Why does Soundstage Depth and Width Change with Toe-in?

[jaybar]

Hi

I have been playing with speaker toe-in. When I move from no toe-in (speakers parallel to the side walls) to on-axis listening, where the speakers are pointing more or less at me, I find that the sound stage width decreases, while soundstage depth increases. Why does this happen?

While I am using the Monitor 30's, I have found this to be the case with most speakers in my room. I am assuming that Harbeth speakers are designed for on-axis listening.

Thanks in advance.

Jay

[DSRANCE]

Alan will come up with a genuine scientific answer for this, but whereas I used to have the speakers slightly too close if anything, a customer showed me that if the speakers are facing you "on axis," then moving them slightly further apart does little harm, even though the "equilateral triangle" idea is scrapped.

An extreme version of this was with a pair of huge Klipsch corner horns, in the corners of a slightly "long" room and the listener listening across (room was about 18' by 13'). The soundstage was palpable and these speakers sounded superb with a Quad 99 system driving them (the whole much better than the supposed sum of the parts)...

[A.S.]

I think that it is not possible to give you a completely factual reason for this and your experience may be different to others - or the same.

The key point to remember is that stereophonic reproduction at home is an illusion. It is a trick played on the mind by the ears. It is entirely in your brain that the magic of width and depth is created from two loudspeakers. How this precisely works I don't know, but I do know that the notches, cavities and protrusions that define the shape of your outer ear all have an important part to play in directional location.

Occasionally my wife asks me to peg out the washing on the washing line in the garden. It is over a hard pathway. Quite often there are aircraft at about 5000 feet making a circuitous approach to a nearby airport. It always interests me that when they are passing overhead, if I bend down to the washing basket that there is a audible phasiness to the sound of their engines - a swooshing in the tone. If you bob up and down you can clearly hear how the ear uses the reflection from the ground to tell your brain that the noise (of the plane) is up high above in the same way that the shape of your outer ear tells you that birdsong is (generally) associated with birds in trees. Try it yourself but you must be on a hard reflective surface, not grass.

We are not conscious of these reflections but they form a critical part of our 3D location system. And if we did not have this inbuilt audio location capability we would not be here today discussing this point: our ancestors would have been eaten by predators.

[tinears02]

Hello

How then, does a listener 'know' what the right amount of
toe-in is? Or how 'deep' or 'wide' the soundstage should be?
I have had folks tell me my Harbeths should be firing straight
down the room, others have advocated speakers facing me, and
then there are those who recommends everything in between
(including a Harbeth dealer).
In each case, the soundstage and the front-back positioning of
the musicians are different.
I hve experienced two rather distinct characteristics - one
where the instruments and voices are clearly delineated and the
other where orchestra 'gels' more coherently. The former is
usually heard when the toe-in is more and the latter when
toe-in is less. Unfortunately, I hv no idea which is more right,
pointers to the right direction to go?

Thanks in advance,
yh

[jaybar]

I hope Alan or Others can answer the questtions posed by YH. There must be a way of coming to a "right" answer regarding toe-in.

Also does listener distance from the speakers have anything to do with it?

I tend to listen nearfield.

Thanks,

Jay

[A.S.]

Really! You are both worrying far, far too much! Do what seems right to you. This question of 'what is best' cannot be answered scientifically because there are so many variables, including where the microphones were positioned, the shape of your outer ear etc. etc. etc.. I have already stated in my previous post here, stereo imaging is an illusion. It is entirely a construct inside your own brain. Your brain (somehow) builds a mental model by mapping the sound that you hear over your speakers via your two ears to those that you have previously experienced in real. All this exposure is knitted together into a sonic model that allows you to imagine in your head how performers were arranged in 3D space at the recording venue. But the person sitting next to you may have a radically different mental model. Wives, for example, frequently cannot understand or appreciate their husbands fascination with hi-fi - they are entirely happy with the kitchen radio. This is because they have a very different mental model of how music sounds.

Your brain creates a sonic database before birth and refines it throughout your life according to your sonic experiences, the concerts you have attended, the types of instruments you have heard, different acoustic environments etc.. If you have never been to a live concert, never heard a live instrument but only been exposed to sound via a cheap radio you would have a very different mental sound database to draw experience from. Conversely, if you are a professional musician living and working with your instrument, you may find it impossible to listen to hifi sound. Many professional musicians seem perfectly satisfied with very modest low-fi audio equipment at home.

Throw the grand theory out of the window - what is right for your brain, your room, your music, your taste is right. Go with what sound best to you.

P.S. I strongly recommend that you make an effort to go to live (classical) concerts where the instruments can be heard live, not via a PA speaker system.. Your concept of stereo imaging, depth, perspective etc. may well radically change after such exposure. For one thing, at a real live concert, you will find that 'pin-point imaging' and great depth does not exist. What you experience live is a wash of sound .....

