Against the wall loudspeakers, pro's and con's?

I just had an idea and I'm sure I'm not the first.
Carlsson OAxx's were designed for placement against the wall with a pre-chosen toe-in built into the design.

A close to the wall placement will give some bass boost so much is well known to me. What are the pro's and con's of building a speaker with a built in toe-in for flush against the wall placement?

What difficulties will I have to resolve to make a good sounding speaker?
 
The big issue is the depth of the cabinet and the destructive interference in the midrange caused by the strong wall reflection. Even a strongly rounded cabinet will have this problem. So a completely flush mounted baffle or a very wide, slightly sloped baffle (like the Stage Accompany S27) is what you need.
 
ok, so basically it's just cancellation from the reflective surfaces?
Try to avoid having the same distances from driver | floor | ceiling | rear wall | side wall.
This should make the dip wider but not quite as pronounced and hopefully the rest is fixable with dsp and room correction?

Am I getting the gist of it?
 
It's always been my understanding that imaging is best when speakers are located out, away from wall boundries. So, I guess your proposal to locate them against a wall would be counter to good imaging placement.
The trade off is bass enhancement against imaging.

The Audio Note AN-E speakers are supposed to be placed near a wall at a slight angle so the low placed, rear firing vent has some space to breath. They compensate for the imaging issue with a very wide baffle board configuration which has the drivers almost essentially operating in 2 pi space.
 

kipman725

Member
Paid Member
2007-06-10 12:41 pm
Warrington
I have often toyed with the idea of a super flat speaker that is designed for against wall usage. In wall speakers are the logical extreme. If the design is very careful you could ensure that the drivers are directional at the frequency at which the discontinuity between the box sides and the wall becomes a problem.
 

tinitus

Ex-Moderator R.I.P.
2005-11-24 1:47 am
free standing speakers and listening direct on axis is optimal if you want the most precise reproduction

everything else tend to be more 'diffuse', and with less 'attack'
might be more forgiving and pleasing

I wouldnt say one is more right than the other
only depends on what kind of sound you want

try to hang a small 2way from the ceiling, in the corners ;)
 
How would the "Poor Man's Stradivarius" perform in the sort of location. It is wide, slightly curved and quite shallow?

After reading the short paper referred to by Markus76 I then wonder about the PMS shape referred to above with a
wave guide on the mid and the tweeter. Is there any merit in this. I know the quite a few significant othder halfs would
accept a larger enclosure if it does not have the appearance of being half way out into the room. This is a problem for
some of us with open baffles! I like good sound but I,m not in a position to alter my house as well as build speakers and
I am sure that quite a few others would be in this position also.

Toe in if required could be built into the PMS shape by angling the centre panel also and not having it parallel with the rear
of the enclosure
jamikl
 
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On Wall can be great.

After years of massive floor standers, sealed, open baffle, two way, three way, fully active, DSP ( DEQX) etc I have finally arrived at a great sounding, great looking High WAF, no hassle solution.
On Wall, line array BMR, full range ( no Xover at all for music) with Eq using the fab JRiver 18 media host with the even fabber(!) Jplay plugin.

On wall gives you "natural" low mid and bass extension ie no extra amp power input and no extra cone excursion.
Using the BMR's gives you almost 180 degrees even power response ie on and off axis is all very even and balanced.
Line Array ( 8, 12 or 16 drivers per speaker) gives you a massive reduction in cone excursion and therefore a corresponding massive drop in all " traditional " distortions that the objectivists love to measure.
Far more important ( IMO), time domain distortions ie mass on a spring / cone on a suspension are greatly reduced as the cones are not pumping in and out 5mm or 10mm but only 0.5mm or 1mm instead.
I encourage you to try on wall or in wall line arrays, esp with BMR drivers, the results are really great!
Cheers
Derek.
 

