Speaker placement within the room . .

I've been distracted for the last couple of weeks by yer domesticals so I haven't been able to give this subject the attention that I'd hoped I would.
I still don't really, but I thought I could copy something I wrote back in April 2009 (bloody hell....nearly 3 years ago) in a thread which (for other reasons) has now become one of those legendary things which is still discussed every now & then. (This mythical thread will be the subject of a 'From The Grave' in due course).

It was in response to a member's first photos of his system in The Gallery & we all universally pleaded with him to get his stand mount speakers off the floor & onto stands and with appropriate attention to their position in the room.
Anyway, here's what I said:





Get the speakers up onto some sort of stands & try experimenting with the positioning if you can. This will make the sound a little brighter & focussed. Even a pair of small tables will do for now - you can work on her for the stands later! If not you may try tilting them up a bit, so they beam towards ear height when seated.

Even without intruding into the room too much, there appears to be enough room to pull them away from the rear wall. You'd be amazed at the difference you may hear from doing just this.

In particular, listen to the bass - I would expect to hear differences in both quality and quantity depending on the position in relation to the rear wall. As you move them out you will reach a point where the balance of the bass weight & bass definition seem most correct to you.

Put 2 pieces of tape on the floor at the corner of each speaker (say the front / inside corner) in an 'L' - shape to define the placement so you can find it again if you need it.

Now do the same excercise, but this time listen out for changes to the soundstage. You'll find that the soundstage becomes deeper, the further away the speakers are from the wall. However, there will probably be a position when the soundstage begins to lose its 'focus'. This is easier for you to spot, than it is for me to describe, but you will know what I mean when you hear it!!

Again you will then be able to identify the optimum spot for this perameter - mark this with more tape. You now have what I think of as the 2 'polar positions'. Somewhere on or between these two, will be the perfect spot - but you'll find that later.

Now, leaving the speakers in the last position, try adjusting the toe-in. This is the angle at which they present themselves to the room (& your ears). Start off by just facing them straight out into the room at 90 degrees to the rear wall. Now compare this to a situation where each box has it's axis crossing at a point just behind you head. The easiest way to do this is to place them so you can just see the faces of the inside walls of each cabinet (in the case of your 'boat-tailed' speakers, you need to be seeing equal portions of perhaps the front 1/5th of the cabinet walls

Now listen & compare the two sounds you're hearing. You should hear differences in the sharpness of the sound & also your ability to hear what the different instruments are doing will be affected. There may be a further change to the soundstage definition and width and it will affect the relative positions of the players upon it. If you then play about with the degrees of toe in you'll find one where it all seems to snap into place.

If you notice a slight loss of clarity with the toe-in, then try moving them slightly further apart.

Now go back to finding you optimum position between the polars.

That would be my first move - I promise you that your set up isn't giving you what it's capable of!





I've found that working systematically to this method is the easiest way of getting the basics right. The fine tuning is the tricky, time consuming part, where you're moving things in tiny increments.

I like to live with them in what I think is about right for an extended period (a couple of weeks or more) before I get down to the real fine tuning stuff. In fact, this is exactly what I'm doing now as I've had to have a major system placement unheaval & I'm now able to place the speakers in the orientation I'd always wanted to put them in, in the first place - firing across the room rather than down it.

So do any of you folks have some thoughts on what I've copied above?

Quote:

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Originally Posted by The Grand Wazoo

I've been distracted for the last couple of weeks by yer domesticals so I haven't been able to give this subject the attention that I'd hoped I would.
I still don't really, but I thought I could copy something I wrote back in April 2009 (bloody hell....nearly 3 years ago) in a thread which (for other reasons) has now become one of those legendary things which is still discussed every now & then. (This mythical thread will be the subject of a 'From The Grave' in due course).

It was in response to a member's first photos of his system in The Gallery & we all universally pleaded with him to get his stand mount speakers off the floor & onto stands and with appropriate attention to their position in the room.
Anyway, here's what I said:





Get the speakers up onto some sort of stands & try experimenting with the positioning if you can. This will make the sound a little brighter & focussed. Even a pair of small tables will do for now - you can work on her for the stands later! If not you may try tilting them up a bit, so they beam towards ear height when seated.

Even without intruding into the room too much, there appears to be enough room to pull them away from the rear wall. You'd be amazed at the difference you may hear from doing just this.