P.P.S. The fact that different people have different exposure to live sound - and hence, a different internal sonic database in their brain to draw on - makes the business of hi-fi reviewing rather problematic. When we read a hi-fi review, there are so many unknowns for us, the reader, to contend with. Not only have we no exposure to the equipment under review we don't know about the reviewer's associated equipment, his room room, his musical taste or his previous exposure to live music (if any) and how sophisticated his mental sonic look-up table is. However, one thing we all do know about is speech since we are surrounded by live speech all our lives even if we have never seen or heard an instrument. That makes speech an excellent test material for evaluating loudspeakers.

[Pluto]

I would add to this by supporting the use of mono material to assist in the evaluation of speakers - simple speech is once again ideal. Sit in the classic apex between the two speakers and ask yourself if you have an image so solid that it could almost be emanating from a non-existent centre speaker. If the image sounds soggy, blurred or in any way insecure, it is likely that you are hearing the result of reflections off nearby surfaces (or there is a mismatch between the speakers). Until a system can pass this simple test with ease, all other bets regarding imaging are off.

As Alan has stated, imaging is entirely an illusion created by giving the auditory system certain "hints" that relate to our life-experience. For instance, by adding artificial reverberation it becomes very easy to create the illusion of distance (or depth), because we associate the hearing of large amounts of reverberation with great distance between the listener and source. A lot of work has been done on creating images that appear to emanate from beyond the arc subtended by the speakers. This is done by creating certain artificial phase / frequency relationships that sometimes fool our auditory systems ino believing that they are having an "out of the box" experience! But such tricks tend to affect people in unpredictable ways, hence they are not part of the everyday armoury available to producers.

I get concerned when people believe that electronics such as amplifiers and CD players have properties that can affect stereo imaging. Any equipment designed for stereo use is built so that the two channels perform identically in every respect. It is only when a difference exists (phase variance for argument's sake) that the equipment can affect the imaging outcome. It goes without saying that any equipment designed competently with stereo in mind should have its two channels matched with exquisite accuracy, and only if that match is less than perfect can the equipment degrade the illusion of image. It is important to understand that nothing can be done electronically to improve the imaging if the two channels are perfectly matched.

[David Schalkwyk]

I second Alan's point about the illusion of soundstaging, and the importance of going to live music. But the experience of live music isn't always simple.

I went to a concert a couple of months ago of a symphony orchestra playing two romantic pieces (concerto and symphony), one before and one after interval. The hall seated about 800 people and was purpose-built and designed for classical music. My tickets were in the front row, but I arrived late and had to sit in the back row until interval. Listening to the music was a strange experience. There was little sound-stage to speak of. The sound seemed to pass over my head and then rebound, so it was both dull and overwhelming, especially in the bass. Brass was too loud and harsh; woodwinds and strings distant and soft. If I'd been auditioning a pair of loudspeakers I would have crossed them off the list at once.

After interval, in the middle of the front row, the experience was very different. I seemed to be in the middle of the orchestra, with an immense soundstage, both in depth and breadth. Balance was better, but one tended to hear individual instruments rather than groups. It was an amazing experience (Sibelius 2), but not really natural.

So, even live music has no natural sound. It depends on where you are sitting, the design of the hall, the kind of music you're listening to, the balance imposed by the conductor, and, I suppose, one's mood--one's receptivity to what is happening. And we talk about an accurate reproduction of an original event. There were at least two, totally different, events happening at the same time in the same space.

David

[A.S.]

...There were at least two, totally different, events happening at the same time in the same space {at the concert hall, depending upon your seat}

Indeed. Imagine a situation where listener A habitually sits in the front row; he would have programmed himself with the expectation of an orchestra sounding immediate, with lots of attack and presence. Conversely listener B, frequenting the back of the hall, builds a mental model of sound swimming around him - a wash of sound - with no precision, no imaging and (to our ears and taste) a very strange balance across the orchestra*. Take those two individuals to a hi-fi shop and little wonder that they would express quite opposite tastes in loudspeakers. Each would truly believe that his speakers gave him 'the concert hall experience' and both would be right.

For this reason, I strongly resist marketing that says 'these speakers are the best in he world'. The very idea is ludicrous. The listener's perception of what makes a great loudspeaker wholly depends upon the listener's expectations. And we build sonic expectations over a lifetime as we hone and refine our mental model depending upon our exposure to sound in our environment.

But at least we here are crystal clear about what we are trying to achieve - an experience akin to, say, the 7-12 row in the hall. Harbeth has the traditional, proven technology to deliver exactly that. Perhaps, as I've mentioned, not to everyone's taste (because of their different expectations) but certainly to sufficient home and professionals listener's tastes that we can run a viable, vibrant business.

P.S. I should add another observation. As sound travels through air, the high frequencies are progressively absorbed. You can calculate by how much according to the distance from the source (and probably temperature and humidity too) and the absorptive nature of any objects the sound wave impinges upon such as walls, chairs, people etc... So, listener B, at the back of the hall would experience significantly less high frequencies simply because he is further from the instruments than listener A at the front. As the audience absorbs HF, and the hall acoustics also does, overall B hears less sparkle in the high frequencies and attack in the lower treble than A. But to both A and B, if these are their preferred seats, that is how an orchestra sounds to them. Could one hi-fi system completely satisfy A and B listening at home? It's unlikely.

