Speaker Placement and Room Coupling

Speaker Placement and Room Coupling

A group of top Hong Kong audiophiles has just ended their hifi auditioning tour of Klang Valley, Ipoh and Penang. The group is led by Top guru, Ivan Li. For those of us who is not familiar with Room Coupling theory, here is an article by Ivan Li on Speaker Placement which was published sometime ago. Enjoy!



PANEL SPEAKER PLACEMENT & ROOM
COUPLING 15-4-2007 by Ivan Li

Few of us, except perhaps the rare species of odd fossils of the pre-historic
era, would have questioned the paramount importance of speaker placement
nowadays. What is more debatable is where and how the speaker positions are to
be determined. I have been a faithful follower of the room-coupling school and
I believe that should be the best way out.

Room coupling, I am quite positive by now, really goes beyond the deliberations
over direct verses reflected sound sources, because the focal point remains
relatively constant irrespective of what damping treatments we have on the wall
surfaces in any given room. This focal point does not seem to move until the
dimension of the room is drastically changed.

To achieve effective room coupling, one has to locate the focal spot of the
room first. There is a simple yet effective method to find this spot but I
shall come back to that a while later. Every room has its own peaks and valleys
acoustically. The peaks are resonances and the valleys are just the opposite,
the suck-outs as a result of phase cancellation. I used to believe the coupling
point is the spot where multiple resonances gravitate since it clocks the
highest sound level throughout the audio band. If we look at it the other way
round, however, the focal point of the room should more correctly be taken as
the spot where phase cancellation is the lowest.

When the speakers are placed along this focal spot, phase cancellation would be
at its minimal obtainable within the room and the system will then be able to
resolve, with the best of fidelity and the least of distortion, the myriads of
spatial information contained in the recording. The width and depth, the
ambience, the layering and instrument placements etc. will all spring to life.
Proper sound staging, no doubt, has much to do with this phase coherency across
the audible frequency range. We all know what would happen if one speaker is
inverted in phase—there will be no imaging, no soundstage, and even no sense of
direction. This is the result of serious phase cancellation. Even if the
speakers are properly in phase, however, there would still be a fair amount of
cancellation depending on where the speakers are placed.

Ideally speaking, the room should be symmetrical in overall shape and the
speakers symmetrically placed along the lengths of the rectangle. If one
speaker is close to the side wall while the other is in the middle of the room,
a rather common sight given the popular L-shape layout of sitting rooms in HK,
there exist more chances for cancellation taking place at various frequencies,
rendering the imaging blurred, stage collapsed and ambience lost.

Once the speakers are coupled to the room, the two merge into one. The room
becomes an effective extension of the speakers which in turn would cease to
exist visually. Tuning for solid imaging then becomes much easier. Human ears
locate the sound source by detecting the time difference of direct sound
arriving at the ears. To achieve three dimensional imaging, all we have to do
is to cut down secondary reflections from overwhelming the direct sound. While
on this subject, I like to point out that I have tried the live-end-dead-end
approach and it did not work to my satisfaction. I believe speakers are
designed with the average western style living room in mind where upholstery,
curtain, carpet and furniture all contribute to an acoustic environment which
is neither too dead nor too live, but moderate throughout. This is something
worth considering when we set about fabricating our listening area. It is not
uncommon to find that the more elaborately contrived the HiFi room is, the less
satisfactory it often turns out.

All in all, phase coherence does appear to be the key and with this key we
stand every good chance to unleash a completely new dimension of audio realism.

*****

Here comes the core—the action part of the whole thing, a method that has
proven to work wonders for me over the last 30 odd years.

Have the speakers placed along the lengths of the room, about Ľ to 1/3 from the
back wall, and Ľ the breadth roughly. Then play some vocal music, the hilarious
type, the more instruments the better.

Now walk slowly to and fro along the mid-line between the speakers, from one
end of the room to the other and then back, may be several times to get the
mind set (if the speakers are standing low, you may well have to crawl).
Somewhere along the aisle, you would hear the sound getting louder and at the
same time it rises above your head, filling the ceiling as if you’ve entered a
Gothic church. Bingo, that is it, the focal point.

Mark this focal point and drag your speakers over the lateral line crossing the
spot. You’ve just coupled your speakers to your room. What is left, may be the
crucial part yet, is to find the perfect stereo seat. As the name suggests,
you’ll have to look for the widest stereo soundstage again along the aisle,
between the speakers. If one side of the room does not give you the best
definition and soundstage, try the other side. I was the one having my seat
moved over to the wrong side of the room to get the best out of my present
system.

Final note, if you are unable to find the focal spot despite trekking up and
down diligently the whole afternoon, your room dimension is probably too bad to
be a listening room. Try another room if you have one. If not you’ll have to
move house.

