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Near Field vs. Far Field

MartinC

pfm Member
Having a room that doubles as an office and listening room and therefore doesn't have to abide by any WAF's I decided to play around with near field speaker placement and compare it to the more usual (at least for domestic environments) far field arrangement.

Speakers, Ergo IX) were placed around 4' from the back wall and set apart around 6' with the listening spot forming an equilateral triangle and toed in a bit. I kept the sub against the back wall.

The Ergo's throw a very pronounced soundstage so I wasn't expecting a massive change but perhaps a slightly harsher balance with the speakers being only 6 feet away. Interestingly it was the other way around, some of the harshness that is evident on certain recordings seemed reduce, soundstage was improved and every aspect of the recording felt better, not by a huge amount but certainly noticeable. I was also surprised that bass did not reduce noticeably with the Ergo's that far away form the rear wall. Overall impression was positive, and sonically seemed closer to listening with Stax electrostatic headphones.

Obviously near field setup isn't practical in most environments and my guess is that small speakers with drivers set close together are most suited.

Anyone else compared near field vs far field?
 
Anyone else compared near field vs far field?

I’ve been lucky enough to have relatively large rooms for my hifi for many years, with no real constraints on where I put my speakers. I’ve always found near field - 6’ equilateral triangle give or take, speakers and me well away from walls - gives the best, most immersive, uncoloured and satisfying result. The closer you are to your speakers the more the direct sound dominates, rather than the room.
 
Anyone else compared near field vs far field?
At the risk of appearing a pedantic curmudgeon the misuse of the technical terms near field and far field by audiophiles is irritating. Listening at 6' with 1' speakers you are not close enough to be in the near field (which would be undesirable anyway in terms of sound quality) and the room boundaries prevents the establishment of the speaker's far field. If you were to listen in a large empty space or an anechoic chamber apart from level there would be little difference in what you heard at your two listening distances but in a room it is likely to be substantial because of the presence of the room not the speakers sound field although the two obviously interact.

If you sit close to speakers in a room it tends to make the sound clearer by making the direct sound louder relative to the reflected sound. This can be beneficial for some studio created music but can also be detrimental to other types like orchestral music where higher levels of reflected sound tends to be expected due to being closer to what is heard in concert halls. However, the quality of the reflections matters in the latter case with poor quality reflections likely to make the sound quality worse not better. Improving the quality of the reflections in a small room is an interesting and challenging task which can only be of limited success compared to what can be achieved in a larger room.

Moving speakers away from walls reduces the low frequency reinforcement by the wall behind the speakers but it also changes a bunch of other things as well. The cancellation dip due to interference of the direct sound and that reflected off the wall behind changes frequency, magnitude and the significance of harmonics. The room modes are driven differently with some being louder and others quieter changing the character of the low frequency response heard. Whether for the better or worse in terms of sound quality will depend on the details of what is going on.

One factor which is likely to be relevant is if the crossover in your speakers is designed for wall placement or out in the room?
 
Moving speakers away from walls reduces the low frequency reinforcement by the wall behind the speakers

Doesn't this depend upon the design of the speaker? You'd never put rear ported speakers anywhere near a rear wall and conversely, Briks should be as close as poss. Folded horns, corner horns, I.B., front ported and ESLs all have their preferred approximate placement.
 
I sit about 5’ from my LS3/5a speakers and they’re about the same distance apart, with quite a bit of toe-in and about 3’ from the wall behind them. Roughly the same position I had my Harbeth M30.1 in. I wouldn’t want to sit much further from speakers than this, things get too diffuse for my liking.
 
Doesn't this depend upon the design of the speaker?

Not usually. At low frequencies the sound radiation is pretty much uniform in all directions and so moving away from the wall allows more sound to radiate rearward reducing the amount radiating forward. This excludes rare radiation patterns like cardioid which radiate no sound rearward.

