yep its a benefit - but in my experience one is still talking serious change for the headphones and suitable amp/source - but yes i put in an approx ratio of about 1 to 5 ~ 8
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Oh yeahā¦ Empy, TT2 + MScaler + Infected Mushroom / Iām the Supervisor (trance) for my 1st day back at work and itās certainly blowing away the cobwebs!
NF for me is like a big walk in pair of headphones but with big air and soundstageā¦ massive energy etc. However, not very practical if you want to share the experience.
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Dips are usually caused by SBR which is caused by standing waves generated by the interaction of the room and speakers. the phase of the bass reflections and direct sound are cancelling each other out at those Freq. All speakers suffer from it to some extent. You can try and move speakers to compensate for it but its hard to remove completely. Closer to the wall can help but then can boost bass too much and dependant on the freq it occurs wonāt be enough to eliminate it. Further away moves it up the frequency response where it comes less noticeable as it only effects bass regions as they unidirectional where higher up is more directional and has less standing waves. Modifying the room and sound mods are the best to tackle this but. The hf is likely down to first reflections, toe-in reduces the effect as its changing the angle as which it happens so they are reduced or hit after the initial direct sound.
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Excellent summary. Get the distance to walls correct for the room and speakers, toe in and it can make a massive difference. When I first started playing around with speaker position and got it right for the room it was like a free upgrade. Itās about getting things in proportion for the room and avoiding first reflections for HF.
iĀ“ve also notice a matter of taste*: we have opposite ones:
you prefer headphones>near field> xtended field .
iāll prefer the inverse.
But granted: all approachs have compromises.
*good taste: after all, we are here under the Naim umbrella 
i was not stating preference so much rather more where performance excelsā¦ extended field listening has a lot going for it - and is probably the most accessible way to listen in my listening room - if I really want to get under the skin of a recording then headphones or more near field it is.
But yes our tastes vary - and for me one size doesnāt fit all.
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Thanks JSA, that looks like an interesting link. Will need time to experiment, though. 
I have a roughly 2.5m equilateral triangle with my Tab 10 Signature and get a beautiful big rich bass that truly defies their size.
G
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Toonartist, an interesting idea. My CD system is in the study with the speakers either side of the desk. They have twin rear ports and are close to the wall, bass is strong, although the whole sound is better if I push the chair back 3 feet or so when reading rather than typing.
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Graeme, good to hear your voice! I always used to subscribe to the equilateral triangle. I was partially influenced by our music teacher at school who had pencilled in a cross on the ceiling above the sweetspot in the classroom. I experimented with different listening positions when I could, and so became attuned to the vagaries of listener to speaker distances, symmetry and speaker angles.
I have played around with Russ Andrewsā theories about keeping the speakers as far apart as possible, but this approach can lead to some odd responses and to my ears reduces precision and bass reinforcement.
Linnās own advice about the distance Keilidhs like from the rear wall are a good rule of thumb and starting point, but that Mid bass 120Hz muddying point is overcome largely by moving them out a bit more from the rear wall and corners.
I guess what Iām asking is whether or not there is any mathematical basis; a formula / ratio perchance, which can explain and identify the different modes where bass will be reinforced or weakened. For example; āevery 5 metres there is positive reinforcement; every 2.5 metres there is destructive interferenceā, or some such? Is there such a simple rule of thumb?
Of course the final placement will be influenced by room dimensions, furniture, speaker capabilities and system resolution, but it was the mathematical/physical principles I was primarily interested in.
The halls of Valhalla have their own peculiar resonances! 
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I spent a lot of time mucking around with speaker and sitting positions. I didnāt want to get too close the wall behind me as Iād start hearing reflections from it. Soā¦ once I had at least 75cm of space behind me and the speakers were 50cm in front of the wall they were up against, this sort of set the speaker width for me along with distance from side walls.
I guess when you have a small space to work with, it really helps to focus the mind on squeezing every last drop of sound improvement from positioning. My early mistake was setting the speakers too far apart thinking it would give a better soundstageā¦ the opposite was true. The wider the speakers were apart, the more likely it would introduce reflections from other parts of the room.
Once I established a max of a 4ft triangle, I was able to move that triangle forward/backwards until the bass was just right. This meant I had great bass and detail but also a soundstage that wraps around me. Some instruments can sound like theyāre behind meā¦. itās like sitting in a big pair of headphones.