Ivan Li (Limage)

Interesting read but I do hope he is joking in his last paragraph . If he was serious, its not a solution to everyone....or maybe even to anyone hehehe.

elhefe wrote: If he was serious, its not a solution to everyone....or maybe even to anyone hehehe.

Die hard Audiophiles will take unconventional routes to achieve their Audio Nivarna. In Hong Kong it is not unheard off for audiophiles to have a sound room away from their apartment. Back home, I am aware of someone contemplating or have already decided to buy another house to house his hifi system because his current house is not big enought to accommodate his system and moving out is not an option.

yep... the huge bungalows looming up behind my backyard look very tempting.. must ask my boss for staff discount...

Good, interesting read, thanks DrWho? ...

Are you benefiting from this method of Speaker Placement? It would be interesting to get some feedback. To me, this is the easiest way to get a good sound from your system.
You need a CD with strong vocal plus plenty of upper and mid bass. When you are walking towards the speakers your ear level should be about the same height as the tweeter, yes you might have to be on your knee. Just don't let your spouse see you doing it lest she might think you are proposing to your hifi

DrWho wrote:Are you benefiting from this method of Speaker Placement? It would be interesting to get some feedback. To me, this is the easiest way to get a good sound from your system.
You need a CD with strong vocal plus plenty of upper and mid bass. When you are walking towards the speakers your ear level should be about the same height as the tweeter, yes you might have to be on your knee. Just don't let your spouse see you doing it lest she might think you are proposing to your hifi

thanks drwho to have shared this!

i have realised this many years ago when i played back one technical track i.e. no. 63 of "my disc" published by sheffield lab

the track captures the playback of 440hz ("a") which intended purpose is to test the playback speed of any setup (maybe other frequencies work better?)

as i was playing back no. 63, i knocked my tuning folk ("a" used for my guitar) and checked...

oh yes, absolutely my setup sounded "a"... of course lah!!! otherwise my setup should be returned to alam flora eh



some, some, somehow... as the track was still playing, i moved my head (changed listening positions) and coincidentally i have realised the differences in sound pressure levels, phase swifts... since then i have been continually adjusting my room acoustics and certainly i have been enjoying reasonably easy imaging, soundstaging and even "soundscape extension into listening room" which many find it hard to comprehend







if you want to try this track, avaxhome should make your avenue but please support the cd market which in turn supports the continuity of our passion









have fun fiddling in your listening room but remember to celebrate weekend too!

tlkoo wrote:
some, some, somehow... as the track was still playing, i moved my head (changed listening positions) and coincidentally i have realised the differences in sound pressure levels, phase swifts... since then i have been continually adjusting my room acoustics and certainly i have been enjoying reasonably easy imaging, soundstaging and even "soundscape extension into listening room" which many find it hard to comprehend

tlkoo, congrats! You have achieved what many die hard/mega system owners are pursuing. Many of them will envy you. It is simple yet very effective.

hi drwho



not sure if i have achieved or not though more importantly the "balance" (you call it focal point?) perceived in my head does allow some kind of comfort which i believe should have come from left/right balance of direct sources together with reflective sources too, i am much puzzled in the absence of such "balance"



questions for you:

1. will the "balance" position, measured from rear wall, vary when distance of speakers from rear wall changes?

2. ignore question 1 if the balance position doesn't vary, otherwise how to find 2 unknowns (distances of speakers and "balance" position from rear wall) when none could be eliminated before the other? i mean to expect each distance (infinite?) of speakers to dictate one "balance" position, shall we fix distance of speakers in priority of "balance" position? chicken or egg comes first?



over to you...



cheers

tlkoo

tlkoo,

Why you ask such a difficult question? Get to get this old mind of mine to work again!

If I understand you correctly, I believe that for each set of speakers the focal point will be located at only one particular point. Provided always the speakers are placed at about one third of the room length and away from the side walls. Different speakers will give you a different location of the focal point.
I also believe that there are also other focal points if you place your speakers very close to the speakers rear wall and side walls. I say "believe" because I have not tried it out. Conversely if you now place the speakers using the previous side wall as the new rear wall, the focal point MUST also change.
This is not my theory, it is Ivan Li's which I fully subscribe to.

talking for its sake only, i believe we have similar beliefs!

lets see if soon-coming long weekends could we have music gatherings

oh ya, anyone else care to share experiences on speaker placement methods



cheers

When I first move back into my own house end of 2010 and set up my hifi in the deidcated room, I tried doing the 1/3 rule. But because the shape of my room and also the mini studio that is sharing the same room, I could not get the results that I want. So, I fixed my listening position and started moving around the speakers.

My preference is always to achieve a balanced left and right loudness, a layered overall presentation as if the singer is leveled to the speakers and the band/instrument behind the speakers.

I could only achieve this with a very odd speaker position. If you can see the picture in my signature below, the speakers are toed in at different angle and also at a different distance from the rear wall and side walls.