You'd never put rear ported speakers anywhere near a rear wall

You would need to avoid blocking the port and if the distance from the wall is close to the port diameter it will have the effect of lengthening the port and changing the tuning frequency (speakers with down firing ports often take advantage of this). Otherwise they are no different to any other type of speaker.

and conversely, Briks should be as close as poss. Folded horns, corner horns, I.B., front ported and ESLs all have their preferred approximate placement.

Indeed. All competently designed speakers without tuneable crossovers can only have one preferred location relative to close wall/s (free, wall, edge or corner).
 
When my son was at home he had a shelf above his desk with two old Mission speakers on it. Small ones. From the other side of the room it didn't sound too great but sitting at the deck it was amazing. The speakers were a couple of feet from your head and it was like listening to the best pair of headphones you've ever heard.
 
@h.g. IME, with the exception of the front wall / rear wall axial mode, the flattest bass response is achieved when the speakers are placed hard against the front wall. As I move the speaker away from the wall, the dips in the mid- and upper-bass (e.g. between 60Hz and 300Hz) get worse. The Room Simulator in REW shows the same effect. Is this what you would expect?
 
@h.g. IME, with the exception of the front wall / rear wall axial mode, the flattest bass response is achieved when the speakers are placed hard against the front wall. As I move the speaker away from the wall, the dips in the mid- and upper-bass (e.g. between 60Hz and 300Hz) get worse. The Room Simulator in REW shows the same effect. Is this what you would expect?

In the sense of picking the least worst option then broadly yes. Genelec have a useful summary here covering this and other aspects. However, a speaker genuinely designed to be placed against a wall (which is rare) will almost certainly out perform a conventional one designed without this as one of the objectives. The main problem with a conventional speaker flat against a wall is the hole in the power response as shown in the first post here. Removing this is what a speaker genuinely designed to be used against a wall will do.
 
6' 6" triangle here.

about 2' from the wall, approx. 3'+ from side walls.

Seating position is 2' from the back wall, on a 3 seater sofa. Ideally I would have a single seat comfy armchair here, but the sofa is the only seating in the room, and I need to be able to fit 3 bums in the room.

I did listen for a while on a single seat chair, it sounds better re:soundstage. Something to do with reflections off of the sofa maybe?

One thing I don't like in the 'triangle' is coffee tables etc. I like the sound to have a relatively clear path.
 
What would you define near-field as? And far-field?

This is how it is sometimes roughly defined but context matters (i.e. the purpose for distinguishing the regions). In the link a location is either near field or far field but often there is a gap between the two which is neither near field or far field. This is usually because in the near field you want a set of assumptions related to the propagating and non-propagating waves to hold sufficiently to determine acoustic quantities sufficiently accurately. Similarly in the far field you may want a different set of assumptions to hold sufficiently. This doesn't look like a particularly good paper (not read) but was the first thing google threw up that is reasonably relevant to give a feel for the types of assumptions that people use when they need to locate the acoustical near and far fields sufficiently well to evaluate acoustical quantities via simplifying approximations.

PS A monopole (radially pulsating sphere) will often be described as having no near-field due to no recirculating waves.
 
This is how it is sometimes roughly defined but context matters (i.e. the purpose for distinguishing the regions). In the link a location is either near field or far field but often there is a gap between the two which is neither near field or far field. This is usually because in the near field you want a set of assumptions related to the propagating and non-propagating waves to hold sufficiently to determine acoustic quantities sufficiently accurately. Similarly in the far field you may want a different set of assumptions to hold sufficiently. This doesn't look like a particularly good paper (not read) but was the first thing google threw up that is reasonably relevant to give a feel for the types of assumptions that people use when they need to locate the acoustical near and far fields sufficiently well to evaluate acoustical quantities via simplifying approximations.