In particular, listen to the bass - I would expect to hear differences in both quality and quantity depending on the position in relation to the rear wall. As you move them out you will reach a point where the balance of the bass weight & bass definition seem most correct to you.

Put 2 pieces of tape on the floor at the corner of each speaker (say the front / inside corner) in an 'L' - shape to define the placement so you can find it again if you need it.

Now do the same exercise, but this time listen out for changes to the soundstage. You'll find that the soundstage becomes deeper, the further away the speakers are from the wall. However, there will probably be a position when the soundstage begins to lose its 'focus'. This is easier for you to spot, than it is for me to describe, but you will know what I mean when you hear it!!

Again you will then be able to identify the optimum spot for this parameter - mark this with more tape. You now have what I think of as the 2 'polar positions'. Somewhere on or between these two, will be the perfect spot - but you'll find that later.

Now, leaving the speakers in the last position, try adjusting the toe-in. This is the angle at which they present themselves to the room (& your ears). Start off by just facing them straight out into the room at 90 degrees to the rear wall. Now compare this to a situation where each box has it's axis crossing at a point just behind you head. The easiest way to do this is to place them so you can just see the faces of the inside walls of each cabinet (in the case of your 'boat-tailed' speakers, you need to be seeing equal portions of perhaps the front 1/5th of the cabinet walls

Now listen & compare the two sounds you're hearing. You should hear differences in the sharpness of the sound & also your ability to hear what the different instruments are doing will be affected. There may be a further change to the soundstage definition and width and it will affect the relative positions of the players upon it. If you then play about with the degrees of toe in you'll find one where it all seems to snap into place.

If you notice a slight loss of clarity with the toe-in, then try moving them slightly further apart.

Now go back to finding you optimum position between the polars.

That would be my first move - I promise you that your set up isn't giving you what it's capable of!





I've found that working systematically to this method is the easiest way of getting the basics right. The fine tuning is the tricky, time consuming part, where you're moving things in tiny increments.

I like to live with them in what I think is about right for an extended period (a couple of weeks or more) before I get down to the real fine tuning stuff. In fact, this is exactly what I'm doing now as I've had to have a major system placement unheaval & I'm now able to place the speakers in the orientation I'd always wanted to put them in, in the first place - firing across the room rather than down it.

So do any of you folks have some thoughts on what I've copied above?

---

Often the simplest of questions have the most difficult of answers!

Chris has provided an excellent methodology to try and optimise speaker positioning. But rather than leave it there, it might be useful to look at some more fundamental aspects, if only in order to provide some sort of theoretical basis as to why these things ‘work’.

And by fundamentals, I mean choosing the room in which the speakers are used: the listening room. For most people there is little choice in which room is used. Few of us can enjoy the luxury of a separate, dedicated listening room. The usual choice of room will be the living room, a room which more often or not will house the television, and if your speakers are also to serve as part of your ‘home cinema’ system, then this can restrict freedom in positioning. But let’s put that ‘dual use’ to one side and just consider the room itself: its size, shape and how it is furnished.

I’ll start with furnishing first. Clearly the choice of décor and furniture is a matter of taste, but for most rooms there is an acoustically ‘live’ end and an end that is acoustically ‘deader’. Here we are talking about reverberation time (defined as the time taken for the amplitude to decay to -60dB). Acousticians will tell you that the reverberation time for a domestic listening room (as distinct from a recording studio or a concert hall) should be about 0.5 seconds. Actual measurement in situ requires specialised measuring equipment, but you can get some idea of the acoustic nature of the room by clapping your hands smartly together once, and listen to how it sounds. If the clap has a sort of ‘sting’ to it, then you are in an acoustically live part of the room. Conversely if there is no ‘sting’ to the clap, you are in a deader part of the room. Move about the room, clapping and listening to how it sounds.

Again, acousticians will tell you the sound source should be positioned at the acoustically lively end, with the listeners (the audience) sitting at the deader end. In a concert hall the environment around the stage, where the performers are, is sparsely furnished and walls, floor and ceiling are hard surfaces. The audience are seated in plush upholstered seats, and both their bodies and the upholstery absorb the sound providing a ‘deader’ acoustic. So too, if possible, the speakers ought to be placed in the livelier part of the room and the listening positions (the sofa and chairs) placed in the deader part. If you find the acoustic seems to be uniform through out the room, then as long as it is neither too lively nor too dead, then don’t worry about it.