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tinitus

Ex-Moderator R.I.P.
2005-11-24 1:47 am
for relaxed casual listening or surround, 'on wall array' look very interesting indeed

but for serious music listening, only 'direct on axis' listening works for me
personally I simply cant stand any kind of weird off odd angled speakers
I consider all off axis listening an 'invention' to accommodate speaker design errors
listening off axis is down a path where you might just as well go omni, in wall, or similar

but its my personal opinion only, ofcourse
what other people may prefer is not my concern....IMO
 
for relaxed casual listening or surround, 'on wall array' look very interesting indeed

but for serious music listening, only 'direct on axis' listening works for me
personally I simply cant stand any kind of weird off odd angled speakers
I consider all off axis listening an 'invention' to accommodate speaker design errors
listening off axis is down a path where you might just as well go omni, in wall, or similar

but its my personal opinion only, ofcourse
what other people may prefer is not my concern....IMO

What is the problem with off-axis listening? By the way, angling drivers and asymmetric radiation patterns are all doable in an on-wall design.

P.S. What happened to your shift key and interpunctuation? Makes your posts very hard to read.
 

AllenB

Moderator
Paid Member
2008-10-18 11:31 am
ok, so basically it's just cancellation from the reflective surfaces?
Try to avoid having the same distances from driver | floor | ceiling | rear wall | side wall.
This should make the dip wider but not quite as pronounced and hopefully the rest is fixable with dsp and room correction?

Am I getting the gist of it?

Changing the distances may hide the problem somewhat, or not. I wouldn't count on it. The baffle should be integrated with the wall somehow. Dsp wouldn't be able to fix some of the problems you'd create without doing this.
 
Line array reading

There is a lot of reading material available on Line Arrays,some of it is actually true!
I would recomend a Google around and spend a few weeks researching the effects of placing a Line Array on or in a wall.
Then you need to look at the drivers you use, in particular the off axis response.

In the short term must say that I disagree with AllenB and Tinitus, I am curious to hear about the line array cabinets and drivers they have built and listened to on the wall...any photo's chaps...?

I am experimenting over the next month or two so I hope to have some more measurement based answers later.
At the moment the sonics of the on wall line array are so obviously superior to traditional free standing towers using the same drivers, I am loathed to change too much!

Cheers
D.
 
Personally I'm not going for the line array, I'm thinking keeping to the kiss principle is my preferred cup of tea. (For now anyhow.)

I'll just go ahead and throw some thoughts around. :D
I'm thinking about doing a floorstanding 2-way with controlled directivity.
Placing the cabinet against the wall with a predetermined toe-in will make the driver | wall distance pretty small on the one side and somewhere between factor 1 - 1/sqrt(2) * the driver diameter on the other side. Let's say 15" just for arguments sake.
Centering the driver fairly high isn't an issue so driver | floor distance is easily in the 30" area.
Driver | Ceiling should be something like 70".

If I'm not totally off target we should have some 1/4 wave cancellations and 1/2 wave reinforcements cancelling each other out.
Hopefully this would eliminate the serious dips and peaks but than again, I'm just spitballing here.
Just a rough draft of my initial thoughts.

I'm just toying with the idea and trying to learn about the pitfalls. :h_ache:
 

AllenB

Moderator
Paid Member
2008-10-18 11:31 am
I think this is a good thing to do, but may not be a complete solution. The response is 'fixed' at one point in your room with things being more random or possibly averaging in the bigger picture. Treating the room may have benefits.

personally I simply cant stand any kind of weird off odd angled speakers I consider all off axis listening an 'invention' to accommodate speaker design errorsIMO
This is simply not the case. Zero degrees normally sounds different to the rest of the speaker and a point off axis often better represents the speakers true response. Most speakers are different off to the sides and when you average out the sound coming from the speaker in all directions and try to find a point that resembles and best represents this tone, it is more likely to be some angle off-axis.

Furthermore, consider the radiation pattern as if it were a soccer ball with a small speaker inside. Zero degrees would cover one patch facing you. If you move a little off axis, the tone you hear is also being radiated over the area of the five adjacent patches. It is therefore more respresentative of the sound entering the room in that regard.
 
There are some pointers that might help understanding my thoughts.
My rig is in my living room and quite honestly I don't have neither the space or means to build it into a dedicated listening room.

I like the idea of a "wide sweet spot" so that the larger part of the sofa will have good audio.

I'm willing to sacrifice pinpoint accuracy to some degree but waveguides seem to get the job done well enough without sacrificing too much.

Against the wall placement will make the room more livable and easier to furnish.

So, if there is a way to pull it off I think it might be worth the hassle.
Dare to think outside the box.
If it turns out the obstacles are to great I don't mind taking a step back to reevaluate the ideas.