[Ned Mast]

David's experience recently at a live orchestral performance was interesting. My first thought, though, is that an 800 seat hall is rather small for a full orchestra. I would think more appropriate for a chamber orchestra. We have a wonderful 600 seat hall at our local universtiy that is good for chamber orchestras, but I think is too small for large orchestras doing music since the classical period. Our new downtown concert hall, on the other hand - which seats 2200 - is marvelous for a full orchestra, but the hall can be tuned for smaller grouops. My experience hearing two concerts there recently done with the Cleveland Orchestra was absolutely thrilling, and I was sitting towards the rear of the hall in the second balcony. The clarity was wonderful and the balance of instruments equally wonderful. Out of curiosity, the following morning I played a recording of one of the works from the live performance (Dvorak's Symphony from the New World) to compare my memory of live vs recorded as it sounds in my room. What surprised me was that - in trying to match the volumes or the live and recorded performance - two or three times I found myself getting up to turn the volume DOWN to match the level of the live performance. The volume of the live music was definitly not high from my seat, but was nevertheless thrilling. I attribute that to the excellence of the orchestra; music played with rhythmic precision, in tune, with subtle gradations of dynamics can draw the listener in even at lower volumes.

[David Schalkwyk]

Ned's right that the hall is a bit small. It's probably more like a 1 000-seater, but the primary purpose was indeed conceived for chamber ensembles.

Last night threw up another, similar experience, this time in our Edwardian City Hall (probably 2000 seats), where I sat about 20 rows back, just below a large balcony, while my son sat a futher 4 rows behind me, under the balcony. My experience was fine. It was a perfectly balanced performance of the Sibelius Violin Concerto, but with little sense of individual instrumental texture. My son found the sound "muffled".

After interval, however, the orchestra played the Shostakowitch Symphony No 12 so loudly and intensely that 1) I found my ears hurting, 2) I knew that nothing I had heard in the hi-fi world could begin to reproduce the sheer intensity of sound. This morning I've stuck to solo instrumental music through the Compact 7s. I don't even want to try to reproduce a full orchestra for at least a few days!

David

[Sebastien]

... at a real live concert, you will find that 'pin-point imaging' and great depth does not exist .....

At a live jazz concert, you will. Even more if it is a small trio, quartet or quintet for example.

Sébastien

[STHLS5]

.... This question of 'what is best' cannot be answered scientifically because there are so many variables, including where the microphones were positioned, the shape of your outer ear etc. etc. etc.. I have already stated in my previous post here, stereo imaging is an illusion. It is entirely a construct inside your own brain. Your brain (somehow) builds a mental model by mapping the sound that you hear over your speakers via your two ears to those that you have previously experienced in real. All this exposure is knitted together into a sonic model that allows you to imagine in your head how performers were arranged in 3D space at the recording venue. But the person sitting next to you may have a radically different mental model. ......

[/U][/I][/B]P.S. I strongly recommend that you make an effort to go to live (classical) concerts where the instruments can be heard live, not via a PA speaker system.. Your concept of stereo imaging, depth, perspective etc. may well radically change after such exposure. For one thing, at a real live concert, you will find that 'pin-point imaging' and great depth does not exist. What you experience live is a wash of sound .....

P.P.S. The fact that different people have different exposure to live sound - and hence, a different internal sonic database in their brain to draw on - makes the business of hi-fi reviewing rather problematic. When we read a hi-fi review, there are so many unknowns for us, the reader, to contend with. ...

A friend brought over his church choir test CD and described to me how he could hear the exact locations of the children and the adults listening over my SHL5. According to him, he could pin point the children singing in the front row and the adults (much louder) at the back.

I perceived it differently, i.e. the children at the back and the adults much closer to me. Out of curiosity, I asked my 12 and 8 year old children to pin point to us where the singers were and they pointed out that the adults were much closer to them.

My friend is exposed to church choir, perhaps, on weekly basis. Could he be filling in non existent information of the placement based on his experience in seeing and listening to live church choirs? Guess, we all listen very differently.

ST

[STHLS5]

Could he be filling in non existent information of the placement based on his experience in seeing and listening to live church choirs? Guess, we all listen very differently.

On further discussion with my friend, he mentioned that he sensed the depth of the singers based on the reverberation in the adults singing which to him indicates they must be further deep inside of the stage. This is exactly opposite of what I perceived. My brain draw a false image of the adults being closer to me based on the louder voices.

Now, why to untrained ears we could not sense the reverb for localization. Is this a skill that one acquires over time with experience? Recently, it was pointed out to me that there were more reverbs in one recording than the other but unfortunately I am unable to discern the difference.

ST