Sorry, no magic rule nor formula. Just based on listening.

elhefe wrote:I could only achieve this with a very odd speaker position. If you can see the picture in my signature below, the speakers are toed in at different angle and also at a different distance from the rear wall and side walls.

Sorry, no magic rule nor formula. Just based on listening.

bet you a lot of rookies walk into your room and think "this guy knows zero about hifi, cheh... speaker cincai put one"

and Mr Elhefe keeps quiet, smiles away and think "hmm... now who's the rookie?" clap clap

tlkoo wrote:
lets see if soon-coming long weekends could we have music gatherings

Great idea. I am only available during Merdeka weekend.

Hi DrWHO, you reckon many like to adjust the toe-in angles of speakers as if they rotate their camera lenses to focus? Misconception at all since focal point is relativity between distances of speakers and of listening position? I am puzzled by well-focused setups with zero toe-in ;-/ pardon my ignorance :")





Regards/tlkoo

DrWho wrote:tlkoo,

Why you ask such a difficult question? Get to get this old mind of mine to work again!

If I understand you correctly, I believe that for each set of speakers the focal point will be located at only one particular point. Provided always the speakers are placed at about one third of the room length and away from the side walls. Different speakers will give you a different location of the focal point.
I also believe that there are also other focal points if you place your speakers very close to the speakers rear wall and side walls. I say "believe" because I have not tried it out. Conversely if you now place the speakers using the previous side wall as the new rear wall, the focal point MUST also change.
This is not my theory, it is Ivan Li's which I fully subscribe to.

Hi DrWho


Should I assume the liberty to expand a little to invite more thoughts and views, I should say I reckon that we could either:
- fix the listening position with adjustments to distance of the speakers to "render/cause" the listening position so fixed to be "focal point"; or
- conversely fix the distance of the speakers then find the "focal point" to be listening position.

If we explore further from these choices, we may find the need to have distance of the speakers to take priority since it shall dictate low frequency response and the scale of music reproduction! But shi... what if distance of speakers so fixed has to demolish the front wall or force one out of his room??? Hahh hah ahhhahhh...




Thanks for reading but more importantly happy weekend!


tlkoo

elhefe wrote:When I first move back into my own house end of 2010 and set up my hifi in the deidcated room, I tried doing the 1/3 rule. But because the shape of my room and also the mini studio that is sharing the same room, I could not get the results that I want. So, I fixed my listening position and started moving around the speakers.

My preference is always to achieve a balanced left and right loudness, a layered overall presentation as if the singer is leveled to the speakers and the band/instrument behind the speakers.

I could only achieve this with a very odd speaker position. If you can see the picture in my signature below, the speakers are toed in at different angle and also at a different distance from the rear wall and side walls.

Sorry, no magic rule nor formula. Just based on listening.

Hey Elhefe

I see that your speakers are not placed symetrically to adjust for room imbalance. So long as you have the centre alignment locked in, no one cares how it looks but sings after all "aural space" is to prevail but not "visual space".


Happy playing!

Regards

tlkoo

Central alignment, focal point etc... I call it my sweet spot. I found it, I embraced it and I sure like the taste of it....

tlkoo,
I believe the purpose of Ivan Li method of speaker placement is to achieve optimum Tonal Balance and to reduce the reliance of exotic power cord, interconnect, speaker cable, cones, rack and etc to achieve the correct total balance. Assuming Fine tuning of the speakers position is achieved, I adjust the position of the sweet spot to obtain sharper images and micro dynamic details.
Regarding toe in, excessive toe in will give a sharp center image but also produces a triangular soungstage. Slight or no toe in can produce sound stage beyond the speakers. Ideally the soundstage should be rectangular and from wall to wall. Layering and holographic images are achieved mainly via jitter reduction and power line noise reduction.

Dear DrWho

I hear you regarding speaker placements and room coupling!

Jitter reduction with Rubidium clock seems like rocket science, not easy to fiddle with and for this, I have a sincere "tabik hormat" for you!





Cheers

tlkoo

tlkoo wrote:Dear DrWho

I hear you regarding speaker placements and room coupling!

Jitter reduction with Rubidium clock seems like rocket science, not easy to fiddle with and for this, I have a sincere "tabik hormat" for you!





Cheers

tlkoo

Thank you for your kind words. Rubidium clock implementation is really not that difficult, provided you have the detailed schematics of your CD player/transport or DAC. Rubidium clock, by virtual of being at least 10,000 times more accurate than most oscillators found in high end devices, will help in reducing clock induced jitter. Even a dCS DAC will benefit greatly with an external Rubidium driven Word Clock. The improvement in sound quality achieved by clock accuracy is very substantial, just like upgrading a few level up but at a fraction of the cost. An Esoteric external Rubidium Clock costs about USD12,000 whereas a DIY one can be built at about RM1000. Jitters caused by power supply noise and vibration are easier to reduce by DIY.