At one point, I had small room syndrome and decided to move everything down into the living room. After what seemed like an age setting it all up I was somewhat disappointed with it. Yes it sounded really good but, I lost that intimacy of being right in the music. It was all shifted back into the small room asap. I will, at some point, add a system into the living room but it could never replace my NF listening system.
Ultimately, I donāt believe there is a hard and fast rule for distance from speakers. Room and speakers will dictate to a large degree where you sit in order to get the right balance of bass, detail and soundstage/imaging. No point in setting a distance if that distance only works in a room that is bigger than the one youāre in.
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Never a truer statement. I cant postion the speakers or my listening postion in whats considered the best place, but I have optimised it as much as I can and I am happy. I dont live in a recording studio so acoustic treatments are out. I did use DSP for a while with my old speakers, but when I changed to the tab 10 sigs this has not been as necessary. I might go this route again and get some new filters made by HAF as it wont cost much to update them as it might just make it all fit even better.
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Yes there is. But it is primarily room dimensions (width, length and height, simple in a rectangular room) and your position in the room rather than speaker-listener distance.
The wavelength of any frequency is the speed of sound (343m/s) divided by the frequency, so 50Hz = 6.86m.
There will be a standing wave with a room dimension between parallel walls (or floor and ceiling) of half wavelenth distance (3.43m at 50 Hz). That will give maximum amplitude in the centre of that room dimension.
There will be another at a full wavelength (6.86m at 50 Hz, with a null (no sound) in the centre of the dimension and two points of maximum amplitude at 25% and 75% of the dimension. Or the other way round a 3.43 dimension will have that full wavelength standing wave at 100 Hz, wheras at 50 Hz there will be a maximum amplitude in the centre of the dimension there will be no sound at 100 Hz.
Fortunately the other two dimensions are usually different, unless a cubic room, so you donāt get complete cancellation nor enhancement.
This basic physical relationship is what leads to the recommendation of 38% of room distance from front wall to back wall as an ideal listening spot (or 38% from rear wall, but that has negatives from rear reflections).
Look in the thread linked from my post number 3 in this thread - at least a couple of the links in that thread have calculators allowing you to enter room dimensions and see a plot of the various nodes. There are also various different recommended processes for determining likely best positioning.
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Sh#t.
This ( the explanation that followed) was game over for me.
Thank you IB. That is exactly the information I needed and may help explain the reinforced bass at a point just over half way (60%?) down the rectangular room from the speakers (firing lengthways). I guess the usual spot is roughly 38% down the great listening chamber.
Incidentally, is there a mathematical correlative here to the way in which guitar strings resonate, and the sweet spots for playing harmonics can be found?
I am interested on how you settled on 4ā as your optimum measurement? Was it just a matter of that particular room or that particular set of speakers or both?
The answer there is again yes, and is based on the same principles, though it would take some time calculating (of course a spreadsheet would simplify).
Many years ago I made myself a bass guitar, and calculated the fret positions: IIRC I calculated the speed of sound in the string, using the frequency of the fundamental and open string length (half wavelength, lowest frequency standing wave). Then using the speed of sound in the string and next note frequency I calculated the required new length and thus fret position.
It would be the same process, but the harmonics would be full wavelength, 1.5 wavelengths, 2 wavelengths etc, and use those to identify the positions of null points for harmonics of interest.
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Size of room really and then bought speakers to fit system. Once I decided to build the system in a small room, I read up about near field listening and went from there. At the time websites for NF recommended around 3-5 feet from the speakers. I did try 5ft to begin with as I had enough room for that but as I reduced it down to 4ft it sounded Better. I would have tried 3 - 3.5ft but furniture layout wouldnāt allow.
This was setup by the time I bought my current speakers and I emailed PMC for their advice explaining the room size and NF. They advised the Twenty5 22 would work well in that environment and shouldnāt have any issues with bass. PMCās Laminair front ported bass with ATL really works wonders in a small room.
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The ante room to Valhallaās main hall is 4m (13ā) x 8.5m (28ā)
Toed-in Keilidhs are: 2.4m (7.9ā) apart (inner closest edges) and 27cm from rear wall
Listening position is 3.2m (10.5ā) from speakers.
If that is āfiringā across the room width, I think the listening position may be far too close to the back wall unless there is very heavily absorbent material on the wall behind the listener. Firing down the length of the room would be different