PS A monopole (radially pulsating sphere) will often be described as having no near-field due to no recirculating waves.
I’m not sure that is a relevant definition. Defining “near-field” in that sense as less than two wave-lengths away could mean a very long way indeed. I think in the context of a recording studio near-field is generally understood to be on the top of the monitor console - ie around 4’, perhaps a little closer for small boxes, perhaps a little further for speakers used on stands behind the console. This constrasts with more distant, typically soffit mounted, loudspeakers. Here is a wiki which gives the history and the normally understood range, 3 - 5 feet for small speakers, perhaps a bit more for larger ones. It follows that when speakers are used close to the listener they will often be a meter or two away from walls, which has all sorts of benefits to do with intelligibility, lack of colouration etc.
 
My music room is only about 5m x3m, or just over.
I did try my speakers (Focal 1028be’s at the time) firing across the shorter dimension, so allowing for them being away from the wall a bit, maybe they were only 5 or 6 ft from my ears. Does that qualify as “near field”?
It was an experiment, just to see if it sounded better having them close to me, but benefitting from being well away from the side-walls........ taking the room out of the equation to a large extent, or
in a more orthodox fashion firing down the longer dimension, so 8 or 9 ft away from me, but closer to the side walls.
The Near Field gave some pluses, some negatives. Plenty of detail, separation, & unsurprisingly maybe approaching a headphone type experience. The flutter echo I had in the room was much improved.
Ultimately though, it was just too close & cramped feeling, so I reverted to them firing down the room & accepting the fact that the side walls will influence the sound. Adding some GIK acoustic panels mainly for taming the flutter echo & controlling the 1st & 2nd reflection points helped.
I now have active ATC SCM40’s in the same room & I’m very happy with how it all sounds.
Like many things in life, most of the time there are compromises with either set up, not definitive rights & wrongs. It’s just getting it right for the individual as best you can.
 
I'm more of a mid-field kinda guy.
Interestingly a near field measurement as discussed by Keele, Small et al is usually within 1/10 the diameter of the cone piston but in commonly used terms within recording studios it is used to define the size and capability of the monitor ie Near field/on the meter bridge 2m away, Midfield 2 to 4 m from the listening position and Mains/stand back and run for cover.
No need to get into a Dougal and cows situation....
 
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I’m not sure that is a relevant definition. Defining “near-field” in that sense as less than two wave-lengths away could mean a very long way indeed.

Near field is the region containing non-propagating as well as propagating waves. Far field is only propagating waves. Where the regions begin/end is to some extent up for grabs but the definition of what they are isn't or at least not in a technical sense. It is a concept used for all types of propagating waves not just sound waves.

I think in the context of a recording studio near-field is generally understood to be on the top of the monitor console - ie around 4’, perhaps a little closer for small boxes, perhaps a little further for speakers used on stands behind the console.

But why call it "near field" which is an existing acoustical term that doesn't match causing confusion/irritation for those familiar with the technical term. Why not call it something like "close field" which seems to be just as technical sounding but won't cause confusion/irritation? The article you cite seems to want to use the word close rather than near despite having to acknowledge that nearfield is the term widely used.

Anyone aware of the first/early use of the term nearfield monitor? I am guessing it is likely to have come from the marketing side of things.
 
Near field is the region containing non-propagating as well as propagating waves. Far field is only propagating waves. Where the regions begin/end is to some extent up for grabs but the definition of what they are isn't or at least not in a technical sense. It is a concept used for all types of propagating waves not just sound waves.



But why call it "near field" which is an existing acoustical term that doesn't match causing confusion/irritation for those familiar with the technical term. Why not call it something like "close field" which seems to be just as technical sounding but won't cause confusion/irritation? The article you cite seems to want to use the word close rather than near despite having to acknowledge that nearfield is the term widely used.

Anyone aware of the first/early use of the term nearfield monitor? I am guessing it is likely to have come from the marketing side of things.
People who work in studios aren’t short of technical competence, and have no difficulty sharing the understanding that near-field means, in their world, something between arms length and about twice that. And that is the sense that is being used here. There is no need for it to cause any irritation unless you are irritable. A farmer might think near-field means something different, as would a guy that designed radio antennae, and a mathematician something completely different again. There is no need to be irritated. The meaning is pretty clear given the context.
 


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