Now to room size and shape. Unless you are fortunate to live in stately home in which none of the room dimensions are less than 20’ (and that includes floor to ceiling height!), then like it or not, the room will support half-wave resonances that lie in the audible spectrum. These resonances and their harmonics are unwanted and will add or subtract with the wanted tones. The nice smooth and flat frequency response boasted by the speaker manufacturer is anything but when used in most domestic situations. Since most of us have to put up with room resonances (sometimes called “modes”, or even more alarmingly: “eigentones”), the secret is to try and make it difficult for the speakers to excite these modes, and to dampen them down if excited. This is where the shape of the room and the speaker positioning come into play.

Without going into too much technical theory, the better rooms have unequal length, width and height. The worse rooms are cubic, because the three room modes are of identical frequency and so reinforce one another. Fortunately most living/listening rooms are not cubic in shape. It also helps if none of the surfaces are parallel.
Whilst it is unlikely that the walls will be non-parallel and will be reasonably ‘plumb’, some rooms may have a sloping ceiling: especially if the chosen listening room is in the loft. Deviation from parallel surfaces means the room modes are smoothed out to form a continuum, and whilst still unwanted, their effect is more benign.

Excitation of the half-wave room modes occurs easily if the speakers are placed half way between the two parallel surfaces. This is unlikely when it come to room width, or height, but could occur with respect to room length. If the speakers were perfect, the best position would be to place them in the corners of the room. However speakers are not perfect, and should you place almost any speaker in the corner the bass will sound ‘boomy’ (especially with rear ported designs). A good compromise is to place them about a third of the way down the length of room, with a minimum of at least 4’ from the rear wall. Of course some speakers are designed to operate in a corner, or flat against a wall, and in those few cases the manufacturer’s directions ought to be followed to start with. The most difficult speakers are those having a dipole polar response (where almost as much sound is radiated from the rear of the speaker as is radiated in front). All planar speakers have a dipole response and it is imperative that these speakers are placed no closer than about 4 – 6’ from a rear wall.

Floor to ceiling modes are not so severe, because unless you live in an all-concrete construction, the plasterboard, or lath and plaster ceiling is not totally rigid and so will dampen out the floor to ceiling mode to some extent. Furthermore, most rooms are carpeted and this will also help dampen the room mode.

Again many speakers are designed to be mounted on stands, off the floor. This is to improve the bass and to place the tweeters at ear level. Not so good for the floor to ceiling room mode, but this is not the worse mode to worry about. Sidewall room modes are best dealt with by placing the speakers a little away from these walls: say 2’. If you have floor-standing speakers wherein the tweeters are not at ear level, it can often be beneficial to tilt the speakers up so that the direction of the tweeters point at ear level at the listening position.

The worse room mode to deal with is that due to the length of the room. Worse still, many rooms will have large windows at each end (one might even be a floor to ceiling, wall to wall patio window!). If your room is like that, all is not lost, as heavy curtains will reduce the acoustic hardness of the glass – one reason why some systems sound better after dark when the curtains are drawn. The positioning of the speakers is critical in this respect. Follow Chris’s instructions to find the best position for bass quality and depth of soundstage as regards your listening position. With the speakers facing forward, an optimum position will be found at least for one listening position; the ‘hot seat’

Unless you are either single or anti-social, you will want to arrange matters so that a good wide and deep soundstage is available to other listeners. This is where ‘toeing in’ the speakers can help. This is the Hugh Brittain technique, which I won’t burden you with, but essentially it makes use of the loudspeaker’s directional effects. It is usually found that the widest listening area for an acceptable stereo effect occurs when the speaker axes cross over a couple of feet in front of the listeners, themselves seated roughly about as far back as the speakers are apart; making an equilateral triangle.

Again none of this is ‘set in stone’ – you will have to make compromises and all systems/rooms are different, but these are at least guidelines. You will have to do a fair amount of iteration by trial and error; making small adjustments, listening, making further adjustments and so on … But given time and patience, positions will be found that sound best to you. And that is what it is all about, having found the best position don’t worry if the actual positions are nowhere near as described – they are only guidelines.

A good read from one of the U.K.'s most controversial audio nutz.
http://www.audionote.co.uk/products/...lacement.shtml