This is a very interesting topic. I have dedicated much of my audiophile years in room setup, treatment and speakers placements but nothing brought me closer to realism of live music using the Ambiophonics method.

Once you get it right, you will never go back to the usual 60 degrees stereophonic setup. There are cons with this method. You have to sit in line perpendicular to the two speakers but in terms of transient, accuracy and others the difference is day and night irrespective of your system cost.

It doesn't cost anything other than a little effort to move the speakers and a laptop.

STC wrote:This is a very interesting topic. I have dedicated much of my audiophile years in room setup, treatment and speakers placements but nothing brought me closer to realism of live music using the Ambiophonics method.

Once you get it right, you will never go back to the usual 60 degrees stereophonic setup. There are cons with this method. You have to sit in line perpendicular to the two speakers but in terms of transient, accuracy and others the difference is day and night irrespective of your system cost.

It doesn't cost anything other than a little effort to move the speakers and a laptop.

Hi STC

I can't agree more that this is interesting topic alas least attention it has been given by numerous enthusiasts. Care to enlighten me (alone?) with some brief explanations on "60 degrees stereophonic setup". Also care to elaborate on your following sentence in the same paragraph.

Any chance to have an audition? Long weekend is around the corner eh!!!







Thanks/Regards

tlkoo

Hello Koo,

I have experimented with all possible speakers setup combinations including Cardas'. Using the Amused to Death CD as a benchmark for accurate soundstage, I am satisfied with the placements and yet I wasn’t sure about the timbre, transient or the accuracy of the sound.

Stereo is two copies of a single sound. It is like hearing two Tracy Chapmans standing 5 or 6 feet apart and singing “Behind the walls” simultaneously. It cannot sound as accurate as one singing Tracy Chapman standing in the middle while the recording is supposedly made of one Tracy Chapman singing.

If you are familiar with white noise, please try to listen them using one speaker and then the combinations of two. You will distinctly hear the difference in the tone or characteristics of the white noise when listened through a single speaker and in stereo setup. That little tone change indicates that stereo colours or distorts the original sound. Despite the weakness in stereo we accept them for want of soundstage. The realism of live soundstage at the expense of timbre, clarity and transient.

Ambiophonics is an attempt to remedy the doubling effect of same frequencies at the same time capture the original soundstage which can extend beyond 180 degrees. The second sentence was referring to the sitting positing for multiple listeners. Otherwise you can always sit at your sweet spot but your friends must sit in front or behind you to enjoy the effect of Ambiophonics.

And of course, you are welcomed anytime.

Thanks STC for the explanations which to some extent appear technical. Please text me if we may catch up!



Cheers

tlkoo

STC wrote:Hello Koo,

I have experimented with all possible speakers setup combinations including Cardas'. Using the Amused to Death CD as a benchmark for accurate soundstage, I am satisfied with the placements and yet I wasn’t sure about the timbre, transient or the accuracy of the sound.

Stereo is two copies of a single sound. It is like hearing two Tracy Chapmans standing 5 or 6 feet apart and singing “Behind the walls” simultaneously. It cannot sound as accurate as one singing Tracy Chapman standing in the middle while the recording is supposedly made of one Tracy Chapman singing.

If you are familiar with white noise, please try to listen them using one speaker and then the combinations of two. You will distinctly hear the difference in the tone or characteristics of the white noise when listened through a single speaker and in stereo setup. That little tone change indicates that stereo colours or distorts the original sound. Despite the weakness in stereo we accept them for want of soundstage. The realism of live soundstage at the expense of timbre, clarity and transient.

Ambiophonics is an attempt to remedy the doubling effect of same frequencies at the same time capture the original soundstage which can extend beyond 180 degrees. The second sentence was referring to the sitting positing for multiple listeners. Otherwise you can always sit at your sweet spot but your friends must sit in front or behind you to enjoy the effect of Ambiophonics.

And of course, you are welcomed anytime.

Are you using any cross talk cancellation device/method for your ambiophonics setup? If so, which devise/method are you using?

This is very interesting!!

STC, hope you don't mind sharing what is ambiophonics, and how do you set up speakers in a room using this method? I am very intrigued but very blur..... i have a pair of planar speakers, wonder if this method will work for speakers that produce sound front and back unlike a boxed speaker that only produces sound to the front mainly. many thanks my friend -in-our-forum.

Bal.

just read on the internet about 'mini-ambio' product....

DrWho and Bal, Yes I used Hotto Engineering software with my laptop to do the initial setup. Now, I am using the MiniAmbio and pleasantly surprised. IMO, if you have Xonar like soundcard I think it can outperform even the most expensive system.

The ultimate choice would be getting the Tact with Ambio but pls try it with your Ipod or Laptop. You will like what you hear.