurements which you post to support your position, but experimentation has led me to the results I now enjoy.

Do your own listening impressions of your system in your room support what the research tells you regarding first reflection points? And what does the research say about first side reflections versus other side reflections? Remember, I'm only partially absorbing my first reflections. The rest scatter and add life and naturalness to the sound of my room and the reproduced music I listen to.

I agree with the thrust of this post. Particularly the last sentence. Besides, absent a dedicated listening room, the aesthetics of a shared space are more important to me that the ultimate sound I may achieve. I'd rather have a piece of art on a wall than sound absorption, a sculpture on a table rather than a bass trap.

And here is a new topic - how much the enjoyment of your listening space influences how much you enjoy your music: I know when I have demo'ed music in a SOTA listening room , one which felt like a sound proof interrogation room (seriously I was looking for when the waterboarding was about to start), I disliked the experience however "correct" and impressive the sound was (and it was). On the other hand, give me a pair of LS3/5a's on a bookshelf playing via a LP12, in a cosy study with a fire going in winter, and I'm in heaven.

On that subject I asked a friend the other day in the middle of a heatwave here what weather conditions he particularly liked listening to music in - expecting him to say light rain late at night or something - he said, without a moments hesitation, "southerlies" meaning of course when the wind blows hard from the south. Now even for me that was out there - how on earth does wind direction affect sound quality? So I said: 'errr right - why is that?" to which he cheekily replied; "because that is when they don't land the planes over my house".

Sensible person 1, audiophile 0.

 

[DaveC]

Not having to treat the listening space as much is one of the huge advantages of CD speakers. If you set them up right, with toe-in pointed at the listening position, 1st reflections are greatly reduced and all you really need to do is get the room as live or dead as you like it. CD speakers integrate into living spaces much more easily vs typical dynamic speakers and are capable of creating a realistic, immersive soundstage that you can only get in a much more heavily treated room using conventional speakers, and even then, the CD speaker will soundstage better due to preserving the fine detail in the recording.

 

[andrew_stenhouse]

What is a CD speaker?

 

[DaveC]

What is a CD speaker?

Constant Directivity... i.e. waveguide/horn

 

[andrew_stenhouse]

Abit like near field listening then.

But yes - I agree.