The 45 deg toe in will not work well in 25 m2 living room. The contralateral wall is too close.
For a room of this size, illuminating the ipsilateral wall works very well in my experience, however, and I consider it as a preferred method.
- Elias
We admit no such thing
Toe in is nothing to do with not being able to "take" the on axis treble response of the speaker, in fact in a true constant directivity system (say 90 degrees horizontally) there will be virtually no change in response of the direct signal to the listener when toeing in the speaker by varying amounts, over quite a big range of angles.
What will change, is the amplitude of the side-wall reflections, and in the case of a constant directivity system only the amplitude of the reflection will change, not the spectral balance, again over a fairly large range of angles.
We're also not talking about a large shift in angles. If you read my post several pages ago you'll see that yes, I did toe the speakers behind me when they were on the long wall of the room - but only by 10 degrees off the listener axis - hardly a large amount, and very similar to what most people would toe normal speakers.
On the other hand with my speakers on the short wall of the room I now toe them in front of the listener, but again, only by 10 degrees. At most I'm only ever listening to them 10 degrees off axis.
What's more, in the narrow room configuration I'm toeing them in further to reduce the side wall reflection, not increase it, even though the speakers are already quite directional. This goes completely against your suggestion that it's an attempt to increase reflected energy.
The major difference is that when the speaker is minimally toed to heavily illuminate its nearest side-wall, the time delay of the wall reflection is very short, usually too short especially in a narrow room, leading to smearing of the image location and tonal colouration.
Toe the speaker in front of the listener and the time delay of the reflection from the opposite wall is MUCH longer, (work it out for a typical room) so the fact that it's from the "wrong" side really doesn't matter - the time delay is enough to put it well into the "late reflections" range, so it doesn't affect image localization.
One benefit of toeing the speakers in this way is that you are reducing the early reflections but not reducing the overall level of the reverberant field. (assuming roughly equal reflectivity in different parts of the room)
Something that you also fail to notice is that with a directional speaker we can choose which side-wall is more illuminated by adjusting toe in, whilst a wide dispersion speaker will illuminate both the "right" and "wrong" side-walls at the same time, with little opportunity to control it.
I don't see you complaining about conventional speakers (or omni's for that matter) illuminating the "wrong" wall ?
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If maximizing the ITDG while creating a bigger sweet spot is priority then 45° toe-in with the speakers on the short wall and/or absorption is the way to go. With a true constant directivity speaker you can also vary the amount of toe-in and balance the level of side wall reflections pretty easily.
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If your suggestion relies on added heavy room absorption, it will be out of the question for living room use. I'm only interested of systems that do not need room absorption besides normal living room furniturishing.
- Elias
Then just vary toe-in. A wider dispersion design would require a even more strict setup process if you expect more than just a strong early spatial impression from your HiFi.
I don't advocate omnis, and conventional speakers never satisfied me so why should I talk about them
- Elias
- Elias
I don't see you complaining about conventional speakers (or omni's for that matter) illuminating the "wrong" wall ?
"strong early spatial impression", or whatever, is already a major improvement over normal stereo triangle, very worth pursuing !
But I don't have "hifi", gear itself is not the main priority.
- Elias
But I don't have "hifi", gear itself is not the main priority.
- Elias
Originally Posted by Elias
Even you, and others who advocate high directivity treble toed in to cross in front of you, admit that high directivity treble is fundamentally bad, because you cannot take it directly facing you, but you need to turn it away from you, to diminish the direct sound and to emphasise reflected energy.
The purpose / reason for toed in aiming has it’s roots in old time commercial sound. Back when a single voice range horn would do, it was normal to have it aimed at the farthest seats and to use the bottom of the lobe shape to make the SPL more constant vs distance than the inverse square law would suggest.
Here I have drawn the lobe as a simple ellipse to approximate the equal loudness contour that is a real polar plot.
The idea is you aim the loudest part of the beam at the farthest seats and one can imagine how this would be relative to aiming it at the center of the audience.
In hifi, when you have a speaker with directivity, one also finds the center of the beam is normally the loudest and so a more constant loudness is achieved across the seating area (couch). The illustration shows the straight ahead aiming vs toed in. One can also see that far less energy would be hitting the side walls when they are close to the speakers.
In both cases, commercial and home, the more one has a consistent beam width vs frequency, the more effective this trick is. In commercial sound, the problem had been that one often wanted more bandwidth and more acoustic power than a single driver could produce. Multiple sources normally produce an interference pattern and radiate lobes and nulls depending on the frequency and so the trick isn’t as effective.
Our success in commercial sound is partly due to having a single lobe over a broad band and then this aiming trick works over a broad frequency range. It is how one can fill an entire stadium with one speaker with the closest seat only +4 dB louder than the farthest seat. See story #4 here;
Danley Sound Labs Tagged Articles - Pro Sound Web
Best,
Tom
Even you, and others who advocate high directivity treble toed in to cross in front of you, admit that high directivity treble is fundamentally bad, because you cannot take it directly facing you, but you need to turn it away from you, to diminish the direct sound and to emphasise reflected energy.
The purpose / reason for toed in aiming has it’s roots in old time commercial sound. Back when a single voice range horn would do, it was normal to have it aimed at the farthest seats and to use the bottom of the lobe shape to make the SPL more constant vs distance than the inverse square law would suggest.
Here I have drawn the lobe as a simple ellipse to approximate the equal loudness contour that is a real polar plot.
The idea is you aim the loudest part of the beam at the farthest seats and one can imagine how this would be relative to aiming it at the center of the audience.
In hifi, when you have a speaker with directivity, one also finds the center of the beam is normally the loudest and so a more constant loudness is achieved across the seating area (couch). The illustration shows the straight ahead aiming vs toed in. One can also see that far less energy would be hitting the side walls when they are close to the speakers.
In both cases, commercial and home, the more one has a consistent beam width vs frequency, the more effective this trick is. In commercial sound, the problem had been that one often wanted more bandwidth and more acoustic power than a single driver could produce. Multiple sources normally produce an interference pattern and radiate lobes and nulls depending on the frequency and so the trick isn’t as effective.
Our success in commercial sound is partly due to having a single lobe over a broad band and then this aiming trick works over a broad frequency range. It is how one can fill an entire stadium with one speaker with the closest seat only +4 dB louder than the farthest seat. See story #4 here;
Danley Sound Labs Tagged Articles - Pro Sound Web
Best,
Tom
Attachments
Line array is true to the original source. Here on the forum someone wrote (forgot who) not so long ago when he got great imaging from his system, the lips of the singer wrapped the room like there was a visual path into the singer's throath. I found it quite hilarious. And it is exactly what should happen actually, considering the microphone usually is at the singers mouth.
- Elias
Another thing Elias(or maybe it was Graaf) about narrow directivity--instead of placing a pillow in front of your speaker, if you use narrow directivity you can just turn the speaker around facing the front wall or firing into the front corner. Narrow directivity would seem to be the natural choice for research on which set(s) of reflections work best for you. You could even build a remote controlled turn table to place the speakers on. Wouldn't be tough to do. Rotate from the listening position. Hmm, I may do that...
Dan
Hmm, I may do that...Dan
I know what "strong early spatial impression" sounds like but most movie and music recordings don't rely on it. In fact most movie mixes make use of what you probably call "artefacts" to advance the art. "Realism" isn't a priority at all, just like photorealistic drawings are rather boring. Nowadays music recordings could make good use of 5.1 or even 7.1 but obviously nobody is really interested.
Maybe that's the problem why you hear two tweeters instead of one phantom image?
Isn't that because the industry went overboard with huge receivers and their fitting speakers?
I can't be bothered to put even two in our living room. I use one dipole and it is also set up so the sitting area uses the side radiation for even loudness and it's very nice to listen to.
I would put small speakers around to enhance some artificial effect but that isn't popular either.
More information on the crossed-axes configuration can be found in the article below. It also has information about multisubs and flanking subs.
Any discussion about directivity indoors should include a mention about multisubs, since the LF pattern is set largely by room placement and damping. No matter what kind of speakers are used, the room and its layout set the pattern below the Schroeder frequency. Below that (around 200Hz in most homes), multiple subwoofers can be used to create a uniform sound field. Flanking subs (aka helper woofers) work best above 80Hz, and more distant subs work better below that.
Also see the illustration below, taken from the High-Fidelity Uniform-Directivity article referenced above. This helps further illustrate how the crossed-axes method works. Each oval shows areas where SPL is uniform from side to side, when a speaker having constant directivity is employed. Where those regions intersect, there is stereo balance, or equal volume between speakers. It makes a very large "sweet spot" where sound is balanced and imaging is good. You see listener A and listener B are separated by some distance, yet each enjoys good stereo balance and high-quality sound. No more "head in a vice", the sweet spot covers the half the living room.
Crossed-axes configuration
Any discussion about directivity indoors should include a mention about multisubs, since the LF pattern is set largely by room placement and damping. No matter what kind of speakers are used, the room and its layout set the pattern below the Schroeder frequency. Below that (around 200Hz in most homes), multiple subwoofers can be used to create a uniform sound field. Flanking subs (aka helper woofers) work best above 80Hz, and more distant subs work better below that.
Also see the illustration below, taken from the High-Fidelity Uniform-Directivity article referenced above. This helps further illustrate how the crossed-axes method works. Each oval shows areas where SPL is uniform from side to side, when a speaker having constant directivity is employed. Where those regions intersect, there is stereo balance, or equal volume between speakers. It makes a very large "sweet spot" where sound is balanced and imaging is good. You see listener A and listener B are separated by some distance, yet each enjoys good stereo balance and high-quality sound. No more "head in a vice", the sweet spot covers the half the living room.
Crossed-axes configuration
Yes, it's a no-baffle OB, and the woofer and mid operate below the dipole peak.
It doesn't confine me to that sweet spot for stereo recordings in everyday listening. The closest seat is amost right next to the speaker and the farthest is facing it.
It's funny how much your brain tricks you into believing that the sound is moving too, for example when watching TV and something loud moves across the screen. A bigger TV seems to help (42" here).
Of course I still have some good stereo records here, but what can you do.
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I don't care about most music. Actually most music is pure crap !
If it's the artists' agenda to introduce those sterephonic "artefacts" like singer split into the two tweeters to "advance the art", I couldn't care less about it.
The music I like, I care for. For that I have found for me a better presentation of the recording than stereo triangle could offer.
It depends who you ask. In any day I would choose "realism" over the "artefacts".
Of course. Thank you for pointing that out
Or maybe there is just a problem with my ears 
- Elias
I also used to listen to one mono dipole line array for a couple of years. It was very pleasant, no need to suffer from stereophonic artefacts.
- Elias
- Elias
Documantation ongoing. And system under continuous development.
You didn't hear anything with your stereosphere?
- Elias
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